One document matched: draft-amit-quick-start-04.ps

%!PS-Adobe-3.0
%%Creator: groff version 1.19
%%CreationDate: Sun Feb 20 22:20:23 2005
%%DocumentNeededResources: font Courier-Bold
%%+ font Times-Bold
%%+ font Times-Roman
%%DocumentSuppliedResources: procset grops 1.19 0
%%Pages: 45
%%PageOrder: Ascend
%%DocumentMedia: Default 612 792 0 () ()
%%Orientation: Portrait
%%EndComments
%%BeginDefaults
%%PageMedia: Default
%%EndDefaults
%%BeginProlog
%%BeginResource: procset grops 1.19 0
/setpacking where{
pop
currentpacking
true setpacking
}if
/grops 120 dict dup begin
/SC 32 def
/A/show load def
/B{0 SC 3 -1 roll widthshow}bind def
/C{0 exch ashow}bind def
/D{0 exch 0 SC 5 2 roll awidthshow}bind def
/E{0 rmoveto show}bind def
/F{0 rmoveto 0 SC 3 -1 roll widthshow}bind def
/G{0 rmoveto 0 exch ashow}bind def
/H{0 rmoveto 0 exch 0 SC 5 2 roll awidthshow}bind def
/I{0 exch rmoveto show}bind def
/J{0 exch rmoveto 0 SC 3 -1 roll widthshow}bind def
/K{0 exch rmoveto 0 exch ashow}bind def
/L{0 exch rmoveto 0 exch 0 SC 5 2 roll awidthshow}bind def
/M{rmoveto show}bind def
/N{rmoveto 0 SC 3 -1 roll widthshow}bind def
/O{rmoveto 0 exch ashow}bind def
/P{rmoveto 0 exch 0 SC 5 2 roll awidthshow}bind def
/Q{moveto show}bind def
/R{moveto 0 SC 3 -1 roll widthshow}bind def
/S{moveto 0 exch ashow}bind def
/T{moveto 0 exch 0 SC 5 2 roll awidthshow}bind def
/SF{
findfont exch
[exch dup 0 exch 0 exch neg 0 0]makefont
dup setfont
[exch/setfont cvx]cvx bind def
}bind def
/MF{
findfont
[5 2 roll
0 3 1 roll
neg 0 0]makefont
dup setfont
[exch/setfont cvx]cvx bind def
}bind def
/level0 0 def
/RES 0 def
/PL 0 def
/LS 0 def
/MANUAL{
statusdict begin/manualfeed true store end
}bind def
/PLG{
gsave newpath clippath pathbbox grestore
exch pop add exch pop
}bind def
/BP{
/level0 save def
1 setlinecap
1 setlinejoin
72 RES div dup scale
LS{
90 rotate
}{
0 PL translate
}ifelse
1 -1 scale
}bind def
/EP{
level0 restore
showpage
}bind def
/DA{
newpath arcn stroke
}bind def
/SN{
transform
.25 sub exch .25 sub exch
round .25 add exch round .25 add exch
itransform
}bind def
/DL{
SN
moveto
SN
lineto stroke
}bind def
/DC{
newpath 0 360 arc closepath
}bind def
/TM matrix def
/DE{
TM currentmatrix pop
translate scale newpath 0 0 .5 0 360 arc closepath
TM setmatrix
}bind def
/RC/rcurveto load def
/RL/rlineto load def
/ST/stroke load def
/MT/moveto load def
/CL/closepath load def
/Fr{
setrgbcolor fill
}bind def
/setcmykcolor where{
pop
/Fk{
setcmykcolor fill
}bind def
}if
/Fg{
setgray fill
}bind def
/FL/fill load def
/LW/setlinewidth load def
/Cr/setrgbcolor load def
/setcmykcolor where{
pop
/Ck/setcmykcolor load def
}if
/Cg/setgray load def
/RE{
findfont
dup maxlength 1 index/FontName known not{1 add}if dict begin
{
1 index/FID ne{def}{pop pop}ifelse
}forall
/Encoding exch def
dup/FontName exch def
currentdict end definefont pop
}bind def
/DEFS 0 def
/EBEGIN{
moveto
DEFS begin
}bind def
/EEND/end load def
/CNT 0 def
/level1 0 def
/PBEGIN{
/level1 save def
translate
div 3 1 roll div exch scale
neg exch neg exch translate
0 setgray
0 setlinecap
1 setlinewidth
0 setlinejoin
10 setmiterlimit
[]0 setdash
/setstrokeadjust where{
pop
false setstrokeadjust
}if
/setoverprint where{
pop
false setoverprint
}if
newpath
/CNT countdictstack def
userdict begin
/showpage{}def
/setpagedevice{}def
}bind def
/PEND{
clear
countdictstack CNT sub{end}repeat
level1 restore
}bind def
end def
/setpacking where{
pop
setpacking
}if
%%EndResource
%%BeginFeature: *PageSize Default
<< /PageSize [ 612 792 ] /ImagingBBox null >> setpagedevice
%%EndFeature
%%IncludeResource: font Courier-Bold
%%IncludeResource: font Times-Bold
%%IncludeResource: font Times-Roman
grops begin/DEFS 1 dict def DEFS begin/u{.001 mul}bind def end/RES 72
def/PL 792 def/LS false def/ENC0[/asciicircum/asciitilde/Scaron/Zcaron
/scaron/zcaron/Ydieresis/trademark/quotesingle/Euro/.notdef/.notdef
/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef
/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef/.notdef
/.notdef/.notdef/space/exclam/quotedbl/numbersign/dollar/percent
/ampersand/quoteright/parenleft/parenright/asterisk/plus/comma/hyphen
/period/slash/zero/one/two/three/four/five/six/seven/eight/nine/colon
/semicolon/less/equal/greater/question/at/A/B/C/D/E/F/G/H/I/J/K/L/M/N/O
/P/Q/R/S/T/U/V/W/X/Y/Z/bracketleft/backslash/bracketright/circumflex
/underscore/quoteleft/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y
/z/braceleft/bar/braceright/tilde/.notdef/quotesinglbase/guillemotleft
/guillemotright/bullet/florin/fraction/perthousand/dagger/daggerdbl
/endash/emdash/ff/fi/fl/ffi/ffl/dotlessi/dotlessj/grave/hungarumlaut
/dotaccent/breve/caron/ring/ogonek/quotedblleft/quotedblright/oe/lslash
/quotedblbase/OE/Lslash/.notdef/exclamdown/cent/sterling/currency/yen
/brokenbar/section/dieresis/copyright/ordfeminine/guilsinglleft
/logicalnot/minus/registered/macron/degree/plusminus/twosuperior
/threesuperior/acute/mu/paragraph/periodcentered/cedilla/onesuperior
/ordmasculine/guilsinglright/onequarter/onehalf/threequarters
/questiondown/Agrave/Aacute/Acircumflex/Atilde/Adieresis/Aring/AE
/Ccedilla/Egrave/Eacute/Ecircumflex/Edieresis/Igrave/Iacute/Icircumflex
/Idieresis/Eth/Ntilde/Ograve/Oacute/Ocircumflex/Otilde/Odieresis
/multiply/Oslash/Ugrave/Uacute/Ucircumflex/Udieresis/Yacute/Thorn
/germandbls/agrave/aacute/acircumflex/atilde/adieresis/aring/ae/ccedilla
/egrave/eacute/ecircumflex/edieresis/igrave/iacute/icircumflex/idieresis
/eth/ntilde/ograve/oacute/ocircumflex/otilde/odieresis/divide/oslash
/ugrave/uacute/ucircumflex/udieresis/yacute/thorn/ydieresis]def
/Times-Roman@0 ENC0/Times-Roman RE/Times-Bold@0 ENC0/Times-Bold RE
/Courier-Bold@0 ENC0/Courier-Bold RE
%%EndProlog
%%Page: 1 1
%%BeginPageSetup
BP
%%EndPageSetup
/F0 10/Courier-Bold@0 SF(Internet Engineering Task Force)72 85 Q
(A. Jain)204 E 276(INTERNET-DRAFT F5)72 98 R(Networks)6 E 210
(draft-amit-quick-start-04.ps S.)72 111 R(Floyd)6 E
(Expires: August 2005)72 124 Q(M. Allman)258 E(ICIR)480 137 Q
(P. Sarolahti)432 150 Q(Nokia / Univ. Helsinki)372 163 Q
(20 February 2005)408 176 Q/F1 14/Times-Bold@0 SF(Quick-Start f)204.175
201 Q(or TCP and IP)-.35 E/F2 11/Times-Bold@0 SF(Status of this Memo)72
233 Q/F3 11/Times-Roman@0 SF
(By submitting this Internet-Draft, we certify that an)100.8 259 Q 2.75
(ya)-.165 G(pplicable patent or other IPR claims)-2.75 E
(of which we are a)100.8 272 Q -.11(wa)-.165 G(re ha).11 E .33 -.165
(ve b)-.22 H(een disclosed, or will be disclosed, and an).165 E 2.75(yo)
-.165 G 2.75(fw)-2.75 G(hich we)-2.75 E(become a)100.8 285 Q -.11(wa)
-.165 G(re will be disclosed, in accordance with RFC 3668 \(BCP 79\).)
.11 E(By submitting this Internet-Draft, we accept the pro)100.8 311 Q
(visions of Section 3 of RFC 3667)-.165 E(\(BCP 78\).)100.8 324 Q
(Internet-Drafts are w)100.8 350 Q
(orking documents of the Internet Engineering T)-.11 E(ask F)-.88 E
(orce \(IETF\), its)-.165 E(areas, and its w)100.8 363 Q
(orking groups. Note that other groups may also distrib)-.11 E(ute w)
-.22 E(orking)-.11 E(documents as Internet-Drafts.)100.8 376 Q
(Internet-Drafts are draft documents v)100.8 402 Q
(alid for a maximum of six months and may be)-.275 E
(updated, replaced, or obsoleted by other documents at an)100.8 415 Q
2.75(yt)-.165 G(ime. It is inappropriate to use)-2.75 E(Internet- Draft\
s as reference material or to cite them other than as "w)100.8 428 Q
(ork in progress.")-.11 E
(The list of current Internet-Drafts can be accessed at http://www)100.8
454 Q(.ietf.or)-.715 E(g/ietf/1id-)-.198 E(abstracts.txt)100.8 467 Q
(The list of Internet-Draft Shado)100.8 493 Q 2.75(wD)-.275 G
(irectories can be accessed at)-2.75 E(http://www)100.8 506 Q(.ietf.or)
-.715 E(g/shado)-.198 E -.715(w.)-.275 G(html.).715 E F2(Abstract)72 532
Q F3(This draft speci\214es an optional Quick-Start mechanism for trans\
port protocols, in)100.8 571 Q
(cooperation with routers, to determine an allo)100.8 584 Q
(wed sending rate at the start and at times in)-.275 E
(the middle of a data transfer)100.8 597 Q 5.5(.W)-.605 G
(hile Quick-Start is designed to be used by a range of)-5.5 E
(transport protocols, in this document we describe its use with TCP)
100.8 610 Q 5.5(.B)-1.221 G 2.75(yu)-5.5 G(sing Quick-Start,)-2.75 E
2.75(aT)100.8 623 S(CP host, say)-2.75 E 2.75(,h)-.715 G(ost A, w)-2.75
E(ould indicate its desired sending rate in bytes per second, using a)
-.11 E(Quick Start Request option in the IP header of a TCP pack)100.8
636 Q 2.75(et. A)-.11 F(Quick-Start request for a)2.75 E
(higher sending rate w)100.8 649 Q(ould be sent in a TCP pack)-.11 E
(et. Each router along the path could, in)-.11 E(turn, either appro)
100.8 662 Q .33 -.165(ve t)-.165 H(he requested rate, reduce the reques\
ted rate, or indicate that the Quick-).165 E(Start request is not appro)
100.8 675 Q -.165(ve)-.165 G 2.75(d. If).165 F
(the Quick-Start request is not appro)2.75 E -.165(ve)-.165 G
(d, then the sender).165 E -.11(wo)100.8 688 S(uld use the def).11 E
(ault congestion control mechanisms.)-.11 E
(The Quick-Start mechanism can)5.5 E(determine if there are routers alo\
ng the path that do not understand the Quick-Start Request)100.8 701 Q
(option, or ha)100.8 714 Q .33 -.165(ve n)-.22 H
(ot agreed to the Quick-Start rate request.).165 E
(TCP host B communicates the)5.5 E(Jain/Flo)72 769 Q 267.275
(yd/Allman/Sarolahti [P)-.11 F(age 1])-.165 E 0 Cg EP
%%Page: 2 2
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
(\214nal rate request to TCP host A in a transport-le)100.8 85 Q -.165
(ve)-.275 G 2.75(lQ).165 G(uick-Start Response in an answering)-2.75 E
(TCP pack)100.8 98 Q 2.75(et. Quick-Start)-.11 F(is designed to allo)
2.75 E 2.75(wc)-.275 G(onnections to use higher sending rates)-2.75 E(w\
hen there is signi\214cant unused bandwidth along the path, and all of \
the routers along the)100.8 111 Q(path support the Quick-Start Request.)
100.8 124 Q(Jain/Flo)72 769 Q 267.275(yd/Allman/Sarolahti [P)-.11 F
(age 2])-.165 E 0 Cg EP
%%Page: 3 3
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E .396 -.198(TO B)100.8 85 T
2.75(ED).198 G(ELETED BY THE RFC EDIT)-2.75 E(OR UPON PUBLICA)-.198 E
(TION:)-1.221 E(Changes from draft-amit-quick-start-03.txt:)103.55 98 Q
2.75(*A)103.55 111 S(dded a citation to the paper on "Ev)-2.75 E
(aluating Quick-Start for)-.275 E(TCP", and added pointers to the w)
109.05 124 Q(ork in that paper)-.11 E(.)-.605 E(This w)109.05 137 Q
(ork includes:)-.11 E 2.75(-D)109.05 150 S
(iscussions of router algorithms.)-2.75 E 2.75(-D)109.05 163 S
(iscussions of sizing Quick-Start requests.)-2.75 E 2.75(*A)103.55 176 S
(dded sections on "Misbeha)-2.75 E(ving Middlebox)-.22 E
(es", and on "Attacks on)-.165 E(Quick-Start".)109.05 189 Q
(Changes from draft-amit-quick-start-02.txt:)103.55 215 Q 2.75(*A)103.55
228 S(dded a discussion on Using Quick-Start in the Middle of a)-2.75 E
2.75(Connection. The)109.05 241 R(request w)2.75 E
(ould be on the total rate,)-.11 E(not on the additional rate.)109.05
254 Q 2.75(*C)103.55 267 S
(hanged name "Initial Rate" to "Rate Request", and changed)-2.75 E
(the units from pack)109.05 280 Q(ets per second to bytes per second.)
-.11 E 2.75(*T)103.55 293 S(he follo)-2.75 E(wing sections are ne)-.275
E(w:)-.275 E 2.75(-T)109.05 306 S
(he Quick-Start Request Option for IPv6)-2.75 E 2.75(-Q)109.05 319 S
(uick-Start in IP T)-2.75 E(unnels)-.495 E 2.75(-W)109.05 332 S
(hen to Use Quick-Start)-2.75 E 2.75(-T)109.05 345 S
(CP: Responding to a Loss of a Quick-Start P)-2.75 E(ack)-.165 E(et)-.11
E 2.75(-T)109.05 358 S(CP: A Quick-Start Request for a Lar)-2.75 E
(ger Initial W)-.198 E(indo)-.44 E(w)-.275 E 2.75(-T)109.05 371 S
(CP: A Quick-Start Request after an Idle Period)-2.75 E 2.75(-T)109.05
384 S(he Quick-Start Mechanisms in DCCP and other T)-2.75 E(ransport)
-.385 E(Protocols)114.55 397 Q 2.75(-Q)109.05 410 S
(uick-Start with DCCP)-2.75 E 2.75(-I)109.05 423 S
(mplementation and Deplo)-2.75 E(yment Issues)-.11 E 2.75(-D)109.05 436
S(esign Decisions)-2.75 E 2.75(*A)103.55 449 S(dded a discussion of K)
-2.75 E(unniyur')-.165 E 2.75(sA)-.605 G(nti-ECN proposal.)-2.75 E 2.75
(*A)103.55 462 S
(dded a section on simulations, with a brief discussion of the)-2.75 E
(simulations by Srikanth Sundarrajan.)109.05 475 Q
(Changes from draft-amit-quick-start-01.txt:)103.55 501 Q 2.75(*A)103.55
514 S(dded a discussion in the related w)-2.75 E(ork section about the)
-.11 E(possibility of optimistically sending a lar)109.05 527 Q
(ge initial windo)-.198 E -.715(w,)-.275 G(without e)109.05 540 Q
(xplicit permission of routers.)-.165 E 2.75(*A)103.55 553 S
(dded a discussion in the related w)-2.75 E(ork section about the)-.11 E
(tradeof)109.05 566 Q(fs of XCP vs. Quick-Start.)-.275 E 2.75(*A)103.55
579 S(dded a section on "The Quick-Start Request: P)-2.75 E(ack)-.165 E
(ets or Bytes?")-.11 E(Changes from draft-amit-quick-start-00.txt:)
103.55 605 Q 2.75(*T)103.55 618 S(he addition of a citation to [KHR02].)
-2.75 E 2.75(*T)103.55 631 S(he addition of a Related W)-2.75 E
(ork section.)-.88 E 2.75(*D)103.55 644 S(eleted the QS Nonce, in f)
-2.75 E -.22(avo)-.11 G 2.75(ro).22 G 2.75(far)-2.75 G(andom initial v)
-2.75 E(alue for the)-.275 E(QS TTL.)109.05 657 Q(Jain/Flo)72 769 Q
267.275(yd/Allman/Sarolahti [P)-.11 F(age 3])-.165 E 0 Cg EP
%%Page: 4 4
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 13/Times-Bold@0 SF -1.196
(Ta)253.526 85 S(ble of Contents)1.196 E/F2 10/Times-Roman@0 SF
(1. Introduction)100.8 110 Q F0 11(.......................)11.01 G F2(6)
11.5 E(2. Assumptions and General Principles)100.8 122 Q F0 11
(................)10.88 G F2(7)11.5 E(2.1. Ov)115.8 134 Q(ervie)-.15 E
2.5(wo)-.25 G 2.5(fQ)-2.5 G(uick-Start)-2.5 E F0 11(..................)
7.68 G F2(8)11.5 E(3. The Quick-Start Request in IP)100.8 146 Q F0 11
(..................)8.1 G F2(10)6.5 E
(3.1. The Quick-Start Request Option for IPv4)115.8 158 Q F0 11
(.............)10.19 G F2(10)6.5 E
(3.2. The Quick-Start Request Option for IPv6)115.8 170 Q F0 11
(.............)10.19 G F2(12)6.5 E
(3.3. Processing the Quick-Start Request at Routers)115.8 182 Q F0 11
(............)3.94 G F2(12)6.5 E
(3.4. Deciding the Permitted Rate Request at a Router)115.8 194 Q F0 11
(...........)8.25 G F2(13)6.5 E(3.5. Quick-Start in IP T)115.8 206 Q
(unnels)-.45 E F0 11(..................)4.1 G F2(13)6.5 E
(4. The Quick-Start Mechanisms in TCP)100.8 218 Q F0 11
(................)7.82 G F2(15)6.5 E(4.1. When to Use Quick-Start)115.8
230 Q F0 11(..................)5.33 G F2(15)6.5 E
(4.2. The Quick-Start Response Option in the TCP header)115.8 242 Q F0
11(..........)5.89 G F2(16)6.5 E
(4.3. TCP: Sending the Quick-Start Response)115.8 254 Q F0 11
(..............).59 G F2(17)6.5 E(4.4. TCP: Recei)115.8 266 Q
(ving and Using the Quick-Start Response P)-.25 E(ack)-.15 E(et)-.1 E F0
11(........)3.33 G F2(17)6.5 E
(4.5. TCP: Responding to a Loss of a Quick-Start P)115.8 278 Q(ack)-.15
E(et)-.1 E F0 11(..........)10.85 G F2(18)6.5 E
(4.6. TCP: A Quick-Start Request for a Lar)115.8 290 Q(ger Initial W)
-.18 E(indo)-.4 E(w)-.25 E F0 11(.........)2.98 G F2(19)6.5 E
(4.7. TCP: A Quick-Start Request after an Idle Period)115.8 302 Q F0 11
(...........)8.81 G F2(20)6.5 E
(4.8. An Example Quick-Start Scenario with TCP)115.8 314 Q F0 11
(............)11.16 G F2(21)6.5 E
(5. The Quick-Start Mechanism in other T)100.8 326 Q(ransport Protocols)
-.35 E F0 11(..........)10.69 G F2(21)6.5 E(5.1. Quick-Start with DCCP)
115.8 338 Q F0 11(..................)11.14 G F2(22)6.5 E(6. Ev)100.8 350
Q(aluation of Quick-Start)-.25 E F0 11(...................)12.38 G F2
(23)6.5 E(6.1. Bene\214ts of Quick-Start)115.8 362 Q F0 11
(...................).18 G F2(24)6.5 E(6.2. Costs of Quick-Start)115.8
374 Q F0 11(...................)10.73 G F2(24)6.5 E(6.3. Protection ag)
115.8 386 Q(ainst Misbeha)-.05 E(ving Nodes)-.2 E F0 11(..............)
7.24 G F2(25)6.5 E(6.4. Quick-Start with QoS-enabled T)115.8 398 Q(raf)
-.35 E<8c63>-.25 E F0 11(..............)10.94 G F2(27)6.5 E
(6.5. Limitations of Quick-Start)115.8 410 Q F0 11(..................)
.59 G F2(27)6.5 E(6.6. Attacks on Quick-Start)115.8 422 Q F0 11
(...................).74 G F2(28)6.5 E
(6.7. Simulations with Quick-Start)115.8 434 Q F0 11(.................)
3.22 G F2(28)6.5 E(7. Related W)100.8 446 Q(ork)-.8 E F0 11
(.......................)5.43 G F2(28)6.5 E(7.1. F)115.8 458 Q
(ast Start-ups without Explicit Information from Routers)-.15 E F0 11
(.........)2.27 G F2(29)6.5 E
(7.2. Optimistic Sending without Explicit Information from Routers)115.8
470 Q F0 11(.......)7.39 G F2(29)6.5 E(7.3. F)115.8 482 Q
(ast Start-ups with other Information from Routers)-.15 E F0 11
(..........)12.42 G F2(30)6.5 E(7.4. F)115.8 494 Q
(ast Start-ups with more Fine-Grained Feedback from Routers)-.15 E F0 11
(.......)7.3 G F2(31)6.5 E(8. Implementation and Deplo)100.8 506 Q
(yment Issues)-.1 E F0 11(...............)11.4 G F2(31)6.5 E
(8.1. Implementation Issues for Sending Quick-Start Requests)115.8 518 Q
F0 11(.........)2.97 G F2(31)6.5 E
(8.2. Implementation Issues for Processing Quick-Start Requests)115.8
530 Q F0 11(........)6.17 G F2(32)6.5 E(8.3. Possible Deplo)115.8 542 Q
(yment Scenarios)-.1 E F0 11(................)7.64 G F2(32)6.5 E(8.4. W)
115.8 554 Q(ould QuickStart pack)-.8 E(ets tak)-.1 E 2.5(et)-.1 G
(he slo)-2.5 E 2.5(wp)-.25 G(ath in routers?)-2.5 E F0 11(.........)6.18
G F2(33)6.5 E(8.5. A Comparison with the Deplo)115.8 566 Q
(yment Problems of ECN)-.1 E F0 11(.........)11.39 G F2(33)6.5 E
(9. Security Considerations)100.8 578 Q F0 11(....................)5.87
G F2(33)6.5 E(10. Conclusions)100.8 590 Q F0 11(.......................)
6 G F2(33)6.5 E(11. Ackno)100.8 602 Q(wledgements)-.25 E F0 11
(.....................)3.77 G F2(34)6.5 E(A. Design Decisions)100.8 614
Q F0 11(......................)1.71 G F2(34)6.5 E
(A.1. Alternate Mechanisms for the Quick-Start Request: ICMP and RSVP)
115.8 626 Q F0 11(.....)6.03 G F2(34)6.5 E(A.1.1. ICMP)130.8 638 Q F0 11
(......................)2.53 G F2(34)6.5 E(A.1.2. RSVP)130.8 650 Q F0 11
(......................)1.97 G F2(35)6.5 E
(A.2. Alternate Encoding Functions)115.8 662 Q F0 11(................)
11.99 G F2(36)6.5 E(A.3. The Quick-Start Request: P)115.8 674 Q(ack)-.15
E(ets or Bytes?)-.1 E F0 11(............)11.42 G F2(37)6.5 E
(A.4. Quick-Start Semantics: T)115.8 686 Q
(otal Rate or Additional Rate?)-.8 E F0 11(.........)10.16 G F2(38)6.5 E
(A.5. Alternate Responses to the Loss of a Quick-Start P)115.8 698 Q
(ack)-.15 E(et)-.1 E F0 11(.........)4.07 G F2(38)6.5 E(A.6. Wh)115.8
710 Q 2.5(yN)-.05 G(ot Include More Functionality?)-2.5 E F0 11
(..............)5.66 G F2(39)6.5 E(A.7. A QuickStart Nonce?)115.8 722 Q
F0 11(...................)4.64 G F2(41)6.5 E F0(Jain/Flo)72 769 Q
267.275(yd/Allman/Sarolahti [P)-.11 F(age 4])-.165 E 0 Cg EP
%%Page: 5 5
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 10/Times-Roman@0 SF
(Normati)100.8 84 Q .3 -.15(ve R)-.25 H(eferences).15 E F0 11
(.....................)8.66 G F1(41)6.5 E(Informati)100.8 96 Q .3 -.15
(ve R)-.25 H(eferences).15 E F0 11(.....................)4.22 G F1(42)
6.5 E(IAN)100.8 108 Q 2.5(AC)-.35 G(onsiderations)-2.5 E F0 11
(.....................)10.81 G F1(44)6.5 E -.55(AU)100.8 120 S
(THORS' ADDRESSES).55 E F0 11(....................)1.97 G F1(44)6.5 E
(Full Cop)100.8 132 Q(yright Statement)-.1 E F0 11(....................)
10.12 G F1(44)6.5 E(Intellectual Property)100.8 144 Q F0 11
(......................)2.27 G F1(45)6.5 E F0(Jain/Flo)72 769 Q 267.275
(yd/Allman/Sarolahti [P)-.11 F(age 5])-.165 E 0 Cg EP
%%Page: 6 6
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(1.)72
85 Q/F2 14/Times-Bold@0 SF(Intr)5.5 E(oduction)-.252 E F0
(Each TCP connection be)100.8 124 Q
(gins with a question: "What is the appropriate sending rate for the)
-.165 E(current netw)100.8 137 Q(ork path?")-.11 E
(The question is not answered e)5.5 E(xplicitly for TCP)-.165 E 2.75(,b)
-1.221 G(ut each TCP)-2.97 E
(connection determines the sending rate by probing the netw)100.8 150 Q
(ork path and altering the)-.11 E(congestion windo)100.8 163 Q 2.75(w\()
-.275 G(cwnd\) based on percei)-2.75 E -.165(ve)-.275 G 2.75(dc).165 G
2.75(ongestion. Each)-2.75 F(connection starts with a)2.75 E
(pre-con\214gured initial congestion windo)100.8 176 Q 2.75(w\()-.275 G
2.75(ICW\). Currently)-2.75 F 2.75(,T)-.715 G(CP allo)-2.75 E
(ws an initial windo)-.275 E(w)-.275 E
(of between one and four MSS-sized se)100.8 189 Q
(gments [RFC2581,RFC3390].)-.165 E(The TCP connection)5.5 E
(then probes the netw)100.8 202 Q(ork for a)-.11 E -.275(va)-.22 G
(ilable bandwidth using the slo).275 E(w-start procedure)-.275 E([Jac88\
,RFC2581], doubling cwnd during each congestion-free round-trip time \(\
R)100.8 215 Q(TT\).)-.66 E(The slo)100.8 241 Q
(w-start algorithm can be time-consuming --- especially o)-.275 E -.165
(ve)-.165 G 2.75(rn).165 G(etw)-2.75 E(orks with lar)-.11 E(ge)-.198 E
(bandwidth or long delays.)100.8 254 Q(It may tak)5.5 E 2.75(ean)-.11 G
(umber of R)-2.75 E(TTs in slo)-.66 E(w-start before the TCP)-.275 E
(connection be)100.8 267 Q(gins to fully use the a)-.165 E -.275(va)-.22
G(ilable bandwidth of the netw).275 E 2.75(ork. F)-.11 F
(or instance, it)-.165 E(tak)100.8 280 Q
(es log_2\(N\) - 2 round-trip times to b)-.11 E(uild cwnd up to N se)
-.22 E(gments, assuming an initial)-.165 E(congestion windo)100.8 293 Q
2.75(wo)-.275 G 2.75(f4s)-2.75 G -.165(eg)-2.75 G 2.75(ments. This).165
F(time in slo)2.75 E(w-start is not a problem for lar)-.275 E(ge \214le)
-.198 E(transfers, where the slo)100.8 306 Q
(w-start stage is only a fraction of the total transfer time.)-.275 E
(Ho)5.5 E(we)-.275 E -.165(ve)-.275 G -.44(r,).165 G(in the case of mod\
erate-sized web transfers the connection might carry out its entire)
100.8 319 Q(transfer in the slo)100.8 332 Q(w-start phase, taking man)
-.275 E 2.75(yr)-.165 G(ound-trip times, where one or tw)-2.75 E 2.75
(oR)-.11 G(TTs)-3.41 E(might ha)100.8 345 Q .33 -.165(ve b)-.22 H
(een suf).165 E(\214cient.)-.275 E 2.75(Af)100.8 371 S(air amount of w)
-2.86 E
(ork has already been done to address the issue of choosing the initial)
-.11 E(congestion windo)100.8 384 Q 2.75(wf)-.275 G(or TCP)-2.75 E 2.75
(,w)-1.221 G(ith RFC 3390 allo)-2.75 E(wing an initial windo)-.275 E
2.75(wo)-.275 G 2.75(fu)-2.75 G 2.75(pt)-2.75 G 2.75(of)-2.75 G(our)
-2.75 E(se)100.8 397 Q
(gments based on the MSS used by the connection [RFC3390].)-.165 E
(Our underlying premise)5.5 E(is that e)100.8 410 Q
(xplicit feedback from all of the routers along the path w)-.165 E
(ould be required, in the)-.11 E(current architecture, for best-ef)100.8
423 Q(fort connections to use initial windo)-.275 E
(ws signi\214cantly lar)-.275 E(ger)-.198 E(than those allo)100.8 436 Q
(wed by [RFC3390], in the absence of other information about the path.)
