One document matched: draft-ietf-rmt-bb-fec-supp-compact-01.ps

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/F0 10/Courier-Bold@0 SF(Internet Engineering Task Force)72 85 Q(RMT WG)
209.999 E 299.999(INTERNET-DRAFT M.)72 98 R(Luby)6 E 89.999
(draft-ietf-rmt-bb-fec-supp-compact-01.ps Digital)72 111 R(Fountain)6 E
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(Expires: November 2003)371.999 163 Q/F1 14/Times-Bold@0 SF(Compact F)
133.3 188 Q(orward Err)-.35 E(or Corr)-.252 E(ection \(FEC\) Schemes)
-.252 E/F2 11/Times-Bold@0 SF(Status of this Document)72 226 Q/F3 11
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formance with all pro)72 245 Q(visions of Section 10 of)-.165 E
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(Internet-Drafts are v)72 310 Q
(alid for a maximum of six months and may be updated, replaced, or)-.275
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(ime. It)-2.75 F(is inappropriate to use Internet-Drafts as reference)
2.75 E(material or to cite them other than as a "w)72 336 Q
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(The list of current Internet-Drafts can be accessed at http://www)72
362 Q(.ietf.or)-.715 E(g/ietf/1id-abstracts.txt)-.198 E 1.76 -.88(To v)
72 388 T(ie).88 E 2.75(wt)-.275 G(he list Internet-Draft Shado)-2.75 E
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(This document is a product of the IETF RMT WG.)72 414 Q
(Comments should be addressed to the)5.5 E(authors, or the WG')72 427 Q
2.75(sm)-.605 G(ailing list at rmt@lbl.go)-2.75 E -.715(v.)-.165 G F2
(Abstract)72 459 Q F3(This document introduces some F)72 481.6 Q(orw)
-.165 E(ard Error Correction \(FEC\) schemes that supplement the)-.11 E
(FEC schemes described in RFC 3452 [6]. The primary bene\214ts of these\
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G(re designed for reliable b)-2.75 E(ulk deli)-.22 E -.165(ve)-.275 G
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72 520.6 S(yload ID, and the).165 E 2.75(yc)-.165 G
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(ferent deli)-.275 E -.165(ve)-.275 G(ry models with less pack).165 E
(et header)-.11 E -.165(ove)72 546.6 S(rhead.).165 E(This document also\
 describes the Fully-Speci\214ed FEC scheme corresponding to FEC Encodi\
ng)72 572.6 Q(ID 0. This Fully-Speci\214ed FEC scheme requires no FEC c\
oding and is introduced primarily to)72 585.6 Q(allo)72 598.6 Q 2.75(ws)
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(ferent implementations of protocol instantiations)-.275 E
(that use the FEC b)72 611.6 Q(uilding block.)-.22 E(Luby/V)72 769 Q
327.731(icisano [P)-.66 F(age 1])-.165 E EP
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(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E/F1 13
/Times-Bold@0 SF -1.196(Ta)239.126 85 S(ble of Contents)1.196 E/F2 10
/Times-Roman@0 SF(1. Introduction)72 123 Q F0 11
(.........................)12.31 G F2(3)11.5 E(2. P)72 135 Q(ack)-.15 E
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159 Q F0 11(..................)11.9 G F2(5)11.5 E
(2.3. Compact FEC scheme)82 171 Q F0 11(.....................)9.81 G F2
(5)11.5 E(3. Compact No-Code FEC scheme)72 183 Q F0 11
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195 Q F0 11(.....................)5.92 G F2(6)11.5 E
(3.2. Sending and Recei)82 207 Q(ving a Source Block)-.25 E F0 11
(................)11.88 G F2(7)11.5 E(4. Usage Examples)72 219 Q F0 11
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(4.1. Reliable Bulk Data Deli)82 231 Q -.15(ve)-.25 G(ry).15 E F0 11
(...................)13 G F2(8)11.5 E(4.2. Block-Stream Deli)82 243 Q
-.15(ve)-.25 G(ry).15 E F0 11(.....................)6.61 G F2(8)11.5 E
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(..........................)3.58 G F2(9)11.5 E(8. Authors' Addresses)72
291 Q F0 11(.......................)10.1 G F2(10)6.5 E(9. Full Cop)72
303 Q(yright Statement)-.1 E F0 11(......................)1.42 G F2(11)
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-.252 E F0(This document describes tw)72 101.6 Q 2.75(on)-.11 G .55
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(ard Error Correction \(FEC\) schemes corresponding to)-.11 E(FEC Encod\
ing IDs 0 and 130 which supplement the FEC schemes corresponding to FEC)
72 114.6 Q
(Encoding IDs 128 and 129 described in the FEC Building Block [6].)72
127.6 Q(The ne)72 144.2 Q 2.75(wF)-.275 G(EC schemes are particularly a\
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(source blocks.)72 157.2 Q(In this case, the source block length common\
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(This Fully-Speci\214ed FEC scheme)5.5 E
(requires no FEC coding and is speci\214ed primarily to allo)72 417.2 Q
2.75(ws)-.275 G(imple interoperability testing between)-2.75 E(dif)72
430.2 Q
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he companion document [7] which)72 469.2 Q
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(an introduction to some commonly used FEC codes.)72 495.2 Q(Building b\
locks are de\214ned in RFC 3048 [9]. This document is a product of the \
IETF RMT WG)72 521.2 Q(and follo)72 534.2 Q
(ws the general guidelines pro)-.275 E(vided in RFC 3269 [3].)-.165 E
(The k)72 550.8 Q .33 -.165(ey w)-.11 H(ords "MUST", "MUST NO).055 E
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 FEC Encoding ID 0 is Fully-Speci\214ed whereas the FEC schemes)72 649 Q
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72 714 Q(ferent, and is described in the subsequent tw)-.275 E 2.75(os)
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(implementations of protocol instantiations that use the FEC b)72 719.8
Q(uilding block.)-.22 E(The v)5.5 E(alue of this)-.275 E(Luby/V)72 769 Q
269.981(icisano Section)-.66 F 2.75(2.2. [P)2.75 F(age 4])-.165 E EP
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/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 65.641(-DRAFT Expires:)-1.012 F
(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E(FEC sch\
eme is that no FEC encoding or decoding is required to implement it and\
 therefore it is)72 85 Q
(easy to test interoperability between protocols that may use dif)72 98
Q(ferent proprietary FEC schemes in)-.275 E
(production in their \214rst implementations.)72 111 Q(The FEC P)72 137
Q
(ayload ID format for FEC Encoding ID 0 is described in Subsection 2.1.)
