One document matched: draft-ietf-ion-sig-uni4.0-00.txt
ION WG M.Maher, A.Mankin
Category: internet-draft June 1996
draft-ietf-ion-sig-uni4.0-00.txt Expires: Dec 13, 1996
ATM Signalling Support for IP over ATM - UNI 4.0 Update
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
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Rim).
Abstract
This memo describes how to efficiently use the ATM call control
signalling procedures defined in UNI 4.0 [UNI96] to support IP over
ATM environments as described in RFC 1577 [LAUB94] and in [KATZ96].
Among the new features found in UNI 4.0 signalling are Available Bit
Rate (ABR) signalling and traffic parameter negotiation. This
initial draft highlights the features of UNI 4.0 signalling that
provide IP entities capabilities for requesting ATM service in sites
with SVC support, whether it is private ATM or publicly provisioned
ATM, in which case the SVC support is probably configured inside
PVPs.
This document is only relevant to IP when used as the well know "best
effort" connectionless service. In particular, this means that this
document does not pertain to IP in the presence of implemented IP
Integrated Services (ISS) and RSVP. The topic of IP with ISS over
ATM will be handled by a different specification or set of
specifications being worked on in the ISSLL WG.
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This specification is follow-on to RFC 1755, "ATM Signaling Support
for IP over ATM", which is based on UNI signalling 3.1. Readers are
assumed to be familiar with RFC 1755.
1. Overview
UNI Signalling version 4.0 is the ATM Forum follow-on specification
to UNI Signalling 3.1. Among the new features in UNI 4.0, those of
particular interest to IP over ATM enviroments are:
o ABR Signalling for Point-to-Point Calls
o Traffic Parameter Negotiation
o Frame Discard Support
o Leaf Initiated Join (LIJ) Capability
o ATM Anycast Capability
o Switched Virtual Path (VP) Service
This draft highlights the first three capabilities listed above. The
last three capabilities are not discussed mainly because models for
their use in IP over ATM environments have not yet been defined.
2. Overview of Call Establishment Message Content
Signalling messages are structured to contain mandatory and optional
variable length information elements (IEs). A SETUP message which
establishes an ATM connection to be used for IP and multiprotocol
interconnection calls MUST contain the following IEs:
AAL Parameters
ATM Traffic Descriptor
Broadband Bearer Capability
Broadband Low Layer Information
QoS Parameter
Called Party Number
Calling Party Number
and MAY, under certain circumstance contain the following IEs :
Calling Party Subaddress
Called Party Subaddress
Transit Network Selection
(New in UNI 4.0:)
Minimum Acceptable ATM Traffic Descriptor
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Alternative ATM Traffic Descriptor
ABR Setup Parameters
ABR Additional Parameters
Connection Scope Selection
Extended QoS Parameters
End-to-End Transit Delay
In UNI 4.0, like UNI 3.1, the AAL Parameters and the Broadband Low
Layer Information IEs are optional in a SETUP message. However, in
support of IP over ATM these two IEs MUST be included. Appendix A
shows a sample setup message.
3. Description of Information Elements
This section describes the coding of, and procedures surrounding,
information elements in SETUP and CONNECT messages. The first two IEs
described, ATM Adaptation Layer Parameters and Broadband Low Layer
Information, are categorized as having significance only to the end-
points of an ATM call supporting IP. That is, the network does not
process these IEs.
3.1. ATM Adaptation Layer (AAL) Parameters
The AAL Parameters IE carries information about the ATM adaptation
layer to be used on the connection. The parameters specified in this
IE are the same as specified in [PER95].
Format and field values of AAL Parameters IE
----------------------------------------------------------
| aal_parameters |
----------------------------------------------------------
| aal_type 5 (AAL 5) |
| fwd_max_sdu_size_identifier 140 |
| fwd_max_sdu_size 65,535 (desired IP MTU) |
| bkw_max_sdu_size_identifier 129 |
| bkw_max_sdu_size 65,535 (desired IP MTU) |
| sscs_type identifier 132 |
| sscs_type 0 (null SSCS) |
----------------------------------------------------------
This shows maximum size MTUs. In practice, most sites have used 9180
IP MTUs for ATM [RFC1626].
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3.2. Broadband Low Layer Information
Selection of an encapsulation to support IP over an ATM VCC is done
using the Broadband Low Layer Information (B-LLI) IE, along with the
AAL Parameters IE, and the B-LLI negotiation procedure. B-LLI nego-
tiation is described in [PER95] in Appendix D. The procedures remain
the same for this UNI 4.0 based specification.