-.275 E(The Congestion Manager [RFC3124] and TCP control block sharing \
[RFC2140] both)100.8 462 Q(propose sharing congestion information among\
 multiple TCP connections with the same)100.8 475 Q 2.75(endpoints. W)
100.8 488 R(ith the Congestion Manager)-.44 E 2.75(,an)-.44 G .55 -.275
(ew T)-2.75 H(CP connection could start with a high).275 E
(initial cwnd if it w)100.8 501 Q
(as sharing the path and the cwnd with a pre-e)-.11 E
(xisting TCP connection to)-.165 E
(the same destination that had already obtained a high congestion windo)
100.8 514 Q 4.18 -.715(w. R)-.275 H(FC 2140).715 E
(discusses ensemble sharing, where an established connection')100.8 527
Q 2.75(sc)-.605 G(ongestion windo)-2.75 E 2.75(wc)-.275 G(ould)-2.75 E
(be `di)100.8 540 Q(vided up' to be shared with a ne)-.275 E 2.75(wc)
-.275 G(onnection to the same host.)-2.75 E(Ho)5.5 E(we)-.275 E -.165
(ve)-.275 G .88 -.44(r, n).165 H(either of).44 E
(these approaches addresses the case of a connection to a ne)100.8 553 Q
2.75(wd)-.275 G(estination, with no e)-2.75 E(xisting)-.165 E(or recent\
 connection \(and therefore congestion control state\) to that destinat\
ion.)100.8 566 Q(Quick-Start w)100.8 592 Q
(ould not be the \214rst mechanism for e)-.11 E
(xplicit communication from routers to)-.165 E
(transport protocols about sending rates.)100.8 605 Q
(Explicit Congestion Noti\214cation \(ECN\) gi)5.5 E -.165(ve)-.275 G(s)
.165 E -.165(ex)100.8 618 S(plicit congestion control feedback from rou\
ters to transport protocols, based on the).165 E
(router detecting congestion before b)100.8 631 Q(uf)-.22 E(fer o)-.275
E -.165(ve)-.165 G(r\215o).165 E 2.75(w[)-.275 G 2.75(RFC3168]. In)-2.75
F(contrast, routers do not)2.75 E
(use Quick-Start to get congestion information, b)100.8 644 Q
(ut instead use Quick-Start as an optional)-.22 E(mechanism to gi)100.8
657 Q .33 -.165(ve p)-.275 H
(ermission to transport protocols to use higher sending rates, based on)
.165 E(the ability of all the routers along the path to determine if th\
eir respecti)100.8 670 Q .33 -.165(ve o)-.275 H(utput links are).165 E
(signi\214cantly underutilized.)100.8 683 Q(Jain/Flo)72 769 Q 217.775
(yd/Allman/Sarolahti Section)-.11 F 2.75(1. [P)2.75 F(age 6])-.165 E 0
Cg EP
%%Page: 7 7
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(2.)72
85 Q/F2 14/Times-Bold@0 SF(Assumptions and General Principles)5.5 E F0(\
This section describes the assumptions and general principles behind th\
e design of the)100.8 111 Q(Quick-Start mechanism.)100.8 124 Q
(Assumptions:)100.8 150 Q 2.75(*T)100.8 176 S
(he data transfer in the tw)-2.75 E 2.75(od)-.11 G
(irections of a connection tra)-2.75 E -.165(ve)-.22 G(rses dif).165 E
(ferent queues, and)-.275 E(possibly e)100.8 189 Q -.165(ve)-.275 G 2.75
(nd).165 G(if)-2.75 E(ferent routers.)-.275 E(Thus, an)5.5 E 2.75(ym)
-.165 G(echanism for determining the allo)-2.75 E(wed sending)-.275 E
(rate w)100.8 202 Q(ould ha)-.11 E .33 -.165(ve t)-.22 H 2.75(ob).165 G
2.75(eu)-2.75 G(sed independently for each direction.)-2.75 E 2.75(*T)
100.8 228 S(he path between the tw)-2.75 E 2.75(oe)-.11 G
(ndpoints is relati)-2.75 E -.165(ve)-.275 G
(ly stable, such that the path used by the).165 E(Quick-Start request i\
s generally the same path used by the Quick-Start pack)100.8 241 Q
(ets one round-)-.11 E(trip time later)100.8 254 Q(.)-.605 E 2.75(*A)
100.8 280 S .33 -.165(ny n)-2.75 H .55 -.275(ew m).165 H
(echanism must be incrementally deplo).275 E
(yable, and might not be supported by)-.11 E
(all of the routers and/or end-hosts.)100.8 293 Q(Thus, an)5.5 E 2.75
(yn)-.165 G .55 -.275(ew m)-2.75 H(echanism must be able to).275 E(acco\
mmodate non-supporting routers or end-hosts without disturbing the curr\
ent Internet)100.8 306 Q(semantics.)100.8 319 Q(General Principles:)
100.8 345 Q 2.75(*O)100.8 371 S(ur underlying premise is that e)-2.75 E
(xplicit feedback from all of the routers along the path)-.165 E -.11
(wo)100.8 384 S
(uld be required, in the current architecture, for best-ef).11 E
(fort connections to use initial)-.275 E(windo)100.8 397 Q
(ws signi\214cantly lar)-.275 E(ger than those allo)-.198 E
(wed by [RFC3390], in the absence of other)-.275 E
(information about the path.)100.8 410 Q 2.75(*Ar)100.8 436 S
(outer should only appro)-2.75 E .33 -.165(ve a r)-.165 H
(equest for a higher sending rate if the output link is).165 E 2.75
(underutilized. An)100.8 449 R 2.75(yo)-.165 G
(ther approach will result in either per)-2.75 E(-\215o)-.22 E 2.75(ws)
-.275 G(tate at the router)-2.75 E 2.75(,o)-.44 G 2.75(rt)-2.75 G(he)
-2.75 E(possibility of a \(possibly transient\) queue at the router)
100.8 462 Q(.)-.605 E 2.75(*N)100.8 488 S 2.75(op)-2.75 G(er)-2.75 E
(-\215o)-.22 E 2.75(ws)-.275 G(tate should be required at the router)
-2.75 E(.)-.605 E(There are also a number of questions re)100.8 514 Q
-.055(ga)-.165 G(rding the Quick-Start mechanism that are).055 E
(discussed later in this document.)100.8 527 Q(Open Questions:)100.8 553
Q 2.75(*W)100.8 579 S
(ould the bene\214ts of the Quick-Start mechanism be w)-3.63 E
(orth the added comple)-.11 E(xity?)-.165 E(The bene\214ts and dra)100.8
605 Q
(wbacks of Quick-Start are discussed in more detail in Section 6 on)
-.165 E("Ev)100.8 618 Q(aluation of Quick-Start".)-.275 E 2.75(*Ap)100.8
644 S(ractical consideration is that pack)-2.75 E(ets with kno)-.11 E
(wn and unkno)-.275 E(wn IP options are often)-.275 E
(dropped in the current Internet [MAF04].)100.8 657 Q
(This does not preclude using Quick-Start in Intranets.)100.8 683 Q
(Further)5.5 E 2.75(,[)-.44 G(MAF04] also sho)-2.75 E(ws that)-.275 E
-.165(ove)100.8 696 S 2.75(rt).165 G(ime the blocking of pack)-2.75 E
(ets ne)-.11 E(gotiating ECN has dropped, and therefore an)-.165 E
(incremental deplo)100.8 709 Q
(yment story for Quick-Start based on IP Options is not out of the)-.11
E 2.75(question. Appendix)100.8 722 R
(A.1 on "Alternate Mechanisms for the Quick-Start Request" discusses)
2.75 E(Jain/Flo)72 769 Q 217.775(yd/Allman/Sarolahti Section)-.11 F 2.75
(2. [P)2.75 F(age 7])-.165 E 0 Cg EP
%%Page: 8 8
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(the possibility of using RS\
VP or ICMP instead of IP Options for carrying Quick-Start)100.8 85 Q
(Requests to routers.)100.8 98 Q 2.75(*A)100.8 124 S(part from the meri\
ts and shortcomings of the Quick-Start mechanism, is there lik)-2.75 E
(ely to)-.11 E(be a compelling need to add e)100.8 137 Q
(xplicit congestion-related feedback from routers o)-.165 E -.165(ve)
-.165 G 2.75(ra).165 G(nd)-2.75 E(abo)100.8 150 Q .33 -.165(ve t)-.165 H
(he one-bit feedback from ECN?).165 E(If the answer to the question abo)
100.8 176 Q .33 -.165(ve i)-.165 H 2.75(sy).165 G
(es, should we be considering mechanisms that,)-2.75 E
(while more comple)100.8 189 Q(x, are also suf)-.165 E
(\214ciently more po)-.275 E(werful than Quick-Start?)-.275 E(This is)
5.5 E(discussed further in Appendix A.6 on "Wh)100.8 202 Q 2.75(yN)-.055
G(ot Include More Functionality".)-2.75 E/F1 11/Times-Bold@0 SF(2.1.)72
241 Q/F2 13/Times-Bold@0 SF(Ov)5.5 E(er)-.13 E(view of Quick-Start)-.13
E F0(In this section we gi)100.8 267 Q .33 -.165(ve a)-.275 H 2.75(no)
.165 G -.165(ve)-2.915 G(rvie).165 E 2.75(wo)-.275 G 2.75(ft)-2.75 G
(he use of Quick-Start with TCP)-2.75 E 2.75(,u)-1.221 G
(sed to request a)-2.75 E(higher congestion windo)100.8 280 Q 4.18 -.715
(w. T)-.275 H(he description in this section is non-normati).715 E -.165
(ve)-.275 G 2.75(;t).165 G(he normati)-2.75 E -.165(ve)-.275 G
(description of Quick-Start with IP and TCP follo)100.8 293 Q
(ws in Sections 3 and 4. Quick-Start can be)-.275 E(used in the middle \
of a connection, e.g., after an idle or underutilized period, as well a\
s for)100.8 306 Q(the initial sending rate; these uses of Quick-Start a\
re discussed later in the document.)100.8 319 Q
(Quick-Start requires end-points and routers to w)100.8 345 Q
(ork together)-.11 E 2.75(,w)-.44 G(ith end-points requesting a)-2.75 E
(higher sending rate in the Quick-Start Request \(QSR\) option in IP)
100.8 358 Q 2.75(,a)-1.221 G(nd routers along the)-2.75 E(path appro)
100.8 371 Q
(ving, modifying, discarding or ignoring \(and therefore disallo)-.165 E
(wing\) the Quick-)-.275 E(Start Request.)100.8 384 Q(The recei)5.5 E
-.165(ve)-.275 G 2.75(ru).165 G(ses reliable, transport-le)-2.75 E -.165
(ve)-.275 G 2.75(lm).165 G(echanisms to inform the sender)-2.75 E
(of the status of the Quick-Start Request.)100.8 397 Q
(In addition, Quick-Start assumes a unicast,)5.5 E(congestion-controlle\
d transport protocol; we do not consider the use of Quick-Start for)
100.8 410 Q(multicast traf)100.8 423 Q(\214c.)-.275 E(The Quick-Start R\
equest Option includes a request for a sending rate in bytes per second\
,)100.8 449 Q(and a Quick-Start TTL \(QS TTL\) to be decremented by e)
100.8 462 Q -.165(ve)-.275 G(ry router along the path that).165 E
(understands the option and appro)100.8 475 Q -.165(ve)-.165 G 2.75(st)
.165 G(he request.)-2.75 E(The Quick-Start TTL is initialized by the)5.5
E(sender to a random v)100.8 488 Q 2.75(alue. The)-.275 F
(transport recei)2.75 E -.165(ve)-.275 G 2.75(rr).165 G
(eturns the rate and information about the)-2.75 E
(TTL to the sender using transport-le)100.8 501 Q -.165(ve)-.275 G 2.75
(lm).165 G 2.75(echanisms. In)-2.75 F(particular)2.75 E 2.75(,t)-.44 G
(he recei)-2.75 E -.165(ve)-.275 G 2.75(rc).165 G(omputes)-2.75 E
(the dif)100.8 514 Q(ference between the Quick-Start TTL and the TTL in\
 the IP header of the Quick-)-.275 E(Start request pack)100.8 527 Q
(et, and returns this in the Quick-Start response.)-.11 E
(The sender uses this)5.5 E(information to determine if all of the rout\
ers along the path decremented the Quick-Start)100.8 540 Q(TTL, appro)
100.8 553 Q(ving the Quick-Start Request.)-.165 E
(If the request is appro)100.8 579 Q -.165(ve)-.165 G 2.75(db).165 G
2.75(ya)-2.75 G(ll of the routers along the path, then the TCP sender)
-2.75 E(combines this allo)100.8 592 Q
(wed rate with the measurement of the round-trip time, and ends up with)
-.275 E(an allo)100.8 605 Q(wed TCP windo)-.275 E 4.18 -.715(w. T)-.275
H(his windo).715 E 2.75(wi)-.275 G 2.75(ss)-2.75 G(ent rate-paced o)
-2.75 E -.165(ve)-.165 G 2.75(rt).165 G(he round-trip time, or until)
-2.75 E(an A)100.8 618 Q(CK pack)-.44 E(et is recei)-.11 E -.165(ve)
-.275 G(d.).165 E(Figure 1 sho)100.8 644 Q(ws a successful use of Quick\
-Start, with both routers along the path appro)-.275 E(ving)-.165 E
(the Quick-Start Request.)100.8 657 Q(In this e)5.5 E
(xample, Quick-Start is used by TCP to establish the)-.165 E
(initial congestion windo)100.8 670 Q -.715(w.)-.275 G(Jain/Flo)72 769 Q
209.525(yd/Allman/Sarolahti Section)-.11 F 2.75(2.1. [P)2.75 F(age 8])
-.165 E 0 Cg EP
%%Page: 9 9
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 19.25(Sender Router)145.05
85 R 19.25(1R)2.75 G(outer 2)-19.25 E(Recei)27.5 E -.165(ve)-.275 G(r)
.165 E 19.25(------ --------)145.05 98 R 24.75(-------- --------)19.25 F
2.75(|Q)139.55 111 S(uick-Start Request)-2.75 E 2.75(|i)139.55 124 S
2.75(nS)-2.75 G(YN or SYN/A)-2.75 E(CK -->)-.44 E(|)139.55 137 Q 41.25
(|D)139.55 150 S(ecrement)-41.25 E 41.25(|Q)139.55 163 S 2.75(ST)-41.25
G(TL)-2.75 E 41.25(|t)139.55 176 S 2.75(oa)-41.25 G(ppro)-2.75 E -.165
(ve)-.165 G 41.25(|r)139.55 189 S(equest -->)-41.25 E(|)139.55 202 Q
82.5(|D)139.55 215 S(ecrement)-82.5 E 82.5(|Q)139.55 228 S 2.75(ST)-82.5
G(TL)-2.75 E 82.5(|t)139.55 241 S 2.75(oa)-82.5 G(ppro)-2.75 E -.165(ve)
-.165 G 82.5(|r)139.55 254 S(equest -->)-82.5 E(|)139.55 267 Q 118.25
(|R)139.55 280 S(eturn Quick-Start)-118.25 E 121(|i)139.55 293 S
(nfo to sender in)-121 E 115.5(|<)139.55 306 S(-- TCP A)-115.5 E
(CK pack)-.44 E(et.)-.11 E(|)139.55 319 Q 2.75(|Q)139.55 332 S
(uick-Start appro)-2.75 E -.165(ve)-.165 G(d,).165 E 2.75(|t)139.55 345
S(ranslate to cwnd.)-2.75 E 2.75(VS)139.55 358 S(end cwnd paced o)-2.75
E -.165(ve)-.165 G 2.75(ro).165 G(ne R)-2.75 E(TT)-.66 E 2.75(.-)-.814 G
(->)-2.75 E(Figure 1: A successful Quick-Start Request.)167.05 384 Q
(Figure 2 sho)100.8 416 Q(ws an unsuccessful use of Quick-Start, with o\
ne of the routers along the path)-.275 E(not appro)100.8 429 Q
(ving the Quick-Start Request.)-.165 E
(If the Quick-Start Request is not appro)5.5 E -.165(ve)-.165 G(d, then)
.165 E(the sender uses the def)100.8 442 Q
(ault congestion control mechanisms for that transport protocol,)-.11 E
(including the def)100.8 455 Q(ault initial congestion windo)-.11 E 1.43
-.715(w, r)-.275 H(esponse to idle periods, etc.).715 E(Jain/Flo)72 769
Q 209.525(yd/Allman/Sarolahti Section)-.11 F 2.75(2.1. [P)2.75 F(age 9])
-.165 E 0 Cg EP
%%Page: 10 10
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 19.25(Sender Router)145.05
85 R 19.25(1R)2.75 G(outer 2)-19.25 E(Recei)27.5 E -.165(ve)-.275 G(r)
.165 E 19.25(------ --------)145.05 98 R 24.75(-------- --------)19.25 F
2.75(|Q)139.55 111 S(uick-Start Request)-2.75 E 2.75(|i)139.55 124 S
2.75(nS)-2.75 G(YN or SYN/A)-2.75 E(CK -->)-.44 E(|)139.55 137 Q 41.25
(|D)139.55 150 S(ecrement)-41.25 E 41.25(|Q)139.55 163 S 2.75(ST)-41.25
G(TL)-2.75 E 41.25(|t)139.55 176 S 2.75(oa)-41.25 G(ppro)-2.75 E -.165
(ve)-.165 G 41.25(|r)139.55 189 S(equest -->)-41.25 E(|)139.55 202 Q
82.5(|F)139.55 215 S(orw)-82.665 E(ard pack)-.11 E(et)-.11 E 82.5(|w)
139.55 228 S(ithout modifying)-82.5 E 82.5(|Q)139.55 241 S
(uick-Start Option. -->)-82.5 E(|)139.55 254 Q 118.25(|R)139.55 267 S
(eturn Quick-Start)-118.25 E 121(|i)139.55 280 S(nfo to sender in)-121 E
115.5(|<)139.55 293 S(-- TCP A)-115.5 E(CK pack)-.44 E(et.)-.11 E(|)
139.55 306 Q 2.75(|Q)139.55 319 S(uick-Start not appro)-2.75 E -.165(ve)
-.165 G(d.).165 E 2.75(VU)139.55 332 S(se def)-2.75 E
(ault initial cwnd. -->)-.11 E
(Figure 2: An unsuccessful Quick-Start Request.)167.05 358 Q/F1 11
/Times-Bold@0 SF(3.)72 416 Q/F2 14/Times-Bold@0 SF
(The Quick-Start Request in IP)5.5 E F1(3.1.)72 455 Q/F3 13/Times-Bold@0
SF(The Quick-Start Request Option f)5.5 E(or IPv4)-.325 E F0
(The Quick-Start Request for IPv4 is de\214ned as follo)100.8 481 Q(ws:)
-.275 E 27.5(0123)122.8 507 S
(+----------+----------+----------+----------+)109.05 520 Q 2.75(|O)
109.05 533 S 5.5(ption |)-2.75 F(Length=4 |)2.75 E(QS TTL)5.5 E 2.75(|R)
5.5 G 11(ate |)-2.75 F 27.5(||||)109.05 546 S 2.75(Request |)-24.75 F
(+----------+----------+----------+----------+)109.05 559 Q(Figure 1.)
109.05 585 Q(The Quick-Start Request Option for IPv4.)5.5 E(The \214rst\
 byte contains the option \214eld, which includes the one-bit cop)100.8
611 Q 2.75<798d>-.11 G(ag, the 2-bit class)-2.75 E
(\214eld, and the 5-bit option number \(to be assigned by IAN)100.8 624
Q(A\).)-.385 E(The second byte contains the length \214eld, indicating \
an option length of four bytes.)100.8 650 Q
(The third byte contains the Quick-Start TTL \(QS TTL\) \214eld.)100.8
676 Q(The sender sets the QS TTL)5.5 E(\214eld to a random v)100.8 689 Q
2.75(alue. Routers)-.275 F(that appro)2.75 E .33 -.165(ve t)-.165 H
(he Quick-Start Request decrement the QS).165 E(TTL \(mod 256\).)100.8
702 Q(The QS TTL is used by the sender to detect if all of the routers \
along the)5.5 E(path understood and appro)100.8 715 Q -.165(ve)-.165 G
2.75(dt).165 G(he Quick-Start option.)-2.75 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(3.1. [P)2.75 F(age 10])-.165 E
0 Cg EP
%%Page: 11 11
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
(The transport sender also calculates and remembers the TTL Dif)100.8 85
Q(f, the dif)-.275 E(ference between)-.275 E(the IP TTL v)100.8 98 Q
(alue and the QS TTL v)-.275 E(alue in the Quick-Start request pack)
-.275 E(et, as follo)-.11 E(ws:)-.275 E(TTL Dif)100.8 124 Q 2.75(f=\(I)
-.275 G 2.75(PT)-2.75 G(TL - QS TTL \) mod 256.)-2.75 E(\(1\))68.75 E
(The fourth byte is the Rate Request \214eld.)100.8 150 Q
(The sender initializes the Rate Request to the)5.5 E(desired sending r\
ate, including an estimate of the transport and IP header o)100.8 163 Q
-.165(ve)-.165 G(rhead.).165 E(Our current proposal for an encoding fun\
ction uses only the \214rst four bits of the fourth)100.8 189 Q
(byte, lea)100.8 202 Q(ving the other four bits reserv)-.22 E
(ed for future use.)-.165 E(The encoding function sets the)5.5 E
(request rate to K*2^N bps, for N the v)100.8 215 Q
(alue in the Rate Request \214eld, and for K set to)-.275 E 2.75
(40,000. F)100.8 228 R(or N=0, the rate request w)-.165 E
(ould be set to zero, re)-.11 E -.055(ga)-.165 G
(rdless of the encoding function.).055 E
(This is illustrated in the table belo)100.8 241 Q 4.18 -.715(w. F)-.275
H(or a four).55 E(-bit Rate Request \214eld, the request range)-.22 E
-.11(wo)100.8 254 S(uld be from 80 Kbps to 1.3 Gbps.).11 E
(Alternate encodings for the Rate Request are gi)5.5 E -.165(ve)-.275 G
2.75(ni).165 G(n)-2.75 E(Appendix A.2.)100.8 267 Q 13.75(NR)139.55 286 S
(ate Request \(in Kbps\))-13.75 E 8.25(--- -------------------)136.8 299
R 33(00)139.55 312 S 30.25(18)139.55 325 S(0)-30.25 E 27.5(21)139.55 338
S(60)-27.5 E 27.5(33)139.55 351 S(20)-27.5 E 27.5(46)139.55 364 S(40)
-27.5 E 22(51)139.55 377 S(,280)-22 E 22(62)139.55 390 S(,560)-22 E 22
(75)139.55 403 S(,120)-22 E 19.25(81)139.55 416 S(0,240)-19.25 E 19.25
(92)139.55 429 S(0,480)-19.25 E 16.5(10 40,960)136.8 442 R 16.5
(11 81,920)136.8 455 R 13.75(12 163,840)136.8 468 R 13.75(13 327,680)
136.8 481 R 13.75(14 655,360)136.8 494 R 8.25(15 1,310,720)136.8 507 R
(Mapping from the Rate Request \214eld to the rate request in Kbps.)
136.8 533 Q(Routers can appro)100.8 565 Q .33 -.165(ve t)-.165 H
(he Quick-Start Request for a lo).165 E(wer rate by decreasing the Rate)
-.275 E(Request in the Quick-Start Request.)100.8 578 Q 1.76 -.88(We n)
100.8 604 T(ote that unlik).88 E 2.75(eaQ)-.11 G
(uick-Start Request sent at the be)-2.75 E
(ginning of a connection, when a)-.165 E(Quick-Start Request is sent in\
 the middle of a connection, the connection could already)100.8 617 Q
(ha)100.8 630 Q .33 -.165(ve a)-.22 H 2.75(ne).165 G
(stablished congestion windo)-2.75 E 2.75(wo)-.275 G 2.75(rs)-2.75 G
(ending rate.)-2.75 E(The Rate Request is the requested)5.5 E(total rat\
e for the connection, including the current rate of the connection; the\
 Rate Request)100.8 643 Q
(is *not* a request for an additional sending rate o)100.8 656 Q -.165
(ve)-.165 G 2.75(ra).165 G(nd abo)-2.75 E .33 -.165(ve t)-.165 H
(he current sending rate.).165 E(If)5.5 E
(the Rate Request is denied, or lo)100.8 669 Q(wered to a v)-.275 E
(alue belo)-.275 E 2.75(wt)-.275 G(he connection')-2.75 E 2.75(sc)-.605
G(urrent sending)-2.75 E
(rate, then the sender can ignore the request, and re)100.8 682 Q -.165
(ve)-.275 G(rt to the def).165 E(ault congestion control)-.11 E
(mechanisms of the transport protocol.)100.8 695 Q(In IPv4, a change in\
 IP options at routers requires recalculating the IP header checksum.)
100.8 721 Q(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F
2.75(3.1. [P)2.75 F(age 11])-.165 E 0 Cg EP
%%Page: 12 12
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(3.2.)
72 85 Q/F2 13/Times-Bold@0 SF(The Quick-Start Request Option f)5.5 E
(or IPv6)-.325 E F0(The Quick-Start Request Option for IPv6 is placed i\
n the Hop-by-Hop Options e)100.8 111 Q(xtension)-.165 E
(header that is processed at e)100.8 124 Q -.165(ve)-.275 G(ry netw).165
E(ork node along the communication path [RFC 2460].)-.11 E
(The option format follo)100.8 137 Q
(wing the generic Hop-by-Hop Options header is similar to the IPv4)-.275
E(format with the e)100.8 150 Q
(xception that the Length \214eld should e)-.165 E
(xclude the common type and length)-.165 E
(\214elds in the option format and be set to 2.)100.8 163 Q 27.5(0123)
122.8 189 S(+----------+----------+----------+----------+)109.05 202 Q
2.75(|O)109.05 215 S 5.5(ption |)-2.75 F(Length=2 |)2.75 E(QS TTL)5.5 E
2.75(|R)5.5 G 11(ate |)-2.75 F 27.5(||||)109.05 228 S 2.75(Request |)
-24.75 F(+----------+----------+----------+----------+)109.05 241 Q
(Figure 2.)109.05 267 Q(The Quick-Start Request Option for IPv6.)5.5 E
(The transport recei)100.8 293 Q -.165(ve)-.275 G 2.75(rc).165 G
(ompares the Quick-Start TTL with the IPv6 Hop Limit \214eld in)-2.75 E
(order to calculate the TTL Dif)100.8 306 Q 2.75(f. \(The)-.275 F
(Hop Limit in IPv6 is the equi)2.75 E -.275(va)-.275 G
(lent of the TTL in).275 E 2.75(IPv6.\) That)100.8 319 R(is, TTL Dif)
2.75 E 2.75(fi)-.275 G 2.75(sc)-2.75 G(alculated as follo)-2.75 E(ws:)
-.275 E(TTL Dif)100.8 345 Q 2.75(f=\(I)-.275 G
(Pv6 Hop Limit - QS TTL \) mod 256.)-2.75 E(\(1\))68.75 E(Unlik)100.8
371 Q 2.75(eI)-.11 G(Pv4, modifying or deleting the Quick-Start Request\
 IPv6 Option does not require)-2.75 E
(checksum re-calculation, because the IPv6 header does not ha)100.8 384
Q .33 -.165(ve a c)-.22 H(hecksum \214eld, and).165 E(modifying the Qui\
ck-Start Request in the IPv6 Hop-by-Hop options header does not af)100.8
397 Q(fect)-.275 E(the IPv6 pseudo-header checksum used in upper)100.8
410 Q(-layer checksum calculations.)-.22 E
(Note that [RFC2460] speci\214es that when a speci\214c \215o)100.8 436
Q 2.75(wl)-.275 G(abel has been assigned to pack)-2.75 E(ets,)-.11 E
(the contents of the Hop-by-Hop options, e)100.8 449 Q(xcluding the ne)
-.165 E(xt header \214eld, must originate)-.165 E
(with the same contents throughout the IP \215o)100.8 462 Q 2.75(wl)
-.275 G 2.75(ifetime. This)-2.75 F(requirement w)2.75 E(ould ha)-.11 E
.33 -.165(ve t)-.22 H 2.75(ob).165 G(e)-2.75 E(modi\214ed to implement \
Quick-Start on an IPv6 implementation that uses \215o)100.8 475 Q 2.75
(wl)-.275 G(abels,)-2.75 E(because the Quick-Start Request option w)
100.8 488 Q(ould be included in only a small fraction of the)-.11 E
(pack)100.8 501 Q(ets during a \215o)-.11 E 2.75(wl)-.275 G(ifetime.)
-2.75 E F1(3.3.)72 540 Q F2(Pr)5.5 E
(ocessing the Quick-Start Request at Routers)-.234 E F0
(Each participating router can either terminate or forw)100.8 566 Q
(ard the Quick-Start Request.)-.11 E(The)5.5 E(router terminates the Qu\
ick-Start Request if the router is not underutilized, and therefore)
100.8 579 Q(has decided not to grant the Quick-Start Request.)100.8 592
Q(The preferable method for a router to terminate the Quick-Start Reque\
st is to delete the)100.8 618 Q(Quick-Start Request from the IP header)
100.8 631 Q 5.5(.A)-.605 G(less preferable b)-2.75 E
(ut possibly more ef)-.22 E(\214cient)-.275 E(method is to simply forw)
100.8 644 Q(ard the pack)-.11 E
(et with the Quick-Start Request unchanged, or with)-.11 E
(the Rate Request set to zero.)100.8 657 Q
(If the participating router has decided to appro)100.8 683 Q .33 -.165
(ve t)-.165 H(he Quick-Start Request, it does the).165 E(follo)100.8 696
Q(wing:)-.275 E 2.75(*I)100.8 722 S 2.75(td)-2.75 G
(ecrements the QS TTL by one.)-2.75 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(3.3. [P)2.75 F(age 12])-.165 E
0 Cg EP
%%Page: 13 13
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 2.75(*I)100.8 85 S 2.75(ft)
-2.75 G(he router is only willing to appro)-2.75 E .33 -.165(ve a)-.165
H 2.75(nR).165 G(ate Request less than that in the Quick-Start)-2.75 E(\
Request, then the router puts the smaller Rate Request in that \214eld \
of the Quick-Start)100.8 98 Q 2.75(Request. The)100.8 111 R
(router MUST NO)2.75 E 2.75(Ti)-.44 G
(ncrease the Rate Request in the Quick-Start Request.)-2.75 E 2.75(*I)
100.8 137 S 2.75(nI)-2.75 G(Pv4, it updates the IP header checksum.)
-2.75 E 2.75(An)100.8 163 S(on-participating router forw)-2.75 E
(ards the Quick-Start Request unchanged, without)-.11 E
(decrementing the QS TTL.)100.8 176 Q
(Of course, the non-participating router still decrements the)5.5 E
(TTL \214eld in the IP header)100.8 189 Q 2.75(,a)-.44 G 2.75(si)-2.75 G
2.75(sr)-2.75 G(equired for all routers [RFC1812].)-2.75 E
(As a result, the TCP)5.5 E(sender will be able to detect that the Quic\
k-Start Request had not been understood or)100.8 202 Q(appro)100.8 215 Q
-.165(ve)-.165 G 2.75(db).165 G 2.75(ya)-2.75 G
(ll of the routers along the path.)-2.75 E 2.75(Ar)100.8 241 S(outer th\
at modi\214es or deletes the Quick-Start Request in the IPv4 header als\
o has to)-2.75 E(update the IPv4 Header checksum.)100.8 254 Q -.165(Fo)
5.5 G 2.75(rI).165 G(Pv6, no checksum updates are needed.)-2.75 E/F1 11
/Times-Bold@0 SF(3.4.)72 293 Q/F2 13/Times-Bold@0 SF(Deciding the P)5.5
E(ermitted Rate Request at a Router)-.26 E F0
(In this section we brie\215y outline ho)100.8 319 Q 2.75(war)-.275 G
(outer might decide whether or not to appro)-2.75 E .33 -.165(ve a)-.165
H(Quick-Start Request.)100.8 332 Q(As an e)5.5 E
(xample, the router could ask the follo)-.165 E(wing questions:)-.275 E
2.75(*H)100.8 358 S(as the router')-2.75 E 2.75(so)-.605 G
(utput link been underutilized for some time \(e.g., se)-2.75 E -.165
(ve)-.275 G(ral seconds\).).165 E 2.75(*W)100.8 384 S
(ould the output link remain underutilized if the arri)-3.63 E -.275(va)
-.275 G 2.75(lr).275 G(ate w)-2.75 E(as to increase by the)-.11 E(aggre)
100.8 397 Q -.055(ga)-.165 G(te rate requests that the router has appro)
.055 E -.165(ve)-.165 G 2.75(do).165 G -.165(ve)-2.915 G 2.75(rt).165 G
(he last fraction of a second?)-2.75 E
(Answering this question requires that the router ha)100.8 423 Q .33
-.165(ve s)-.22 H(ome kno).165 E(wledge of the a)-.275 E -.275(va)-.22 G
(ilable).275 E(bandwidth on the output link for that output queue.)100.8
436 Q(It also requires that the router k)5.5 E(eep tw)-.11 E(o)-.11 E
(counters, one indicating the total aggre)100.8 449 Q -.055(ga)-.165 G
(te Rate Requests that ha).055 E .33 -.165(ve b)-.22 H(een appro).165 E
-.165(ve)-.165 G 2.75(do).165 G -.165(ve)-2.915 G 2.75(rt).165 G(he)
-2.75 E(recent interv)100.8 462 Q
(al of time, and one for the total aggre)-.275 E -.055(ga)-.165 G
(te Rate Requests appro).055 E -.165(ve)-.165 G 2.75(do).165 G -.165(ve)
-2.915 G 2.75(rt).165 G(he)-2.75 E(pre)100.8 475 Q(vious interv)-.275 E
(al of time.)-.275 E(Thus, if an underutilized router e)5.5 E
(xperiences a SYN \215ood, then)-.165 E(the router w)100.8 488 Q
(ould be)-.11 E(gin to den)-.165 E 2.75(yR)-.165 G
(ate Request requests, e)-2.75 E -.165(ve)-.275 G 2.75(ni).165 G 2.75
(ft)-2.75 G(he router remains)-2.75 E(underutilized.)100.8 501 Q 2.75
(*I)100.8 527 S 2.75(ft)-2.75 G(he router')-2.75 E 2.75(so)-.605 G
(utput link has been underutilized and the aggre)-2.75 E -.055(ga)-.165
G(te Quick Start Request).055 E(Rate options granted is lo)100.8 540 Q
2.75(we)-.275 G(nough to pre)-2.75 E -.165(ve)-.275 G(nt a near).165 E
(-term bandwidth shortage, then the)-.22 E(router could appro)100.8 553
Q .33 -.165(ve t)-.165 H(he Quick-Start Request.).165 E(Section 8.2 dis\
cusses some of the implementation issues in processing Quick-Start requ\
ests)100.8 579 Q(at routers.)100.8 592 Q([SAF05] discusses the range of\
 possible Quick-Start algorithms at the router for)5.5 E
(deciding whether to appro)100.8 605 Q .33 -.165(ve a Q)-.165 H
(uick-Start request.).165 E(In order to e)5.5 E
(xplore the limits of the)-.165 E(possible functionality at routers, [S\
AF05] also discusses Extreme Quick-Start mechanisms)100.8 618 Q
(at routers, where the router w)100.8 631 Q(ould k)-.11 E(eep per)-.11 E
(-\215o)-.22 E 2.75(ws)-.275 G(tate concerning appro)-2.75 E -.165(ve)
-.165 G 2.75(dQ).165 G(uick-Start)-2.75 E(requests.)100.8 644 Q F1(3.5.)