-.165 E(The FEC)5.5 E(Object T)72 150 Q
(ransmission Information has the follo)-.385 E
(wing speci\214c information:)-.275 E 11(oT)77.5 179.6 S
(he FEC Encoding ID 0.)-11 E 11(oF)77.5 196.2 S(or each source block of\
 the object, the length in bytes of the encoding symbol carried in the)
-11.165 E(pack)94 209.2 Q(et payload.)-.11 E
(This length MUST be the same for all pack)5.5 E
(ets sent for the same source)-.11 E(block, b)94 222.2 Q(ut MA)-.22 E
2.75(Yb)-1.155 G 2.75(ed)-2.75 G(if)-2.75 E(ferent for dif)-.275 E
(ferent source blocks in the same object.)-.275 E 11(oF)77.5 238.8 S(or\
 each source block of the object, the length of the source block in byt\
es.)-11.165 E -.88(Ty)5.5 G(pically).88 E 2.75(,e)-.715 G(ach)-2.75 E(s\
ource block for the object has the same length and thus only one length\
 common to all)94 251.8 Q(source blocks need be communicated, b)94 264.8
Q(ut this is not a requirement.)-.22 E -.165(Fo)5.5 G 2.75(rc).165 G(on)
-2.75 E -.165(ve)-.44 G(nience, the).165 E(source block length MA)94
277.8 Q 2.75(Yb)-1.155 G 2.75(eam)-2.75 G
(ultiple of the length of the encoding symbol carried in one)-2.75 E
(pack)94 290.8 Q(et payload.)-.11 E(Ho)72 320.4 Q 2.75(wt)-.275 G(his o\
ut-of-band information is communicated is outside the scope of this doc\
ument.)-2.75 E(Other information, such as the object length and the num\
ber of source blocks of the object for an)72 346.4 Q(object of kno)72
359.4 Q(wn length may be needed by a recei)-.275 E -.165(ve)-.275 G 2.75
(rt).165 G 2.75(os)-2.75 G(upport some deli)-2.75 E -.165(ve)-.275 G
(ry models such as).165 E(reliable b)72 372.4 Q(ulk data deli)-.22 E
-.165(ve)-.275 G(ry).165 E(.)-.715 E/F1 11/Times-Bold@0 SF(2.3.)72 415 Q
/F2 13/Times-Bold@0 SF(Compact FEC scheme)5.5 E F0
(This subsection reserv)72 431.6 Q
(es FEC Encoding ID 130 for the Compact FEC scheme that is described in)
-.165 E(this subsection.)72 444.6 Q(This is an Under)5.5 E
(-Speci\214ed FEC scheme.)-.22 E
(This FEC scheme is similar in spirit to)5.5 E
(the Compact No-Code FEC scheme, e)72 457.6 Q(xcept that a non-tri)-.165
E(vial FEC encoding \(that is Under)-.275 E(-)-.22 E(Speci\214ed\) may \
be used to generate encoding symbol\(s\) placed in the payload of each \
pack)72 470.6 Q(et and)-.11 E 2.75(ac)72 483.6 S(orresponding FEC decod\
er may be used to produce the source block from recei)-2.75 E -.165(ve)
-.275 G 2.75(dp).165 G(ack)-2.75 E(ets.)-.11 E(The FEC P)72 509.6 Q
(ayload ID format for FEC Encoding ID 0 is described in Subsection 2.1.)
-.165 E(The FEC)5.5 E(Object T)72 522.6 Q
(ransmission Information has the follo)-.385 E
(wing speci\214c information:)-.275 E 11(oT)77.5 552.2 S
(he FEC Encoding ID 130.)-11 E 11(oT)77.5 568.8 S
(he FEC Instance ID associated with the FEC Encoding ID 130 to be used.)