Format of B-LLI IE indicating LLC/SNAP encapsulation
----------------------------------------------------------
| bb_low_layer_information |
----------------------------------------------------------
| layer_2_id 2 |
| user_information_layer 12 (lan_llc - ISO 8802/2) |
----------------------------------------------------------
3.3. Traffic Management Issues and Related IEs
The ATM Forum Traffic Management Sub-working group has completed ver-
sion 4.0 of their specification [TMGT96]. This latest version focuses
primarily on the definition of the ABR service category. As opposed
to the Unspecified Bit Rate (UBR) traffic class, ABR uses a rate-
based flow control mechanism to assure certain traffic guarantees
(bandwidth and delay). There has been much debate on whether IP
benefits from ABR, and if so, how IP should use ABR. The Integrated
Internet Services (IIS) and RSVP models in IP add complexity to this
issue because mapping IIS traffic classes to ATM traffic classes is
not straightforward.
This draft attempts only to present the required IP to ATM signalling
interface for IP over ATM systems that do not support IIS as yet. It
is an attempt to cause IP over ATM vendors to support enough options
for signalling the traffic characteristics of VCs serving non-IIS IP
datagrams. This specification also aims to give guidance to ATM sys-
tem administrators so that they can configure their IP over ATM enti-
ties to conform to the varied services that their ATM provider may
have sold to them. By definition, IP without IIS cannot be expected
to provide a signalling interface that is flexible and allows appli-
cation specific traffic descriptors. The topic of IP over ATM signal-
ling for IP _with_ IIS is to presented other specifications produced
by the ISSLL WG of the IETF.
An IP over ATM interface may be configured to support all the defined
ATM Service Categories (ASC). They are:
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- CBR
- CBR with CLR specified (loss-permitting CBR)
- ABR
- UBR
- real time VBR
- non-real time VBR
[We don't think it's likely that realtime VBR would be a provisioned
service to a site, but we expect to discuss this with the WG]
The ATM Traffic Descriptor IE, Broadband Bearer Capability IE, and
the QoS Parameter IE together define the signalling view of ATM
traffic management. Additionally, the Extended QoS parameters IE and
the End-to-end Transit Delay IE may be used to provide more specifics
about traffic requirements. Annex 9 of [TMGT96] describes a set of
allowable combinations of traffic and QoS related paramenters defined
for UNI 4.0 signalling. This set includes all forms of non-IIS IP
signalling configurations that MUST be implemented in ATM endsystems
to accomodate varied sites' needs. The principle is that IP over ATM
service may be provided by different sites by different types of pro-
cured ATM service; for one site, a CBR PVP might be cost-effective
and then the SVCs that IP over ATM without IIS must establish must be
CBR. Similarly, VBR or ABR PVPs could be provisioned. We want to
fill in the table parameters to offer the most sensible parameters
within this non-IIS configuration. For instance, for non-IIS VBR,
the SCR value may need to be hand-configured for IP users. Or for
ABR, the PCR value may be link-rate with a 0 MCR.
For the reader's convenience, we have replicated the tables found in
Annex 9 of [TMGT96] in Appendix B of this documents. Amendments to
this set of tables will be iterated in WG discussion.
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3.3.1. ATM Traffic Descriptor
Even with the newly defined ABR ASC, the most convenient model of IP
behavior still corresponds to the Best Effort Capability. Best
effort service MAY be requested by including the forward and backward
peak cell rate (CLP=0+1) and the Best Effort Indicator fields in the
ATM Traffic Descriptor IE. As stated above, this may not be the
choice that a site's configuration allows.
In support of ABR service two new subfields have been added to the
Traffic Descriptor IE, forward and backward 'Minimum Cell Rate'
fields.
3.3.2. Traffic Parameter Negotiation
UNI 4.0 allows certain traffic parameters to be negotiated during the
call establishment phase Traffic parameters cannot be 'renegotiated'
after the call is active. Two new IEs make negotiation possible:
- the Minimum Acceptable ATM Traffic Descriptor IE allows
negotiation of PCR parameters
- the Alternative ATM Traffic Descriptor IE allows negotiation of
other traffic parameters
A SETUP or CONNECT message may include ONLY one of the above IEs.