72 683 Q F2(Quick-Start in IP T)5.5 E(unnels)-1.196 E F0
(In this section we consider the ef)100.8 709 Q
(fect of IP tunnels on Quick-Start.)-.275 E(In the discussion, we)5.5 E
(use TTL Dif)100.8 722 Q(f, de\214ned earlier as the dif)-.275 E
(ference between the IP TTL and the Quick-Start)-.275 E(Jain/Flo)72 769
Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(3.5. [P)2.75 F
(age 13])-.165 E 0 Cg EP
%%Page: 14 14
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(TTL, mod 256.)100.8 85 Q
(Recall that the sender considers the Quick-Start request appro)5.5 E
-.165(ve)-.165 G 2.75(di).165 G 2.75(ft)-2.75 G(he)-2.75 E -.275(va)
100.8 98 S(lue of TTL Dif).275 E 2.75(ff)-.275 G(or the pack)-2.75 E
(et entering the netw)-.11 E(ork is the same as the v)-.11 E
(alue of TTL Dif)-.275 E(f)-.275 E(for the pack)100.8 111 Q(et e)-.11 E
(xiting the netw)-.165 E(ork.)-.11 E(There are tw)100.8 137 Q 2.75(ol)
-.11 G -.165(eg)-2.75 G(itimate w).165 E
(ays for handling the Quick-Start Request with IP tunnels:)-.11 E(\(1\)\
 The tunnel ingress node does not support Quick-Start, or does not appr\
o)100.8 163 Q .33 -.165(ve t)-.165 H(he Quick-).165 E(Start request. Th\
e node could strip the Quick-Start Request option from the IP header)
100.8 176 Q(before encapsulation.)100.8 189 Q(Alternately)5.5 E 2.75(,t)
-.715 G(he ingress node can decrement the IP TTL before)-2.75 E
(encapsulation, while lea)100.8 202 Q
(ving the Quick-Start TTL unchanged, changing TTL Dif)-.22 E 2.75
(f. This)-.275 F(is)2.75 E(the assumed beha)100.8 215 Q
(vior of current IP tunnels that are not a)-.22 E -.11(wa)-.165 G
(re of Quick-Start.).11 E -.165(Fo)100.8 241 S 2.75(rat).165 G(unnel in\
gress node that does not support Quick-Start, problems with a Quick-Sta\
rt)-2.75 E
(Request could still occur if a tunnel discards the outer header at e)
100.8 254 Q(gress and does not)-.165 E
(decrement the inner IP TTL at the ingress.)100.8 267 Q
(In this case, if both the inner IP TTL and the)5.5 E
(Quick-Start TTL are decremented after decapsulation at a Quick-Start a)
100.8 280 Q -.11(wa)-.165 G(re e).11 E(gress, or if)-.165 E
(neither is decremented at the e)100.8 293 Q(gress, then TTL Dif)-.165 E
2.75(fw)-.275 G(ould be the same after e)-2.86 E(gress as it w)-.165 E
(as)-.11 E(before ingress, so that it w)100.8 306 Q
(ould wrongly appear that all the routers in the tunnel had)-.11 E
(appro)100.8 319 Q -.165(ve)-.165 G 2.75(dt).165 G
(he Quick-Start request.)-2.75 E -.165(Fo)5.5 G(rtunately).165 E 2.75
(,w)-.715 G 2.75(ea)-2.75 G(re not a)-2.75 E -.11(wa)-.165 G
(re of tunnel technologies).11 E(that operate this w)100.8 332 Q
(ay; to the best of our kno)-.11 E
(wledge, all tunnels decrement the IP TTL either)-.275 E
(at the ingress before encapsulation, or at the e)100.8 345 Q
(gress router after decapsulation, thus)-.165 E(changing TTL Dif)100.8
358 Q(f.)-.275 E(Ev)100.8 384 Q(en the e)-.165 E(xtreme case when the t\
unnel ingress is at the TCP sender and the tunnel e)-.165 E(gress is)
-.165 E(at the TCP recei)100.8 397 Q -.165(ve)-.275 G .88 -.44(r, o).165
H(ur assumption is that the IP TTL will be decremented either at the).44
E(tunnel ingress or at the tunnel e)100.8 410 Q(gress, changing TTL Dif)
-.165 E 2.75(fa)-.275 G(nd pre)-2.75 E -.165(ve)-.275 G
(nting the end-nodes).165 E
(from wrongly inferring that the Quick-Start Request w)100.8 423 Q
(as appro)-.11 E -.165(ve)-.165 G 2.75(db).165 G 2.75(ya)-2.75 G
(ll of the routers)-2.75 E(along the path.)100.8 436 Q(If there are tun\
nels where the IP TTL in not decremented, perhaps for PPP)5.5 E -.165
(ove)100.8 449 S 2.75(rS).165 G(SH, then additional attention will ha)
-2.75 E .33 -.165(ve t)-.22 H 2.75(ob).165 G 2.75(ep)-2.75 G
(aid to the rob)-2.75 E(ustness of Quick-Start in)-.22 E(these en)100.8
462 Q(vironments.)-.44 E 2.75(AQ)100.8 488 S(uick-Start a)-2.75 E -.11
(wa)-.165 G(re e).11 E(gress must also mak)-.165 E 2.75(es)-.11 G
(ure that the Quick-Start Request is not)-2.75 E(appro)100.8 501 Q -.165
(ve)-.165 G 2.75(di).165 G 2.75(ff)-2.75 G(or some reason the inner hea\
der includes the Quick-Start Request option, b)-2.75 E(ut)-.22 E
(the outer header does not.)100.8 514 Q(In this case the e)5.5 E
(gress node should remo)-.165 E .33 -.165(ve t)-.165 H(he Quick-Start)
.165 E(Request option from the inner header after decapsulation.)100.8
527 Q(Alternately)5.5 E 2.75(,t)-.715 G(he e)-2.75 E(gress node)-.165 E
(could decrement the Rate Request in the Quick-Start Request option to \
zero.)100.8 540 Q(\(2\) The tunnel ingress node may choose to support Q\
uick-Start, and locally appro)100.8 566 Q .33 -.165(ve t)-.165 H(he).165
E(Quick-Start Request.)100.8 579 Q
(In this case the IP TTL and Quick-Start option must be copied from)5.5
E(the inner IP header to the outer header at the tunnel ingress. Upon d\
ecapsulation, the IP)100.8 592 Q(TTL and the Quick-Start option in the \
outer IP header must be copied back to the inner)100.8 605 Q(header)
100.8 618 Q 5.5(.I)-.605 G 2.75(ft)-5.5 G
(he ingress router decrements the IP TTL in the inner header before)
-2.75 E(encapsulation, or in the outer header after encapsulation, then\
 if the ingress router wishes)100.8 631 Q(to appro)100.8 644 Q .33 -.165
(ve t)-.165 H(he Quick-Start request, it must decrement the Quick-Start\
 TTL at the same).165 E(time, so as not to change TTL Dif)100.8 657 Q
2.75(f. Similarly)-.275 F 2.75(,i)-.715 G 2.75(ft)-2.75 G(he e)-2.75 E
(gress router wishes to appro)-.165 E .33 -.165(ve t)-.165 H(he).165 E(\
Quick-Start request, then when it decrements the IP TTL in the outer he\
ader before)100.8 670 Q(decapsulation, or in the inner header after dec\
apsulation, it must decrement the Quick-Start)100.8 683 Q
(TTL at the same time.)100.8 696 Q 2.75(At)100.8 722 S
(unnel ingress node can support a Quick-Start request without e)-2.75 E
(xplicitly v)-.165 E(erifying that)-.165 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(3.5. [P)2.75 F(age 14])-.165 E
0 Cg EP
%%Page: 15 15
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(the tunnel e)100.8 85 Q
(gress also supports Quick-Start.)-.165 E
(All that the ingress node has to do is to)5.5 E
(decrement the IP TTL, b)100.8 98 Q
(ut not the Quick-Start TTL, in the inner header after)-.22 E 2.75
(encapsulation. In)100.8 111 R(this case, if the e)2.75 E
(gress node simply discards the outer header at the e)-.165 E(gress)
-.165 E(point, TTL Dif)100.8 124 Q 2.75(fw)-.275 G(ill be dif)-2.75 E
(ferent after the tunnel e)-.275 E(gress than it w)-.165 E
(as at the tunnel ingress,)-.11 E
(and the Quick-Start will not be considered by the end-nodes as ha)100.8
137 Q(ving been appro)-.22 E -.165(ve)-.165 G 2.75(di).165 G 2.75(nt)
-2.75 G(he)-2.75 E(netw)100.8 150 Q 2.75(ork. Thus,)-.11 F
(the tunnel ingress node on its o)2.75 E(wn can pro)-.275 E
(vide protection ag)-.165 E(ainst e)-.055 E(gress)-.165 E
(nodes that might discard the outer header at the e)100.8 163 Q
(gress point.)-.165 E/F1 11/Times-Bold@0 SF(4.)72 202 Q/F2 14
/Times-Bold@0 SF(The Quick-Start Mechanisms in TCP)5.5 E F0
(This section describes ho)100.8 228 Q 2.75(wt)-.275 G
(he Quick-Start mechanism w)-2.75 E(ould be used in TCP)-.11 E 5.5(.W)
-1.221 G 2.75<658c>-6.38 G(rst)-2.75 E(sk)100.8 241 Q(etch the procedur\
e and then tightly de\214ne it in the subsequent subsections.)-.11 E
(If a TCP sender)100.8 267 Q 2.75(,s)-.44 G(ay host A, w)-2.75 E
(ould lik)-.11 E 2.75(et)-.11 G 2.75(ou)-2.75 G
(se Quick-Start, the TCP sender puts the)-2.75 E(requested sending rate\
 in bytes per second, appropriately formatted, in the Quick-Start)100.8
280 Q(Request option in the IP header of the TCP pack)100.8 293 Q
(et, called the Quick-Start request pack)-.11 E(et.)-.11 E(\(W)100.8 306
Q 2.75(ew)-.88 G(ill be some)-2.75 E(what loose in our use of "pack)
-.275 E(et" vs. "se)-.11 E(gment" in this section.\))-.165 E -.165(Fo)
5.5 G(r).165 E(initial start-up, the Quick-Start request pack)100.8 319
Q(et can be either the SYN or SYN/A)-.11 E(CK pack)-.44 E(et,)-.11 E
(as described abo)100.8 332 Q -.165(ve)-.165 G 5.5(.T).165 G
(he requested rate includes an estimate for the transport and IP header)
-5.5 E -.165(ove)100.8 345 S 2.75(rhead. The).165 F(TCP recei)2.75 E
-.165(ve)-.275 G .88 -.44(r, s).165 H
(ay host B, returns the Quick-Start Response option in the).44 E
(TCP header in the responding SYN/A)100.8 358 Q(CK pack)-.44 E(et or A)
-.11 E(CK pack)-.44 E(et, called the Quick-Start)-.11 E(response pack)
100.8 371 Q(et, informing host A of the results of their request.)-.11 E
(If the ackno)100.8 397 Q(wledging pack)-.275 E
(et does not contain a Quick-Start Response, or contains a Quick-)-.11 E
(Start Response with the wrong v)100.8 410 Q(alue for the TTL Dif)-.275
E(f, then host A MUST assume that its)-.275 E(Quick-Start request f)
100.8 423 Q 2.75(ailed. In)-.11 F(this case, host A uses TCP')2.75 E
2.75(sd)-.605 G(ef)-2.75 E(ault congestion control)-.11 E 2.75
(procedure. F)100.8 436 R(or initial start-up, host A uses the def)-.165
E(ault initial congestion windo)-.11 E -.715(w.)-.275 G
(If the returning pack)100.8 462 Q(et contains a v)-.11 E
(alid Quick-Start Response, then host A uses the)-.275 E(information in\
 the response, along with its measurement of the round-trip time, to)
100.8 475 Q(determine the Quick-Start congestion windo)100.8 488 Q 2.75
(w\()-.275 G 2.75(QS-cwnd\). Quick-Start)-2.75 F(pack)2.75 E
(ets are de\214ned)-.11 E(as pack)100.8 501 Q(ets sent as the result of\
 a successful Quick-Start request, up to the time when the)-.11 E
(\214rst Quick-Start pack)100.8 514 Q(et is ackno)-.11 E 2.75
(wledged. In)-.275 F(order to use Quick-Start, the TCP host is also)2.75
E(required to use rate-based pacing to pace out Quick-Start pack)100.8
527 Q(ets at the rate indicated in the)-.11 E(Quick-Start Response.)
100.8 540 Q(The tw)100.8 566 Q 2.75(oT)-.11 G
(CP end-hosts can independently decide whether to request Quick-Start.)
-2.75 E -.165(Fo)5.5 G(r).165 E -.165(ex)100.8 579 S
(ample, host A could sent a Quick-Start Request in the SYN pack).165 E
(et, and host B could also)-.11 E
(send a Quick-Start Request in the SYN/A)100.8 592 Q(CK pack)-.44 E(et.)
-.11 E F1(4.1.)72 631 Q/F3 13/Times-Bold@0 SF(When to Use Quick-Start)
5.5 E F0(In addition to the use of Quick-Start when a connection is est\
ablished, there are se)100.8 657 Q -.165(ve)-.275 G(ral).165 E
(additional points in a connection when a transport protocol may w)100.8
670 Q(ant to issue a Rate)-.11 E 2.75(Request. W)100.8 683 R 2.75<658c>
-.88 G(rst re-iterate the notion that Quick-Start is a coarse-grained m\
echanism.)-2.75 E(That is, Quick-Start')100.8 696 Q 2.75(sR)-.605 G
(ate Requests are not meant to be used for \214ne-grained control of)
-2.75 E(the transport')100.8 709 Q 2.75(ss)-.605 G(ending rate.)-2.75 E
(Rather)5.5 E 2.75(,t)-.44 G
(he transport can issue a Rate Request when no)-2.75 E
(information about the appropriate sending rate is a)100.8 722 Q -.275
(va)-.22 G(ilable, and the def).275 E(ault congestion)-.11 E(Jain/Flo)72
769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(4.1. [P)2.75 F
(age 15])-.165 E 0 Cg EP
%%Page: 16 16
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(control mechanisms might be\
 signi\214cantly underestimating the appropriate sending rate.)100.8 85
Q(The follo)100.8 111 Q
(wing are the potential points where Quick-Start may be useful:)-.275 E
(\(1\) At connection initiation when the transport has no idea of the c\
apacity of the)129.6 140.6 Q(netw)129.6 153.6 Q(ork, as discussed abo)
-.11 E -.165(ve)-.165 G 5.5(.\().165 G 2.75(At)-5.5 G
(ransport that uses TCP Control Block sharing, the)-2.75 E
(Congestion Manager)129.6 166.6 Q 2.75(,o)-.44 G 2.75(rt)-2.75 G(he lik)
-2.75 E 2.75(em)-.11 G(ay not need Quick-Start to determine an)-2.75 E
(appropriate rate.\))129.6 179.6 Q(\(2\) After a length)129.6 209.2 Q
2.75(yi)-.055 G(dle period when the transport no longer has a v)-2.75 E
(alidated estimate)-.275 E(of the a)129.6 222.2 Q -.275(va)-.22 G
(ilable bandwidth for this \215o).275 E -.715(w.)-.275 G
(\(3\) After a host has been e)129.6 251.8 Q
(xplicitly informed that a link in the path has gone do)-.165 E(wn)-.275
E(and has come back up.)129.6 264.8 Q(In this case, the netw)5.5 E
(ork has changed in unkno)-.11 E(wn w)-.275 E(ays and)-.11 E
(the sender has lost its v)129.6 277.8 Q
(alidated assessment of the appropriate sending rate.)-.275 E
(\(4\) After a host has recei)129.6 307.4 Q -.165(ve)-.275 G 2.75(de)
.165 G(xplicit indications that one of the endpoints has mo)-2.915 E
-.165(ve)-.165 G(d).165 E(its point of netw)129.6 320.4 Q
(ork attachment.)-.11 E(This can happen due to some underlying mobility)
5.5 E(mechanism lik)129.6 333.4 Q 2.75(eM)-.11 G
(obile IP [RFC3344,RFC3775].)-2.75 E(Some transports, such as SCTP)5.5 E
([RFC2960], may associate with multiple IP addresses and can switch add\
resses \(and,)129.6 346.4 Q(therefore netw)129.6 359.4 Q
(ork paths\) in mid-connection.)-.11 E
(If the transport has concrete kno)5.5 E(wledge)-.275 E
(of a changing netw)129.6 372.4 Q
(ork path then the current sending rate may not be appropriate and)-.11
E(the transport sender may use Quick-Start to probe the netw)129.6 385.4
Q(ork for the appropriate)-.11 E(rate at which to send.)129.6 398.4 Q
(\(Alternati)5.5 E -.165(ve)-.275 G(ly).165 E 2.75(,t)-.715 G
(raditional slo)-2.75 E 2.75(ws)-.275 G(tart should be used in this)
-2.75 E(case when Quick-Start is not a)129.6 411.4 Q -.275(va)-.22 G
(ilable.\)).275 E(\(5\) After an application-limited period when the se\
nder has been using only a small)129.6 441 Q
(amount of its appropriate share of the netw)129.6 454 Q(ork capacity)
-.11 E 2.75(,a)-.715 G(nd has no v)-2.75 E(alid estimate for)-.275 E
(its f)129.6 467 Q(air share.)-.11 E
(In this case, Quick-Start may be an appropriate mechanism to assess)5.5
E(the a)129.6 480 Q -.275(va)-.22 G(ilable capacity on the netw).275 E
(ork path.)-.11 E(Of the abo)100.8 509.6 Q -.165(ve)-.165 G 2.75(,t).165
G(his document recommends that a TCP MA)-2.75 E 2.75(Ya)-1.155 G
(ttempt to use Quick-Start in)-2.75 E(cases \(1\) and \(2\).)100.8 522.6
Q(Cases \(3\) and \(4\) require e)5.5 E
(xternal noti\214cations not presently de\214ned for)-.165 E
(TCP or other transport protocols.)100.8 535.6 Q
(Case \(5\) requires further thought and in)5.5 E -.165(ve)-.44 G(stig)
.165 E(ation with)-.055 E(re)100.8 548.6 Q -.055(ga)-.165 G(rd to ho)
.055 E 2.75(wt)-.275 G(he transport protocol could detect it w)-2.75 E
(as in a situation that w)-.11 E(ould w)-.11 E(arrant)-.11 E
(transmitting a Quick-Start Rate Request.)100.8 561.6 Q(Section 4.6 dis\
cusses some of the issues of using Quick-Start at connection initiation\
, and)100.8 587.6 Q(Section 4.7 discusses issues that arise when Quick-\
Start is used to request a lar)100.8 600.6 Q(ger sending)-.198 E
(rate after an idle period.)100.8 613.6 Q/F1 11/Times-Bold@0 SF(4.2.)72
652.6 Q/F2 13/Times-Bold@0 SF
(The Quick-Start Response Option in the TCP header)5.5 E F0(TCP')100.8
678.6 Q 2.75(sQ)-.605 G
(uick-Start Response option is de\214ned as follo)-2.75 E(ws:)-.275 E
(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75
(4.2. [P)2.75 F(age 16])-.165 E 0 Cg EP
%%Page: 17 17
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 27.5(0123)122.8 85 S
(+----------+----------+----------+----------+)109.05 98 Q 5.5(|K)109.05
111 S 8.25(ind |)-5.5 F(Length=4 |)2.75 E 8.25(Rate |)5.5 F 8.25(TTL |)
8.25 F 27.5(|||)109.05 124 S 2.75(Request |)-24.75 F(Dif)8.25 E 8.25(f|)
-.275 G(+----------+----------+----------+----------+)109.05 137 Q
(Figure 2.)109.05 163 Q
(The Quick-Start Response option in the TCP header)5.5 E(.)-.605 E(The \
\214rst byte of the Quick-Start Response option contains the option kin\
d, identifying the)100.8 189 Q(TCP option \(to be assigned by IAN)100.8
202 Q(A\).)-.385 E(The second byte of the Quick-Start Response option c\
ontains the option length in bytes.)100.8 228 Q
(The length \214eld is set to four bytes.)100.8 241 Q
(The third byte of the Quick-Start Response option contains the allo)
100.8 267 Q(wed Rate Request,)-.275 E
(formatted as in the Quick-Start Request option.)100.8 280 Q
(The fourth byte of the TCP option contains the TTL Dif)100.8 306 Q 2.75
(f. The)-.275 F(TTL Dif)2.75 E 2.75(fc)-.275 G(ontains the)-2.75 E(dif)
100.8 319 Q(ference between the IP TTL and QS TTL \214elds in the recei)
-.275 E -.165(ve)-.275 G 2.75(dQ).165 G(uick-Start request)-2.75 E(pack)
100.8 332 Q(et, as calculated in equation \(1\).)-.11 E/F1 11
/Times-Bold@0 SF(4.3.)72 371 Q/F2 13/Times-Bold@0 SF
(TCP: Sending the Quick-Start Response)5.5 E F0
(An end host, say host B, that recei)100.8 397 Q -.165(ve)-.275 G 2.75
(saT).165 G(CP pack)-2.75 E(et containing a Quick-Start Request)-.11 E
(passes the Quick-Start Request, along with the v)100.8 410 Q
(alue in the IP TTL \214eld, to the recei)-.275 E(ving)-.275 E
(TCP layer)100.8 423 Q(.)-.605 E(If the TCP host is willing to permit t\
he Quick-Start Request, then a Quick-Start Response)100.8 449 Q
(option is included in the TCP header of the corresponding ackno)100.8
462 Q(wledgement pack)-.275 E 2.75(et. The)-.11 F
(Rate Request in the Quick-Start Response option is set to the recei)
100.8 475 Q -.165(ve)-.275 G 2.75(dv).165 G(alue of the Rate)-3.025 E
(Request in the Quick-Start Request option, or to a lo)100.8 488 Q
(wer v)-.275 E(alue if the TCP recei)-.275 E -.165(ve)-.275 G 2.75(ri)
.165 G 2.75(so)-2.75 G(nly)-2.75 E(willing to allo)100.8 501 Q 2.75(wal)
-.275 G -.275(ow)-2.75 G(er Rate Request.).275 E(The TTL Dif)5.5 E 2.75
(fi)-.275 G 2.75(nt)-2.75 G(he Quick-Start Response is set to)-2.75 E
(the dif)100.8 514 Q(ference between the IP TTL v)-.275 E
(alue and the QS TTL v)-.275 E(alue as gi)-.275 E -.165(ve)-.275 G 2.75
(ni).165 G 2.75(ne)-2.75 G(quation \(1\).)-2.75 E
(When the Quick-Start Response is being sent on the SYN/A)100.8 540 Q
(CK, in response to a Quick-)-.44 E(Start Request on the SYN, then the \
Quick-Start Response will be resent if the SYN/A)100.8 553 Q(CK is)-.44
E 2.75(retransmitted. When)100.8 566 R
(the Quick-Start Response is being sent on an A)2.75 E(CK, for e)-.44 E
(xample in)-.165 E(response to the Quick-Start Request on the SYN/A)
100.8 579 Q(CK, then the Quick-Start Response)-.44 E
(MUST be resent on data pack)100.8 592 Q(ets until that TCP host recei)
-.11 E -.165(ve)-.275 G 2.75(sa).165 G 2.75(na)-2.75 G(ckno)-2.75 E
(wledgement from)-.275 E(the other endpoint.)100.8 605 Q F1(4.4.)72 644
Q F2(TCP: Recei)5.5 E(ving and Using the Quick-Start Response P)-.13 E
(ack)-.13 E(et)-.13 E F0 2.75(AT)100.8 670 S
(CP host, say TCP host A, that sent a Quick-Start Request and recei)
-2.75 E -.165(ve)-.275 G 2.75(sa).165 G 2.75(na)-2.75 G(nswering)-2.75 E
(Quick-Start Response in the ackno)100.8 683 Q
(wledgement \214rst checks that the Quick-Start Response)-.275 E(is v)
100.8 696 Q 2.75(alid. The)-.275 F(Quick-Start Response is v)2.75 E
(alid if it contains the correct v)-.275 E(alue for the TTL Dif)-.275 E
(f,)-.275 E(and an equal or lesser v)100.8 709 Q
(alue for the Rate Request than that transmitted in the Quick-Start)
-.275 E 2.75(Request. If)100.8 722 R
(this check is not successful, then the Quick-Start request f)2.75 E
(ailed, and the TCP)-.11 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(4.4. [P)2.75 F(age 17])-.165 E
0 Cg EP
%%Page: 18 18
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(host MUST use the def)100.8
85 Q(ault TCP congestion windo)-.11 E 2.75(wt)-.275 G(hat it w)-2.75 E
(ould ha)-.11 E .33 -.165(ve u)-.22 H(sed without).165 E(Quick-Start.)
100.8 98 Q(If the checks of the TTL Dif)100.8 124 Q 2.75(fa)-.275 G
(nd the Rate Request are successful, then the TCP host sets)-2.75 E
(its Quick-Start congestion windo)100.8 137 Q 2.75(w\()-.275 G
(in terms of MSS-sized se)-2.75 E(gments\), QS-cwnd, as)-.165 E(follo)
100.8 150 Q(ws:)-.275 E(QS-cwnd = \(R * T\) / \(MSS + H\))100.8 176 Q
(\(2\))88 E(where R the Rate Request in bytes per second, T the measure\
d round-trip time in seconds,)100.8 202 Q
(and H the estimated header size in bytes \(e.g., 40 bytes\).)100.8 215
Q([Deri)5.5 E -.275(va)-.275 G(tion: the sender gets R).275 E
(bytes per second including pack)100.8 228 Q(et headers, b)-.11 E
(ut only R*MSS/\(MSS+H\) bytes per second, or)-.22 E(equi)100.8 241 Q
-.275(va)-.275 G(lently R*T*MSS/\(MSS+H\) bytes per round-trip time, of\
 application data.]).275 E(The TCP)5.5 E(host sets its congestion windo)
100.8 254 Q 2.75(wc)-.275 G
(wnd to QS-cwnd only if QS-cwnd is greater than cwnd;)-2.75 E
(otherwise QS-cwnd is ignored.)100.8 267 Q
(If QS-cwnd is used, the TCP host sets a \215ag that it is in)5.5 E(Qui\
ck-Start mode, and while in Quick-Start mode the TCP sender uses rate-b\
ased pacing,)100.8 280 Q(pacing out Quick-Start pack)100.8 293 Q
(ets at the speci\214ed Rate Request.)-.11 E(Quick-Start mode ends when)
5.5 E(the TCP host recei)100.8 306 Q -.165(ve)-.275 G 2.75(sa).165 G
2.75(nA)-2.75 G(CK for one of the Quick-Start pack)-3.19 E(ets.)-.11 E
(Because the Quick-Start request pack)100.8 332 Q(et might not ha)-.11 E
.33 -.165(ve u)-.22 H(sed the f).165 E(ast path in routers, the)-.11 E(\
round-trip time measurement for the Quick-Start request might be unnece\
ssarily lar)100.8 345 Q 2.75(ge. If)-.198 F(the congestion windo)100.8
358 Q 2.75(wh)-.275 G(as not been fully used when the \214rst ack arri)
-2.75 E -.165(ve)-.275 G 2.75(se).165 G(nding the Quick-)-2.75 E
(Start mode, then the congestion windo)100.8 371 Q 2.75(wi)-.275 G 2.75
(sd)-2.75 G(ecreased to the amount that has actually been)-2.75 E
(used so f)100.8 384 Q(ar)-.11 E 5.5(.T)-.605 G
(his should address the problem of an o)-5.5 E -.165(ve)-.165 G(rly-lar)
.165 E(ge congestion windo)-.198 E 2.75(wf)-.275 G(rom)-2.75 E(an o)
100.8 397 Q -.165(ve)-.165 G(rly-lar).165 E
(ge measurement of the round-trip time.)-.198 E
(If the Quick-Start mode ends with all Quick-Start pack)100.8 423 Q
(ets being successfully)-.11 E(ackno)100.8 436 Q
(wledged, the TCP sender returns to using the def)-.275 E
(ault congestion control mechanisms.)-.11 E(After all the pack)100.8 449
Q(ets are ackno)-.11 E
(wledged from a Quick-Start request for an initial windo)-.275 E -.715
(w,)-.275 G(for e)100.8 462 Q(xample, the TCP sender remains in slo)
-.165 E(w-start, if permitted by ssthresh, continuing to)-.275 E
(increase its congestion windo)100.8 475 Q 2.75(wr)-.275 G
(ather aggressi)-2.75 E -.165(ve)-.275 G
(ly from one round-trip time to the ne).165 E(xt.)-.165 E 1.76 -.88
(To a)100.8 488 T(dd rob).88 E
(ustness, the TCP sender is required to use Limited Slo)-.22 E
(w-Start along with Quick-)-.275 E 2.75(Start. W)100.8 501 R
(ith Limited Slo)-.44 E
(w-Start, the TCP sender limits the number of pack)-.275 E
(ets by which the)-.11 E(congestion windo)100.8 514 Q 2.75(wi)-.275 G
2.75(si)-2.75 G(ncreased for one windo)-2.75 E 2.75(wo)-.275 G 2.75(fd)
-2.75 G(ata during slo)-2.75 E(w-start [F04].)-.275 E/F1 11/Times-Bold@0
SF(4.5.)72 553 Q/F2 13/Times-Bold@0 SF
(TCP: Responding to a Loss of a Quick-Start P)5.5 E(ack)-.13 E(et)-.13 E
F0 -.165(Fo)100.8 579 S 2.75(rT).165 G(CP)-2.75 E 2.75(,w)-1.221 G 2.75
(eh)-2.75 G -2.475 -.22(av e)-2.75 H(de\214ned a `)2.97 E
(`Quick-Start pack)-.814 E(et')-.11 E 2.75('a)-.814 G 2.75(so)-2.75 G
(ne of the pack)-2.75 E(ets sent in the windo)-.11 E(w)-.275 E
(immediately follo)100.8 592 Q(wing a successful Quick-Start request.)
-.275 E(After detecting the loss of a)5.5 E(Quick-Start pack)100.8 605 Q
(et, TCP MUST re)-.11 E -.165(ve)-.275 G(rt to the def).165 E
(ault congestion control procedures that)-.11 E -.11(wo)100.8 618 S
(uld ha).11 E .33 -.165(ve b)-.22 H
(een used if the Quick-Start request had not been appro).165 E -.165(ve)
-.165 G 2.75(d. F).165 F(or e)-.165 E(xample, if)-.165 E
(Quick-Start is used for setting the initial windo)100.8 631 Q 1.43
-.715(w, a)-.275 H(nd a pack).715 E(et from the initial windo)-.11 E
2.75(wi)-.275 G(s)-2.75 E(lost, then the TCP sender must then slo)100.8
644 Q(w-start with the def)-.275 E(ault initial windo)-.11 E 2.75(wt)
-.275 G(hat w)-2.75 E(ould)-.11 E(ha)100.8 657 Q .33 -.165(ve b)-.22 H
(een used if Quick-Start had not been used.).165 E(In addition to re)5.5
E -.165(ve)-.275 G(rting to the def).165 E(ault)-.11 E
(congestion control mechanisms, the sender must tak)100.8 670 Q 2.75(ei)
-.11 G(nto account that the Quick-Start)-2.75 E(congestion windo)100.8
683 Q 2.75(ww)-.275 G(as too lar)-2.86 E 2.75(ge. Thus,)-.198 F
(the sender should decrease ssthresh to at most)2.75 E
(half the number of Quick-Start pack)100.8 696 Q
(ets that were successfully transmitted.)-.11 E(Section A.5)5.5 E
(discusses possible alternati)100.8 709 Q -.165(ve)-.275 G 2.75(si).165
G 2.75(nr)-2.75 G(esponding to the loss of a Quick-Start pack)-2.75 E
(et.)-.11 E(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F
2.75(4.5. [P)2.75 F(age 18])-.165 E 0 Cg EP
%%Page: 19 19
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(4.6.)
72 85 Q/F2 13/Times-Bold@0 SF(TCP: A Quick-Start Request f)5.5 E
(or a Lar)-.325 E(ger Initial W)-.13 E(indo)-.234 E(w)-.13 E F0(Some of\
 the issues of using Quick-Start are related to the speci\214c scenario\
 in which Quick-)100.8 111 Q(Start is used.)100.8 124 Q
(This section discusses the follo)5.5 E
(wing issues that arise when Quick-Start is)-.275 E
(used by TCP to request a lar)100.8 137 Q(ger initial windo)-.198 E
(w: \(1\) determining the rate to request; \(2\))-.275 E
(interactions with P)100.8 150 Q(ath MTU Disco)-.165 E -.165(ve)-.165 G
(ry; and \(3\) Quick-Start request pack).165 E(ets that are eaten)-.11 E
(by middlebox)100.8 163 Q(es.)-.165 E
(\(1\) Determining the rate to request:)100.8 189 Q
(As discussed in [SAF05], the data sender does not necessarily ha)100.8
202 Q .33 -.165(ve i)-.22 H(nformation about the).165 E
(size of the data transfer at connection initiation; for e)100.8 215 Q
(xample, in request-response protocols)-.165 E(such as HTTP)100.8 228 Q
2.75(,t)-1.221 G(he serv)-2.75 E(er doesn')-.165 E 2.75(tk)-.198 G(no)
-2.75 E 2.75(wt)-.275 G(he size or name of the requested object during)
-2.75 E(connection initiation.)100.8 241 Q([SAF05] e)5.5 E
(xplores some of the performance implications of o)-.165 E -.165(ve)
-.165 G(rly-).165 E(lar)100.8 254 Q(ge Quick-Start requests, and discus\
ses heuristics that end-nodes could use to size their)-.198 E
(requests appropriately)100.8 267 Q(.)-.715 E
(In the absence of other information, there could be a con\214gured v)
100.8 293 Q(alue for the Quick-Start)-.275 E(Rate Request.)100.8 306 Q
(Quick-Start will be more ef)5.5 E(fecti)-.275 E .33 -.165(ve i)-.275 H
2.75(fQ).165 G(uick-Start requests are not lar)-2.75 E(ger than)-.198 E
2.75(necessary; e)100.8 319 R -.165(ve)-.275 G
(ry Quick-Start request that is appro).165 E -.165(ve)-.165 G 2.75(db)
.165 G(ut not used tak)-2.97 E(es a)-.11 E -.11(wa)-.165 G 2.75(yf).11 G
(rom the)-2.75 E(bandwidth pool a)100.8 332 Q -.275(va)-.22 G
(ilable for granting successi).275 E .33 -.165(ve Q)-.275 H
(uick-Start requests.).165 E(Therefore, it is)5.5 E
(recommended that the request for the initial sending rate be some)100.8
345 Q(what conserv)-.275 E(ati)-.275 E -.165(ve)-.275 G 2.75(,i).165 G
(n)-2.75 E(order to impro)100.8 358 Q .33 -.165(ve t)-.165 H
(he chances for more Quick-Start requests to be appro).165 E -.165(ve)
-.165 G(d.).165 E(\(2\) Interactions with P)100.8 384 Q(ath MTU Disco)
-.165 E -.165(ve)-.165 G(ry:).165 E 2.75(As)100.8 397 S
(econd issue when Quick-Start is used to request a lar)-2.75 E
(ge initial windo)-.198 E 2.75(wc)-.275 G(oncerns the)-2.75 E
(interactions between the lar)100.8 410 Q(ge initial windo)-.198 E 2.75
(wa)-.275 G(nd P)-2.75 E(ath MTU Disco)-.165 E -.165(ve)-.165 G(ry).165
E 5.5(.S)-.715 G(ome of the issues)-5.5 E(are discussed in RFC 3390:)
100.8 423 Q("When lar)129.6 452.6 Q(ger initial windo)-.198 E
(ws are implemented along with P)-.275 E(ath MTU Disco)-.165 E -.165(ve)
-.165 G(ry).165 E([RFC1191], alternati)129.6 465.6 Q -.165(ve)-.275 G
2.75(sa).165 G(re to set the "Don')-2.75 E 2.75(tF)-.198 G
(ragment" \(DF\) bit in all se)-2.75 E(gments in)-.165 E
(the initial windo)129.6 478.6 Q 1.43 -.715(w, o)-.275 H 2.75(rt).715 G
2.75(os)-2.75 G(et the "Don')-2.75 E 2.75(tF)-.198 G
(ragment" \(DF\) bit in one of the se)-2.75 E 2.75(gments. It)-.165 F
(is an open question as to which of these tw)129.6 491.6 Q 2.75(oa)-.11
G(lternati)-2.75 E -.165(ve)-.275 G 2.75(si).165 G 2.75(sb)-2.75 G
(est.")-2.75 E(Unfortunately)100.8 508.2 Q 2.75(,t)-.715 G
(he sender doesn')-2.75 E 2.75(tn)-.198 G(ecessarily kno)-2.75 E 2.75
(wt)-.275 G(he P)-2.75 E(ath MTU when it sends pack)-.165 E(ets in)-.11
E(the initial windo)100.8 521.2 Q 4.18 -.715(w. T)-.275 H
(he sender should be conserv).715 E(ati)-.275 E .33 -.165(ve i)-.275 H
2.75(nt).165 G(he pack)-2.75 E(et size used.)-.11 E(Sending a)5.5 E(lar)
100.8 534.2 Q(ge number of o)-.198 E -.165(ve)-.165 G(rly-lar).165 E
(ge pack)-.198 E(ets with the DF bit set is not desirable, b)-.11 E
(ut sending a)-.22 E(lar)100.8 547.2 Q(ge number of pack)-.198 E
(ets that are fragmented in the netw)-.11 E
(ork can be equally undesirable.)-.11 E(One possibility w)100.8 573.2 Q
(ould be for the sender to delay using the appro)-.11 E -.165(ve)-.165 G
2.75(dr).165 G(ate request for one)-2.75 E
(round-trip time, while it sends a small number of pack)100.8 586.2 Q
(ets to do P)-.11 E(ath MTU Disco)-.165 E -.165(ve)-.165 G(ry).165 E(.)