-11 E 11(oF)77.5 585.4 S(or each source block of the object, the aggre)
-11.165 E -.055(ga)-.165 G
(te length of the encoding symbol\(s\) carried).055 E(in one pack)94
598.4 Q(et payload.)-.11 E(This length MUST be the same for all pack)5.5
E(ets sent for the same)-.11 E(source block, b)94 611.4 Q(ut MA)-.22 E
2.75(Yb)-1.155 G 2.75(ed)-2.75 G(if)-2.75 E(ferent for dif)-.275 E
(ferent source blocks in the same object.)-.275 E 11(oF)77.5 628 S(or e\
ach source block of the object, the length of the source block in bytes\
.)-11.165 E -.88(Ty)5.5 G(pically).88 E 2.75(,e)-.715 G(ach)-2.75 E(sou\
rce block for the object has the same length and thus only one length c\
ommon to all)94 641 Q(source blocks need be communicated, b)94 654 Q
(ut this is not a requirement.)-.22 E -.165(Fo)5.5 G 2.75(rc).165 G(on)
-2.75 E -.165(ve)-.44 G(nience, the).165 E(source block length MA)94 667
Q 2.75(Yb)-1.155 G 2.75(eam)-2.75 G(ultiple of the aggre)-2.75 E -.055
(ga)-.165 G(te length of the encoding symbol\(s\)).055 E
(carried in one pack)94 680 Q(et payload.)-.11 E(Ho)72 709.6 Q 2.75(wt)
-.275 G(his out-of-band information is communicated is outside the scop\
e of this document.)-2.75 E(Luby/V)72 769 Q 269.981(icisano Section)-.66
F 2.75(2.3. [P)2.75 F(age 5])-.165 E EP
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/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 65.641(-DRAFT Expires:)-1.012 F
(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E(Other i\
nformation, such as the object length and the number of source blocks o\
f the object for an)72 85 Q(object of kno)72 98 Q
(wn length may be needed by a recei)-.275 E -.165(ve)-.275 G 2.75(rt)
.165 G 2.75(os)-2.75 G(upport some deli)-2.75 E -.165(ve)-.275 G
(ry models such as).165 E(reliable b)72 111 Q(ulk data deli)-.22 E -.165
(ve)-.275 G(ry).165 E(.)-.715 E/F1 11/Times-Bold@0 SF(3.)72 153.6 Q/F2
14/Times-Bold@0 SF(Compact No-Code FEC scheme)5.5 E F0(In this section \
we describe a Fully-Speci\214ed FEC scheme corresponding to FEC Encodin\
g ID 0.)72 183.2 Q
(The primary purpose for introducing this FEC schemes is to allo)72
196.2 Q 2.75(ws)-.275 G(imple interoperability testing)-2.75 E
(between dif)72 209.2 Q(ferent implementations of the same protocol ins\
tantiation that uses the FEC b)-.275 E(uilding)-.22 E(block.)72 222.2 Q
(The Compact No-Code FEC scheme does not require FEC encoding or decodi\
ng.)72 248.2 Q(Instead, each)5.5 E
(encoding symbol consists of consecuti)72 261.2 Q .33 -.165(ve b)-.275 H
(ytes of a source block of the object.).165 E(The FEC P)5.5 E(ayload)
-.165 E(ID consists of tw)72 274.2 Q 2.75<6f8c>-.11 G(elds, the 16-bit \
Source Block Number and the 16-bit Encoding Symbol ID, as)-2.75 E
(described in Subsection 2.1. The relati)72 287.2 Q .33 -.165(ve l)-.275
H(engths of these \214elds were chosen for their similarity).165 E
(with the corresponding \214elds of the FEC P)72 300.2 Q
(ayload ID associated with FEC Encoding ID 130, and)-.165 E(because of \
this testing interoperability of the FEC scheme associated with FEC Enc\
oding ID 0)72 313.2 Q(pro)72 326.2 Q(vides a \214rst basic step to test\
ing interoperability of an FEC scheme associated with FEC)-.165 E
(Encoding ID 130.)72 339.2 Q(The mapping between source blocks of an ob\
ject and Source Block Numbers is as described in)72 365.2 Q
(Subsection 2.1. The ne)72 378.2 Q(xt tw)-.165 E 2.75(os)-.11 G
(ubsections describe the details of ho)-2.75 E 2.75(wt)-.275 G
(he Compact No-Code FEC)-2.75 E(scheme operates for each source block o\
f an object. These subsections are not meant to suggest a)72 391.2 Q
(particular implementation, b)72 404.2 Q(ut just to illustrate the gene\
ral algorithm through the description of a)-.22 E
(simple, non-optimized implementation.)72 417.2 Q F1(3.1.)72 459.8 Q/F3
13/Times-Bold@0 SF(Sour)5.5 E(ce Block Logistics)-.234 E F0
(Let X > 0 be the length of a source block in bytes.)72 489.4 Q(The v)
5.5 E(alue of X is part of the FEC Object)-.275 E -.385(Tr)72 502.4 S
(ansmission Information, and ho).385 E 2.75(wt)-.275 G
(his information is communicated to a recei)-2.75 E -.165(ve)-.275 G
2.75(ri).165 G 2.75(so)-2.75 G(utside the)-2.75 E
(scope of this document.)72 515.4 Q(Let L > 0 be the length of the enco\
ding symbol contained in the payload of each pack)72 541.4 Q 2.75
(et. There)-.11 F(are se)72 554.4 Q -.165(ve)-.275 G(ral possible w).165
E(ays the length of the encoding symbol L can be communicated to the)
-.11 E(recei)72 567.4 Q -.165(ve)-.275 G .88 -.44(r, a).165 H(nd ho).44
E 2.75(wt)-.275 G(his is done is outside the scope of this document.)