That is, the calling party may only offer an 'alternative' or
'minimum' to the requested traffic parameters. (See Section 8 of
[UNI96].) IP over ATM entities SHOULD take advantage of this capabil-
ity whenever possible. In order to do so, IP over ATM entities SHOULD
specify PCR _equal_ to the link rate in the ATM Traffic Descriptor IE
of the SETUP message and a minimum of zero PCR in the Minimum Accept-
able ATM Traffic Descriptor IE. (WG agreed to this in San Jose.)
3.3.3. Broadband Bearer Capability
A new field in UNI signalling 4.0 called, 'ATM Transfer Capability'
(ATC), has been defined in the Broadband Bearer Capability IE for the
purpose of explicitly specifying the desired ATM traffic catergory.
The figure below shows the allowable ATC values.
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Format and field values of Broadband Bearer Capability IE
-------------------------------------------------------------
| bb_bearer_capability |
------------------------------------------------------------|
| spare 0 |
| bearer_class 16 (bcob-x,c,a or VP) |
| transfer_capability cbr, rt-vbr, nrt-vbr, abr |
| susceptibility_to_clipping 0 (not suscept) |
| spare 0 |
| user_plane_configuration pt-to-pt, pt-to-mpt |
-------------------------------------------------------------
3.3.4. QoS Parameter
Inclusion of the QoS Parameter IE is optional in UNI 4.0 signalling.
It may be omitted from a SETUP message when the Extended QoS Parame-
ters IE, discussed in the next section, is included. This specifica-
tion makes no explicit recommendation on the use of the QoS related
IEs. [WG needs to decide on this. Is there any benefit in using these
or do they just make signalling more complex?)
3.3.4.1. Signalling of Individual QoS Parameters
UNI 4.0 allows for signalling of individual QoS parameters for the
purpose of giving the the network and called party a more exact
description of the desired delay and cell loss characteristics. The
two individual QoS related IEs, Extended QoS Parameters IE and End-
to-End Transit Delay IE, can be used in the SETUP and CONNECT signal-
ling messages in place of the 'generic' QoS Parameter IE. Note that
inclusion of these two IEs depends on the type of ATM service
category requested (see Annex 9 in [TMGT96]).
3.4. ABR Signalling In More Detail
The IEs and procedures pertaining to ABR signalling are briefly
described in this section. Nevertheless, this document makes no
specific recommendation on when to use the ABR service category for
IP VCCs or give suggestions on appropriate values for the various
parameters in the ABR related IEs.
Two new IEs have been defined for ABR signalling:
o ABR Setup Parameters
o ABR Additional Parameters
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These IEs may be optionally included in a SETUP or CONNECT message.
The ABR Setup Parameters IE contains the following subfields:
- Forward/Backward ABR Initital Cell Rate
- Forward/Backward ABR Transient Buffer Exposure
- Cumulative RM Fixed Round Trip Time
- Forward/Backward Rate Increment Factor
- Forward/Backward Rate Decrease Factor
The ABR Additional Parameters IE contains one subfield:
- Forward/Backward Additional Parameters Record
The Additional Parameters Record value is a compressed encoding of a
set of ABR parameters (see TMGT96).
3.5. Frame Discard Capability
The frame discard capabilty in UNI 4.0 is primarily based on the
'Partial Packet Discard' strategy [ROM94]. Its use is defined for any
of the ATM services, except for loss-less CBR. Frame discard signal-
ling MUST be supported by all IP over ATM entities and it is RECOM-
MENDED that frame discard be signalled for all IP SVCs because it has
been proven to increase throughput under network congestion. Signal-
ling for frame discard is done by setting the frame discard bit in
the 'Traffic Management Options' subfield in the Traffic Descriptor
IE. It is possible that not all network entities in the SVC path
support frame discard, but it is requiered that they all forward the
signalling.
3.6. ATM Addressing Information
ATM addressing information is carried in the Called Party Number,
Calling Party Number, and, under certain circumstance, Called Party
Subaddress, and Calling Party Subaddress IE. The ATM Forum ILMI
Specification 4.0 provides the procedure for an ATM endsystem to
learn its own ATM address from the ATM network, for use in populating
the Calling Party Number IE.
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Format and field values of Called Party Number IE
----------------------------------------------------------
| called_party_number |
----------------------------------------------------------
| type_of_number (international number / unknown) |
| addr_plan_ident (ISDN / ATM Endsystem Address) |
| addr_number (E.164 / ATM Endsystem Address) |
----------------------------------------------------------
4. Security Considerations
The ATM Forum has established an ATM Security sub-working group for
the purpose of defining seurity mechanisms in ATM. It is therefore
premature to begin defining IP over ATM signalling's use of ATM secu-
rity. IP Security (RFC1825) can be applied to IP datagrams over any
medium.