-.715 E(While delaying the use of an appro)100.8 599.2 Q -.165(ve)-.165
G 2.75(dr).165 G(ate request inde\214nitely is not acceptable, delaying)
-2.75 E(the use for one round-trip time is within the bounds of accepta\
ble beha)100.8 612.2 Q(vior)-.22 E(.)-.605 E
(In the future, it might be possible for the TCP SYN pack)100.8 638.2 Q
(et to do a probe about the P)-.11 E(ath)-.165 E 2.75(MTU. F)100.8 651.2
R(or e)-.165 E(xample, [W03] has proposed an IP Option that queries rou\
ters for their MTU)-.165 E(before starting a P)100.8 664.2 Q
(ath MTU Disco)-.165 E -.165(ve)-.165 G(ry process.).165 E
(\(3\) Quick-Start request pack)100.8 690.2 Q
(ets that are eaten by middlebox)-.11 E(es:)-.165 E(It is al)100.8 703.2
Q -.11(wa)-.11 G(ys possible for a TCP SYN pack).11 E
(et carrying a Quick-Start request to be dropped in)-.11 E(the netw)
100.8 716.2 Q(ork due to congestion, or to be block)-.11 E
(ed due to interactions with middlebox)-.11 E(es.)-.165 E(Jain/Flo)72
769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(4.6. [P)2.75 F
(age 19])-.165 E 0 Cg EP
%%Page: 20 20
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(Measurement studies of inte\
ractions between transport protocols and middlebox)100.8 85 Q(es)-.165 E
([MAF04] sho)100.8 98 Q 2.75(wt)-.275 G(hat for 70% of the web serv)
-2.75 E(ers in)-.165 E -.165(ve)-.44 G(stig).165 E
(ated, no connection is established if)-.055 E(the TCP SYN pack)100.8
111 Q(et contains an unkno)-.11 E
(wn IP option \(and for 43% of the web serv)-.275 E(ers, no)-.165 E
(connection is established if the TCP SYN pack)100.8 124 Q
(et contains an IP T)-.11 E(imeStamp Option\).)-.385 E(In)5.5 E
(both cases, this is presumably due to middlebox)100.8 137 Q
(es along that path.)-.165 E(If the TCP sender doesn')100.8 163 Q 2.75
(tr)-.198 G(ecei)-2.75 E .33 -.165(ve a r)-.275 H
(esponse to the SYN or SYN/A).165 E(CK pack)-.44 E(et containing)-.11 E
(the Quick-Start Request, then the TCP sender SHOULD resend the SYN or \
SYN/A)100.8 176 Q(CK)-.44 E(pack)100.8 189 Q
(et without the Quick-Start Request.)-.11 E(Similarly)5.5 E 2.75(,i)
-.715 G 2.75(ft)-2.75 G(he TCP sender recei)-2.75 E -.165(ve)-.275 G
2.75(saT).165 G(CP reset)-2.75 E(in response to the SYN or SYN/A)100.8
202 Q(CK pack)-.44 E(et containing the Quick-Start Request, then the)
-.11 E(TCP sender SHOULD resend the SYN or SYN/A)100.8 215 Q(CK pack)
-.44 E(et without the Quick-Start)-.11 E(Request [RFC3360].)100.8 228 Q
(While RFC 1122 and 2988 recommend that the sender should set the initi\
al R)100.8 254 Q .396 -.198(TO t)-.66 H 2.75(ot).198 G(hree)-2.75 E
(seconds, man)100.8 267 Q 2.75(yT)-.165 G
(CP implementations set the initial R)-2.75 E .396 -.198(TO t)-.66 H
2.75(oo).198 G(ne second.)-2.75 E -.165(Fo)5.5 G 2.75(raT).165 G(CP SYN)
-2.75 E(pack)100.8 280 Q
(et sent with a Quick-Start request, we recommend an R)-.11 E .396 -.198
(TO o)-.66 H 2.75(fo).198 G(ne second, so that the)-2.75 E
(sender can retransmit the SYN pack)100.8 293 Q
(et reasonably promptly if the original TCP SYN pack)-.11 E(et)-.11 E
(is dropped by a middlebox in the netw)100.8 306 Q(ork.)-.11 E 1.76 -.88
(We n)100.8 332 T(ote that if the TCP SYN pack).88 E
(et is using the IP Quick-Start Option for a Quick-Start)-.11 E
(request, and it also using bits in the TCP header to ne)100.8 345 Q
(gotiate ECN-capability with the TCP)-.165 E
(host at the other end, then the drop of a TCP SYN pack)100.8 358 Q
(et could be due to congestion, to a)-.11 E(middlebox dropping the pack)
100.8 371 Q(et because of the IP Option, or because of a middlebox)-.11
E(dropping the pack)100.8 384 Q
(et because of the information in the TCP header ne)-.11 E
(gotiating ECN.)-.165 E(In this)5.5 E
(case, the sender could resend the dropped pack)100.8 397 Q
(et without either the Quick-Start or the ECN)-.11 E 2.75
(requests. Alternately)100.8 410 R 2.75(,t)-.715 G
(he sender could resend the dropped pack)-2.75 E(et with only the ECN)
-.11 E(request in the TCP header)100.8 423 Q 2.75(,r)-.44 G
(esending the TCP SYN pack)-2.75 E(et without either the Quick-Start)
-.11 E(or the ECN requests if the second TCP SYN pack)100.8 436 Q
(et is dropped.)-.11 E(The second choice seems)5.5 E
(reasonable to us, gi)100.8 449 Q -.165(ve)-.275 G 2.75(nt).165 G
(hat a TCP SYN pack)-2.75 E(et today is more lik)-.11 E(ely to be block)
-.11 E(ed due to IP)-.11 E
(Options than due to an ECN request in the TCP header)100.8 462 Q(.)
-.605 E/F1 11/Times-Bold@0 SF(4.7.)72 501 Q/F2 13/Times-Bold@0 SF
(TCP: A Quick-Start Request after an Idle P)5.5 E(eriod)-.26 E F0
(This section discusses the follo)100.8 527 Q
(wing issues that arise when Quick-Start is used by TCP to)-.275 E
(request a lar)100.8 540 Q(ger windo)-.198 E 2.75(wa)-.275 G(fter an id\
le period: \(1\) determining the rate to request; and \(2\) the)-2.75 E
(response if Quick-Start pack)100.8 553 Q(ets are dropped;)-.11 E
(\(1\) Determining the rate to request:)100.8 579 Q
(After an idle period, an easy rule of thumb w)100.8 592 Q
(ould be for the TCP sender to determine the)-.11 E(lar)100.8 605 Q
(gest congestion windo)-.198 E 2.75(wt)-.275 G
(hat the TCP connection achie)-2.75 E -.165(ve)-.275 G 2.75(ds).165 G
(ince the last pack)-2.75 E(et drop, to)-.11 E
(translate this congestion windo)100.8 618 Q 2.75(wt)-.275 G 2.75(oas)
-2.75 G(ending rate, and use this rate in the Quick-Start)-2.75 E
(request after the idle period.)100.8 631 Q
(If the request is granted, then the sender essentially restarts)5.5 E
(with its old congestion windo)100.8 644 Q 2.75(wf)-.275 G
(rom before the idle period.)-2.75 E(The sender should not use Quick-St\
art if the idle period has been less than an R)100.8 670 Q -.198(TO)-.66
G 2.75(,a).198 G(nd the)-2.75 E(congestion windo)100.8 683 Q 2.75(wh)
-.275 G(as not decayed do)-2.75 E(wn to less than half of its v)-.275 E
(alue at the start of the)-.275 E(idle period.)100.8 696 Q
(\(2\) Response if Quick-Start pack)100.8 722 Q(ets are dropped:)-.11 E
(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75
(4.7. [P)2.75 F(age 20])-.165 E 0 Cg EP
%%Page: 21 21
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(If Quick-Start pack)100.8 85
Q(ets are dropped after an idle period, then the sender should re)-.11 E
-.165(ve)-.275 G(rt to half).165 E(of the Quick-Start windo)100.8 98 Q
1.43 -.715(w, o)-.275 H 2.75(rt).715 G 2.75(ot)-2.75 G
(he congestion windo)-2.75 E 2.75(wt)-.275 G(hat the sender w)-2.75 E
(ould ha)-.11 E .33 -.165(ve u)-.22 H(sed if).165 E
(the Quick-Start request had not been appro)100.8 111 Q -.165(ve)-.165 G
(d, whiche).165 E -.165(ve)-.275 G 2.75(ri).165 G 2.75(ss)-2.75 G
(maller)-2.75 E(.)-.605 E 2.75(At)100.8 137 S(echnical question is whet\
her a Quick-Start Request sent in the middle of a connection)-2.75 E
(could carry a data payload.)100.8 150 Q -.165(Fo)5.5 G 2.75(re).165 G
(xample, for TCP)-2.915 E 2.75(,aQ)-1.221 G
(uick-Start Request in the middle of a)-2.75 E
(connection could carry a data payload, or could be in a TCP ackno)100.8
163 Q(wledgement pack)-.275 E 2.75(et. Is)-.11 F(there an)100.8 176 Q
2.75(ya)-.165 G(dvice in this re)-2.75 E -.055(ga)-.165 G
(rd that should be of).055 E(fered to the transport protocol?)-.275 E/F1
11/Times-Bold@0 SF(4.8.)72 215 Q/F2 13/Times-Bold@0 SF
(An Example Quick-Start Scenario with TCP)5.5 E F0(The follo)100.8 241 Q
(wing is an e)-.275 E
(xample scenario in the case when both hosts request Quick-Start for)
-.165 E(setting their initial windo)100.8 254 Q(ws:)-.275 E 2.75(*T)
100.8 280 S(he TCP SYN pack)-2.75 E
(et from Host A contains a Quick-Start Request in the IP header)-.11 E
(.)-.605 E 2.75(*R)100.8 306 S(outers along the forw)-2.75 E
(ard path modify the Quick-Start Request as appropriate.)-.11 E 2.75(*H)
100.8 332 S(ost B recei)-2.75 E -.165(ve)-.275 G 2.75(st).165 G
(he Quick-Start Request in the SYN pack)-2.75 E
(et, and calculates the TTL Dif)-.11 E(f.)-.275 E(If Host B appro)100.8
345 Q -.165(ve)-.165 G 2.75(st).165 G
(he Quick-Start Request, then Host B sends a Quick-Start Response in)
-2.75 E(the TCP header of the SYN/A)100.8 358 Q(CK pack)-.44 E 2.75
(et. Host)-.11 F 2.75(Ba)2.75 G(lso sends a Quick-Start Request in the)
-2.75 E(IP header of the SYN/A)100.8 371 Q(CK pack)-.44 E(et.)-.11 E
2.75(*R)100.8 397 S(outers along the re)-2.75 E -.165(ve)-.275 G
(rse path modify the Quick-Start Request as appropriate.).165 E 2.75(*H)
100.8 423 S(ost A recei)-2.75 E -.165(ve)-.275 G 2.75(st).165 G
(he Quick-Start Response in the SYN/A)-2.75 E(CK pack)-.44 E
(et, and checks the TTL)-.11 E(Dif)100.8 436 Q 2.75(fa)-.275 G
(nd Rate Request for v)-2.75 E(alidity)-.275 E 5.5(.I)-.715 G 2.75(ft)
-5.5 G(he)-2.75 E 2.75(ya)-.165 G(re v)-2.75 E
(alid, then Host A sets its initial congestion)-.275 E(windo)100.8 449 Q
2.75(wa)-.275 G(ppropriately)-2.75 E 2.75(,a)-.715 G
(nd sets up rate-based pacing to be used with the initial windo)-2.75 E
4.18 -.715(w. I)-.275 H(f).715 E(the Quick-Start Response is not v)100.8
462 Q(alid, then Host A uses TCP')-.275 E 2.75(sd)-.605 G(ef)-2.75 E
(ault initial windo)-.11 E -.715(w.)-.275 G
(Host A also calculates the TTL Dif)100.8 488 Q 2.75(ff)-.275 G
(or the Quick-Start Request in the incoming)-2.75 E(SYN/A)100.8 501 Q
(CK pack)-.44 E
(et, and sends a Quick-Start Response in the TCP header of the A)-.11 E
(CK)-.44 E(pack)100.8 514 Q(et.)-.11 E 2.75(*H)100.8 540 S
(ost A repeats sending the Quick-Start Response in data pack)-2.75 E
(ets at least once per round-)-.11 E(trip time until it recei)100.8 553
Q -.165(ve)-.275 G 2.75(sa).165 G 2.75(na)-2.75 G(ckno)-2.75 E
(wledgement from Host B for one of those data pack)-.275 E(ets.)-.11 E
2.75(*H)100.8 579 S(ost B recei)-2.75 E -.165(ve)-.275 G 2.75(st).165 G
(he Quick-Start Response in an A)-2.75 E(CK pack)-.44 E
(et, and checks the TTL Dif)-.11 E(f)-.275 E(and Rate Request for v)
100.8 592 Q(alidity)-.275 E 5.5(.I)-.715 G 2.75(ft)-5.5 G
(he Quick-Start Response is v)-2.75 E(alid, then Host B sets its)-.275 E
(initial congestion windo)100.8 605 Q 2.75(wa)-.275 G(ppropriately)-2.75
E 2.75(,a)-.715 G(nd sets up rate-based pacing to be used with its)-2.75
E(initial windo)100.8 618 Q 4.18 -.715(w. I)-.275 H 2.75(ft).715 G
(he Quick-Start Response is not v)-2.75 E(alid, then Host B uses TCP')
-.275 E 2.75(sd)-.605 G(ef)-2.75 E(ault)-.11 E(initial windo)100.8 631 Q
-.715(w.)-.275 G F1(5.)72 670 Q/F3 14/Times-Bold@0 SF
(The Quick-Start Mechanism in other T)5.5 E(ransport Pr)-1.036 E
(otocols)-.252 E F0
(The section earlier speci\214ed the use of Quick-Start in TCP)100.8 696
Q 5.5(.I)-1.221 G 2.75(nt)-5.5 G(his section, we generalize)-2.75 E
(this to gi)100.8 709 Q .33 -.165(ve g)-.275 H
(uidelines for the use of Quick-Start with other transport protocols.)
.165 E 1.76 -.88(We a)5.5 H(lso).88 E(discuss brie\215y ho)100.8 722 Q
2.75(wQ)-.275 G
(uick-Start could be speci\214ed for other transport protocols.)-2.75 E
(Jain/Flo)72 769 Q 212.275(yd/Allman/Sarolahti Section)-.11 F 2.75
(5. [P)2.75 F(age 21])-.165 E 0 Cg EP
%%Page: 22 22
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(The general guidelines for \
Quick-Start in transport protocols are as follo)100.8 85 Q(ws:)-.275 E
2.75(*Q)100.8 111 S(uick-Start is only speci\214ed for unicast transpor\
t protocols with appropriate congestion)-2.75 E(control mechanisms.)
100.8 124 Q 2.75(*At)100.8 150 S(ransport-le)-2.75 E -.165(ve)-.275 G
2.75(lm).165 G
(echanism is needed for the Quick-Start response from the recei)-2.75 E
-.165(ve)-.275 G 2.75(rt).165 G(o)-2.75 E(the sender)100.8 163 Q 5.5(.T)
-.605 G(his response contains the Rate Request and the TTL Dif)-5.5 E
2.75(f. The)-.275 F(Quick-Start)2.75 E
(response should ideally be sent reliably)100.8 176 Q(.)-.715 E 2.75(*T)
100.8 202 S(he sender checks the v)-2.75 E
(alidity of the Quick-Start response.)-.275 E 2.75(*T)100.8 228 S(he se\
nder has an estimate of the round-trip time, and translates the Quick-S\
tart response)-2.75 E(into an allo)100.8 241 Q(wed windo)-.275 E 2.75
(wo)-.275 G 2.75(ra)-2.75 G(llo)-2.75 E(wed sending rate.)-.275 E
(The sender starts sending Quick-Start)5.5 E(pack)100.8 254 Q
(ets, rate-paced out at the appro)-.11 E -.165(ve)-.165 G 2.75(ds).165 G
(ending rate.)-2.75 E 2.75(*A)100.8 280 S(fter the sender recei)-2.75 E
-.165(ve)-.275 G 2.75(st).165 G(he \214rst ackno)-2.75 E
(wledgement pack)-.275 E(et for a Quick-Start pack)-.11 E(et, no)-.11 E
(more Quick-Start pack)100.8 293 Q(ets are sent.)-.11 E
(The sender adjusts its current congestion windo)5.5 E 2.75(wo)-.275 G
(r)-2.75 E
(sending rate to be consistent with the actual amount of data that w)
100.8 306 Q(as transmitted in that)-.11 E(round-trip time.)100.8 319 Q
2.75(*W)100.8 345 S(hen the last Quick-Start pack)-2.75 E(et is ackno)
-.11 E(wledged, the sender continues using the)-.275 E
(standard congestion control mechanisms of that protocol.)100.8 358 Q
2.75(*I)100.8 384 S 2.75(fo)-2.75 G(ne of the Quick-Start pack)-2.75 E
(ets is lost, then the sender re)-.11 E -.165(ve)-.275 G
(rts to the standard congestion).165 E
(control method of that protocol that w)100.8 397 Q(ould ha)-.11 E .33
-.165(ve b)-.22 H(een used if the Quick-Start request had).165 E
(not been appro)100.8 410 Q -.165(ve)-.165 G 2.75(d. In).165 F
(addition, the sender tak)2.75 E
(es into account the information that the)-.11 E
(Quick-Start congestion windo)100.8 423 Q 2.75(ww)-.275 G(as too lar)
-2.86 E(ge \(e.g., by decreasing ssthresh in TCP\).)-.198 E/F1 11
/Times-Bold@0 SF(5.1.)72 462 Q/F2 13/Times-Bold@0 SF
(Quick-Start with DCCP)5.5 E F0(DCCP is a ne)100.8 488 Q 2.75(wt)-.275 G
(ransport protocol for congestion-controlled, unreliable datagrams,)
-2.75 E
(intended for applications such as streaming media, Internet telephon)
100.8 501 Q 1.43 -.715(y, a)-.165 H(nd on-line g).715 E(ames.)-.055 E
(In DCCP)100.8 514 Q 2.75(,t)-1.221 G
(he application has a choice of congestion control mechanisms, with the)
-2.75 E(currently-speci\214ed Congestion Control Identi\214ers \(CCIDs\
\) being CCID 2 for TCP-lik)100.8 527 Q(e)-.11 E(congestion control, an\
d CCID 3 for TFRC, an equation-based form of congestion control.)100.8
540 Q 1.76 -.88(We r)100.8 553 T
(efer the reader to [KHF04] for a more detailed description of DCCP).88
E 2.75(,a)-1.221 G(nd of the)-2.75 E(congestion control mechanisms.)
100.8 566 Q(Because CCID 3 uses a rate-based congestion control mechani\
sm, it raises some ne)100.8 592 Q(w)-.275 E
(issues about the use of Quick-Start with transport protocols.)100.8 605
Q(In this document we don')5.5 E(t)-.198 E
(attempt to specify the use of Quick-Start with DCCP)100.8 618 Q 5.5(.H)
-1.221 G -.275(ow)-5.5 G -2.365 -.275(ev e).275 H .88 -.44(r, w).275 H
2.75(ed).44 G 2.75(od)-2.75 G(iscuss some of the)-2.75 E
(issues that might arise.)100.8 631 Q(In considering the use of Quick-S\
tart with CCID 3 for requesting a higher initial sending)100.8 657 Q
(rate, the follo)100.8 670 Q(wing questions arise: \(1\) ho)-.275 E 2.75
(wd)-.275 G(oes the sender respond if a Quick-Start pack)-2.75 E(et)-.11
E(is dropped; and \(2\) when does the sender determine that there has b\
een no feedback from)100.8 683 Q(the recei)100.8 696 Q -.165(ve)-.275 G
.88 -.44(r, a).165 H(nd reduce the sending rate?).44 E(\(1\) Ho)100.8
722 Q 2.75(wd)-.275 G(oes the sender respond if a Quick-Start pack)-2.75
E(et is dropped:)-.11 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(5.1. [P)2.75 F(age 22])-.165 E
0 Cg EP
%%Page: 23 23
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(As in TCP)100.8 85 Q 2.75
(,i)-1.221 G 2.75(fa)-2.75 G 2.75(ni)-2.75 G(nitial Quick-Start pack)
-2.75 E(et is dropped, the CCID 3 sender should re)-.11 E -.165(ve)-.275
G(rt to).165 E(the congestion control mechanisms it w)100.8 98 Q
(ould ha)-.11 E .33 -.165(ve u)-.22 H
(sed if the Quick-Start request had not).165 E(been appro)100.8 111 Q
-.165(ve)-.165 G(d.).165 E(\(2\) When does the sender decide there has \
been no feedback from the recei)100.8 137 Q -.165(ve)-.275 G(r:).165 E
(Unlik)100.8 150 Q 2.75(eT)-.11 G(CP)-2.75 E 2.75(,C)-1.221 G
(CID 3 does not use ackno)-2.75 E(wledgements for e)-.275 E -.165(ve)
-.275 G(ry pack).165 E(et, or for e)-.11 E -.165(ve)-.275 G(ry other)
.165 E(pack)100.8 163 Q 2.75(et. In)-.11 F(contrast, the CCID 3 recei)
2.75 E -.165(ve)-.275 G 2.75(rs).165 G
(ends feedback to the sender roughly once per)-2.75 E(round-trip time.)
100.8 176 Q(In CCID 3, the allo)5.5 E(wed sending rate is halv)-.275 E
(ed if no feedback is recei)-.165 E -.165(ve)-.275 G(d).165 E
(from the recei)100.8 189 Q -.165(ve)-.275 G 2.75(ri).165 G 2.75(na)
-2.75 G 2.75(tl)-2.75 G
(east four round-trip times \(when the sender is sending at least one)
-2.75 E(pack)100.8 202 Q(et e)-.11 E -.165(ve)-.275 G(ry tw).165 E 2.75
(or)-.11 G(ound-trip times\).)-2.75 E
(When a Quick-Start request is used, it w)5.5 E(ould seem)-.11 E
(prudent to use a smaller time interv)100.8 215 Q
(al, e.g., to reduce the sending rate if no feedback is)-.275 E(recei)
100.8 228 Q -.165(ve)-.275 G 2.75(df).165 G(rom the recei)-2.75 E -.165
(ve)-.275 G 2.75(ri).165 G 2.75(na)-2.75 G 2.75(tl)-2.75 G(east tw)-2.75
E 2.75(or)-.11 G(ound-trip times.)-2.75 E
(The question also arises of ho)100.8 254 Q 2.75(wt)-.275 G
(he sending rate should be reduced after a period of no)-2.75 E
(feedback from the recei)100.8 267 Q -.165(ve)-.275 G 3.96 -.605(r. T)
.165 H(he def).605 E
(ault CCID 3 response of halving the sending rate might)-.11 E
(not be suf)100.8 280 Q(\214cient; an alternati)-.275 E .33 -.165(ve w)
-.275 H(ould be to reduce the sending rate to the sending rate that).055
E -.11(wo)100.8 293 S(uld ha).11 E .33 -.165(ve b)-.22 H
(een used if no Quick-Start request had been appro).165 E -.165(ve)-.165
G 2.75(d. That).165 F(is, if a CCID 3)2.75 E(sender uses a Quick-Start \
request, special rules might be required to handle the sender')100.8 306
Q(s)-.605 E(response to a period of no feedback from the recei)100.8 319
Q -.165(ve)-.275 G 2.75(rr).165 G -2.475 -.165(eg a)-2.75 H
(rding the Quick-Start pack).165 E(ets.)-.11 E(Similarly)100.8 345 Q
2.75(,i)-.715 G 2.75(nc)-2.75 G
(onsidering the use of Quick-Start with CCID 3 for requesting a higher)
-2.75 E(sending rate after an idle period, the follo)100.8 358 Q
(wing questions arise: \(1\) what rate does the)-.275 E(sender request;\
 \(2\) what is the response to a loss; and \(3\) when does the sender d\
etermine)100.8 371 Q(that there has been no feedback from the recei)
100.8 384 Q -.165(ve)-.275 G .88 -.44(r, a).165 H
(nd the sending rate must be reduced?).44 E
(\(1\) What rate does the sender request:)100.8 410 Q(As in TCP)100.8
423 Q 2.75(,t)-1.221 G(here is a straightforw)-2.75 E
(ard answer to the rate request that the CCID 3 sender)-.11 E
(should use in requesting a higher sending rate after an idle period.)
100.8 436 Q(The sender kno)5.5 E(ws the)-.275 E(current loss e)100.8 449
Q -.165(ve)-.275 G(nt rate, either from its o).165 E
(wn calculations or from feedback from the recei)-.275 E -.165(ve)-.275
G -.44(r,).165 G(and can determine the sending rate allo)100.8 462 Q
(wed by that loss e)-.275 E -.165(ve)-.275 G(nt rate.).165 E
(This is the upper bound)5.5 E
(on the sending rate that should be requested by the CCID 3 sender)100.8
475 Q 5.5(.A)-.605 G(Quick-Start request)-2.75 E(is useful with CCID 3 \
when the sender is coming out of an idle or underutilized period,)100.8
488 Q(because in standard operation CCID 3 does not allo)100.8 501 Q
2.75(wt)-.275 G(he sender to send more that twice as)-2.75 E -.11(fa)
100.8 514 S(st as the recei).11 E -.165(ve)-.275 G 2.75(rh).165 G
(as reported recei)-2.75 E -.165(ve)-.275 G 2.75(di).165 G 2.75(nt)-2.75
G(he most recent feedback message.)-2.75 E
(\(2\) What is the response to loss:)100.8 540 Q
(The response to the loss of Quick-Start pack)100.8 553 Q
(ets should be to return to the sending rate that)-.11 E -.11(wo)100.8
566 S(uld ha).11 E .33 -.165(ve b)-.22 H
(een used if Quick-Start had not been requested.).165 E(\(3\) When does\
 the sender decide there has been no feedback from the recei)100.8 592 Q
-.165(ve)-.275 G(r:).165 E
(As in the case of the initial sending rate, it w)100.8 605 Q
(ould seem prudent to reduce the sending rate if)-.11 E
(no feedback is recei)100.8 618 Q -.165(ve)-.275 G 2.75(df).165 G
(rom the recei)-2.75 E -.165(ve)-.275 G 2.75(ri).165 G 2.75(na)-2.75 G
2.75(tl)-2.75 G(east tw)-2.75 E 2.75(or)-.11 G(ound-trip times.)-2.75 E
(It seems lik)5.5 E(ely)-.11 E(that in this case, the sending rate shou\
ld be reduced to the sending rate that w)100.8 631 Q(ould ha)-.11 E
-.165(ve)-.22 G(been used if no Quick-Start request had been appro)100.8
644 Q -.165(ve)-.165 G(d.).165 E/F1 11/Times-Bold@0 SF(6.)72 683 Q/F2 14
/Times-Bold@0 SF(Ev)5.5 E(aluation of Quick-Start)-.14 E F0(Jain/Flo)72
769 Q 212.275(yd/Allman/Sarolahti Section)-.11 F 2.75(6. [P)2.75 F
(age 23])-.165 E 0 Cg EP
%%Page: 24 24
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(6.1.)
72 85 Q/F2 13/Times-Bold@0 SF(Bene\214ts of Quick-Start)5.5 E F0
(The main bene\214t of Quick-Start is the f)100.8 111 Q
(aster start-up for the transport connection itself.)-.11 E -.165(Fo)5.5
G(r).165 E 2.75(as)100.8 124 S(mall TCP transfer of one to \214v)-2.75 E
2.75(ep)-.165 G(ack)-2.75 E(ets, Quick-Start is probably of v)-.11 E
(ery little bene\214t;)-.165 E(at)5.5 E
(best, it might shorten the connection lifetime from three to tw)100.8
137 Q 2.75(or)-.11 G(ound-trip times \(including)-2.75 E
(the round-trip time for connection establishment\).)100.8 150 Q
(Similarly)5.5 E 2.75(,f)-.715 G(or a v)-2.75 E(ery lar)-.165 E
(ge transfer)-.198 E(,)-.44 E(where the slo)100.8 163 Q(w-start phase w)
-.275 E(ould ha)-.11 E .33 -.165(ve b)-.22 H
(een only a small fraction of the connection).165 E
(lifetime, Quick-Start w)100.8 176 Q(ould be of limited bene\214t.)-.11
E(Quick-Start w)5.5 E(ould not signi\214cantly)-.11 E
(shorten the connection lifetime, b)100.8 189 Q
(ut it might eliminate or at least shorten the start-up phase.)-.22 E
(Ho)100.8 202 Q(we)-.275 E -.165(ve)-.275 G .88 -.44(r, f).165 H
(or moderate-sized connections in a well-pro).44 E(visioned en)-.165 E
(vironment, Quick-Start)-.44 E(could allo)100.8 215 Q 2.75(wt)-.275 G
(he entire transfer of M pack)-2.75 E
(ets to be completed in one round-trip time \(after)-.11 E
(the initial round-trip time for the SYN e)100.8 228 Q
(xchange\), instead of the log_2\(M\)-2 round-trip)-.165 E
(times that it w)100.8 241 Q(ould normally for the data transfer)-.11 E
2.75(,i)-.44 G 2.75(na)-2.75 G 2.75(nu)-2.75 G(ncongested en)-2.75 E
(vironments)-.44 E(\(assuming an initial windo)100.8 254 Q 2.75(wo)-.275
G 2.75(ff)-2.75 G(our pack)-2.75 E(ets\).)-.11 E F1(6.2.)72 293 Q F2
(Costs of Quick-Start)5.5 E F0(This section discusses the costs of Quic\
k-Start for the connection and for the routers along)100.8 332 Q
(the path.)100.8 345 Q(The cost of ha)100.8 371 Q
(ving a Quick-Start pack)-.22 E(et dropped:)-.11 E -.165(Fo)100.8 384 S
2.75(rt).165 G(he sender the biggest risk in using Quick-Start lies in \
the possibility of suf)-2.75 E(fering from)-.275 E
(congestion-related losses of the Quick-Start pack)100.8 397 Q 2.75
(ets. This)-.11 F(should be an unlik)2.75 E(ely situation)-.11 E
(because routers are e)100.8 410 Q(xpected to appro)-.165 E .33 -.165
(ve Q)-.165 H(uick-Start Requests only when the).165 E 2.75(ya)-.165 G
(re)-2.75 E(signi\214cantly underutilized. Ho)100.8 423 Q(we)-.275 E
-.165(ve)-.275 G .88 -.44(r, a t).165 H(ransient increase in cross-traf)
.44 E(\214c in one of the)-.275 E(routers, a sudden decrease in a)100.8
436 Q -.275(va)-.22 G
(ilable bandwidth on one of the links, or congestion at a).275 E
(non-IP queue could result in pack)100.8 449 Q(et losses e)-.11 E -.165
(ve)-.275 G 2.75(nw).165 G(hen the Quick-Start Request w)-2.75 E(as)-.11
E(appro)100.8 462 Q -.165(ve)-.165 G 2.75(db).165 G 2.75(ya)-2.75 G
(ll of the routers along the path.)-2.75 E(If a Quick-Start pack)5.5 E
(et is dropped, then the)-.11 E(sender re)100.8 475 Q -.165(ve)-.275 G
(rts to the congestion control mechanisms it w).165 E(ould ha)-.11 E .33
-.165(ve u)-.22 H(sed if the Quick-Start).165 E
(request has not been appro)100.8 488 Q -.165(ve)-.165 G
(d, so the performance cost to the connection of ha).165 E(ving a)-.22 E
(Quick-Start pack)100.8 501 Q
(et dropped is small, compared to the performance without Quick-Start.)