-2.75 E(As an e)5.5 E(xample, a sender)-.165 E(could \214x the pack)72
580.4 Q(et payload length to be L in order to place the encoding symbol\
 of length L into)-.11 E(the pack)72 593.4 Q(et, and then a recei)-.11 E
-.165(ve)-.275 G 2.75(rc).165 G(ould infer the v)-2.75 E
(alue of L from the length of the recei)-.275 E -.165(ve)-.275 G 2.75
(dp).165 G(ack)-2.75 E(et)-.11 E 2.75(payload. It)72 606.4 R(is REQ)2.75
E(UIRED that L be the same for all pack)-.11 E
(ets sent for the same source block b)-.11 E(ut)-.22 E(MA)72 619.4 Q
2.75(Yb)-1.155 G 2.75(ed)-2.75 G(if)-2.75 E(ferent for dif)-.275 E
(ferent source blocks within the same object.)-.275 E -.165(Fo)72 645.4
S 2.75(rag).165 G -2.365 -.275(iv e)-2.75 H 2.75(ns).275 G(ource block \
X bytes in length with Source Block Number I, let N = X/L rounded up)
-2.75 E(to the nearest inte)72 658.4 Q(ger)-.165 E 5.5(.T)-.605 G
(he encoding symbol carried in the payload of a pack)-5.5 E
(et consists of a)-.11 E(consecuti)72 671.4 Q .33 -.165(ve p)-.275 H
(ortion of the source block.).165 E
(The source block is logically partitioned into N)5.5 E(encoding symbol\
s, each L bytes in length, and the corresponding Encoding Symbol IDs ra\
nge)72 684.4 Q(from 0 through N-1 starting at the be)72 697.4 Q
(ginning of the source block and proceeding to the end.)-.165 E(Thus,)
5.5 E(the encoding symbol with Encoding Symbol ID Y consists of bytes L\
*Y through L*\(Y+1\)-1 of)72 710.4 Q(the source block, where the bytes \
of the source block are numbered from 0 through X-1.)72 723.4 Q
(If X/L is)5.5 E(Luby/V)72 769 Q 269.981(icisano Section)-.66 F 2.75
(3.1. [P)2.75 F(age 6])-.165 E EP
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/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 65.641(-DRAFT Expires:)-1.012 F
(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E
(not inte)72 85 Q(gral then the last encoding symbol with Encoding Symb\
ol ID = N-1 consists of bytes)-.165 E(L*\(N-1\) through the last byte X\
-1 of the source block, and the remaining L*N - X bytes of the)72 98 Q
(encoding symbol can by padded out with zeroes.)72 111 Q(As an e)72 137
Q(xample, suppose that the source block length X = 20,400 and encoding \
symbol length L =)-.165 E 2.75(1,000. The)72 150 R(encoding symbol with\
 Encoding Symbol ID = 10 contains bytes 10,000 through)2.75 E(10,999 of\
 the source block, and the encoding symbol with Encoding Symbol ID = 20\
 contains)72 163 Q(bytes 20,000 through the last byte 20,399 of the sou\
rce block and the remaining 600 bytes of the)72 176 Q
(encoding symbol can be padded with zeroes.)72 189 Q
(There are no restrictions be)72 215 Q(yond the rules stated abo)-.165 E
.33 -.165(ve o)-.165 H 2.75(nh).165 G .55 -.275(ow a s)-2.75 H
(ender generates encoding).275 E(symbols to send from a source block.)72
228 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(sr)-2.75 G(ecommended that an implementor of refer)-2.75 E
(to the companion document [7] for general advice.)72 241 Q(In the ne)72
267 Q(xt subsection a procedure is recommended for sending and recei)
-.165 E(ving source blocks.)-.275 E/F1 11/Times-Bold@0 SF(3.2.)72 309.6
Q/F2 13/Times-Bold@0 SF(Sending and Recei)5.5 E(ving a Sour)-.13 E
(ce Block)-.234 E F0(The follo)72 339.2 Q
(wing carousel procedure is RECOMMENDED for a sender to generate pack)
-.275 E(ets)-.11 E(containing FEC P)72 352.2 Q(ayload IDs and correspon\
ding encoding symbols for a source block with Source)-.165 E
(Block Number I.)72 365.2 Q
(Set the length in bytes of an encoding symbol to a \214x)5.5 E(ed v)
-.165 E(alue L which is)-.275 E(reasonable for a pack)72 378.2 Q
(et payload \(e.g., ensure that the total pack)-.11 E
(et size does not e)-.11 E(xceed the MTU\))-.165 E(and that is smaller \
than the source block length X, e.g., L = 1,000 for X >= 1,000.)72 391.2
Q(Initialize Y to)5.5 E 2.75(av)72 404.2 S
(alue randomly chosen in the interv)-3.025 E(al [0..N-1].)-.275 E
(Repeat the follo)5.5 E(wing for each pack)-.275 E(et of the)-.11 E
(source block to be sent.)72 417.2 Q 11(oI)77.5 433.8 S 2.75(fY<N)-11 G
(-1 then generate the encoding symbol consisting of the L bytes of the \
source block)-2.75 E(numbered L*Y through L*\(Y+1\)-1.)94 446.8 Q 11(oI)
77.5 463.4 S 2.75(fY=N)-11 G(-1 then generate the encoding symbol consi\