5. Open Issues
Description of Leaf Initiated Join (LIJ) signalling is not discussed
because the use of LIJ in IP over ATM has not been defined. [those
various drafty bits]
REFERENCES
[PER95] Perez Maher, M. et al, ""ATM Signaling Support for IP over
ATM", RFC1755, February 1995
[LAUB93] Laubach, M., "Classical IP and ARP over ATM", RFC1577,
Hewlett-Packard Laboratories, December 1993
[UNI96] ATM Forum, "ATM User-Network Interface Specification Version
4.0", 1996 Work in Progress.
[UNI94] ATM Forum, "ATM User-Network Interface Specification Version
3.1", (Englewood Cliffs, NJ: Prentice Hall, 1994)
[TMGT96] ATM Forum, "ATM Forum Traffic Management Specification Ver-
sion 4.0", 1996, Work in Progress.
[KATZ96] "NBMA Next Hop Resolution Protocol (NHRP)", Katz, Pisci-
tello, Cole, Luciani, draft-ietf-rolc-nhrp-08.txt. Work in Pro-
gress.
Maher, Mankin [Page 9]
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[BRAD89] Braden, R., Editor, "Requirements for Internet Hosts -- Com-
munication Layers", RFC 1122, USC/Information Science Institute,
October 1989.
[BRAD94] Braden, R., Clark, D, Shenker, S., "Integrated Service in
the Internet Architecture: An Overview", RFC 1633,
USC/Information Science Institute, June 1994.
[HEIN93] Heinanen, J., "Multiprotocol Encapsulation over ATM Adapta-
tion Layer 5", RFC 1483, Telecom Finland, July 1993.
[ISO8473] ISO/IEC 8473, Information processing systems - Data commun-
ications - Protocol for providing the connectionless-mode network
service, 1988.
[ISO9577] Information Technology - Telecommunication and information
exchange between systems - Protocol identification in the network
layer ISO/IEC TR9577 (International Standards Organization:
Geneva, 1990)
[ROM94] Romanow, A., and Floyd, S., Dynamics of TCP Traffic over ATM
Networks. IEEE JSAC, V. 13 N. 4, May 1995, p. 633-641. Abstract.
An earlier version appeared in SIGCOMM '94, August 1994, pp. 79-
88.
[PART92] Partridge, C., "A Proposed Flow Specification", RFC1363,
BBN, September 92
Authors' Addresses
Maryann Perez Maher
maher@isi.edu
Allison Mankin
mankin@isi.edu
4350 N. Fairfax Drive, Suite 620
Arlington VA 22203
703-807-0133
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Appendix A. A Sample UNI 4.0 SETUP Message
+--------------------------------------------------------------------+
SETUP
Information Elements/
Fields Value/(Meaning)
-------------------- ---------------
aal_parameters
aal_type 5 (AAL 5)
fwd_max_sdu_size_ident 140
fwd_max_sdu_size (send IP MTU value)
bkw_max_sdu_size_ident 129
bkw_max_sdu_size (recv IP MTU value)
sscs_type identifier 132
sscs_type 0 (null SSCS)
traffic_descriptor
fwd_peak_cell_rate_0_1_ident 132
fwd_peak_cell_rate_0_1 (link rate)
bkw_peak_cell_rate_0_1_ident 133
bkw_peak_cell_rate_0_1 (link rate)
traff_mngt_options_ident 191
fwd_frame_discard 1 (on)
bkw_frame_discard 1 (on)
spare 0
tagging_bkw 1 (on)
tagging_fwd 1 (on)
best_effort_indication 190 (on)
minimum_acceptable_traffic_descriptor
fwd_peak_cell_rate_0_1_ident 132
fwd_peak_cell_rate_0_1 0
bkw_peak_cell_rate_0_1_ident 133
bkw_peak_cell_rate_0_1 0
bb_bearer_capability /* a coding for specifying UBR like service */
spare 0
bearer_class 16 (BCOC-X)
spare 0
atm_transfer_capability nrt-vbr (
susceptibility_to_clipping 0 (not susceptible to clipping)
spare 0
user_plane_configuration 0 (point_to_point)
bb_low_layer_information
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layer_2_id 2
user_information_layer 12 (lan_llc - ISO 8802/2)
qos_parameter
qos_class_fwd 0 (class 0)
qos_class_bkw 0 (class 0)
called_party_number
type_of_number (international number / unknown)
addr_plan_ident (ISDN / ATM Endsystem Address)
number (E.164 / ATM Endsystem Address)
calling_party_number
type_of_number (international number / unknown)
addr_plan_ident (ISDN / ATM Endsystem Address)
presentation_indic (presentation allowed)
spare 0
screening_indic (user_provided verified and passed)
number (E.164 / ATM Endsystem Address)
+--------------------------------------------------------------------+
Figure 1.