-.11 E(\(On the other hand, the performance dif)100.8 514 Q
(ference between Quick-Start with a Quick-Start)-.275 E(pack)100.8 527 Q
(et dropped and Quick-Start with no Quick-Start pack)-.11 E
(et dropped can be considerable.\))-.11 E(Added comple)100.8 553 Q
(xity at routers:)-.165 E(The main cost of Quick-Start at routers conce\
rns the costs of added comple)100.8 566 Q(xity)-.165 E 5.5(.T)-.715 G
(he added)-5.5 E(comple)100.8 579 Q(xity at the end-points is moderate,\
 and might easily be outweighed by the bene\214t of)-.165 E
(Quick-Start to the end hosts.)100.8 592 Q(The added comple)5.5 E
(xity at the routers is also some)-.165 E(what)-.275 E(moderate; it in)
100.8 605 Q -.22(vo)-.44 G(lv).22 E
(es estimating the unused bandwidth on the output link o)-.165 E -.165
(ve)-.165 G 2.75(rt).165 G(he last)-2.75 E(se)100.8 618 Q -.165(ve)-.275
G(ral seconds, processing the Quick-Start request, and k).165 E
(eeping a counter of the aggre)-.11 E -.055(ga)-.165 G(te).055 E
(Quick-Start rate appro)100.8 631 Q -.165(ve)-.165 G 2.75(do).165 G
-.165(ve)-2.915 G 2.75(rt).165 G(he last fraction of a second.)-2.75 E
(Ho)5.5 E(we)-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(his added).44
E(comple)100.8 644 Q(xity at routers adds to the de)-.165 E -.165(ve)
-.275 G(lopment c).165 E(ycle, and could pre)-.165 E -.165(ve)-.275 G
(nt the addition of).165 E(other competing functionality to routers.)
100.8 657 Q(Thus, careful thought w)5.5 E(ould ha)-.11 E .33 -.165(ve t)
-.22 H 2.75(ob).165 G 2.75(eg)-2.75 G -2.365 -.275(iv e)-2.75 H 2.75(nt)
.275 G(o)-2.75 E(the addition of Quick-Start to IP)100.8 670 Q(.)-1.221
E(The slo)100.8 696 Q 2.75(wp)-.275 G(ath in routers:)-2.75 E
(Another dra)100.8 709 Q(wback of Quick-Start is that pack)-.165 E
(ets containing the Quick-Start Request)-.11 E(message might not tak)
100.8 722 Q 2.75(et)-.11 G(he f)-2.75 E(ast path in routers.)-.11 E
(This w)5.5 E(ould mean e)-.11 E(xtra delay for the end)-.165 E
(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75
(6.2. [P)2.75 F(age 24])-.165 E 0 Cg EP
%%Page: 25 25
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(hosts, and e)100.8 85 Q
(xtra processing b)-.165 E(urden for the routers.)-.22 E(This e)5.5 E
(xtra b)-.165 E(urden is mitig)-.22 E(ated)-.055 E(some)100.8 98 Q
(what by the follo)-.275 E(wing f)-.275 E(actors: only v)-.11 E(ery fe)
-.165 E 2.75(wp)-.275 G(ack)-2.75 E(ets w)-.11 E
(ould carry the Quick-Start)-.11 E(Request option;)100.8 111 Q -.165(ve)
5.5 G(ry small \215o).165 E(ws of, say)-.275 E 2.75(,o)-.715 G
(ne to \214v)-2.75 E 2.75(ep)-.165 G(ack)-2.75 E(ets w)-.11 E
(ould recei)-.11 E .33 -.165(ve l)-.275 H(ittle bene\214t).165 E
(from Quick-Start, and presumably w)100.8 124 Q
(ould not use the Quick-Start Request;)-.11 E<8d6f>5.5 E(ws from end)
-.275 E(hosts with lo)100.8 137 Q(w-bandwidth access links w)-.275 E
(ould recei)-.11 E .33 -.165(ve l)-.275 H
(ittle bene\214t from Quick-Start, and).165 E
(hopefully could be con\214gured not to use the Quick-Start Request.)
100.8 150 Q(In addition, in typical)5.5 E(en)100.8 163 Q
(vironments where most of the pack)-.44 E(ets belong to lar)-.11 E
(ge \215o)-.198 E(ws, the b)-.275 E(urden of the Quick-)-.22 E
(Start Option on routers w)100.8 176 Q(ould be considerably reduced.)
-.11 E(Ne)5.5 E -.165(ve)-.275 G(rtheless, it is still).165 E(concei)
100.8 189 Q -.275(va)-.275 G(ble, in the w).275 E
(orst case, that up to 10% of the pack)-.11 E(ets were Quick-Start pack)
-.11 E(ets, and)-.11 E(this could slo)100.8 202 Q 2.75(wd)-.275 G -.275
(ow)-2.75 G 2.75(nt).275 G(he processing of Quick-Start pack)-2.75 E
(ets in routers considerably)-.11 E 5.5(.I)-.715 G(n)-5.5 E(particular)
100.8 215 Q 2.75(,b)-.44 G(ecause man)-2.75 E 2.75(yQ)-.165 G
(uick-Start pack)-2.75 E(ets are lik)-.11 E(ely to be TCP SYN or SYN/A)
-.11 E(CK)-.44 E(pack)100.8 228 Q(ets, the slo)-.11 E 2.75(wp)-.275 G
(rocessing of Quick-Start pack)-2.75 E(ets w)-.11 E(ould slo)-.11 E 2.75
(wd)-.275 G -.275(ow)-2.75 G 2.75(nt).275 G(he establishment of)-2.75 E
(the corresponding TCP connections.)100.8 241 Q(Multiple paths:)100.8
267 Q
(One limitation of Quick-Start is that it presumes that the data pack)
100.8 280 Q(ets of a connection will)-.11 E(follo)100.8 293 Q 2.75(wt)
-.275 G(he same path as the Quick-Start request pack)-2.75 E 2.75
(et. If)-.11 F(this is not the case, then the)2.75 E
(connection could be sending the Quick-Start pack)100.8 306 Q
(ets, at the appro)-.11 E -.165(ve)-.165 G 2.75(dr).165 G
(ate, along a path that)-2.75 E -.11(wa)100.8 319 S 2.75(sa).11 G(lread\
y congested, or that became congested as a result of this connection.)
-2.75 E(This is,)5.5 E(ho)100.8 332 Q(we)-.275 E -.165(ve)-.275 G .88
-.44(r, s).165 H(imilar to what w).44 E(ould happen if the connection')
-.11 E 2.75(sp)-.605 G(ath w)-2.75 E(as changed in the middle)-.11 E(of\
 the connection, when the connection had already established the allo)
100.8 345 Q(wed initial rate.)-.275 E(Non-IP queues:)100.8 371 Q 2.75
(Ap)100.8 384 S(roblem of an)-2.75 E 2.75(ym)-.165 G
(echanism for feedback from routers at the IP le)-2.75 E -.165(ve)-.275
G 2.75(li).165 G 2.75(st)-2.75 G(hat there can be)-2.75 E
(queues and bottlenecks in the end-to-end path that are not in IP-le)
100.8 397 Q -.165(ve)-.275 G 2.75(lr).165 G 2.75(outers. As)-2.75 F(an)
2.75 E -.165(ex)100.8 410 S(ample, these include queues in layer).165 E
(-tw)-.22 E 2.75(oE)-.11 G(thernet or A)-2.75 E(TM netw)-1.221 E 2.75
(orks. One)-.11 F(possibility)2.75 E -.11(wo)100.8 423 S
(uld be that an IP-le).11 E -.165(ve)-.275 G 2.75(lr).165 G
(outer adjacent to such a non-IP queue or bottleneck w)-2.75 E(ould be)
-.11 E(con\214gured to reject Quick-Start requests if that w)100.8 436 Q
(as appropriate.)-.11 E/F1 11/Times-Bold@0 SF(6.3.)72 475 Q/F2 13
/Times-Bold@0 SF(Pr)5.5 E(otection against Misbeha)-.234 E(ving Nodes)
-.325 E F0(In this section we discuss the protection ag)100.8 501 Q
(ainst recei)-.055 E -.165(ve)-.275 G(rs lying about the Quick-Start)
.165 E(Request, and ag)100.8 514 Q(ainst other possible misbeha)-.055 E
(viors re)-.22 E -.055(ga)-.165 G(rding Quick-Start.).055 E
(First, we note that)5.5 E(it is not necessarily in the recei)100.8 527
Q -.165(ve)-.275 G(r').165 E 2.75(si)-.605 G
(nterest to lie about the Quick-Start Request.)-2.75 E(If the)5.5 E
(sender sends at too-high of an initial rate, and has a pack)100.8 540 Q
(et dropped, this does not impro)-.11 E -.165(ve)-.165 G
(the performance of the connection, relati)100.8 553 Q .33 -.165(ve t)
-.275 H 2.75(ot).165 G(he case when the Quick-Start Request w)-2.75 E
(as)-.11 E(not appro)100.8 566 Q -.165(ve)-.165 G(d.).165 E(Recei)100.8
592 Q -.165(ve)-.275 G(rs lying about whether the request w).165 E
(as appro)-.11 E -.165(ve)-.165 G(d:).165 E
(The use of the Quick-Start TTL initialized by the sender to a random v)
100.8 605 Q(alue mak)-.275 E(es it)-.11 E(dif)100.8 618 Q
(\214cult for the recei)-.275 E -.165(ve)-.275 G 2.75(rt).165 G 2.75(ol)
-2.75 G(ie to the sender about whether the request has been appro)-2.75
E -.165(ve)-.165 G 2.75(db).165 G(y)-2.75 E
(all of the routers along the path.)100.8 631 Q
(If a router that understands the Quick-Start Request)5.5 E(deletes the\
 Request, or zeroes the QS TTL in the request, then the chances of a do)
100.8 644 Q(wnstream)-.275 E(router or misbeha)100.8 657 Q(ving recei)
-.22 E -.165(ve)-.275 G 2.75(rg).165 G(uessing the v)-2.75 E
(alue of the QS TTL is at most 1/256.)-.275 E(In particular)100.8 683 Q
2.75(,i)-.44 G 2.75(far)-2.75 G
(outer deletes the Quick-Start Request, it is unlik)-2.75 E
(ely that the recei)-.11 E -.165(ve)-.275 G(r).165 E -.11(wo)100.8 696 S
(uld be able to send a v).11 E
(alid Quick-Start Response back to the sender)-.275 E 5.5(.S)-.605 G
(imilarly)-5.5 E 2.75(,i)-.715 G 2.75(ft)-2.75 G(here)-2.75 E
(are routers along the path that do not understand or appro)100.8 709 Q
.33 -.165(ve o)-.165 H 2.75(ft).165 G(he Quick-Start Request,)-2.75 E
(and that forw)100.8 722 Q(ard the Quick-Start Request unchanged, it w)
-.11 E(ould be not be easy for a)-.11 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(6.3. [P)2.75 F(age 25])-.165 E
0 Cg EP
%%Page: 26 26
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(do)100.8 85 Q
(wnstream router or the recei)-.275 E -.165(ve)-.275 G 2.75(rt).165 G
2.75(oc)-2.75 G(heat and modify the QS TTL \214eld so that the request)
-2.75 E -.11(wa)100.8 98 S 2.75(sc).11 G(onsidered v)-2.75 E
(alid, because the do)-.275 E(wnstream routers do not kno)-.275 E 2.75
(wt)-.275 G(he initial v)-2.75 E(alue for the)-.275 E(QS TTL.)100.8 111
Q(Recei)100.8 137 Q -.165(ve)-.275 G(rs lying about the rate request:)
.165 E(The recei)100.8 150 Q -.165(ve)-.275 G 2.75(rc).165 G
(ould lie to the sender about the Rate Request in the recei)-2.75 E
-.165(ve)-.275 G 2.75(dQ).165 G(uick-Start)-2.75 E 2.75(Request. Ho)
100.8 163 R(we)-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(he recei)
.44 E -.165(ve)-.275 G 2.75(rd).165 G(oesn')-2.75 E 2.75(tk)-.198 G(no)
-2.75 E 2.75(wt)-.275 G(he Rate Request in the original Quick-Start)
-2.75 E(Request sent by the sender)100.8 176 Q 2.75(,a)-.44 G
(nd a higher Rate Request reported by the recei)-2.75 E -.165(ve)-.275 G
2.75(rw).165 G(ill only be)-2.75 E(considered v)100.8 189 Q(alid by the\
 sender if it is no higher than the Rate Request originally requested)
-.275 E(by the sender)100.8 202 Q 5.5(.T)-.605 G
(his limits the ability of the recei)-5.5 E -.165(ve)-.275 G 2.75(rt)
.165 G 2.75(oc)-2.75 G 2.75(heat. F)-2.75 F(or e)-.165 E
(xample, if the sender)-.165 E
(sends a Quick-Start Request with an Rate Request of X, and the recei)
100.8 215 Q -.165(ve)-.275 G 2.75(rr).165 G(eports recei)-2.75 E(ving a)
-.275 E
(Quick-Start Request with an Rate Request of Y > X, then the sender kno)
100.8 228 Q(ws that either)-.275 E(some router along the path malfuncti\
oned \(increasing the Rate Request inappropriately\), or)100.8 241 Q
(the recei)100.8 254 Q -.165(ve)-.275 G 2.75(ri).165 G 2.75(sl)-2.75 G
(ying about the Rate Request in the recei)-2.75 E -.165(ve)-.275 G 2.75
(dp).165 G(ack)-2.75 E(et.)-.11 E(Ho)100.8 280 Q(we)-.275 E -.165(ve)
-.275 G .88 -.44(r, i).165 H 2.75(ft).44 G(he sender sends a Quick-Star\
t Request with an Rate Request of Z, the recei)-2.75 E -.165(ve)-.275 G
(r).165 E(recei)100.8 293 Q -.165(ve)-.275 G 2.75(st).165 G
(he Quick-Start Request with an appro)-2.75 E -.165(ve)-.165 G 2.75(dR)
.165 G(ate Request of X, and reports an Rate)-2.75 E(Request of Y)100.8
306 Q 2.75(,f)-1.419 G(or X < Y < Z, then the recei)-2.75 E -.165(ve)
-.275 G 2.75(rs).165 G(ucceeds in lying to the sender about the)-2.75 E
(appro)100.8 319 Q -.165(ve)-.165 G 2.75(dr).165 G(ate.)-2.75 E
(One protection ag)100.8 345 Q(ainst such misbeha)-.055 E
(vior from the recei)-.22 E -.165(ve)-.275 G 2.75(rw).165 G
(ould be for a router decreasing)-2.86 E 2.75(aR)100.8 358 S(ate Reques\
t in a Quick-Start Request to report the decrease directly to the sende\
r)-2.75 E(.)-.605 E(Ho)100.8 371 Q(we)-.275 E -.165(ve)-.275 G .88 -.44
(r, i).165 H 2.75(ti).44 G 2.75(sh)-2.75 G(opefully suf)-2.75 E
(\214cient protection that the recei)-.275 E -.165(ve)-.275 G 2.75(rd)
.165 G(oes not kno)-2.75 E 2.75(wt)-.275 G(he Rate)-2.75 E
(Request in the original Quick-Start Request.)100.8 384 Q(One w)100.8
410 Q(ay to add additional protection w)-.11 E
(ould be for senders to use some de)-.11 E(gree of)-.165 E
(randomization in the requested Rate Request, so that it is dif)100.8
423 Q(\214cult for recei)-.275 E -.165(ve)-.275 G(rs to guess the).165 E
(original v)100.8 436 Q(alue for the Rate Request.)-.275 E(Ho)5.5 E(we)
-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(his is more dif).44 E
(\214cult if there is f)-.275 E(airly coarse)-.11 E
(granularity in the set of rate requests a)100.8 449 Q -.275(va)-.22 G
(ilable to the sender).275 E(.)-.605 E(Similarly)100.8 475 Q 2.75(,ar)
-.715 G(outer could attempt to cheat and increase the rate request, b)
-2.75 E(ut this w)-.22 E(ould only)-.11 E(be ef)100.8 488 Q(fecti)-.275
E .33 -.165(ve i)-.275 H 2.75(ft).165 G(here were no do)-2.75 E
(wnstream routers that denied the Rate Request.)-.275 E(Misbeha)100.8
514 Q(ving routers:)-.22 E(In addition to protecting ag)100.8 527 Q
(ainst misbeha)-.055 E(ving recei)-.22 E -.165(ve)-.275 G
(rs, it is necessary also to protect).165 E(ag)100.8 540 Q
(ainst misbeha)-.055 E(ving routers.)-.22 E
(Consider collusion between an ingress router and an e)5.5 E(gress)-.165
E(router belonging to the same Intranet.)100.8 553 Q
(The ingress router could decrement the Rate)5.5 E
(Request at the ingress, with the e)100.8 566 Q
(gress router increasing it ag)-.165 E(ain at the e)-.055 E 2.75
(gress. The)-.165 F(routers)2.75 E(between the ingress and e)100.8 579 Q
(gress that appro)-.165 E -.165(ve)-.165 G 2.75(dt).165 G
(he decremented rate request might not ha)-2.75 E -.165(ve)-.22 G
(been willing to appro)100.8 592 Q .33 -.165(ve t)-.165 H(he lar).165 E
(ger)-.198 E 2.75(,o)-.44 G(riginal request.)-2.75 E
(Another form of collusion w)100.8 618 Q
(ould be for the ingress router to inform the e)-.11 E
(gress router out-)-.165 E
(of-band of the IP TTL and QS TTL in the request pack)100.8 631 Q
(et at the ingress.)-.11 E(This w)5.5 E(ould enable)-.11 E(the e)100.8
644 Q(gress router to modify the QS TTL so that it appeared that all of\
 the routers along the)-.165 E(path had appro)100.8 657 Q -.165(ve)-.165
G 2.75(dt).165 G(he request.)-2.75 E 1.76 -.88(We w)5.5 H
(ould note that in the e).77 E(xtreme case, there does not)-.165 E
(appear to be an)100.8 670 Q 2.75(yp)-.165 G(rotection ag)-2.75 E
(ainst a colluding ingress and e)-.055 E(gress router)-.165 E 5.5(.E)
-.605 G -.165(ve)-5.5 G 2.75(ni).165 G 2.75(fa)-2.75 G(n)-2.75 E(interm\
ediate router had deleted the Quick-Start Request Option from the pack)
100.8 683 Q(et, the)-.11 E(ingress router could ha)100.8 696 Q .33 -.165
(ve s)-.22 H(ent the Quick-Start Request Option to the e).165 E
(gress router out-of-)-.165 E(band, with the e)100.8 709 Q(gress router\
 inserting the Quick-Start Request Option, with a modi\214ed QS)-.165 E
(TTL \214eld, back in the pack)100.8 722 Q(et.)-.11 E(Jain/Flo)72 769 Q
204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(6.3. [P)2.75 F(age 26])
-.165 E 0 Cg EP
%%Page: 27 27
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(Ho)100.8 85 Q(we)-.275 E
-.165(ve)-.275 G .88 -.44(r, u).165 H(nlik).44 E 2.75(eE)-.11 G
(CN, there is some)-2.75 E(what less incenti)-.275 E .33 -.165(ve f)
-.275 H(or cooperating ingress and e).165 E(gress)-.165 E
(routers to collude to f)100.8 98 Q
(alsely modify the Quick-Start Request so that it appears to ha)-.11 E
.33 -.165(ve b)-.22 H(een).165 E(appro)100.8 111 Q -.165(ve)-.165 G 2.75
(db).165 G 2.75(ya)-2.75 G(ll of the routers along the path.)-2.75 E
-.44(Wi)5.5 G(th ECN, a colluding ingress router could).44 E -.11(fa)
100.8 124 S(lsely mark a pack).11 E
(et as ECN-capable, with the colluding e)-.11 E
(gress router returning the ECN)-.165 E(\214eld in the IP header to its\
 original non-ECN-capable codepoint, and congested routers)100.8 137 Q
(along the path could ha)100.8 150 Q .33 -.165(ve b)-.22 H
(een fooled into not dropping that pack).165 E 2.75(et. This)-.11 F
(collusion w)2.75 E(ould)-.11 E(gi)100.8 163 Q .33 -.165(ve a)-.275 H
2.75(nu).165 G(nf)-2.75 E(air competiti)-.11 E .33 -.165(ve a)-.275 H
(dv).165 E(antage to the traf)-.275 E
(\214c protected by the colluding ingress and)-.275 E -.165(eg)100.8 176
S(ress routers.).165 E(In contrast, with Quick-Start, the ingress and e)
100.8 202 Q(gress routers colluding to mak)-.165 E 2.75(ei)-.11 G 2.75
(tf)-2.75 G(alsely)-2.86 E(appear that a Quick-Start request w)100.8 215
Q(as appro)-.11 E -.165(ve)-.165 G 2.75(dd).165 G
(oes not necessarily gi)-2.75 E .33 -.165(ve a)-.275 H 2.75(na).165 G
(dv)-2.75 E(antage to)-.275 E(the traf)100.8 228 Q(\214c co)-.275 E
-.165(ve)-.165 G(red by that collusion.).165 E
(If some router along the path really does not ha)5.5 E -.165(ve)-.22 G
(enough a)100.8 241 Q -.275(va)-.22 G(ilable bandwidth to appro).275 E
.33 -.165(ve t)-.165 H(he Quick-Start request, then the Quick-Start).165
E(pack)100.8 254 Q(ets sent as a result of the f)-.11 E(alsely-appro)
-.11 E -.165(ve)-.165 G 2.75(dr).165 G
(equest could be dropped in the netw)-2.75 E(ork, to)-.11 E
(the resulting disadv)100.8 267 Q(antage of the connection.)-.275 E
(Thus, while the ingress and e)5.5 E(gress routers)-.165 E
(could collude to pre)100.8 280 Q -.165(ve)-.275 G
(nt intermediate routers from den).165 E
(ying a Quick-Start request, it w)-.165 E(ould)-.11 E
(generally not be to the connection')100.8 293 Q 2.75(sa)-.605 G(dv)
-2.75 E(antage for this to happen.)-.275 E
(Of course, if the congested router w)100.8 319 Q
(as ECN-capable, and the colluding ingress and e)-.11 E(gress)-.165 E(r\
outers were lying about ECN-capability as well as about Quick-Start, th\
en the result could)100.8 332 Q(be that the Quick-Start request f)100.8
345 Q(alsely appears to the sender to ha)-.11 E .33 -.165(ve b)-.22 H
(een appro).165 E -.165(ve)-.165 G(d, the).165 E(Quick-Start pack)100.8
358 Q(ets f)-.11 E
(alsely appear to the congested router to be ECN-capable, and the)-.11 E
(colluding routers succeed in gi)100.8 371 Q(ving a competiti)-.275 E
.33 -.165(ve a)-.275 H(dv).165 E(antage to the traf)-.275 E
(\214c protected by their)-.275 E(collusion.)100.8 384 Q(Misbeha)100.8
410 Q(ving middlebox)-.22 E(es:)-.165 E 2.75(As)100.8 423 S
(eparate possibility is that of traf)-2.75 E
(\214c normalizers or other middlebox)-.275 E(es along that path)-.165 E
(that re-write IP TTLs, in order to foil other kinds of attacks in the \
netw)100.8 436 Q 2.75(ork. If)-.11 F(such a traf)2.75 E<8c63>-.275 E
(normalizer re-wrote the IP TTL, b)100.8 449 Q
(ut did not adjust the Quick-Start TTL by the same)-.22 E
(amount, then the sender')100.8 462 Q 2.75(sm)-.605 G
(echanism for determining if the request w)-2.75 E(as appro)-.11 E -.165
(ve)-.165 G 2.75(db).165 G 2.75(ya)-2.75 G(ll)-2.75 E
(routers along the path w)100.8 475 Q(ould no longer be reliable.)-.11 E
(Re-writing the IP TTL could result in)5.5 E -.11(fa)100.8 488 S
(lse positi).11 E -.165(ve)-.275 G 2.75(s\().165 G
(with the sender incorrectly belie)-2.75 E
(ving that the Quick-Start request w)-.275 E(as)-.11 E(appro)100.8 501 Q
-.165(ve)-.165 G(d\) as well as f).165 E(alse ne)-.11 E -.055(ga)-.165 G
(ti).055 E -.165(ve)-.275 G 2.75(s\().165 G
(with the sender incorrectly belie)-2.75 E(ving that the Quick-)-.275 E
(Start request w)100.8 514 Q(as denied\).)-.11 E/F1 11/Times-Bold@0 SF
(6.4.)72 553 Q/F2 13/Times-Bold@0 SF(Quick-Start with QoS-enabled T)5.5
E(raf\214c)-.962 E F0(The discussion in this paper has lar)100.8 579 Q
(gely been of Quick-Start with def)-.198 E(ault, best-ef)-.11 E
(fort traf)-.275 E(\214c.)-.275 E(Ho)100.8 592 Q(we)-.275 E -.165(ve)
-.275 G .88 -.44(r, Q).165 H(uick-Start could also be used by traf).44 E
(\214c using some form of dif)-.275 E(ferentiated)-.275 E
(services, and routers could tak)100.8 605 Q 2.75(et)-.11 G(he traf)
-2.75 E(\214c class into account when deciding whether or not)-.275 E
(to grant the Quick-Start request.)100.8 618 Q 1.76 -.88(We d)5.5 H(on')
.88 E 2.75(ta)-.198 G(ddress this conte)-2.75 E
(xt further in this paper)-.165 E 2.75(,s)-.44 G(ince it)-2.75 E
(is orthogonal to the speci\214cation of Quick-Start.)100.8 631 Q(Ho)5.5
E(we)-.275 E -.165(ve)-.275 G .88 -.44(r, w).165 H 2.75(en).44 G
(ote that routers should be)-2.75 E
(discouraged from granting Quick-Start requests for higher)100.8 644 Q
(-priority traf)-.22 E(\214c when this is)-.275 E(lik)100.8 657 Q
(ely to result in signi\214cant pack)-.11 E(et loss for lo)-.11 E(wer)
-.275 E(-priority traf)-.22 E(\214c.)-.275 E F1(6.5.)72 696 Q F2
(Limitations of Quick-Start)5.5 E F0(The Quick-Start proposal, tak)100.8
722 Q(en together with the recent proposal for HighSpeed TCP)-.11 E
(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75
(6.5. [P)2.75 F(age 27])-.165 E 0 Cg EP
%%Page: 28 28
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
([F03], could go a signi\214cant w)100.8 85 Q(ay to)-.11 E -.11(wa)-.275
G(rds e).11 E(xtending the range of performance for best-)-.165 E(ef)
100.8 98 Q(fort traf)-.275 E(\214c in the Internet.)-.275 E(Ho)5.5 E(we)
-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(here are man).44 E 2.75
(yt)-.165 G(hings that the Quick-Start proposal)-2.75 E -.11(wo)100.8
111 S(uld not accomplish.).11 E
(Quick-Start is not a congestion control mechanism, and w)5.5 E
(ould not)-.11 E(help in making more precise use of the a)100.8 124 Q
-.275(va)-.22 G(ilable bandwidth, that is, of achie).275 E
(ving the goal)-.275 E(of v)100.8 137 Q(ery high throughput with v)-.165
E(ery lo)-.165 E 2.75(wd)-.275 G(elay and v)-2.75 E(ery lo)-.165 E 2.75
(wp)-.275 G(ack)-2.75 E(et loss rates.)-.11 E(Quick-Start)5.5 E -.11(wo)
100.8 150 S(uld not gi).11 E .33 -.165(ve r)-.275 H
(outers more control o).165 E -.165(ve)-.165 G 2.75(rt).165 G
(he decrease rates of acti)-2.75 E .33 -.165(ve c)-.275 H 2.75
(onnections. One).165 F(of)2.75 E(the open questions addressed later in\
 this document is whether the limited capabilities of)100.8 163 Q
(Quick-Start are suf)100.8 176 Q(\214cient to w)-.275 E
(arrant standardization and deplo)-.11 E(yment, or whether more)-.11 E
-.11(wo)100.8 189 S(rk is needed to e).11 E
(xplore the space of potential mechanisms.)-.165 E/F1 11/Times-Bold@0 SF
(6.6.)72 228 Q/F2 13/Times-Bold@0 SF(Attacks on Quick-Start)5.5 E F0
(As discussed in [SAF05], Quick-Start is vulnerable to tw)100.8 254 Q
2.75(ok)-.11 G(inds of Quick-Start attacks:)-2.75 E(\(1\) attacks to in\
crease the routers' processing and state load; and \(2\) attacks with b\
ogus)100.8 267 Q(Quick-Start requests to temporarily tie up a)100.8 280
Q -.275(va)-.22 G(ilable Quick-Start bandwidth, pre).275 E -.165(ve)
-.275 G(nting).165 E(routers from appro)100.8 293 Q
(ving Quick-Start requests from other connections.)-.165 E
(Routers can protect)5.5 E(ag)100.8 306 Q(ainst the \214rst kind of att\
ack by applying a simple limit on the rate at which Quick-Start)-.055 E
(requests will be considered by the router)100.8 319 Q 5.5(.T)-.605 G
(he second kind of attack, which is more)-5.5 E(dif)100.8 332 Q
(\214cult to defend ag)-.275 E
(ainst, is discussed in more detail in [SAF05].)-.055 E F1(6.7.)72 371 Q
F2(Simulations with Quick-Start)5.5 E F0(Quick-Start w)100.8 397 Q(as a\
dded to the NS simulator [SH02] by Srikanth Sundarrajan, and additional)
-.11 E(functionality w)100.8 410 Q(as added by P)-.11 E(asi Sarolahti.)
-.165 E(The v)5.5 E(alidation test is at `test-all-quickstart' in)-.275
E(the ')100.8 423 Q(tcl/test' directory in NS.)-.198 E
(The initial simulation studies from [SH02] sho)5.5 E 2.75(was)-.275 G
(igni\214cant)-2.75 E(performance impro)100.8 436 Q -.165(ve)-.165 G
(ment using Quick-Start for moderate-sized \215o).165 E
(ws \(between 4KB and)-.275 E(128KB\) in under)100.8 449 Q(-utilized en)
-.22 E 2.75(vironments. These)-.44 F
(studies are of \214le transfers, with the)2.75 E(impro)100.8 462 Q
-.165(ve)-.165 G(ment measured as the relati).165 E .33 -.165(ve i)-.275
H(ncrease in the o).165 E -.165(ve)-.165 G
(rall throughput for the \214le).165 E(transfer)100.8 475 Q 5.5(.T)-.605
G(he study sho)-5.5 E(ws that potential impro)-.275 E -.165(ve)-.165 G
(ment from Quick-Start is proportional to).165 E
(the delay-bandwidth product of the path.)100.8 488 Q
(The Quick-Start simulations in [SAF05] e)100.8 514 Q(xplore the follo)
-.165 E(wing: the potential bene\214t of)-.275 E
(Quick-Start for the connection; the relati)100.8 527 Q .33 -.165(ve b)
-.275 H(ene\214ts of dif).165 E(ferent router)-.275 E
(-based algorithms for)-.22 E(appro)100.8 540 Q
(ving Quick-Start requests; and the ef)-.165 E(fecti)-.275 E -.165(ve)
-.275 G(ness of Quick-Start as a function of the).165 E
(senders' algorithms for choosing the size of the rate request.)100.8
553 Q([SAF05] also consideres the)5.5 E
(potential of Extreme Quick-Start algorithms at routers, which k)100.8
566 Q(eep per)-.11 E(-\215o)-.22 E 2.75(ws)-.275 G(tate at routers)-2.75
E(for Quick-Start connections, in protecting the a)100.8 579 Q -.275(va)
-.22 G(ilability of Quick-Start bandwidth in the).275 E -.11(fa)100.8
592 S(ce of frequent o).11 E -.165(ve)-.165 G
(rly-larqe Quick-Start requests.).165 E F1(7.)72 631 Q/F3 14
/Times-Bold@0 SF(Related W)5.5 E(ork)-1.05 E F0(An)100.8 657 Q 2.75(ye)
-.165 G -.275(va)-3.025 G
(luation of Quick-Start must include a discussion of the relati).275 E
.33 -.165(ve b)-.275 H(ene\214ts of).165 E(approaches that use no e)
100.8 670 Q
(xplicit information from routers, and of approaches that use more)-.165
E(\214ne-grained feedback from routers as part of a lar)100.8 683 Q
(ger congestion control mechanism.)-.198 E -.88(We)5.5 G
(discuss three classes of proposals \(no e)100.8 696 Q
(xplicit feedback from routers; e)-.165 E(xplicit feedback)-.165 E(abou\
t the initial rate; and more \214ne-grained feedback from routers\) in \
the sections belo)100.8 709 Q -.715(w.)-.275 G(Jain/Flo)72 769 Q 212.275
(yd/Allman/Sarolahti Section)-.11 F 2.75(7. [P)2.75 F(age 28])-.165 E 0
Cg EP
%%Page: 29 29
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 11/Times-Bold@0 SF(7.1.)
72 85 Q/F2 13/Times-Bold@0 SF -.325(Fa)5.5 G
(st Start-ups without Explicit Inf).325 E(ormation fr)-.325 E
(om Routers)-.234 E F0(One possibility w)100.8 111 Q
(ould be for senders to use information from the pack)-.11 E
(et streams to learn)-.11 E(about the a)100.8 124 Q -.275(va)-.22 G
(ilable bandwidth, without e).275 E(xplicit information from routers.)