sting of the last X - L*\(N-1\) bytes of the)-2.75 E
(source block numbered L*\(N-1\) through X-1 follo)94 476.4 Q
(wed by L*N - X padding bytes of zeroes.)-.275 E 11(oS)77.5 493 S(et th\
e Source Block Length to X, set the Source Block Number = I, set the En\
coding)-11 E(Symbol ID = Y)94 506 Q 2.75(,p)-1.419 G(lace the FEC P)
-2.75 E(ayload ID and the encoding symbol into the pack)-.165 E
(et to send.)-.11 E 11(oI)77.5 522.6 S 2.75(np)-11 G
(reparation for the generation of the ne)-2.75 E(xt pack)-.165 E
(et: if Y < N-1 then increment Y by one)-.11 E
(elseif Y = N-1 then reset Y to zero.)94 535.6 Q(The follo)72 565.2 Q
(wing procedure is RECOMMENDED for a recei)-.275 E -.165(ve)-.275 G 2.75
(rt).165 G 2.75(or)-2.75 G(eco)-2.75 E -.165(ve)-.165 G 2.75(rt).165 G
(he source block based)-2.75 E(on recei)72 578.2 Q(ving pack)-.275 E(et\
s for the source block from a sender that is using the carousel procedu\
re)-.11 E(describe abo)72 591.2 Q -.165(ve)-.165 G 5.5(.T).165 G
(he recei)-5.5 E -.165(ve)-.275 G 2.75(rc).165 G
(an determine from which source block a recei)-2.75 E -.165(ve)-.275 G
2.75(dp).165 G(ack)-2.75 E(et w)-.11 E(as)-.11 E
(generated by the Source Block Number carried in the FEC P)72 604.2 Q
(ayload ID.)-.165 E(Upon receipt of the \214rst)5.5 E(FEC P)72 617.2 Q
(ayload ID for a source block, the recei)-.165 E -.165(ve)-.275 G 2.75
(ru).165 G(ses the source block length recei)-2.75 E -.165(ve)-.275 G
2.75(do).165 G(ut-of-)-2.75 E(band as part of the FEC Object T)72 630.2
Q(ransmission Information to determine the length X in bytes of)-.385 E
(the source block, and allocates space for the X bytes that the source \
block requires.)72 643.2 Q(The recei)5.5 E -.165(ve)-.275 G(r).165 E(al\
so computes the length L of the encoding symbol\(s\) in the payload of \
the pack)72 656.2 Q(et by subtracting)-.11 E(the pack)72 669.2 Q
(et header length from the total length of the recei)-.11 E -.165(ve)
-.275 G 2.75(dp).165 G(ack)-2.75 E(et \(and the recei)-.11 E -.165(ve)
-.275 G 2.75(rc).165 G(hecks that)-2.75 E
(this length is the same in each subsequent recei)72 682.2 Q -.165(ve)
-.275 G 2.75(dp).165 G(ack)-2.75 E(et from the same source block\).)-.11
E(After)5.5 E(calculating N = X/L rounded up to the nearest inte)72
695.2 Q(ger)-.165 E 2.75(,t)-.44 G(he recei)-2.75 E -.165(ve)-.275 G
2.75(ra).165 G(llocates a boolean array)-2.75 E
(RECEIVED[0..N-1] with all N entries initialized to f)72 708.2 Q
(alse to track recei)-.11 E -.165(ve)-.275 G 2.75(de).165 G
(ncoding symbols.)-2.75 E(The recei)72 721.2 Q -.165(ve)-.275 G 2.75(rk)
.165 G(eeps recei)-2.86 E(ving pack)-.275 E
(ets for the source block as long as there is at least one entry in)-.11
E(Luby/V)72 769 Q 269.981(icisano Section)-.66 F 2.75(3.2. [P)2.75 F
(age 7])-.165 E EP
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/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 65.641(-DRAFT Expires:)-1.012 F
(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E
(RECEIVED still set to f)72 85 Q
(alse or until the application decides to gi)-.11 E .33 -.165(ve u)-.275
H 2.75(po).165 G 2.75(nt)-2.75 G(his source block and)-2.75 E(mo)72 98 Q
.33 -.165(ve o)-.165 H 2.75(nt).165 G 2.75(oo)-2.75 G
(ther source blocks.)-2.75 E -.165(Fo)5.5 G 2.75(re).165 G(ach recei)
-2.75 E -.165(ve)-.275 G 2.75(dp).165 G(ack)-2.75 E
(et for the source block \(including the \214rst)-.11 E(pack)72 111 Q
(et\) the steps to be tak)-.11 E(en to help reco)-.11 E -.165(ve)-.165 G
2.75(rt).165 G(he source block are as follo)-2.75 E 2.75(ws. Let)-.275 F
2.75(Yb)2.75 G 2.75(et)-2.75 G(he v)-2.75 E(alue)-.275 E
(of the Encoding Symbol ID within FEC P)72 124 Q(ayload ID of the pack)
-.165 E 2.75(et. If)-.11 F 2.75(Y<N)2.75 G(-1 then the recei)-2.75 E
-.165(ve)-.275 G(r).165 E(copies the L bytes of the encoding symbol int\
o bytes numbered L*Y through L*\(Y+1\)-1 of the)72 137 Q(space reserv)72
150 Q(ed for the source block. If Y = N-1 then the recei)-.165 E -.165
(ve)-.275 G 2.75(rc).165 G(opies the \214rst X - L*\(N-1\))-2.75 E(byte\
s of the encoding symbol into bytes numbered L*\(N-1\) through X-1 of t\
he space reserv)72 163 Q(ed for)-.165 E(the source block.)72 176 Q
(In either case, the recei)5.5 E -.165(ve)-.275 G 2.75(rs).165 G