-.165 E(These techniques)5.5 E -.11(wo)100.8 137 S(uld not allo).11 E
2.75(was)-.275 G(tart-up as f)-2.75 E(ast as that a)-.11 E -.275(va)-.22
G(ilable from Quick-Start, in an underutilized).275 E(en)100.8 150 Q
2.75(vironment; one)-.44 F(has to ha)2.75 E .33 -.165(ve s)-.22 H
(ent some pack).165 E(ets already to use the pack)-.11 E
(et stream to learn)-.11 E(about a)100.8 163 Q -.275(va)-.22 G
(ilable bandwidth.).275 E(Ho)5.5 E(we)-.275 E -.165(ve)-.275 G .88 -.44
(r, t).165 H(hese techniques could allo).44 E 2.75(was)-.275 G
(tart-up considerably)-2.75 E -.11(fa)100.8 176 S
(ster than the current slo).11 E 2.75(w-start. While)-.275 F
(it seems clear that approaches *without* e)2.75 E(xplicit)-.165 E
(feedback from the routers will be strictly less po)100.8 189 Q
(werful that is possible *with* e)-.275 E(xplicit)-.165 E
(feedback, it is also possible that approaches that are more aggressi)
100.8 202 Q .33 -.165(ve t)-.275 H(han slo).165 E(w-start are)-.275 E
(possible without e)100.8 215 Q(xplicit feedback from routers.)-.165 E
(Periodic pack)100.8 241 Q(et streams:)-.11 E([JD02] e)100.8 254 Q
(xplores the use of periodic pack)-.165 E(et streams to estimate the a)
-.11 E -.275(va)-.22 G(ilable bandwidth).275 E(along a path.)100.8 267 Q
(The idea is that the one-w)5.5 E(ay delays of a periodic pack)-.11 E
(et stream sho)-.11 E 2.75(wa)-.275 G(n)-2.75 E
(increasing trend when the stream')100.8 280 Q 2.75(sr)-.605 G
(ate is higher than the a)-2.75 E -.275(va)-.22 G(ilable bandwidth.).275
E(While)5.5 E([JD02] states that the proposed mechanism does not cause \
signi\214cant increases in netw)100.8 293 Q(ork)-.11 E
(utilization, losses, or delays when done by one \215o)100.8 306 Q 2.75
(wa)-.275 G 2.75(tat)-2.75 G(ime, the approach could be)-2.75 E
(problematic if conducted concurrently by a number of \215o)100.8 319 Q
2.75(ws. [JD02])-.275 F(also gi)2.75 E -.165(ve)-.275 G 2.75(sa).165 G
(n)-2.75 E -.165(ove)100.8 332 S(rvie).165 E 2.75(wo)-.275 G 2.75(fs)
-2.75 G(ome of the earlier w)-2.75 E(ork on inferring the a)-.11 E -.275
(va)-.22 G(ilable bandwidth from pack).275 E(et)-.11 E(trains.)100.8 345
Q(Swift-Start:)100.8 371 Q
(The Swift Start proposal from [PRAKS02] combines pack)100.8 384 Q
(et-pair and pack)-.11 E(et-pacing)-.11 E(techniques, be)100.8 397 Q
(ginning with a four)-.165 E(-se)-.22 E(gment b)-.165 E(urst of pack)
-.22 E(ets to estimate the a)-.11 E -.275(va)-.22 G(ilable).275 E
(bandwidth along the path.)100.8 410 Q(While continued research on the \
limits of the ability of TCP and other transport protocols)100.8 436 Q
(to learn of a)100.8 449 Q -.275(va)-.22 G(ilable bandwidth without e)
.275 E(xplicit feedback from the router seems useful, we)-.165 E
(note that there are se)100.8 462 Q -.165(ve)-.275 G
(ral fundamental adv).165 E(antages of e)-.275 E
(xplicit feedback from routers.)-.165 E(\(1\) Explicit feedback is f)
100.8 488 Q(aster than implicit feedback:)-.11 E(One adv)100.8 501 Q
(antage of e)-.275 E(xplicit feedback from the routers is that it allo)
-.165 E(ws the transport sender to)-.275 E(reliably learn of a)100.8 514
Q -.275(va)-.22 G(ilable bandwidth in one round-trip time.).275 E
(\(2\) Explicit feedback is more reliable than implicit feedback:)100.8
540 Q 2.75(As)100.8 553 S(econd adv)-2.75 E(antage of e)-.275 E
(xplicit feedback from the routers is that the a)-.165 E -.275(va)-.22 G
(ilable bandwidth).275 E
(along the path does not necessarily map to the allo)100.8 566 Q
(wed sending rate for an indi)-.275 E(vidual \215o)-.275 E -.715(w.)
-.275 G(As an e)100.8 579 Q(xample, if the TCP sender sends four pack)
-.165 E(ets back-to-back in the initial windo)-.11 E -.715(w,)-.275 G
(and the TCP recei)100.8 592 Q -.165(ve)-.275 G 2.75(rr).165 G
(eports that the data pack)-2.75 E(ets were recei)-.11 E -.165(ve)-.275
G 2.75(dw).165 G(ith roughly the same)-2.75 E(spacing as the)100.8 605 Q
2.75(yw)-.165 G(ere transmitted, does this mean that the \215o)-2.75 E
2.75(wc)-.275 G(an infer an underutilized)-2.75 E 2.75(path? And)100.8
618 R(ho)2.75 E 2.75(wf)-.275 G(ast can the \215o)-2.86 E 2.75(ws)-.275
G(end in the ne)-2.75 E(xt round-trip time?)-.165 E
(Do the results depend)5.5 E(on the le)100.8 631 Q -.165(ve)-.275 G 2.75
(lo).165 G 2.75(fs)-2.75 G(tatistical multiple)-2.75 E
(xing at the congested link, and on the number of \215o)-.165 E(ws)-.275
E(attempting a f)100.8 644 Q(aster start-up at the same time?)-.11 E F1
(7.2.)72 683 Q F2(Optimistic Sending without Explicit Inf)5.5 E
(ormation fr)-.325 E(om Routers)-.234 E F0(Another possibility that has\
 been suggested [S02] is for the sender to start with a lar)100.8 709 Q
(ge)-.198 E(initial windo)100.8 722 Q 2.75(ww)-.275 G(ithout e)-2.75 E
(xplicit permission from the routers and without bandwidth)-.165 E
(Jain/Flo)72 769 Q 204.025(yd/Allman/Sarolahti Section)-.11 F 2.75
(7.2. [P)2.75 F(age 29])-.165 E 0 Cg EP
%%Page: 30 30
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
(estimation techniques, and for the \214rst pack)100.8 85 Q
(et of the initial windo)-.11 E 2.75(wt)-.275 G 2.75(oc)-2.75 G
(ontain information)-2.75 E
(such as the size or sending rate of the initial windo)100.8 98 Q 4.18
-.715(w. T)-.275 H(he proposal w).715 E(ould be that)-.11 E
(congested routers w)100.8 111 Q
(ould use this information in the \214rst data pack)-.11 E
(et to drop or delay man)-.11 E(y)-.165 E(or all of the pack)100.8 124 Q
(ets from that initial windo)-.11 E 4.18 -.715(w. I)-.275 H 2.75(nt).715
G(his w)-2.75 E(ay a \215o)-.11 E(w')-.275 E 2.75(so)-.605 G
(ptimistically-lar)-2.75 E(ge)-.198 E(initial windo)100.8 137 Q 2.75(ww)
-.275 G(ould not force the router to drop pack)-2.86 E
(ets from competing \215o)-.11 E(ws in the)-.275 E(netw)100.8 150 Q 2.75
(ork. Such)-.11 F(an approach w)2.75 E
(ould seem to require some mechanism for the sender to)-.11 E(ensure th\
at the routers along the path understood the mechanism for marking the \
\214rst)100.8 163 Q(pack)100.8 176 Q(et of a lar)-.11 E
(ge initial windo)-.198 E -.715(w.)-.275 G(Ob)100.8 202 Q
(viously there w)-.165 E
(ould be a number of questions to consider about an approach of)-.11 E
(optimistic sending.)100.8 215 Q(\(1\) Incremental deplo)100.8 241 Q
(yment:)-.11 E(One question w)100.8 254 Q
(ould be the potential complications of incremental deplo)-.11 E
(yment, where some)-.11 E
(of the routers along the path might not understand the pack)100.8 267 Q
(et information describing the)-.11 E(initial windo)100.8 280 Q -.715
(w.)-.275 G(\(2\) Congestion collapse:)100.8 306 Q
(There could also be concerns about congestion collapse if man)100.8 319
Q 2.75<798d>-.165 G -.275(ow)-2.75 G 2.75(su).275 G(sed lar)-2.75 E
(ge initial)-.198 E(windo)100.8 332 Q(ws, man)-.275 E 2.75(yp)-.165 G
(ack)-2.75 E(ets were dropped from optimistic initial windo)-.11 E
(ws, and man)-.275 E(y)-.165 E(congested links ended up carrying pack)
100.8 345 Q(ets that are only going to be dropped do)-.11 E(wnstream.)
-.275 E(\(3\) Distrib)100.8 371 Q(uted Denial of Service attacks:)-.22 E
2.75(At)100.8 384 S(hird k)-2.75 E .33 -.165(ey q)-.11 H(uestion w).165
E(ould be the potential role of optimistic sender in amplifying the)-.11
E(damage done by a Distrib)100.8 397 Q
(uted Denial of Service \(DDoS\) attack.)-.22 E
(\(4\) Performance hits if a pack)100.8 423 Q(et is dropped:)-.11 E 2.75
(Af)100.8 436 S(ourth issue w)-2.75 E
(ould be to quantify the performance hit to the connection when a pack)
-.11 E(et is)-.11 E(dropped from one of the initial windo)100.8 449 Q
(ws.)-.275 E/F1 11/Times-Bold@0 SF(7.3.)72 488 Q/F2 13/Times-Bold@0 SF
-.325(Fa)5.5 G(st Start-ups with other Inf).325 E(ormation fr)-.325 E
(om Routers)-.234 E F0(There ha)100.8 514 Q .33 -.165(ve b)-.22 H
(een se).165 E -.165(ve)-.275 G(ral proposals some).165 E
(what similar to Quick-Start, where the transport)-.275 E
(protocol collects e)100.8 527 Q
(xplicit information from the routers along the path.)-.165 E
(An IP Option about the free b)100.8 553 Q(uf)-.22 E(fer size:)-.275 E
(In related w)100.8 566 Q(ork, Joon-Sang P)-.11 E
(ark and John Heidemann in)-.165 E -.165(ve)-.44 G(stig).165 E
(ated the use of a slightly)-.055 E(dif)100.8 579 Q
(ferent IP option for TCP connections to disco)-.275 E -.165(ve)-.165 G
2.75(rt).165 G(he a)-2.75 E -.275(va)-.22 G
(ilable bandwidth along the path).275 E 2.75([P00]. In)100.8 592 R
(that proposal, the IP option w)2.75 E
(ould query the routers along the path about the)-.11 E(smallest a)100.8
605 Q -.275(va)-.22 G(ilable free b).275 E(uf)-.22 E
(fer size. Also, the IP option w)-.275 E(ould ha)-.11 E .33 -.165(ve b)
-.22 H(een sent after the initial).165 E(SYN e)100.8 618 Q(xchange, whe\
n the TCP sender already had an estimate of the round-trip time.)-.165 E
(The Performance T)100.8 644 Q(ransparenc)-.385 E 2.75(yP)-.165 G
(rotocol:)-2.75 E(The Performance T)100.8 657 Q(ransparenc)-.385 E 2.75
(yP)-.165 G(rotocol \(PTP\) includes a proposal for a single PTP pack)
-2.75 E(et)-.11 E(that w)100.8 670 Q(ould collect information from rout\
ers along the path from the sender to the recei)-.11 E -.165(ve)-.275 G
(r).165 E 2.75([W00]. F)100.8 683 R(or e)-.165 E
(xample, a single PTP pack)-.165 E
(et could be used to determine the bottleneck)-.11 E
(bandwidth along a path.)100.8 696 Q(ETEN:)100.8 722 Q(Jain/Flo)72 769 Q
204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(7.3. [P)2.75 F(age 30])
-.165 E 0 Cg EP
%%Page: 31 31
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
(Additional proposals for end nodes to collect e)100.8 85 Q
(xplicit information from routers include)-.165 E(Explicit T)100.8 98 Q
(ransport Error Noti\214cation \(ETEN\), which includes a cumulati)-.385
E .33 -.165(ve m)-.275 H(echanism to).165 E(notify endpoints of aggre)
100.8 111 Q -.055(ga)-.165 G
(te congestion statistics along the path [KAPS02].).055 E/F1 11
/Times-Bold@0 SF(7.4.)72 150 Q/F2 13/Times-Bold@0 SF -.325(Fa)5.5 G
(st Start-ups with mor).325 E 3.25(eF)-.234 G(ine-Grained F)-3.25 E
(eedback fr)-.325 E(om Routers)-.234 E F0(Proposals for more \214ne-gra\
ined congestion-related feedback from routers include XCP)100.8 176 Q
([KHR02] and AntiECN marking [K03].)100.8 189 Q
(Section A.6 discusses in more detail the)5.5 E(relationship between Qu\
ick-Start and proposals for more \214ne-grained per)100.8 202 Q(-pack)
-.22 E(et feedback)-.11 E(from routers.)100.8 215 Q(XCP:)100.8 241 Q
(Proposals such as XCP for ne)100.8 254 Q 2.75(wc)-.275 G
(ongestion control mechanisms based on more feedback)-2.75 E
(from routers are more po)100.8 267 Q(werful than Quick-Start, b)-.275 E
(ut also are more comple)-.22 E 2.75(xt)-.165 G 2.75(ou)-2.75 G
(nderstand)-2.75 E(and more dif)100.8 280 Q(\214cult to deplo)-.275 E
4.18 -.715(y. X)-.11 H(CP routers maintain no per).715 E(-\215o)-.22 E
2.75(ws)-.275 G(tate, b)-2.75 E(ut pro)-.22 E(vide more)-.165 E(\214ne-\
grained feedback to end-nodes than the one-bit congestion feedback of E\
CN.)100.8 293 Q(The per)5.5 E(-)-.22 E(pack)100.8 306 Q
(et feedback from XCP can be positi)-.11 E .33 -.165(ve o)-.275 H 2.75
(rn).165 G -2.475 -.165(eg a)-2.75 H(ti).165 E -.165(ve)-.275 G 2.75(,a)
.165 G(nd speci\214es the increase or)-2.75 E(decrease in the sender')
100.8 319 Q 2.75(sc)-.605 G(ongestion windo)-2.75 E 2.75(ww)-.275 G
(hen this pack)-2.75 E(et is ackno)-.11 E(wledged.)-.275 E(AntiECN:)
100.8 345 Q(The AntiECN proposal is for a single bit in the pack)100.8
358 Q(et header that routers could set to)-.11 E(indicate that the)100.8
371 Q 2.75(ya)-.165 G(re underutilized.)-2.75 E -.165(Fo)5.5 G 2.75(re)
.165 G(ach TCP A)-2.75 E(CK arri)-.44 E(ving at the sender indicating)
-.275 E(that a pack)100.8 384 Q(et has been recei)-.11 E -.165(ve)-.275
G 2.75(dw).165 G(ith the Anti-ECN bit set, the sender w)-2.75 E
(ould be able to)-.11 E(increase its congestion windo)100.8 397 Q 2.75
(wb)-.275 G 2.75(yo)-2.75 G(ne pack)-2.75 E(et, as it w)-.11 E
(ould during slo)-.11 E(w-start.)-.275 E F1(8.)72 436 Q/F3 14
/Times-Bold@0 SF(Implementation and Deployment Issues)5.5 E F0(This sec\
tion discusses some of the implementation issues with Quick-Start.)100.8
462 Q(This section)8.25 E(also discusses some of the k)100.8 475 Q .33
-.165(ey d)-.11 H(eplo).165 E(yment issues, such as the chick)-.11 E
(en-and-e)-.11 E(gg deplo)-.165 E(yment)-.11 E
(problems of mechanisms that ha)100.8 488 Q .33 -.165(ve t)-.22 H 2.75
(ob).165 G 2.75(ed)-2.75 G(eplo)-2.75 E
(yed in both routers and end nodes in order to)-.11 E -.11(wo)100.8 501
S(rk, and the problems posed by the wide deplo).11 E(yment of middlebox)
-.11 E(es today that block the)-.165 E(use of kno)100.8 514 Q
(wn or unkno)-.275 E(wn IP Options.)-.275 E F1(8.1.)72 579 Q F2
(Implementation Issues f)5.5 E(or Sending Quick-Start Requests)-.325 E
F0(Section 4.6 has discussed some of the issues with deciding the initi\
al sending rate to)100.8 605 Q 2.75(request. Quick-Start)100.8 618 R
(raises additional issues about the communication between the)2.75 E(tr\
ansport protocol and the application, and about the use of the past his\
tory with Quick-)100.8 631 Q(Start in the end node.)100.8 644 Q
(One possibility is that a protocol implementation could pro)100.8 670 Q
(vide an API for applications to)-.165 E(indicate when the)100.8 683 Q
2.75(yw)-.165 G(ant to request Quick-Start, and what rate the)-2.86 E
2.75(yw)-.165 G(ould lik)-2.86 E 2.75(et)-.11 G 2.75(or)-2.75 G(equest.)
-2.75 E(In the con)100.8 696 Q -.165(ve)-.44 G(ntional sock).165 E
(et API this could be a sock)-.11 E
(et option that is set before a connection)-.11 E(is established.)100.8
709 Q(Some applications, such those that use TCP for b)5.5 E
(ulk transfers, do not ha)-.22 E -.165(ve)-.22 G
(interest in the transmission rate, b)100.8 722 Q(ut the)-.22 E 2.75(ym)
-.165 G(ight kno)-2.75 E 2.75(wt)-.275 G
(he amount of data that can be sent)-2.75 E(Jain/Flo)72 769 Q 204.025
(yd/Allman/Sarolahti Section)-.11 F 2.75(8.1. [P)2.75 F(age 31])-.165 E
0 Cg EP
%%Page: 32 32
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(immediately)100.8 85 Q 2.75
(.B)-.715 G(ased on this, the sender implementation could decide whethe\
r Quick-Start)-2.75 E -.11(wo)100.8 98 S
(uld be useful, and what rate should be requested.).11 E
(Datagram-based real-time streaming)5.5 E
(applications, on the other hand, may ha)100.8 111 Q .33 -.165(ve a s)
-.22 H(peci\214c preference on the transmission rate and).165 E(the)
100.8 124 Q 2.75(yc)-.165 G(ould indicate the required rate e)-2.75 E
(xplicitly to the transport protocol to be used in the)-.165 E
(Quick-Start Request.)100.8 137 Q 1.76 -.88(We n)100.8 163 T(ote that w\
hen Quick-Start is used, the TCP sender is required to implement an).88
E(additional timer for the paced transmission of Quick-Start pack)100.8
176 Q(ets.)-.11 E/F1 11/Times-Bold@0 SF(8.2.)72 215 Q/F2 13/Times-Bold@0
SF(Implementation Issues f)5.5 E(or Pr)-.325 E
(ocessing Quick-Start Requests)-.234 E F0 2.75(Ar)100.8 241 S
(outer or other netw)-2.75 E
(ork host must be able to determine the approximate bandwidth of its)
-.11 E(outbound netw)100.8 254 Q(ork interf)-.11 E
(aces in order to process incoming Quick-Start rate requests,)-.11 E
(including those that originate from the host itself.)100.8 267 Q
(One possibility w)5.5 E(ould be for hosts to)-.11 E(rely on con\214gur\
ation information to determine link bandwidths; this has the dra)100.8
280 Q(wback of)-.165 E(not being rob)100.8 293 Q
(ust to errors in con\214guration.)-.22 E(Another possibility w)5.5 E
(ould be for netw)-.11 E(ork)-.11 E(de)100.8 306 Q(vice dri)-.275 E
-.165(ve)-.275 G(rs to infer the bandwidth for the interf).165 E
(ace and to communicate this to the IP)-.11 E(layer)100.8 319 Q(.)-.605
E -.165(Pa)100.8 345 S
(rticular issues will arise for wireless links with v).165 E
(ariable bandwidth, where decisions will)-.275 E(ha)100.8 358 Q .33
-.165(ve t)-.22 H 2.75(ob).165 G 2.75(em)-2.75 G(ade about ho)-2.75 E
2.75(wf)-.275 G(requently the netw)-2.75 E
(ork host gets updates of the changing)-.11 E 2.75(bandwidth. It)100.8
371 R(seems appropriate that Quick-Start Requests w)2.75 E
(ould be handled particularly)-.11 E(conserv)100.8 384 Q(ati)-.275 E
-.165(ve)-.275 G(ly for links with v).165 E(ariable bandwidth.)-.275 E
(to a)5.5 E -.22(vo)-.22 G(id cases where Quick-Start).22 E
(Requests are appro)100.8 397 Q -.165(ve)-.165 G
(d, the link bandwidth is reduced, and the data pack).165 E
(ets that are send)-.11 E(end up being dropped.)100.8 410 Q F1(8.3.)72
449 Q F2 -.26(Po)5.5 G(ssible Deployment Scenarios).26 E F0
(Because of possible problems discussed abo)100.8 475 Q .33 -.165(ve c)
-.165 H(oncerning using Quick-Start o).165 E -.165(ve)-.165 G 2.75(rs)
.165 G(ome)-2.75 E(netw)100.8 488 Q
(ork paths, the most realistic initial deplo)-.11 E
(yment of Quick-Start w)-.11 E(ould lik)-.11 E(ely to tak)-.11 E(e)-.11
E(place in Intranets and other controlled en)100.8 501 Q 2.75
(vironments. Quick-Start)-.44 F(is most useful on high)2.75 E(bandwidth\
-delay paths that are signi\214cantly underutilized. The primary initia\
l users of)100.8 514 Q(Quick-Start w)100.8 527 Q(ould lik)-.11 E
(ely be in or)-.11 E -.055(ga)-.198 G(nizations that pro).055 E
(vide netw)-.165 E(ork services to their users)-.11 E(and also ha)100.8
540 Q .33 -.165(ve c)-.22 H(ontrol o).165 E -.165(ve)-.165 G 2.75(ral)
.165 G(ar)-2.75 E(ge portion of the netw)-.198 E(ork path.)-.11 E(Belo)
100.8 566 Q 2.75(wa)-.275 G(re a fe)-2.75 E 2.75(we)-.275 G
(xamples of netw)-2.915 E(orking en)-.11 E
(vironments where Quick-Start w)-.44 E(ould)-.11 E
(potentially be useful.)100.8 579 Q(These are the en)5.5 E
(vironments that might consider an initial deplo)-.44 E(yment)-.11 E
(of Quick-Start in the routers and end-nodes, where the incenti)100.8
592 Q -.165(ve)-.275 G 2.75(sf).165 G(or routers to deplo)-2.75 E(y)-.11
E(Quick-Start might be the most clear)100.8 605 Q(.)-.605 E 2.75(*C)
100.8 631 S(entrally-administrated or)-2.75 E -.055(ga)-.198 G
(nizational Intranets often ha).055 E .33 -.165(ve l)-.22 H(ar).165 E
(ge netw)-.198 E(ork capacity and)-.11 E(the netw)100.8 644 Q
(orks are underutilized for most of the time.)-.11 E(with the netw)8.25
E(ork nodes along the path)-.11 E(administrated by a single or)100.8 657
Q -.055(ga)-.198 G 2.75(nization. Such).055 F
(Intranets might also include high-bandwidth)2.75 E
(and high-delay paths to remote sites.)100.8 670 Q(In such an en)5.5 E
(vironment, Quick-Start w)-.44 E(ould be of)-.11 E
(bene\214t to users, and there w)100.8 683 Q(ould be a clear incenti)
-.11 E .33 -.165(ve f)-.275 H(or the deplo).165 E
(yment of Quick-Start in)-.11 E(routers.)100.8 696 Q 2.75(*Q)100.8 722 S
(uick-Start could also be useful in high-delay en)-2.75 E
(vironments of Cellular W)-.44 E(ide-Area)-.44 E(Jain/Flo)72 769 Q
204.025(yd/Allman/Sarolahti Section)-.11 F 2.75(8.3. [P)2.75 F(age 32])
-.165 E 0 Cg EP
%%Page: 33 33
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E -.44(Wi)100.8 85 S
(reless Netw).44 E
(orks such as the GPRS [BW97] and their enhancements and ne)-.11 E(xt)
-.165 E(generations. F)100.8 98 Q(or e)-.165 E
(xample, GPRS EDGE \(Enhanced Data for GSM Ev)-.165 E(olution\) is e)
-.22 E(xpected)-.165 E(to pro)100.8 111 Q
(vide wireless bandwidth of up to 384 Kbps \(roughly 32 1500-byte pack)
-.165 E(ets per)-.11 E(second\) while the GPRS round-trip times are typ\
ically up to one second e)100.8 124 Q(xcluding an)-.165 E(y)-.165 E
(possible queueing delays in the netw)100.8 137 Q(ork [GP)-.11 E
(AR02]. In addition, these netw)-1.012 E(orks sometimes)-.11 E(ha)100.8
150 Q .33 -.165(ve v)-.22 H
(ariable additional delays due to resource allocation that could be a)
-.11 E -.22(vo)-.22 G(ided by k).22 E(eeping)-.11 E
(the connection path constantly utilized, starting from initial slo)
100.8 163 Q 2.75(ws)-.275 G 2.75(tart. Thus,)-2.75 F(Quick-Start)2.75 E
(could be of signi\214cant bene\214t to users in these en)100.8 176 Q
(vironments.)-.44 E 2.75(*G)100.8 202 S
(eostationary Orbit \(GEO\) satellite links ha)-2.75 E .33 -.165(ve o)
-.22 H(ne-w).165 E(ay propag)-.11 E(ation delays on the order)-.055 E
(of 250 ms while the bandwidth is typically measured in me)100.8 215 Q
-.055(ga)-.165 G(bits per second [RFC2488].).055 E
(Because of the considerable bandwidth-delay product on the link, TCP')
100.8 228 Q 2.75(ss)-.605 G(lo)-2.75 E 2.75(ws)-.275 G(tart is a)-2.75 E
(major performance limitation in the be)100.8 241 Q
(ginning of the connection.)-.165 E 2.75(Al)5.5 G(ar)-2.75 E
(ge initial congestion)-.198 E(windo)100.8 254 Q 2.75(ww)-.275 G
(ould be useful to users of such satellite links.)-2.86 E/F1 11
/Times-Bold@0 SF(8.4.)72 293 Q/F2 13/Times-Bold@0 SF -.975(Wo)5.5 G
(uld QuickStart pack).975 E(ets tak)-.13 E 3.25(et)-.13 G(he slo)-3.25 E
3.25(wp)-.13 G(ath in r)-3.25 E(outers?)-.234 E F0(Ho)100.8 319 Q 2.75
(wm)-.275 G(uch delay w)-2.75 E(ould the slo)-.11 E 2.75(wp)-.275 G
(ath add to the processing time for this pack)-2.75 E(et?)-.11 E
(Similarly)100.8 332 Q 2.75(,i)-.715 G 2.75(fQ)-2.75 G(uickStart pack)
-2.75 E(ets took the slo)-.11 E 2.75(wp)-.275 G(ath, ho)-2.75 E 2.75(wm)
-.275 G(uch stress w)-2.75 E(ould it add to routers)-.11 E
(for there to be man)100.8 345 Q 2.75(ym)-.165 G(ore pack)-2.75 E
(ets on the slo)-.11 E 2.75(wp)-.275 G
(ath, because of the number of pack)-2.75 E(ets)-.11 E
(using QuickStart?)100.8 358 Q
(These are both questions to be considered for the deplo)5.5 E
(yment of Quick-)-.11 E(Start in the Internet.)100.8 371 Q F1(8.5.)72
410 Q F2 3.25(AC)5.5 G(omparison with the Deployment Pr)-3.25 E
(oblems of ECN)-.234 E F0 -.165(Fo)100.8 436 S 2.75(rE).165 G
(CN, only one router along the path has to understand.)-2.75 E -.165(Fo)
5.5 G 2.75(rQ).165 G(uick-Start, all of the)-2.75 E
(routers along the path w)100.8 449 Q(ould ha)-.11 E .33 -.165(ve t)-.22
H 2.75(ou).165 G 2.75(nderstand. Also,)-2.75 F
(Quick-Start has the complicating)2.75 E -.11(fa)100.8 462 S(ctor of us\
ing IP Options, while ECN uses a \214eld in the IP header itself.).11 E
F1(9.)72 501 Q/F3 14/Times-Bold@0 SF(Security Considerations)5.5 E F0
(One security consideration w)100.8 527 Q
(ould be if Quick-Start resulted in the sender using an Rate)-.11 E
(Request that w)100.8 540 Q(as inappropriately lar)-.11 E
(ge, resulting in congestion along the path.)-.198 E(Such)5.5 E
(congestion could result in an unacceptable le)100.8 553 Q -.165(ve)
-.275 G 2.75(lo).165 G 2.75(fp)-2.75 G(ack)-2.75 E
(et drops along the path.)-.11 E(Such)5.5 E
(congestion could also be part of a Denial of Service attack.)100.8 566
Q 2.75(Am)100.8 592 S(isbeha)-2.75 E
(ving TCP sender could use a non-conformant initial congestion windo)
-.22 E 2.75(we)-.275 G -.165(ve)-3.025 G(n).165 E(without the use of Qu\
ick-Start, so we restrict our attention to problems with Quick-Start)
100.8 605 Q(with conformant TCP senders.)100.8 618 Q(\(W)5.5 E 2.75(ea)
-.88 G(lso note that if the TCP sender is a b)-2.75 E(usy web serv)-.22
E(er)-.165 E(,)-.44 E(then the TCP sender has some incenti)100.8 631 Q
.33 -.165(ve t)-.275 H 2.75(ob).165 G 2.75(ec)-2.75 G
(onformant in this re)-2.75 E -.055(ga)-.165 G 2.75(rd.\) Section).055 F
(6.3)2.75 E(discusses the dangers of recei)100.8 644 Q -.165(ve)-.275 G
(rs or routers lying about the Quick-Start rate request, or).165 E
(about whether the rate request w)100.8 657 Q(as appro)-.11 E -.165(ve)
-.165 G(d.).165 E F1(10.)72 696 Q F3(Conclusions)5.5 E F0 1.76 -.88
(We a)100.8 722 T(re presenting the Quick-Start mechanism as a proposal\
 for a simple, understandable,).88 E(Jain/Flo)72 769 Q 206.775
(yd/Allman/Sarolahti Section)-.11 F 2.75(10. [P)2.75 F(age 33])-.165 E 0
Cg EP
%%Page: 34 34
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(and incrementally-deplo)
100.8 85 Q(yable mechanism that w)-.11 E(ould be suf)-.11 E
(\214cient to allo)-.275 E 2.75(wc)-.275 G(onnections to)-2.75 E
(start up with lar)100.8 98 Q(ge initial rates, or lar)-.198 E
(ge initial congestion windo)-.198 E(ws, in o)-.275 E -.165(ve)-.165 G
(rpro).165 E(visioned,)-.165 E(high-bandwidth en)100.8 111 Q 2.75
(vironments. W)-.44 F 2.75(ee)-.88 G
(xpect there will be an increasing number of)-2.915 E -.165(ove)100.8
124 S(rpro).165 E(visioned, high-bandwidth en)-.165 E
(vironments where the Quick-Start mechanism, or)-.44 E
(another mechanism of similar po)100.8 137 Q(wer)-.275 E 2.75(,c)-.44 G
(ould be of signi\214cant bene\214t to a wide range of)-2.75 E(traf)
100.8 150 Q 2.75(\214c. W)-.275 F 2.75(ea)-.88 G(re presenting the Quic\
k-Start mechanism as a request for feedback from the)-2.75 E
(Internet community in considering these issues.)100.8 163 Q/F1 11
/Times-Bold@0 SF(11.)72 202 Q/F2 14/Times-Bold@0 SF(Ackno)5.5 E
(wledgements)-.14 E F0(The authors wish to thank Mark Handle)100.8 228 Q
2.75(yf)-.165 G(or discussions of these issues.)-2.75 E
(The authors also)5.5 E(thank the End-to-End Research Group, the T)100.8
241 Q(ransport Services W)-.385 E(orking Group, and)-.88 E
(members of IP)100.8 254 Q(AM')-1.012 E 2.75(sp)-.605 G(rogram on Lar)
-2.75 E(ge Scale Communication Netw)-.198 E(orks for both positi)-.11 E
-.165(ve)-.275 G(and ne)100.8 267 Q -.055(ga)-.165 G(ti).055 E .33 -.165
(ve f)-.275 H(eedback on this proposal.).165 E 1.76 -.88(We t)5.5 H
(hank Srikanth Sundarrajan for the initial).88 E
(implementation of Quick-Start in the NS simulator)100.8 280 Q 2.75(,a)
-.44 G(nd for the initial simulation study)-2.75 E 5.5(.W)-.715 G(e)
-6.38 E(also thank Mohammed Ashraf, John Border)100.8 293 Q 2.75(,T)-.44
G(om Dunig)-3.63 E(an, John Heidemann, P)-.055 E(aul Hyder)-.165 E(,)
-.44 E(Dina Katabi, and V)100.8 306 Q(ern P)-1.221 E
(axson for feedback.)-.165 E(This draft b)5.5 E
(uilds upon the concepts described)-.22 E
(in [RFC3390], [AHO98], [RFC2415], and [RFC3168].)100.8 319 Q(This is a\
 modi\214cation of a draft originally by Amit Jain for Initial W)100.8
345 Q(indo)-.44 E 2.75(wD)-.275 G(isco)-2.75 E -.165(ve)-.165 G(ry).165
E(.)-.715 E F1(A.)72 384 Q F2(Design Decisions)5.5 E F1(A.1.)72 423 Q/F3
13/Times-Bold@0 SF(Alter)5.5 E(nate Mechanisms f)-.195 E
(or the Quick-Start Request: ICMP and RSVP)-.325 E F0(This document has\
 proposed using an IP Option for the Quick-Start Request from the)100.8
449 Q(sender to the recei)100.8 462 Q -.165(ve)-.275 G .88 -.44(r, a)
.165 H(nd using transport mechanisms for the Quick-Start Response from)
.44 E(the recei)100.8 475 Q -.165(ve)-.275 G 2.75(rb).165 G
(ack to the sender)-2.75 E 5.5(.I)-.605 G 2.75(nt)-5.5 G
(his section we discuss alternate mechanisms, and)-2.75 E(consider whet\
her ICMP [RFC792, RFC2463] or RSVP [RFC2205] protocols could be used)
100.8 488 Q(for deli)100.8 501 Q -.165(ve)-.275 G
(ring the Quick-Start Request.).165 E F1 2.75(A.1.1. ICMP)72 540 R F0
(Being a control protocol used between Internet nodes, one could ar)
100.8 566 Q(gue that ICMP is the)-.198 E
(ideal method for requesting a permission for f)100.8 579 Q
(aster startup from routers.)-.11 E(The ICMP header)5.5 E(is abo)100.8
592 Q .33 -.165(ve t)-.165 H(he IP header).165 E 5.5(.Q)-.605 G
(uick-Start w)-5.5 E(ould be done with ICMP as follo)-.11 E
(ws: If the ICMP)-.275 E
(protocol is used to implement Quick-Start, the equi)100.8 605 Q -.275
(va)-.275 G(lent of the Quick-Start IP option).275 E -.11(wo)100.8 618 S
(uld be carried in the ICMP header of the ICMP Quick-Start Request.).11
E(The ICMP Quick-)5.5 E(Start Request w)100.8 631 Q(ould ha)-.11 E .33
-.165(ve t)-.22 H 2.75(op).165 G
(ass by the routers on the path to the recei)-2.75 E -.165(ve)-.275 G
(r; for no).165 E 1.43 -.715(w, w)-.275 H(e).715 E(don')100.8 644 Q 2.75
(ta)-.198 G(ddress the mechanisms that w)-2.75 E
(ould be needed to accomplish this.)-.11 E 2.75(Ar)5.5 G(outer that)
-2.75 E(appro)100.8 657 Q -.165(ve)-.165 G 2.75(st).165 G
(he Quick-Start Request w)-2.75 E(ould tak)-.11 E 2.75(et)-.11 G
(he same actions as in the case with the)-2.75 E
(Quick-Start IP Option, and forw)100.8 670 Q(ard the pack)-.11 E
(et to the ne)-.11 E(xt router along the path.)-.165 E 2.75(Ar)5.5 G
(outer)-2.75 E(that does not appro)100.8 683 Q .33 -.165(ve t)-.165 H
(he Quick-Start Request, e).165 E -.165(ve)-.275 G 2.75(nw).165 G
(ith a decreased v)-2.75 E(alue for the)-.275 E(Requested Rate, w)100.8
696 Q
(ould delete the ICMP Quick-Start Request, and send an ICMP Reply to)
-.11 E(the sender that the request w)100.8 709 Q(as not appro)-.11 E
-.165(ve)-.165 G 2.75(d. If).165 F(the ICMP Reply w)2.75 E
(as dropped in the)-.11 E(netw)100.8 722 Q
(ork, and did not reach the recei)-.11 E -.165(ve)-.275 G .88 -.44(r, t)
.165 H(he sender w).44 E(ould still kno)-.11 E 2.75(wt)-.275 G
(hat the request w)-2.75 E(as)-.11 E(Jain/Flo)72 769 Q 193.333
(yd/Allman/Sarolahti Section)-.11 F 2.75(A.1.1. [P)2.75 F(age 34])-.165
E 0 Cg EP
%%Page: 35 35
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(not appro)100.8 85 Q -.165
(ve)-.165 G 2.75(df).165 G(rom the absence of feedback from the recei)
-2.75 E -.165(ve)-.275 G 3.96 -.605(r. I).165 H 2.75(ft).605 G
(he ICMP Quick-Start)-2.75 E(request w)100.8 98 Q
(as dropped in the netw)-.11 E(ork due to congestion, the sender w)-.11
E(ould assume that the)-.11 E(request w)100.8 111 Q(as not appro)-.11 E
-.165(ve)-.165 G 2.75(d. If).165 F
(the ICMP Quick-Start Request reached the recei)2.75 E -.165(ve)-.275 G
.88 -.44(r, t).165 H(he).44 E(recei)100.8 124 Q -.165(ve)-.275 G 2.75
(rw).165 G(ould use transport-le)-2.86 E -.165(ve)-.275 G 2.75(lm).165 G
(echanisms to send a response to the sender)-2.75 E 2.75(,e)-.44 G
(xactly as)-2.915 E(with the IP Option.)100.8 137 Q
(One bene\214t of using ICMP w)100.8 163 Q(ould be that the deli)-.11 E
-.165(ve)-.275 G(ry of the TCP SYN pack).165 E(et or other)-.11 E
(initial pack)100.8 176 Q(et w)-.11 E
(ould not be delayed by IP option processing at routers.)-.11 E 2.75(Ag)
5.5 G(reater adv)-2.75 E(antage)-.275 E(is that if middlebox)100.8 189 Q
(es were blocking pack)-.165 E
(ets with Quick-Start Requests, using the Quick-)-.11 E
(Start Request in a separate ICMP pack)100.8 202 Q(et w)-.11 E
(ould mean that the middlebox beha)-.11 E(vior w)-.22 E(ould)-.11 E
(not af)100.8 215 Q(fect the connection as a whole.)-.275 E(\(T)5.5 E
2.75(og)-.88 G(et this rob)-2.75 E(ustness to middlebox)-.22 E
(es with TCP)-.165 E(using an IP Quick-Start Option, one w)100.8 228 Q
(ould ha)-.11 E .33 -.165(ve t)-.22 H 2.75(oh).165 G -2.475 -.22(av e)
-2.75 H 2.75(aT)2.97 G(CP-le)-2.75 E -.165(ve)-.275 G 2.75(lQ).165 G
(uick-Start Request)-2.75 E(pack)100.8 241 Q(et that w)-.11 E
(as sent concurrently b)-.11 E(ut separately from the TCP SYN pack)-.22
E(et.\))-.11 E(Ho)100.8 267 Q(we)-.275 E -.165(ve)-.275 G .88 -.44(r, t)
.165 H(here are a number of disadv).44 E(antages to using ICMP)-.275 E
5.5(.S)-1.221 G(ome \214re)-5.5 E -.11(wa)-.275 G(lls and).11 E
(middlebox)100.8 280 Q(es may not forw)-.165 E
(ard the ICMP Quick-Start Request pack)-.11 E 2.75(ets. \(If)-.11 F
(the ICMP Reply)2.75 E(pack)100.8 293 Q(et is dropped in the netw)-.11 E
(ork, this is not a problem, as we stated abo)-.11 E -.165(ve)-.165 G
(.\) In addition, it).165 E -.11(wo)100.8 306 S(uld be dif).11 E(\214cu\
lt, if not impossible, for a router in the middle of an IP tunnel to de\
li)-.275 E -.165(ve)-.275 G 2.75(ra).165 G(n)-2.75 E(ICMP Reply pack)
100.8 319 Q(et to the actual source, for e)-.11 E
(xample when the inner IP header is encrypted)-.165 E
(as in IPsec tunnel mode [RFC2401].)100.8 332 Q(Ag)5.5 E(ain, ho)-.055 E
(we)-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(he ICMP Reply pack).44
E(et w)-.11 E(ould not)-.11 E
(be essential to the correct operation of ICMP Quick-Start.)100.8 345 Q
(Unauthenticated out-of-band ICMP messages could enable some types of a\
ttacks by third-)100.8 371 Q(party malicious hosts that are not possibl\
e when the control information is carried in-band)100.8 384 Q
(with the IP pack)100.8 397 Q(ets that can only be altered by the route\
rs on the connection path. Finally)-.11 E(,)-.715 E
(as a minor concern, using ICMP w)100.8 410 Q
(ould cause a small amount of additional traf)-.11 E(\214c in the)-.275
E(netw)100.8 423 Q(ork, which is not the case when using IP options.)
-.11 E/F1 11/Times-Bold@0 SF 2.75(A.1.2. RSVP)72 462 R F0 -.44(Wi)100.8
488 S(th some modi\214cations RSVP [RFC2205] could be used as a bearer \
protocol for carrying).44 E
(the Quick-Start Requests. Because routers are e)100.8 501 Q
(xpected to process RSVP pack)-.165 E(ets more)-.11 E -.165(ex)100.8 514
S(tensi).165 E -.165(ve)-.275 G
(ly than the normal transport protocol IP pack).165 E(ets, deli)-.11 E
-.165(ve)-.275 G(ring a Quick-Start rate).165 E
(request using an RSVP pack)100.8 527 Q(et w)-.11 E
(ould seem an appealing choice. Ho)-.11 E(we)-.275 E -.165(ve)-.275 G
.88 -.44(r, Q).165 H(uick-Start with).44 E(RSVP w)100.8 540 Q
(ould require a fe)-.11 E 2.75(wd)-.275 G(if)-2.75 E
(ferences from the con)-.275 E -.165(ve)-.44 G(ntional usage of RSVP)
.165 E 2.75(.Q)-1.221 G(uick-Start)-2.75 E -.11(wo)100.8 553 S(uld not \
require periodical refreshing of soft state, because Quick-Start does n\
ot require).11 E(per)100.8 566 Q(-connection state in routers.)-.22 E
(Quick-Start Requests w)5.5 E(ould be transmitted do)-.11 E(wnstream)
-.275 E(from the sender to recei)100.8 579 Q -.165(ve)-.275 G 2.75(ri)
.165 G 2.75(nt)-2.75 G(he RSVP P)-2.75 E(ath messages, which is dif)
-.165 E(ferent from the)-.275 E(con)100.8 592 Q -.165(ve)-.44 G
(ntional RSVP model where the reserv).165 E
(ations originate from the recei)-.275 E -.165(ve)-.275 G 1.21 -.605
(r. F).165 H(urthermore,).605 E(the Quick-Start Response w)100.8 605 Q
(ould be sent using the transport-le)-.11 E -.165(ve)-.275 G 2.75(lm)
.165 G(echanisms instead of)-2.75 E(using the RSVP Resv message.)100.8
618 Q(If RSVP w)100.8 644 Q
(as used for carrying a Quick-Start Request, a ne)-.11 E 2.75(w")-.275 G
(Quick-Start Request" class)-2.75 E(object w)100.8 657 Q
(ould be included in the RSVP P)-.11 E
(ath message that is sent from the sender to)-.165 E(recei)100.8 670 Q
-.165(ve)-.275 G 1.21 -.605(r. T).165 H(he object w).605 E
(ould contain the rate request \214eld in addition to the common length)
-.11 E(and type \214elds. The Send_TTL \214eld in the RSVP common heade\
r could be used as the)100.8 683 Q(equi)100.8 696 Q -.275(va)-.275 G
(lent of the QS TTL \214eld.).275 E
(The Quick-Start capable routers along the path w)5.5 E(ould)-.11 E
(inspect the Quick-Start Request object in the RSVP P)100.8 709 Q
(ath message, decrement Send_TTL)-.165 E(and adjust the rate request \
\214eld if needed. If an RSVP router did not understand the Quick-)100.8
722 Q(Jain/Flo)72 769 Q 193.333(yd/Allman/Sarolahti Section)-.11 F 2.75
(A.1.2. [P)2.75 F(age 35])-.165 E 0 Cg EP
%%Page: 36 36
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(Start Request object, it w)
100.8 85 Q(ould reject the entire RSVP message and send an RSVP P)-.11 E
(athErr)-.165 E(message back to the sender)100.8 98 Q 5.5(.W)-.605 G
(hen an RSVP message with the Quick-Start Request object)-5.5 E
(reaches the recei)100.8 111 Q -.165(ve)-.275 G .88 -.44(r, t).165 H
(he recei).44 E -.165(ve)-.275 G 2.75(rs).165 G
(ends a Quick-Start Reply message in the corresponding)-2.75 E
(transport protocol header in the same w)100.8 124 Q
(ay as described in the conte)-.11 E(xt of IP options earlier)-.165 E(.)
-.605 E(If the RSVP message with the Quick-Start Request object w)100.8
137 Q(as dropped along the path, the)-.11 E(transport sender w)100.8 150
Q(ould simply proceed with the normal congestion control procedures.)
-.11 E(Much of the discussion about bene\214ts and dra)100.8 176 Q
(wbacks of using ICMP for making the)-.165 E(Quick-Start Request also a\
pplies to the RSVP case. If the Quick-Start Request w)100.8 189 Q(as)
-.11 E(transmitted in a separate pack)100.8 202 Q
(et instead of as an IP option, the transport protocol pack)-.11 E(et)
-.11 E(deli)100.8 215 Q -.165(ve)-.275 G(ry w).165 E(ould not be delaye\
d due to IP option processing at the routers, and the initial)-.11 E
(transport pack)100.8 228 Q(ets w)-.11 E
(ould reach their destination more reliably)-.11 E 2.75(.T)-.715 G
(he possible disadv)-2.75 E(antages)-.275 E
(of using ICMP and RSVP are also e)100.8 241 Q
(xpected to be similar: middlebox)-.165 E(es in the netw)-.165 E
(ork may)-.11 E(not be able to forw)100.8 254 Q
(ard the Quick-Start Request messages, and the IP tunnels might cause)
-.11 E(problems for processing the Quick-Start Requests.)100.8 267 Q/F1
11/Times-Bold@0 SF(A.2.)72 306 Q/F2 13/Times-Bold@0 SF(Alter)5.5 E
(nate Encoding Functions)-.195 E F0(In this section we look at alternat\
e encoding functions for the Rate Request \214eld in the)100.8 332 Q
(Quick-Start Request.)100.8 345 Q
(The main requirements for this function is that it should ha)5.5 E .33
-.165(ve a)-.22 H(suf)100.8 358 Q
(\214ciently wide range for the requested rate.)-.275 E
(There is no need for o)5.5 E -.165(ve)-.165 G(rly-\214ne-grained).165 E
(precision in the requested rate.)100.8 371 Q(Similarly)5.5 E 2.75(,w)
-.715 G(hile it w)-2.75 E(ould be attracti)-.11 E .33 -.165(ve f)-.275 H
(or the encoding).165 E(function to be easily computable, it is also po\
ssible for end-nodes and routers to simply)100.8 384 Q
(store the 256-entry table gi)100.8 397 Q
(ving the mapping between the v)-.275 E
(alue N in the Rate Request \214eld,)-.275 E
(and the actual rate request f\(N\).)100.8 410 Q(Linear functions:)100.8
436 Q(The Quick-Start Request contains an 8-bit \214eld for the Rate Re\
quest.)100.8 449 Q(One possible)5.5 E(proposal w)100.8 462 Q(ould be fo\
r this \214eld to be formatted in bits per second, scaled so that one u\
nit)-.11 E(equals 80 Kbps.)100.8 475 Q(Thus, for the v)5.5 E
(alue N in the Rate Request \214eld, the requested rate is)-.275 E
(80,000*N bps.)100.8 488 Q(This gi)5.5 E -.165(ve)-.275 G 2.75(sar).165
G(equest range between 80 Kbps and 20.48 Mbps.)-2.75 E -.165(Fo)5.5 G(r)
.165 E(1500-byte pack)100.8 501 Q
(ets, this corresponds to a request range between 6 and 1706 pack)-.11 E
(ets per)-.11 E(second.)100.8 514 Q(Po)100.8 540 Q(wers of tw)-.275 E
(o:)-.11 E(If a granularity of f)100.8 553 Q(actors of tw)-.11 E 2.75
(oi)-.11 G 2.75(ss)-2.75 G(uf)-2.75 E
(\214cient for the Rate Request, then the encoding)-.275 E
(function with the most range w)100.8 566 Q
(ould be for the requested rate to be K*2^N, for N the v)-.11 E(alue)
-.275 E(in the Rate Request \214eld, and for K some constant.)100.8 579
Q -.165(Fo)5.5 G 2.75(rN).165 G(=0, the rate request w)-2.75 E
(ould be set)-.11 E(to zero, re)100.8 592 Q -.055(ga)-.165 G
(rdless of the encoding function.).055 E -.165(Fo)5.5 G 2.75(re).165 G
(xample, for K=40,000, the request range)-2.915 E -.11(wo)100.8 605 S
(uld be from 80 Kbps to 40*2^256 Kbps.).11 E(This clearly w)5.5 E
(ould be an unnecessarily lar)-.11 E(ge)-.198 E(request range.)100.8 618
Q -.165(Fo)100.8 644 S 2.75(raf).165 G(our)-2.75 E(-bit Rate Request \
\214eld, the upper limit on the rate request is 1.3 Gbps.)-.22 E(It is)
5.5 E(possible that an upper limit of 1.3 Gbps w)100.8 657 Q
(ould be \214ne for the Quick-Start rate request, and)-.11 E(that conne\
ctions wishing to start up with a higher initial sending rate should be\
 encouraged)100.8 670 Q(to use other mechanisms, such as the e)100.8 683
Q(xplicit reserv)-.165 E(ation of bandwidth.)-.275 E
(If an upper limit of)5.5 E(1.3 Gbps is not acceptable, then \214v)100.8
696 Q 2.75(eb)-.165 G(its could be used for the Rate Request \214eld.)
-2.75 E(If the granularity of f)100.8 722 Q(actors of tw)-.11 E 2.75(oi)
-.11 G 2.75(st)-2.75 G
(oo coarse, then the encoding function could use a)-2.75 E(Jain/Flo)72
769 Q 201.583(yd/Allman/Sarolahti Section)-.11 F 2.75(A.2. [P)2.75 F
(age 36])-.165 E 0 Cg EP
%%Page: 37 37
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(base less than tw)100.8 85 Q
2.75(o. An)-.11 F(alternate form for the encoding function w)2.75 E
(ould be to use a h)-.11 E(ybrid)-.055 E(of linear and e)100.8 98 Q
(xponential functions.)-.165 E 1.76 -.88(We n)100.8 124 T(ote that the \
Rate Request also has to be constrained by the abilities of the transpo\
rt).88 E 2.75(protocol. F)100.8 137 R(or e)-.165 E
(xample, for TCP with W)-.165 E(indo)-.44 E 2.75(wS)-.275 G
(caling, the maximum windo)-2.75 E 2.75(wi)-.275 G 2.75(sa)-2.75 G 2.75
(tm)-2.75 G(ost)-2.75 E(2**30 bytes.)100.8 150 Q -.165(Fo)5.5 G 2.75
(raT).165 G(CP connection with a long, 1 second round-trip time, this w)
-2.75 E(ould gi)-.11 E -.165(ve)-.275 G 2.75(am)100.8 163 S
(aximum sending rate of 1.07 Gbps.)-2.75 E/F1 11/Times-Bold@0 SF(A.3.)72
202 Q/F2 13/Times-Bold@0 SF(The Quick-Start Request: P)5.5 E(ack)-.13 E
(ets or Bytes?)-.13 E F0(One of the design questions is whether the Rat\
e Request \214eld should be in bytes per second)100.8 228 Q(or in pack)
100.8 241 Q(ets per second.)-.11 E 1.76 -.88(We w)5.5 H
(ill discuss this separately from the perspecti).88 E .33 -.165(ve o)
-.275 H 2.75(ft).165 G(he)-2.75 E(transport, and from the perspecti)
100.8 254 Q .33 -.165(ve o)-.275 H 2.75(ft).165 G(he router)-2.75 E(.)
-.605 E -.165(Fo)100.8 280 S 2.75(rT).165 G(CP)-2.75 E 2.75(,t)-1.221 G
(he results from the Quick-Start Request are translated into a congesti\
on windo)-2.75 E(w)-.275 E
(in bytes, using the measured round-trip time and the MSS.)100.8 293 Q
(This windo)5.5 E 2.75(wa)-.275 G(pplies only to)-2.75 E(the bytes of d\
ata payload, and does not include the bytes in the TCP or IP pack)100.8
306 Q(et headers.)-.11 E(Other transport protocols w)100.8 319 Q
(ould concei)-.11 E -.275(va)-.275 G
(bly use the Quick-Start Request directly in).275 E(pack)100.8 332 Q(et\
s per second, or could translate the Quick-Start Request to a congestio\
n windo)-.11 E 2.75(wi)-.275 G(n)-2.75 E(pack)100.8 345 Q(ets.)-.11 E
(The assumption of this draft is that the router only appro)100.8 371 Q
-.165(ve)-.165 G 2.75(st).165 G(he Quick-Start Request when)-2.75 E
(the output link is signi\214cantly underutilized.)100.8 384 Q -.165(Fo)
5.5 G 2.75(rt).165 G(his, the router could measure the)-2.75 E -.22(av)
100.8 397 S(ailable bandwidth in bytes per second, or could con)-.055 E
-.165(ve)-.44 G(rt between pack).165 E(ets and bytes by)-.11 E
(some mechanism.)100.8 410 Q(If the Quick-Start Request w)100.8 436 Q
(as in bytes per second, and applied only to the data payload,)-.11 E
(then the router w)100.8 449 Q(ould ha)-.11 E .33 -.165(ve t)-.22 H 2.75
(oc).165 G(on)-2.75 E -.165(ve)-.44 G
(rt from bytes per second of data payload, to bytes per).165 E
(second of pack)100.8 462 Q(ets on the wire.)-.11 E
(If the Rate Request \214eld w)5.5 E(as in bytes per second and the)-.11
E(sender ended up using v)100.8 475 Q(ery small pack)-.165 E
(ets, this could translate to a signi\214cantly lar)-.11 E(ger)-.198 E
(number in terms of bytes per second on the wire.)100.8 488 Q
(Therefore, for a Quick-Start Request in)5.5 E(bytes per second, it mak)
100.8 501 Q
(es most sense for this to include the transport and IP headers as)-.11
E(well as the data payload.)100.8 514 Q
(Of course, this will be at best a rough approximation on the part)5.5 E
(of the sender; the transport-le)100.8 527 Q -.165(ve)-.275 G 2.75(ls)
.165 G(ender might not kno)-2.75 E 2.75(wt)-.275 G
(he size of the transport and IP)-2.75 E
(headers in bytes, and might kno)100.8 540 Q 2.75(wn)-.275 G
(othing at all about the separate headers added in IP)-2.75 E
(tunnels do)100.8 553 Q 2.75(wnstream. This)-.275 F
(rough estimate seems suf)2.75 E(\214cient, ho)-.275 E(we)-.275 E -.165
(ve)-.275 G .88 -.44(r, g).165 H -2.365 -.275(iv e).44 H 2.75(nt).275 G
(he o)-2.75 E -.165(ve)-.165 G(rall lack).165 E
(of \214ne precision in Quick-Start functionality)100.8 566 Q(.)-.715 E
(It has been suggested that the router could possibly use information f\
rom the MSS option)100.8 592 Q(in the TCP pack)100.8 605 Q
(et header of the SYN pack)-.11 E(et to con)-.11 E -.165(ve)-.44 G
(rt the Quick-Start Request from).165 E(pack)100.8 618 Q
(ets per second to bytes per second, or vice v)-.11 E 2.75(ersa. The)
-.165 F(MSS option is de\214ned as the)2.75 E
(maximum MSS that the TCP sender e)100.8 631 Q(xpects to recei)-.165 E
-.165(ve)-.275 G 2.75(,n).165 G(ot the maximum MSS that the)-2.75 E
(TCP sender plans to send [RFC793].)100.8 644 Q(Ho)5.5 E(we)-.275 E
-.165(ve)-.275 G .88 -.44(r, i).165 H 2.75(ti).44 G 2.75(sp)-2.75 G
(robably often the case that this MSS)-2.75 E(also applies as an upper \
bound on the MSS used by the TCP sender in sending.)100.8 657 Q 1.76
-.88(We n)100.8 683 T(ote that the sender does not necessarily kno).88 E
2.75(wt)-.275 G(he P)-2.75 E(ath MTU when the Quick-Start)-.165 E
(Request is sent, or when the initial windo)100.8 696 Q 2.75(wo)-.275 G
2.75(fd)-2.75 G(ata is sent.)-2.75 E(Thus, with IPv4, pack)5.5 E
(ets from)-.11 E(the initial windo)100.8 709 Q 2.75(wc)-.275 G
(ould end up being fragmented in the netw)-2.75 E(ork if the "Don')-.11
E 2.75(tF)-.198 G(ragment")-2.75 E(\(DF\) bit is not set [RFC1191].)
100.8 722 Q 2.75(AR)5.5 G
(ate Request in bytes per second is reasonably rob)-2.75 E(ust to)-.22 E
(Jain/Flo)72 769 Q 201.583(yd/Allman/Sarolahti Section)-.11 F 2.75
(A.3. [P)2.75 F(age 37])-.165 E 0 Cg EP
%%Page: 38 38
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 2.75(fragmentation. Clearly)
100.8 85 R 2.75(aR)2.75 G(ate Request in pack)-2.75 E
(ets per second is less rob)-.11 E(ust in the presence)-.22 E
(of fragmentation.)100.8 98 Q(Interactions between lar)5.5 E
(ger initial windo)-.198 E(ws and P)-.275 E(ath MTU Disco)-.165 E -.165
(ve)-.165 G(ry).165 E
(are discussed in more detail in RFC 3390 [RFC3390].)100.8 111 Q -.165
(Fo)100.8 137 S 2.75(raQ).165 G
(uick-Start Request in bytes per second, the transport senders w)-2.75 E
(ould ha)-.11 E .33 -.165(ve t)-.22 H(he).165 E(additional complication\
 of estimating the bandwidth usage added by the pack)100.8 150 Q
(et headers.)-.11 E 1.76 -.88(We h)100.8 176 T -2.475 -.22(av e).88 H
(chosen an Rate Request \214eld in bytes per second rather than in pack)
2.97 E(ets per second)-.11 E(because it seems some)100.8 189 Q
(what more rob)-.275 E(ust, particularly to routers.)-.22 E/F1 11
/Times-Bold@0 SF(A.4.)72 228 Q/F2 13/Times-Bold@0 SF
(Quick-Start Semantics: T)5.5 E(otal Rate or Additional Rate?)-1.196 E
F0 -.165(Fo)100.8 254 S 2.75(raQ).165 G
(uick-Start Request sent in the middle of a connection, there are tw)
-2.75 E 2.75(op)-.11 G(ossible)-2.75 E
(semantics for the Rate Request \214eld, as follo)100.8 267 Q(ws:)-.275
E(\(1\) T)100.8 293 Q(otal Rate: The requested Rate Request is the requ\
ested total rate for the connection,)-.88 E
(including the current rate; or)100.8 306 Q(\(2\) Additional Rate: The \
requested Rate Request is the requested increase in the total rate)100.8
332 Q(for that connection, o)100.8 345 Q -.165(ve)-.165 G 2.75(ra).165 G
(nd abo)-2.75 E .33 -.165(ve t)-.165 H(he current sending rate.).165 E
(In this section we consider brie\215y the tradeof)100.8 371 Q
(fs between these tw)-.275 E 2.75(oo)-.11 G(ptions, and e)-2.75 E
(xplain)-.165 E(wh)100.8 384 Q 2.75(yw)-.055 G 2.75(eh)-2.75 G -2.475
-.22(av e)-2.75 H(chosen the `T)2.97 E(otal Rate' semantics.)-.88 E
(The T)100.8 410 Q(otal Rate semantics mak)-.88 E
(es it easier for routers to `)-.11 E(`allocate')-.814 E 2.75('t)-.814 G
(he same rate to all)-2.75 E 2.75(connections. This)100.8 423 R
(lends itself to f)2.75 E(airness, and impro)-.11 E -.165(ve)-.165 G
2.75(sc).165 G(on)-2.75 E -.165(ve)-.44 G -.198(rg).165 G
(ence times between old and).198 E(ne)100.8 436 Q 2.75(wc)-.275 G
(onnections.)-2.75 E(The Additional Rate semantics lends itself to g)
100.8 462 Q(aming by the connection, with the sender)-.055 E
(sending frequent Quick-Start Requests in the hope of g)100.8 475 Q
(aining a higher rate.)-.055 E -.165(Fo)100.8 501 S 2.75(re).165 G
(ither of these alternati)-2.75 E -.165(ve)-.275 G(s, there w).165 E
(ould not be room to report the current sending rate)-.11 E(in the Quic\
k-Start Option using the current minimal format for the Quick-Start Req\
uest.)100.8 514 Q(Thus, either the Quick-Start Option w)100.8 527 Q
(ould ha)-.11 E .33 -.165(ve t)-.22 H 2.75(ot).165 G(ak)-2.75 E 2.75(em)
-.11 G(ore than four bytes to include a)-2.75 E
(report of the current sending rate, or the current sending rate w)100.8
540 Q(ould not be reported to the)-.11 E(routers.)100.8 553 Q F1(A.5.)72
605 Q F2(Alter)5.5 E(nate Responses to the Loss of a Quick-Start P)-.195
E(ack)-.13 E(et)-.13 E F0(Section 4.5 discusses TCP')100.8 631 Q 2.75
(sr)-.605 G(esponse to the loss of a Quick-Start pack)-2.75 E
(et in the initial)-.11 E(windo)100.8 644 Q 4.18 -.715(w. T)-.275 H
(his section discusses se).715 E -.165(ve)-.275 G
(ral alternate responses.).165 E(One possible alternati)100.8 670 Q .33
-.165(ve t)-.275 H 2.75(or).165 G -2.365 -.275(ev e)-2.75 H
(rting to the def).275 E(ault slo)-.11 E
(w-start after the loss of a Quick-Start)-.275 E(pack)100.8 683 Q
(et from the initial windo)-.11 E 2.75(ww)-.275 G(ould ha)-2.86 E .33
-.165(ve b)-.22 H(een to halv).165 E 2.75(et)-.165 G
(he congestion windo)-2.75 E 2.75(wa)-.275 G(nd)-2.75 E
(continue in congestion a)100.8 696 Q -.22(vo)-.22 G 2.75(idance. Ho).22
F(we)-.275 E -.165(ve)-.275 G .88 -.44(r, w).165 H 2.75(en).44 G
(ote that this w)-2.75 E(ould not ha)-.11 E .33 -.165(ve b)-.22 H(een a)
.165 E(desirable response for either the connection or for the netw)
100.8 709 Q(ork as a whole.)-.11 E(The pack)5.5 E(et loss)-.11 E
(in the initial windo)100.8 722 Q 2.75(wi)-.275 G
(ndicates that Quick-Start f)-2.75 E
(ailed in \214nding an appropriate congestion)-.11 E(Jain/Flo)72 769 Q
201.583(yd/Allman/Sarolahti Section)-.11 F 2.75(A.5. [P)2.75 F(age 38])
-.165 E 0 Cg EP
%%Page: 39 39
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(windo)100.8 85 Q 1.43 -.715
(w, m)-.275 H(eaning that the congestion windo).715 E 2.75(wa)-.275 G
(fter halving may easily also be wrong.)-2.75 E 2.75(Am)100.8 111 S
(ore moderate alternate w)-2.75 E(ould be to continue in congestion a)
-.11 E -.22(vo)-.22 G(idance from a windo).22 E 2.75(wo)-.275 G(f)-2.75
E(\(W)100.8 124 Q(-D\)/2, where W is the Quick-Start congestion windo)
-.715 E 1.43 -.715(w, a)-.275 H(nd D is the number of pack).715 E(ets)
-.11 E(dropped or mark)100.8 137 Q(ed from that windo)-.11 E -.715(w.)
-.275 G/F1 11/Times-Bold@0 SF(A.6.)72 176 Q/F2 13/Times-Bold@0 SF(Wh)5.5
E 3.25(yN)-.195 G(ot Include Mor)-3.25 E 3.25(eF)-.234 G(unctionality?)
-3.25 E F0(As Section 6.5 discussed, this proposal for Quick-Start is a\
 rather coarse-grained)100.8 202 Q(mechanism that w)100.8 215 Q
(ould allo)-.11 E 2.75(wc)-.275 G(onnections to use lar)-2.75 E
(ger initial windo)-.198 E(ws along underutilized)-.275 E(paths, b)100.8
228 Q(ut that does not attempt to pro)-.22 E(vide a ne)-.165 E
(xt-generation transport protocol, and does)-.165 E
(not attempt the goal of pro)100.8 241 Q(viding v)-.165 E
(ery high throughput with v)-.165 E(ery lo)-.165 E 2.75(wd)-.275 G(elay)
-2.75 E 5.5(.A)-.715 G 2.75(sS)-5.5 G(ection 7.4)-2.75 E(discusses, the\
re are a number of proposals such as XCP and AntiECN for more \214ne-)
100.8 254 Q(grained per)100.8 267 Q(-pack)-.22 E(et feedback from route\
rs that the current congestion control mechanisms,)-.11 E
(that do attempt these more ambitious goals.)100.8 280 Q
(Compared to proposals such as XCP and AntiECN, Quick-Start of)100.8 306
Q(fers much less control;)-.275 E(Quick-Start does not attempt to pro)
100.8 319 Q(vide a ne)-.165 E 2.75(wc)-.275 G
(ongestion control mechanism, b)-2.75 E(ut simply)-.22 E(to get permiss\
ion from routers for a higher sending rate at start-up, or after an idl\
e period.)100.8 332 Q(At the same time, Quick-Start w)100.8 345 Q
(ould allo)-.11 E 2.75(wl)-.275 G(ar)-2.75 E(ger initial windo)-.198 E
(ws that w)-.275 E(ould proposals)-.11 E
(such as AntiECN, requires less input to routers than XCP)100.8 358 Q
2.75(,a)-1.221 G(nd w)-2.75 E(ould require less frequent)-.11 E
(feedback from routers than an)100.8 371 Q 2.75(yn)-.165 G .55 -.275
(ew c)-2.75 H(ongestion control mechanism.).275 E(Thus, Quick-Start is)
5.5 E(less po)100.8 384 Q(werful in general than proposals for ne)-.275
E 2.75(wc)-.275 G(ongestion control mechanisms such as)-2.75 E
(XCP and AntiECN, b)100.8 397 Q(ut as po)-.22 E(werful or more po)-.275
E(werful in terms of the speci\214c issue of)-.275 E(allo)100.8 410 Q
(wing lar)-.275 E(ger initial windo)-.198 E
(ws, and \(we think\) more amenable to incremental deplo)-.275 E(yment)
-.11 E(in the current Internet.)100.8 423 Q 1.76 -.88(We d)100.8 449 T
2.75(on).88 G(ot discuss proposals such as XCP in detail, b)-2.75 E
(ut simply note that there are a number)-.22 E(of open questions.)100.8
462 Q(One question concerns whether there is a pressing need for more)
5.5 E(sophisticated congestion control mechanisms such as XCP in the In\
ternet.)100.8 475 Q(Quick-Start is)5.5 E
(inherently a rather crude tool that does not deli)100.8 488 Q -.165(ve)
-.275 G 2.75(ra).165 G(ssurances about maintaining high link)-2.75 E
(utilization and lo)100.8 501 Q 2.75(wq)-.275 G(ueueing delay;)-2.75 E
(Quick-Start is designed for use in en)5.5 E(vironments that)-.44 E(are\
 signi\214cantly underutilized, and addresses the single question of wh\
ether a higher)100.8 514 Q(sending rate is allo)100.8 527 Q 2.75
(wed. Ne)-.275 F 2.75(wc)-.275 G
(ongestion control mechanisms with more \214ne-grained)-2.75 E
(feedback from routers could allo)100.8 540 Q 2.75(wf)-.275 G
(aster startups e)-2.86 E -.165(ve)-.275 G 2.75(ni).165 G 2.75(ne)-2.75
G -.44(nv)-2.75 G(ironments with rather high).44 E(link utilization.)