(ets RECEIVED[Y] = true.)-2.75 E(At each point in time,)5.5 E(the recei)
72 189 Q -.165(ve)-.275 G 2.75(rh).165 G(as successfully reco)-2.75 E
-.165(ve)-.165 G
(red bytes L*Y through L*\(Y+1\)-1 of the source block for all).165 E
2.75(Yi)72 202 S 2.75(nt)-2.75 G(he interv)-2.75 E
(al [0..N-1] for which RECEIVED[Y] is true.)-.275 E
(If all all N entries of RECEIVED are)5.5 E(true then the recei)72 215 Q
-.165(ve)-.275 G 2.75(rh).165 G(as reco)-2.75 E -.165(ve)-.165 G
(red the entire source block.).165 E/F1 11/Times-Bold@0 SF(4.)72 257.6 Q
/F2 14/Times-Bold@0 SF(Usage Examples)5.5 E F0(The follo)72 287.2 Q
(wing subsections outline some usage e)-.275 E
(xamples for FEC Encoding IDs 0 and 130.)-.165 E F1(4.1.)72 329.8 Q/F3
13/Times-Bold@0 SF(Reliable Bulk Data Deli)5.5 E -.13(ve)-.13 G(ry).13 E
F0(One possible deli)72 359.4 Q -.165(ve)-.275 G
(ry model that can be supported using an).165 E 2.75(yF)-.165 G
(EC scheme described in this)-2.75 E(document is reliable b)72 372.4 Q
(ulk data deli)-.22 E -.165(ve)-.275 G(ry).165 E 5.5(.I)-.715 G 2.75(nt)
-5.5 G(his model, one or more potentially lar)-2.75 E(ge objects are to)
-.198 E(be reliably deli)72 385.4 Q -.165(ve)-.275 G
(red to potentially multiple recei).165 E -.165(ve)-.275 G
(rs using multicast.).165 E -.165(Fo)5.5 G 2.75(rt).165 G(his deli)-2.75
E -.165(ve)-.275 G(ry model the).165 E(unique SBN mode is often used.)72
398.4 Q(Using this mode the maximum length of an object that can be)5.5
E(deli)72 411.4 Q -.165(ve)-.275 G(red is at most the number of possibl\
e source blocks times the maximum length of a source).165 E 2.75
(block. If)72 424.4 R(the aggre)2.75 E -.055(ga)-.165 G
(te length of encoding symbols carried in a pack).055 E
(et payload is L bytes then the)-.11 E(maximum length of a source block\
 is the number of distinct Encoding Symbol IDs times L, or)72 437.4 Q
(2^16 * L for FEC Encoding IDs 0 and 130.)72 450.4 Q(If for e)5.5 E
(xample L = 1 KB then the length of a source)-.165 E
(block can be up to around 65 MB.)72 463.4 Q(Ho)8.25 E(we)-.275 E -.165
(ve)-.275 G .88 -.44(r, i).165 H 2.75(np).44 G
(ractice the length of the source block is usually)-2.75 E(shorter than\
 the number of distinct Encoding Symbol IDs times L, and thus generally\
 the length)72 476.4 Q(of a source block is a fraction of 65 MB.)72
489.4 Q(Since the number of distinct Source Block Numbers is)5.5 E
(2^16, for this e)72 502.4 Q
(xample an object can be more than a terabyte.)-.165 E
(The non-unique SBN mode of deli)72 528.4 Q -.165(ve)-.275 G
(ry can also be ef).165 E(fecti)-.275 E -.165(ve)-.275 G
(ly used for reliably deli).165 E -.165(ve)-.275 G(ring lar).165 E(ge)
-.198 E 2.75(object. In)72 541.4 R
(this case, the length of the object deli)2.75 E -.165(ve)-.275 G
(red could be arbitrarily lar).165 E(ge, depending on the)-.198 E
(out-of-band mapping between source blocks and Source Block Numbers.)72
554.4 Q F1(4.2.)72 597 Q F3(Block-Str)5.5 E(eam Deli)-.234 E -.13(ve)
-.13 G(ry).13 E F0(Another possible deli)72 613.6 Q -.165(ve)-.275 G(ry\
 model that can be supported using FEC Encoding ID 0 or 130 is block-)
.165 E(stream deli)72 626.6 Q -.165(ve)-.275 G(ry of an object.).165 E
(In this model, the source blocks of a potentially indeterminate)5.5 E
(length object are to be reliably deli)72 639.6 Q -.165(ve)-.275 G
(red in sequence to one or multiple recei).165 E -.165(ve)-.275 G 2.75
(rs. Thus,).165 F(the)2.75 E(object could be partitioned into source bl\
ocks on-the-\215y at the sender as the data arri)72 652.6 Q -.165(ve)
-.275 G(s, and all).165 E(pack)72 665.6 Q
(ets generated for one source block are sent before an)-.11 E 2.75(yp)
-.165 G(ack)-2.75 E(ets are sent for the subsequent)-.11 E
(source block.)72 678.6 Q(In this e)5.5 E(xample, all source blocks cou\
ld be of the same length and this length could)-.165 E
(be communicated out-of-band to a recei)72 691.6 Q -.165(ve)-.275 G 2.75
(rb).165 G(efore the recei)-2.75 E -.165(ve)-.275 G 2.75(rj).165 G
(oins the session.)-2.75 E -.165(Fo)5.5 G 2.75(rt).165 G(his deli)-2.75
E -.165(ve)-.275 G(ry).165 E(model it is not required that the Source B\
lock Numbers for all source blocks are unique.)72 704.6 Q(Ho)72 717.6 Q
(we)-.275 E -.165(ve)-.275 G .88 -.44(r, a s).165 H
(uggested usage is to use all 2^16 Source Block Numbers for consecuti)