100.8 553 Q(Is this a pressing requirement?)5.5 E
(Are the other bene\214ts of more \214ne-grained)5.5 E
(congestion control feedback from routers a pressing requirement?)100.8
566 Q 1.76 -.88(We w)100.8 592 T(ould ar).77 E(gue that e)-.198 E -.165
(ve)-.275 G 2.75(ni).165 G 2.75(fm)-2.75 G(ore \214ne-grained per)-2.75
E(-pack)-.22 E(et feedback from routers w)-.11 E(as)-.11 E
(implemented, it is reasonable to ha)100.8 605 Q .33 -.165(ve a s)-.22 H
(eparate mechanism such as Quick-Start for).165 E(indicating an allo)
100.8 618 Q(wed initial sending rate, or an allo)-.275 E
(wed total sending rate after an idle or)-.275 E(underutilized period.)
100.8 631 Q(One fundamental dif)100.8 657 Q
(ference between Quick-Start and current proposals for \214ne-grained)
-.275 E(per)100.8 670 Q(-pack)-.22 E
(et feedback is that the feedback of Quick-Start is per)-.11 E
(-connection, gi)-.22 E(ving an)-.275 E(allo)100.8 683 Q(wed sending ra\
te for the connection as a whole, while the proposals for per)-.275 E
(-pack)-.22 E(et)-.11 E(feedback for congestion control are about the i\
ncrease or decrease in the rate or windo)100.8 696 Q(w)-.275 E(per)100.8
709 Q(-pack)-.22 E(et, when a particular data pack)-.11 E(et is ackno)
-.11 E(wledged.)-.275 E(Jain/Flo)72 769 Q 201.583
(yd/Allman/Sarolahti Section)-.11 F 2.75(A.6. [P)2.75 F(age 39])-.165 E
0 Cg EP
%%Page: 40 40
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E 2.75(As)100.8 85 S
(econd dif)-2.75 E(ference is that unlik)-.275 E 2.75(ep)-.11 G(er)-2.75
E(-pack)-.22 E(et feedback, Quick-Start lends itself to more)-.11 E
(than just a fe)100.8 98 Q 2.75(wb)-.275 G
(its of feedback from routers to indicate the initial sending rate allo)
-2.75 E(wed by)-.275 E(the router)100.8 111 Q 5.5(.W)-.605 G
(hile XCP also allocates a byte for per)-5.5 E(-pack)-.22 E
(et feedback, there has been)-.11 E(discussion of v)100.8 124 Q
(ariants of XCP with less per)-.275 E(-pack)-.22 E(et feedback.)-.11 E
(This w)5.5 E(ould be more lik)-.11 E(e)-.11 E(other proposals such as \
anti-ECN that use a single bit of feedback from routers to indicate)
100.8 137 Q(that the sender can increase as f)100.8 150 Q(ast as slo)
-.11 E(w-starting, in response to this particular pack)-.275 E(et)-.11 E
(ackno)100.8 163 Q 2.75(wledgement. In)-.275 F
(general, there is probably considerable po)2.75 E
(wer in \214ne-grained)-.275 E(proposals with only tw)100.8 176 Q 2.75
(ob)-.11 G(its of feedback, indicating that the sender should decrease,)
-2.75 E(maintain, or increase the sending rate or windo)100.8 189 Q 2.75
(ww)-.275 G(hen this pack)-2.75 E(et is ackno)-.11 E(wledged.)-.275 E
(Ho)100.8 202 Q(we)-.275 E -.165(ve)-.275 G .88 -.44(r, t).165 H(he po)
.44 E(wer of Quick-Start w)-.275 E(ould be considerably limited if it w)
-.11 E(as restricted to)-.11 E(only tw)100.8 215 Q 2.75(ob)-.11 G
(its of feedback; it seems lik)-2.75 E
(ely that determining the initial sending rate)-.11 E(fundamentally req\
uires more bits of feedback from routers than does the e)100.8 228 Q
-.165(ve)-.275 G(ryday).165 E 2.75(,p)-.715 G(er)-2.75 E(-)-.22 E(pack)
100.8 241 Q(et feedback to increase or decrease the sending rate.)-.11 E
(On a more practical le)100.8 267 Q -.165(ve)-.275 G(l, one dif).165 E
(ference between Quick-Start and proposals for per)-.275 E(-pack)-.22 E
(et)-.11 E(feedback is that there are fe)100.8 280 Q
(wer open issues with Quick-Start than there w)-.275 E(ould be with a)
-.11 E(ne)100.8 293 Q 2.75(wc)-.275 G(ongestion control mechanism.)-2.75
E -.165(Fo)5.5 G 2.75(re).165 G
(xample, for a mechanism for requesting a initial)-2.915 E
(sending rate, the f)100.8 306 Q
(airness issues of a general congestion control mechanism go a)-.11 E
-.11(wa)-.165 G 1.43 -.715(y, a).11 H(nd).715 E(there is no need for th\
e end nodes to tell the routers the round-trip time and congestion)100.8
319 Q(windo)100.8 332 Q 1.43 -.715(w, a)-.275 H 2.75(si).715 G 2.75(sd)
-2.75 G(one in XCP; all that is needed is for the end nodes to report t\
he requested)-2.75 E(sending rate.)100.8 345 Q(Proposals for)257.8 377 Q
27.5(Quick-Start Per)197.3 390 R(-P)-.22 E(ack)-.165 E(et Feedback)-.11
E(+------------------+----------------------+----------------------+)
136.8 403 Q 19.25(Semantics: |)139.55 416 R(Allo)2.75 E
(wed sending rate | Change in rate/windo)-.275 E -.715(w,)-.275 G 5.5
(|p)189.05 429 S(er connection.)-5.5 E 5.5(|p)13.75 G(er)-5.5 E(-pack)
-.22 E(et.)-.11 E
(+------------------+----------------------+----------------------+)
136.8 442 Q(Relationship to)139.55 455 Q 2.75(|I)8.25 G 2.75(na)-2.75 G
22(ddition. |)-2.75 F(Replacement.)2.75 E(congestion ctrl:)139.55 468 Q
60.5(||)5.5 G
(+------------------+----------------------+----------------------+)
136.8 481 Q(Frequenc)139.55 494 Q 19.25(y: |)-.165 F(Start-up, or after)
2.75 E 2.75(|E)8.25 G -.165(ve)-2.75 G(ry pack).165 E(et.)-.11 E 5.5(|a)
189.05 507 S 2.75(ni)-5.5 G(dle period.)-2.75 E(|)13.75 E
(+------------------+----------------------+----------------------+)
136.8 520 Q 13.75(Limitations: |)139.55 533 R(Only useful on)2.75 E 2.75
(|G)19.25 G(eneral congestion)-2.75 E 5.5(|u)189.05 546 S
(nderutilized paths.|)-5.5 E(control mechanism.)5.5 E
(+------------------+----------------------+----------------------+)
136.8 559 Q(Input to routers: | Rate request.)139.55 572 Q 2.75(|R)22 G
(TT)-3.41 E 2.75(,c)-.814 G(wnd, request \(XCP\).)-2.75 E 60.5(||)189.05
585 S(None \(Anti-ECN\).)-57.75 E
(+------------------+----------------------+----------------------+)
136.8 598 Q(Bits of feedback: | One byte.)139.55 611 Q 2.75(|Af)33 G .55
-.275(ew b)-2.75 H(its w).275 E(ould)-.11 E 60.5(||)189.05 624 S(suf)-55
E(\214ce?)-.275 E
(+------------------+----------------------+----------------------+)
136.8 637 Q(Dif)142.3 663 Q
(ferences between Quick-Start and Proposals for)-.275 E
(Fine-Grained Per)147.8 676 Q(-P)-.22 E(ack)-.165 E(et Feedback.)-.11 E
2.75(As)100.8 708 S(eparate question concerns whether mechanisms such a\
s Quick-Start, in combination)-2.75 E
(with HighSpeed TCP and other changes in progress, w)100.8 721 Q
(ould mak)-.11 E 2.75(eas)-.11 G(igni\214cant contrib)-2.75 E(ution)-.22
E(Jain/Flo)72 769 Q 201.583(yd/Allman/Sarolahti Section)-.11 F 2.75
(A.6. [P)2.75 F(age 40])-.165 E 0 Cg EP
%%Page: 41 41
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(to)100.8 85 Q -.11(wa)-.275
G(rds meeting some of these needs for ne).11 E 2.75(wc)-.275 G
(ongestion control mechanisms.)-2.75 E(This could)5.5 E(be vie)100.8 98
Q(wed as a positi)-.275 E .33 -.165(ve s)-.275 H
(tep of meeting some of the current needs with a simple and).165 E
(reasonably deplo)100.8 111 Q(yable mechanism, or alternately)-.11 E
2.75(,a)-.715 G 2.75(san)-2.75 G -2.475 -.165(eg a)-2.75 H(ti).165 E .33
-.165(ve s)-.275 H(tep of unnecessarily).165 E
(delaying more fundamental changes.)100.8 124 Q -.44(Wi)5.5 G
(thout answering this question, we w).44 E(ould note that)-.11 E(our o)
100.8 137 Q(wn approach tends to f)-.275 E -.22(avo)-.11 G 2.75(rt).22 G
(he incremental deplo)-2.75 E(yment of relati)-.11 E -.165(ve)-.275 G
(ly simple).165 E(mechanisms, as long as the simple mechanisms are not \
short-term hacks b)100.8 150 Q(ut mechanisms)-.22 E(that lead the o)
100.8 163 Q -.165(ve)-.165 G
(rall architecture in the fundamentally correct direction.).165 E/F1 11
/Times-Bold@0 SF(A.7.)72 202 Q/F2 13/Times-Bold@0 SF 3.25(AQ)5.5 G
(uickStart Nonce?)-3.25 E F0(An earlier v)100.8 228 Q
(ersion of this document included a QuickStart Nonce that w)-.165 E
(as initialized by the)-.11 E
(sender to a non-zero, `random' eight-bit number)100.8 241 Q 2.75(,a)
-.44 G(long with a QS TTL that w)-2.75 E(as initialized)-.11 E
(to the same v)100.8 254 Q(alue as the TTL in the IP header)-.275 E 5.5
(.T)-.605 G(he QuickStart Nonce w)-5.5 E(ould ha)-.11 E .33 -.165(ve b)
-.22 H(een).165 E(returned by the TCP recei)100.8 267 Q -.165(ve)-.275 G
2.75(rt).165 G 2.75(ot)-2.75 G
(he TCP sender in the Quick-Start Response.)-2.75 E 2.75(Ar)5.5 G(outer)
-2.75 E(could den)100.8 280 Q 2.75(yt)-.165 G
(he Quick-Start request by f)-2.75 E
(ailing to decrement the QS TTL \214eld, by zeroing)-.11 E(the QS Nonce\
 \214eld, or by deleting the Quick-Start Request from the pack)100.8 293
Q(et header)-.11 E 5.5(.T)-.605 G(he)-5.5 E(QS Nonce w)100.8 306 Q
(as included to pro)-.11 E(vide some protection ag)-.165 E(ainst brok)
-.055 E(en do)-.11 E(wnstream routers, or)-.275 E(ag)100.8 319 Q
(ainst misbeha)-.055 E(ving TCP recei)-.22 E -.165(ve)-.275 G
(rs who might be inclined to lie about the Rate Request.).165 E
(This protection is no)100.8 332 Q 2.75(wp)-.275 G(ro)-2.75 E
(vided by the use of a random initial v)-.165 E
(alue for the QS TTL \214eld.)-.275 E -.44(Wi)100.8 358 S(th the old Qu\
ickStart Nonce, along with the QS TTL \214eld set to the same v).44 E
(alue as the)-.275 E(TTL \214eld in the IP header)100.8 371 Q 2.75(,t)
-.44 G(he Quick-Start Request mechanism w)-2.75 E(ould ha)-.11 E .33
-.165(ve b)-.22 H(een self-).165 E
(terminating; the Quick-Start Request w)100.8 384 Q
(ould terminate at the \214rst participating router after a)-.11 E
(non-participating router had been encountered on the path.)100.8 397 Q
(This w)5.5 E(ould ha)-.11 E .33 -.165(ve m)-.22 H(inimized).165 E
(unnecessary o)100.8 410 Q -.165(ve)-.165 G(rhead incurred by routers b\
ecause of option processing for the Quick-Start).165 E 2.75
(Request. Thus,)100.8 423 R(one disadv)2.75 E(antage of the ne)-.275 E
2.75(wa)-.275 G(pproach with a random initial v)-2.75 E(alue for the)
-.275 E(QS TTL \214eld is that intermediate routers can no longer deter\
mine when some upstream)100.8 436 Q
(router has not understood the QuickStart option.)100.8 449 Q(Ho)5.5 E
(we)-.275 E -.165(ve)-.275 G .88 -.44(r, a d).165 H(isadv).44 E
(antage of the old)-.275 E(approach w)100.8 462 Q(as that it of)-.11 E
(fered no protection ag)-.275 E(ainst do)-.055 E
(wnstream routers or the TCP recei)-.275 E -.165(ve)-.275 G(r).165 E
(hiding e)100.8 475 Q(vidence of upstream routers that do not understan\
d the QuickStart option.)-.275 E/F3 14/Times-Bold@0 SF(Normati)72 514 Q
.28 -.14(ve R)-.14 H(efer).14 E(ences)-.252 E F0([RFC793] J. Postel, T)
100.8 540 Q(ransmission Control Protocol, RFC 793, September 1981.)-.385
E([RFC1191] Mogul, J. and S. Deering, P)100.8 566 Q(ath MTU Disco)-.165
E -.165(ve)-.165 G(ry).165 E 2.75(,R)-.715 G(FC 1191, No)-2.75 E -.165
(ve)-.165 G(mber 1990.).165 E
([RFC2460] S. Deering and R. Hinden. Internet Protocol, V)100.8 592 Q
(ersion 6 \(IPv6\) Speci\214cation.)-1.221 E(RFC 2460, December 1998.)
100.8 605 Q([RFC2581] M. Allman, V)100.8 631 Q 2.75(.P)-1.419 G
(axson, and W)-2.915 E 2.75(.S)-1.012 G(te)-2.75 E -.165(ve)-.275 G
(ns. TCP Congestion Control.).165 E(RFC 2581.)5.5 E(April 1999.)100.8
644 Q([RFC3168] Ramakrishnan, K.K., Flo)100.8 670 Q
(yd, S., and Black, D.)-.11 E(The Addition of Explicit)5.5 E
(Congestion Noti\214cation \(ECN\) to IP)100.8 683 Q 5.5(.R)-1.221 G
(FC 3168, Proposed Standard, September 2001.)-5.5 E
([RFC3390] M. Allman, S. Flo)100.8 709 Q(yd, and C. P)-.11 E
(artridge. Increasing TCP')-.165 E 2.75(sI)-.605 G(nitial W)-2.75 E
(indo)-.44 E 1.43 -.715(w. R)-.275 H(FC).715 E(3390, October 2002.)100.8
722 Q(Jain/Flo)72 769 Q 261.775(yd/Allman/Sarolahti [P)-.11 F(age 41])
-.165 E 0 Cg EP
%%Page: 42 42
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E/F1 14/Times-Bold@0 SF(Inf)72
85 Q(ormati)-.35 E .28 -.14(ve R)-.14 H(efer).14 E(ences)-.252 E F0([RF\
C792] J. Postel. Internet Control Message Protocol. RFC 792, September \
1981.)100.8 111 Q([RFC1812] F)100.8 137 Q 2.75(.B)-.88 G(ak)-2.75 E
(er \(ed.\). Requirements for IP V)-.11 E
(ersion 4 Routers. RFC 1812, June 1995.)-1.221 E([RFC2140] J. T)100.8
163 Q(ouch. TCP Control Block Interdependence.)-.88 E
(RFC 2140. April 1997.)5.5 E
([RFC2205] R. Braden, et al. Resource ReSerV)100.8 189 Q
(ation Protocol \(RSVP\) -- V)-1.221 E(ersion 1)-1.221 E
(Functional Speci\214cation. RFC 2205, September 1997.)100.8 202 Q
([RFC2309] B. Braden, D. Clark, J. Cro)100.8 228 Q(wcroft, B. Da)-.275 E
(vie, S. Deering, D. Estrin, S. Flo)-.22 E(yd, V)-.11 E(.)-1.419 E
(Jacobson, G. Minshall, C. P)100.8 241 Q(artridge, L. Peterson, K.)-.165
E(Ramakrishnan, S. Shenk)5.5 E(er)-.11 E 2.75(,J)-.44 G(.)-2.75 E
(Wrocla)100.8 254 Q
(wski, L. Zhang, Recommendations on Queue Management and Congestion)
-.165 E -1.342 -.814(Av o)100.8 267 T
(idance in the Internet, RFC 2309, April 1998.).814 E([RFC2401] S. K)
100.8 293 Q(ent and R. Atkinson. Security Architecture for the Internet\
 Protocol. RFC)-.275 E(2401, No)100.8 306 Q -.165(ve)-.165 G(mber 1998.)
.165 E([RFC2415] K. Poduri and K. Nichols. Simulation Studies of Increa\
sed Initial TCP W)100.8 332 Q(indo)-.44 E(w)-.275 E
(Size. RFC 2415. September 1998.)100.8 345 Q([RFC2416] T)100.8 371 Q
2.75(.S)-.814 G(hepard and C. P)-2.75 E 2.75(artridge. When)-.165 F
(TCP Starts Up W)2.75 E(ith F)-.44 E(our P)-.165 E(ack)-.165 E(ets Into)
-.11 E(Only Three Buf)100.8 384 Q 2.75(fers. RFC)-.275 F
(2416. September 1998.)2.75 E([RFC2463] A. Conta and S. Deering. Intern\
et Control Message Protocol \(ICMPv6\) for the)100.8 410 Q
(Internet Protocol V)100.8 423 Q
(ersion 6 \(IPv6\) Speci\214cation. RFC 2463, December 1998.)-1.221 E
([RFC2488] M. Allman, D. Glo)100.8 449 Q -.165(ve)-.165 G .88 -.44(r, a)
.165 H(nd L. Sanchez. Enhancing TCP Ov).44 E(er Satellite)-.165 E
(Channels using Standard Mechanisms. RFC 2488. January 1999.)100.8 462 Q
([RFC2960] R. Ste)100.8 488 Q -.11(wa)-.275 G
(rt, et. al. Stream Control T).11 E
(ransmission Protocol. RFC 2960, October)-.385 E(2000.)100.8 501 Q
([RFC3124] H. Balakrishnan and S. Seshan. The Congestion Manager)100.8
527 Q 2.75(.R)-.605 G(FC 3124. June)-2.75 E(2001.)100.8 540 Q([RFC3344]\
 C. Perkins \(ed.\). IP Mobility Support for IPv4. RFC 3344, August 200\
2.)100.8 566 Q([RFC3360] S. Flo)100.8 592 Q 2.75(yd. Inappropriate)-.11
F(TCP Resets Considered Harmful.)2.75 E(RFC 3360, August)5.5 E(2002.)
100.8 605 Q([RFC3775] D. Johnson, C. Perkins, and J. Arkk)100.8 631 Q
(o. Mobility Support in IPv6. RFC 3775,)-.11 E(June 2004.)100.8 644 Q
([AHO98] M. Allman, C. Hayes and S. Ostermann. An e)100.8 670 Q -.275
(va)-.275 G(luation of TCP with Lar).275 E(ger)-.198 E(Initial W)100.8
683 Q(indo)-.44 E(ws. A)-.275 E(CM Computer Communication Re)-.44 E(vie)
-.275 E 1.43 -.715(w, J)-.275 H(uly 1998.).715 E
([BW97] G. Brasche and B. W)100.8 709 Q(alk)-.88 E
(e. Concepts, Services and Protocols of the ne)-.11 E 2.75(wG)-.275 G
(SM)-2.75 E(Phase 2+ General P)100.8 722 Q(ack)-.165 E
(et Radio Service. IEEE Communications Mag)-.11 E(azine, pages 94--104,)
-.055 E(Jain/Flo)72 769 Q 261.775(yd/Allman/Sarolahti [P)-.11 F(age 42])
-.165 E 0 Cg EP
%%Page: 43 43
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E(August 1997.)100.8 85 Q
([FF99] Flo)100.8 111 Q(yd, S., and F)-.11 E
(all, K., Promoting the Use of End-to-End Congestion Control in the)
-.165 E(Internet, IEEE/A)100.8 124 Q(CM T)-.44 E(ransactions on Netw)
-.385 E(orking, August 1999.)-.11 E([F03] Flo)100.8 150 Q
(yd, S., HighSpeed TCP for Lar)-.11 E(ge Congestion W)-.198 E(indo)-.44
E(ws, RFC 3649, December)-.275 E(2003.)100.8 163 Q([F04] Flo)100.8 189 Q
(yd, S., Limited Slo)-.11 E(w-Start for TCP with Lar)-.275 E
(ge Congestion W)-.198 E(indo)-.44 E(ws, RFC 3742,)-.275 E
(Experimental, March 2004.)100.8 202 Q([GP)100.8 228 Q(AR02] A. Gurto)
-1.012 E 1.43 -.715(v, M)-.165 H 2.75(.P).715 G
(assoja, O. Aalto, and M. Raitola. Multi-Layer Protocol T)-2.915 E
(racing)-.385 E(in a GPRS Netw)100.8 241 Q
(ork. In Proceedings of the IEEE V)-.11 E(ehicular T)-1.221 E
(echnology Conference \(F)-.77 E(all)-.165 E(VTC2002\), V)100.8 254 Q
(ancouv)-1.221 E(er)-.165 E 2.75(,C)-.44 G(anada, September 2002.)-2.75
E([Jac88] V)100.8 280 Q 2.75(.J)-1.419 G(acobson, Congestion A)-2.75 E
-.22(vo)-.814 G(idance and Control, A).22 E(CM SIGCOMM)-.44 E
([JD02] Manish Jain, Constantinos Do)100.8 306 Q(vrolis, End-to-End A)
-.165 E -.275(va)-.814 G(ilable Bandwidth:).275 E
(Measurement Methodology)100.8 319 Q 2.75(,D)-.715 G
(ynamics, and Relation with TCP Throughput, SIGCOMM)-2.75 E(2002.)100.8
332 Q([KHR02] Dina Katabi, Mark Handle)100.8 358 Q 1.43 -.715(y, a)-.165
H(nd Charles Rohrs, Internet Congestion Control for).715 E
(Future High Bandwidth-Delay Product En)100.8 371 Q(vironments. A)-.44 E
(CM Sigcomm 2002, August 2002.)-.44 E
(URL "http://ana.lcs.mit.edu/dina/XCP/".)100.8 384 Q([KHF04] E. K)100.8
410 Q(ohler)-.385 E 2.75(,M)-.44 G 2.75(.H)-2.75 G(andle)-2.75 E 1.43
-.715(y, a)-.165 H(nd S. Flo).715 E
(yd, Datagram Congestion Control Protocol)-.11 E
(\(DCCP\), internet draft draft-ietf-dccp-spec-09.txt, w)100.8 423 Q
(ork in progress, No)-.11 E -.165(ve)-.165 G(mber 2004.).165 E
([K03] S. K)100.8 449 Q(unniyur)-.165 E 2.75(,")-.44 G
(AntiECN Marking: A Marking Scheme for High Bandwidth Delay)-2.75 E
(Connections", Proceedings, IEEE ICC '03, May 2003.)100.8 462 Q(URL)5.5
E("http://www)100.8 475 Q(.seas.upenn.edu/~kunniyur/".)-.715 E
([KAPS02] Rajesh Krishnan, Mark Allman, Craig P)100.8 501 Q
(artridge, James P)-.165 E 2.75(.G. Sterbenz.)-1.221 F(Explicit)2.75 E
-.385(Tr)100.8 514 S(ansport Error Noti\214cation \(ETEN\) for Error)
.385 E(-Prone W)-.22 E(ireless and Satellite Netw)-.44 E(orks.)-.11 E
-.77(Te)100.8 527 S(chnical Report No. 8333, BBN T).77 E
(echnologies, March 2002.)-.77 E(URL)5.5 E("http://roland.lerc.nasa.go)
100.8 540 Q(v/~mallman/papers/".)-.165 E
([MAF04] Alberto Medina, Mark Allman, and Sally Flo)100.8 566 Q
(yd, Measuring Interactions)-.11 E(Between T)100.8 579 Q
(ransport Protocols and Middlebox)-.385 E
(es, Internet Measurement Conference 2004,)-.165 E(August 2004.)100.8
592 Q(URL "http://www)5.5 E(.icir)-.715 E(.or)-.605 E(g/tbit/".)-.198 E
([PK98] V)100.8 618 Q(enkata N. P)-1.221 E
(admanabhan and Randy H. Katz, TCP F)-.165 E(ast Start: A T)-.165 E
(echnique F)-.77 E(or)-.165 E(Speeding Up W)100.8 631 Q(eb T)-.88 E
(ransfers, IEEE GLOBECOM '98, No)-.385 E -.165(ve)-.165 G(mber 1998.)
.165 E([P00] Joon-Sang P)100.8 657 Q(ark, Bandwidth Disco)-.165 E -.165
(ve)-.165 G(ry of a TCP Connection, report to John).165 E
(Jeidemann, 2000, pri)100.8 670 Q -.275(va)-.275 G(te communication.)
.275 E(Citation for ackno)5.5 E(wledgement purposes only)-.275 E(.)-.715
E([PRAKS02] Craig P)100.8 696 Q
(artridge, Dennis Rockwell, Mark Allman, Rajesh Krishnan, James P)-.165
E(.G.)-1.221 E(Sterbenz. A Swifter Start for TCP)100.8 709 Q 2.75(.T)
-1.221 G(echnical Report No. 8339, BBN T)-3.52 E(echnologies, March)-.77
E 2.75(2002. URL)100.8 722 R("http://roland.lerc.nasa.go)2.75 E
(v/~mallman/papers/".)-.165 E(Jain/Flo)72 769 Q 261.775
(yd/Allman/Sarolahti [P)-.11 F(age 43])-.165 E 0 Cg EP
%%Page: 44 44
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E([S02] Ion Stoica, pri)100.8
85 Q -.275(va)-.275 G(te communication, 2002.).275 E(Citation for ackno)
5.5 E(wledgement purposes)-.275 E(only)100.8 98 Q(.)-.715 E([SAF05] P)
100.8 124 Q(asi Sarolahti, Mark Allman, and Sally Flo)-.165 E 2.75
(yd. Ev)-.11 F(aluating Quick-Start for TCP)-.275 E(.)-1.221 E
(Under submission, February 2005.)100.8 137 Q(URL "http://www)5.5 E
(.icir)-.715 E(.or)-.605 E(g/\215o)-.198 E(yd/quickstart.html".)-.11 E
([SH02] Srikanth Sundarrajan and John Heidemann.)100.8 163 Q
(Study of TCP Quick Start with NS-2.)5.5 E
(Class Project, December 2002.)100.8 176 Q(Not publically a)5.5 E -.275
(va)-.22 G(ilable; citation for ackno).275 E(wledgement)-.275 E
(purposes only)100.8 189 Q(.)-.715 E([W00] Michael W)100.8 215 Q
(elzl: PTP: Better Feedback for Adapti)-.88 E .33 -.165(ve D)-.275 H
(istrib).165 E(uted Multimedia)-.22 E(Applications on the Internet, IPC\
CC 2000 \(19th IEEE International Performance,)100.8 228 Q(Computing, A\
nd Communications Conference\), Phoenix, Arizona, USA, 20-22 February)
100.8 241 Q 2.75(2000. URL)100.8 254 R
("http://informatik.uibk.ac.at/users/c70370/research/publications/".)
2.75 E([W03] Michael W)100.8 280 Q(elzl, PMTU-Options: P)-.88 E
(ath MTU Disco)-.165 E -.165(ve)-.165 G(ry Using Options, e).165 E
(xpired)-.165 E(internet-draft draft-welzl-pmtud-options-01.txt, w)100.8
293 Q 2.75(ork-in-progress. February)-.11 F(2003.)2.75 E/F1 14
/Times-Bold@0 SF(IAN)72 332 Q 3.5(AC)-.28 G(onsiderations)-3.5 E F0
(The only IAN)100.8 358 Q 2.75(AC)-.385 G(onsiderations w)-2.75 E
(ould be the addition of an IP option to the list of IP)-.11 E
(options, and the addition of a TCP option to the list of TCP options.)
100.8 371 Q F1 -.7(AU)72 410 S(THORS' ADDRESSES).7 E F0(Amit Jain)100.8
449 Q(F5 Netw)100.8 462 Q(orks)-.11 E(Email : a.jain@f5.com)100.8 475 Q
(Sally Flo)100.8 501 Q(yd)-.11 E(Phone: +1 \(510\) 666-2989)100.8 514 Q
(ICIR \(ICSI Center for Internet Research\))100.8 527 Q(Email: \215o)
100.8 540 Q(yd@icir)-.11 E(.or)-.605 E(g)-.198 E(URL: http://www)100.8
553 Q(.icir)-.715 E(.or)-.605 E(g/\215o)-.198 E(yd/)-.11 E -.165(Pa)
100.8 579 S(si Sarolahti).165 E(Nokia Research Center)100.8 592 Q -1.221
(P.)100.8 605 S(O. Box 407)1.221 E(FI-00045 NOKIA GR)100.8 618 Q(OUP)
-.44 E(Finland)100.8 631 Q(Phone: +358 50 4876607)100.8 644 Q
(Email: pasi.sarolahti@iki.\214)100.8 657 Q F1(Full Copyright Statement)
72 696 Q F0(Cop)100.8 722 Q(yright \(C\) The Internet Society 2004.)-.11
E(This document is subject to the rights, licenses)5.5 E(Jain/Flo)72 769
Q 261.775(yd/Allman/Sarolahti [P)-.11 F(age 44])-.165 E 0 Cg EP
%%Page: 45 45
%%BeginPageSetup
BP
%%EndPageSetup
/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 72.802(-DRAFT Expires:)-1.012 F
(August 2005)2.75 E(February 2005)103.569 E
(and restrictions contained in BCP 78, and e)100.8 85 Q
(xcept as set forth therein, the authors retain all)-.165 E
(their rights.)100.8 98 Q
(This document and the information contained herein are pro)100.8 124 Q
(vided on an "AS IS" basis and)-.165 E(THE CONTRIB)100.8 137 Q(UT)-.11 E
(OR, THE ORGANIZA)-.198 E(TION HE/SHE REPRESENTS OR IS)-1.221 E
(SPONSORED BY \(IF ANY\), THE INTERNET SOCIETY AND THE INTERNET)100.8
150 Q(ENGINEERING T)100.8 163 Q(ASK FORCE DISCLAIM ALL W)-1.023 E
(ARRANTIES, EXPRESS OR)-1.32 E(IMPLIED, INCLUDING B)100.8 176 Q(UT NO)
-.11 E 2.75(TL)-.44 G(IMITED T)-2.75 E 2.75(OA)-.198 G(NY W)-2.75 E
(ARRANTY THA)-1.32 E 2.75(TT)-1.221 G(HE USE)-2.75 E(OF THE INFORMA)
100.8 189 Q(TION HEREIN WILL NO)-1.221 E 2.75(TI)-.44 G
(NFRINGE ANY RIGHTS OR ANY)-2.75 E(IMPLIED W)100.8 202 Q
(ARRANTIES OF MERCHANT)-1.32 E(ABILITY OR FITNESS FOR A)-1.023 E -1.012
(PA)100.8 215 S -.66(RT)1.012 G(ICULAR PURPOSE.).66 E/F1 14/Times-Bold@0
SF(Intellectual Pr)72 254 Q(operty)-.252 E F0(The IETF tak)100.8 280 Q
(es no position re)-.11 E -.055(ga)-.165 G(rding the v).055 E
(alidity or scope of an)-.275 E 2.75(yI)-.165 G(ntellectual Property)
-2.75 E(Rights or other rights that might be claimed to pertain to the \
implementation or use of the)100.8 293 Q
(technology described in this document or the e)100.8 306 Q
(xtent to which an)-.165 E 2.75(yl)-.165 G(icense under such rights)
-2.75 E(might or might not be a)100.8 319 Q -.275(va)-.22 G
(ilable; nor does it represent that it has made an).275 E 2.75(yi)-.165
G(ndependent)-2.75 E(ef)100.8 332 Q(fort to identify an)-.275 E 2.75(ys)
-.165 G(uch rights.)-2.75 E
(Information on the procedures with respect to rights in)5.5 E
(RFC documents can be found in BCP 78 and BCP 79.)100.8 345 Q
(Copies of IPR disclosures made to the IETF Secretariat and an)100.8 371
Q 2.75(ya)-.165 G(ssurances of licenses to)-2.75 E(be made a)100.8 384 Q
-.275(va)-.22 G(ilable, or the result of an attempt made to obtain a ge\
neral license or).275 E(permission for the use of such proprietary righ\
ts by implementers or users of this)100.8 397 Q(speci\214cation can be \
obtained from the IETF on-line IPR repository at)100.8 410 Q(http://www)
100.8 423 Q(.ietf.or)-.715 E(g/ipr)-.198 E(.)-.605 E(The IETF in)100.8
449 Q(vites an)-.44 E 2.75(yi)-.165 G
(nterested party to bring to its attention an)-2.75 E 2.75(yc)-.165 G
(op)-2.75 E(yrights, patents or)-.11 E
(patent applications, or other proprietary rights that may co)100.8 462
Q -.165(ve)-.165 G 2.75(rt).165 G(echnology that may be)-2.75 E
(required to implement this standard.)100.8 475 Q
(Please address the information to the IETF at ietf-)5.5 E(ipr@ietf.or)
100.8 488 Q(g.)-.198 E(Jain/Flo)72 769 Q 261.775(yd/Allman/Sarolahti [P)
-.11 F(age 45])-.165 E 0 Cg EP
%%Trailer
end
%%EOF