.44 E .33 -.165(ve s)-.275 H(ource).165 E(Luby/V)72 769 Q 269.981
(icisano Section)-.66 F 2.75(4.2. [P)2.75 F(age 8])-.165 E EP
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(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E(blocks \
of the object, and thus the time between reuse of a Source Block Number\
 is the time it)72 85 Q(tak)72 98 Q(es to send the pack)-.11 E
(ets for 2^16 source blocks.)-.11 E(This deli)72 124 Q -.165(ve)-.275 G
(ry model can be used to reliably deli).165 E -.165(ve)-.275 G 2.75(ra)
.165 G 2.75(no)-2.75 G(bject to one or multiple recei)-2.75 E -.165(ve)
-.275 G(rs, using).165 E(either an A)72 137 Q(CK or N)-.44 E -.44(AC)
-.385 G 2.75(Kb).44 G(ased ackno)-2.75 E
(wledgement based scheme for each source block.)-.275 E(As)5.5 E
(another e)72 150 Q(xample the sender could send a \214x)-.165 E
(ed number of pack)-.165 E(ets for each source block without)-.11 E(an)
72 163 Q 2.75(ya)-.165 G(ckno)-2.75 E(wledgements from recei)-.275 E
-.165(ve)-.275 G(rs, for e).165 E(xample in a li)-.165 E .33 -.165(ve s)
-.275 H(treaming without feedback).165 E(application.)72 176 Q/F1 11
/Times-Bold@0 SF(5.)72 218.6 Q/F2 14/Times-Bold@0 SF
(Security Considerations)5.5 E F0
(The security considerations for this document are the same as the)72
235.2 Q 2.75(ya)-.165 G(re for RFC 3452 [6].)-2.75 E F1(6.)72 264.8 Q F2
(IAN)5.5 E 3.5(AC)-.28 G(onsiderations)-3.5 E F0 -1.221(Va)72 281.4 S
(lues of FEC Encoding IDs and FEC Instance IDs are subject to IAN)1.221
E 2.75(Ar)-.385 G -.165(eg)-2.75 G(istration. F).165 E(or general)-.165
E(guidelines on IAN)72 294.4 Q 2.75(Ac)-.385 G(onsiderations as the)
-2.75 E 2.75(ya)-.165 G(pply to this document, see RFC 3452 [6].)-2.75 E
(This)5.5 E(document assigns the Fully-Speci\214ed FEC Encoding ID 0 un\
der the ietf:rmt:fec:encoding name-)72 307.4 Q
(space to "Compact No-Code".)72 320.4 Q(The FEC P)5.5 E
(ayload ID format and corresponding FEC Object)-.165 E -.385(Tr)72 333.4
S(ansmission Information associated with FEC Encoding ID 0 is described\
 in Subsections 2.1 and).385 E
(2.2, and the corresponding FEC scheme is described in Section 3.)72
346.4 Q(This document assigns the Under)72 363 Q
(-Speci\214ed FEC Encoding ID 130 under the)-.22 E
(ietf:rmt:fec:encoding name-space to "Compact FEC".)72 376 Q
(This document also establishes a ne)5.5 E(w)-.275 E
("FEC Instance ID" re)72 389 Q(gistry)-.165 E
(ietf:rmt:fec:encoding:instance:130)94 405.6 Q
(ietf:rmt:fec:encoding = 130 \(Compact FEC\))94 422.2 Q(The FEC P)72
438.8 Q(ayload ID format and corresponding FEC Object T)-.165 E
(ransmission Information associated)-.385 E
(with FEC Encoding ID 130 is described in Subsections 2.1 and 2.3.)72
451.8 Q F1(7.)72 481.4 Q F2(Refer)5.5 E(ences)-.252 E F0([1] Bradner)72
511 Q 2.75(,S)-.44 G(., "The Internet Standards Process -- Re)-2.75 E
(vision 3", RFC 2026, October 1996.)-.275 E([2] Bradner)72 537 Q 2.75
(,S)-.44 G(., "K)-2.75 E .33 -.165(ey w)-.275 H
(ords for use in RFCs to Indicate Requirement Le).055 E -.165(ve)-.275 G
(ls", RFC 2119, March).165 E(1997.)72 550 Q([3] K)72 576 Q
(ermode, R., V)-.275 E(icisano, L., `)-.66 E -.88(`A)-.814 G
(uthor Guidelines for Reliable Multicast T).88 E(ransport \(RMT\))-.385
E(Building Blocks and Protocol Instantiation documents')72 589 Q
(', RFC 3269, April 2002.)-.814 E([4] Luby)72 615 Q 2.75(,M)-.715 G
(., Gemmell, J., V)-2.75 E(icisano, L., Rizzo, L. and J.)-.66 E(Cro)5.5
E(wcroft, "Asynchronous Layered)-.275 E
(Coding \(ALC\) Protocol Instantiation", RFC 3450 December 2002.)72 628
Q([5] Luby)72 654 Q 2.75(,M)-.715 G(., Gemmell, J., V)-2.75 E
(icisano, L., Rizzo, L., Handle)-.66 E 1.43 -.715(y, M)-.165 H 2.75(.a)
.715 G(nd J.)-2.75 E(Cro)5.5 E(wcroft, "Layered)-.275 E(Coding T)72 667
Q(ransport \(LCT\) Building Block", RFC 3451 December 2002.)-.385 E
([6] Luby)72 693 Q 2.75(,M)-.715 G(., V)-2.75 E
(icisano, L., Gemmell, J., Rizzo, L., Handle)-.66 E 1.43 -.715(y, M)
-.165 H 2.75(.a).715 G(nd J. Cro)-2.75 E(wcroft, "F)-.275 E(orw)-.165 E
(ard Error)-.11 E
(Correction \(FEC\) Building Block", RFC 3452, December 2002.)72 706 Q
(Luby/V)72 769 Q 278.231(icisano Section)-.66 F 2.75(7. [P)2.75 F
(age 9])-.165 E EP
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(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E
([7] Luby)72 85 Q 2.75(,M)-.715 G(., V)-2.75 E
(icisano, L., Gemmell, J., Rizzo, L., Handle)-.66 E 1.43 -.715(y, M)
-.165 H 2.75(.a).715 G(nd J. Cro)-2.75 E(wcroft, "The Use of)-.275 E
-.165(Fo)72 98 S(rw).165 E(ard Error Correction \(FEC\) in Reliable Mul\
ticast", RFC 3453, December 2002.)-.11 E([8] Mankin, A., Romano)72 124 Q
1.43 -.715(w, A)-.275 H(., Bradner).715 E 2.75(,S)-.44 G(., P)-2.75 E
(axson V)-.165 E(., "IETF Criteria for Ev)-1.419 E(aluating Reliable)
-.275 E(Multicast T)72 137 Q
(ransport and Application Protocols", RFC 2357, June 1998.)-.385 E
([9] Whetten, B., V)72 163 Q(icisano, L., K)-.66 E(ermode, R., Handle)
-.275 E 1.43 -.715(y, M)-.165 H(., Flo).715 E(yd, S., Luby)-.11 E 2.75
(,M)-.715 G(., "Reliable Multicast)-2.75 E -.385(Tr)72 176 S
(ansport Building Blocks for One-to-Man).385 E 2.75(yB)-.165 G
(ulk-Data T)-2.75 E(ransfer", RFC 3048, January 2001.)-.385 E/F1 11
/Times-Bold@0 SF(8.)72 218.6 Q/F2 14/Times-Bold@0 SF -.7(Au)5.5 G
(thors' Addr).7 E(esses)-.252 E F0(Michael Luby)80.25 235.2 Q
(luby@digitalfountain.com)80.25 248.2 Q(Digital F)80.25 261.2 Q
(ountain, Inc.)-.165 E(39141 Ci)80.25 274.2 Q(vic Center Dri)-.275 E
-.165(ve)-.275 G(Suite 300)80.25 287.2 Q(Fremont, CA)80.25 300.2 Q
(94538)5.5 E(Lorenzo V)80.25 326.2 Q(icisano)-.66 E(lorenzo@cisco.com)
80.25 339.2 Q(cisco Systems, Inc.)80.25 352.2 Q(170 W)80.25 365.2 Q
(est T)-.88 E(asman Dr)-.88 E(.,)-.605 E(San Jose, CA, USA, 95134)80.25
378.2 Q(Luby/V)72 769 Q 272.731(icisano Section)-.66 F 2.75(8. [P)2.75 F
(age 10])-.165 E EP
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(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E/F1 11
/Times-Bold@0 SF(9.)72 85 Q/F2 14/Times-Bold@0 SF
(Full Copyright Statement)5.5 E F0(Cop)72 101.6 Q
(yright \(C\) The Internet Society \(2002\).)-.11 E(All Rights Reserv)
5.5 E(ed.)-.165 E(This document and translations of it may be copied an\
d furnished to others, and deri)72 118.2 Q -.275(va)-.275 G(ti).275 E
.33 -.165(ve w)-.275 H(orks).055 E(that comment on or otherwise e)72
131.2 Q
(xplain it or assist in its implementation may be prepared, copied,)
-.165 E(published and distrib)72 144.2 Q
(uted, in whole or in part, without restriction of an)-.22 E 2.75(yk)
-.165 G(ind, pro)-2.75 E(vided that the)-.165 E(abo)72 157.2 Q .33 -.165
(ve c)-.165 H(op).165 E(yright notice and this paragraph are included o\
n all such copies and deri)-.11 E -.275(va)-.275 G(ti).275 E .33 -.165
(ve w)-.275 H(orks.).055 E(Ho)72 170.2 Q(we)-.275 E -.165(ve)-.275 G .88
-.44(r, t).165 H(his document itself may not be modi\214ed in an).44 E
2.75(yw)-.165 G(ay)-2.86 E 2.75(,s)-.715 G(uch as by remo)-2.75 E
(ving the)-.165 E(cop)72 183.2 Q(yright notice or references to the Int\
ernet Society or other Internet or)-.11 E -.055(ga)-.198 G(nizations, e)
.055 E(xcept as)-.165 E(needed for the purpose of de)72 196.2 Q -.165
(ve)-.275 G(loping Internet standards in which case the procedures for)
.165 E(cop)72 209.2 Q
(yrights de\214ned in the Internet languages other than English.)-.11 E
(The limited permissions granted abo)72 225.8 Q .33 -.165(ve a)-.165 H
(re perpetual and will not be re).165 E -.22(vo)-.275 G -.11(ke).22 G
2.75(db).11 G 2.75(yt)-2.75 G(he Internet)-2.75 E
(Society or its successors or assigns.)72 238.8 Q
(This document and the information contained herein is pro)72 255.4 Q
(vided on an "AS IS" basis and THE)-.165 E
(INTERNET SOCIETY AND THE INTERNET ENGINEERING T)72 268.4 Q
(ASK FORCE DISCLAIMS)-1.023 E(ALL W)72 281.4 Q
(ARRANTIES, EXPRESS OR IMPLIED, INCLUDING B)-1.32 E(UT NO)-.11 E 2.75
(TL)-.44 G(IMITED T)-2.75 E 2.75(OA)-.198 G(NY)-2.75 E -1.32(WA)72 294.4
S(RRANTY THA)1.32 E 2.75(TT)-1.221 G(HE USE OF THE INFORMA)-2.75 E
(TION HEREIN WILL NO)-1.221 E 2.75(TI)-.44 G(NFRINGE)-2.75 E
(ANY RIGHTS OR ANY IMPLIED W)72 307.4 Q(ARRANTIES OF MERCHANT)-1.32 E
(ABILITY OR FITNESS)-1.023 E(FOR A P)72 320.4 Q(AR)-1.012 E
(TICULAR PURPOSE.")-.66 E(Luby/V)72 769 Q 272.731(icisano Section)-.66 F
2.75(9. [P)2.75 F(age 11])-.165 E EP
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(No)2.75 E -.165(ve)-.165 G(mber 2003).165 E(May 2003)115.955 E(Luby/V)
72 769 Q 272.731(icisano Section)-.66 F 2.75(9. [P)2.75 F(age 12])-.165
E EP
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