Sample contents of SETUP message
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Appendix B. Combinations of Traffic Related Parameters
This appendix contains a copy of the five tables found in Annex 9 of
[TMGT96] which show the allowable combinations of traffic and QoS related
parameters in a UNI 4.0 SETUP message.
+--------------------------------------------------------------------+
|ATM Service Category| CBR |
|--------------------|---------------|---------------|---------------|
| Conformance |CBR.1 (note 10)| (note 4) | (note 4) |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | A | X | VP | A | X | VP^| A | X | VP^|
|--------------------|---------------|----|-----|----|----|-----|----|
| ATM Transfer | | | 4,5,| | | 4,5,| |
| Capability (note 1)| 7 | abs| or 6| 5 | abs| or 6| 5 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | | | S |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | | | |
|--------------------|---------------|---------------|---------------|
| Best Effort | | | |
|--------------------|---------------|---------------|---------------|
| Tagging | N | N | Y/N |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | * | * | * |
|--------------------|---------------|---------------|---------------|
| Transit Delay | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) | | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1) | 0 | | |
+--------------------------------------------------------------------+
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+--------------------------------------------------------------------+
|ATM Service Category| Real Time VBR |
|--------------------|---------------|---------------|---------------|
| Conformance |VBR.1 (note 10)| VBR.2 | VBR.3 |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | C | X | VP | C | X | VP | C | X | VP |
|--------------------|---------------|----|-----|----|----|-----|----|
| ATM Transfer | | | 1 | | | 1 | |
| Capability | 19 | 9 | or 9| 9 | 9 | or 9| 9 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | S | | |
|--------------------|---------------|---------------|---------------|
| Best Effort | | | |
|--------------------|---------------|---------------|---------------|
| Tagging | N | N | Y/N |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | * | * | * |
|--------------------|---------------|---------------|---------------|
| Transit Delay(nt.2)| 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) | | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1) | 0 | | |
+--------------------------------------------------------------------+
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+--------------------------------------------------------------------+
|ATM Service Category| Real Time VBR |
|--------------------|---------------|---------------|---------------|
| Conformance | (note 4,7) | (note 4,8) | (note 4) |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | X | X | X | C or VP^|
|--------------------|---------------|---------------|-----|---------|
| ATM Transfer | | | | |
| Capability | 1 or 9 | 1 or 9 | 1or9| 9 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | S | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | | | S |
|--------------------|---------------|---------------|---------------|
| Best Effort | | | |
|--------------------|---------------|---------------|---------------|
| Tagging | Y/N | N | N |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | * | * | * |
|--------------------|---------------|---------------|---------------|
| Transit Delay(nt.2)| 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) (nt.11)| 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1)(nt11)| | | |
+--------------------------------------------------------------------+
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+--------------------------------------------------------------------+
|ATM Service Category| Non-Real Time VBR |
|--------------------|---------------|---------------|---------------|
| Conformance |VBR.1 (note 10)| VBR.2 | VBR.3 |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | C | X | VP |C | X | VP|C | X | VP|
|--------------------|---------------|--|--------|---|--|--------|---|
| ATM Transfer | | |abs,0,2,|abs| |abs,0,2,|abs|
| Capability | 11 |ab| 8,10 |10 |ab| 8,10 |10 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | S | | |
|--------------------|---------------|---------------|---------------|
| Best Effort | | | |
|--------------------|---------------|---------------|---------------|
| Tagging | N | N | Y |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | * | * | * |
|--------------------|---------------|---------------|---------------|
| Transit Delay(nt.2)| (note 3) | (note 3) | (note 3) |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | | | |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) | | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1) | 0 | | |
+--------------------------------------------------------------------+
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+--------------------------------------------------------------------+
|ATM Service Category| Non-Real Time VBR |
|--------------------|---------------|---------------|---------------|
| Conformance | (note 4,7) | (note 4,8) | (note 4) |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | C | X | C | X |C | X |VP^|
|--------------------|-------|-------|-------|-------|--|--------|---|
| ATM Transfer | |abs,0,2| |abs,0,2| |abs,0,2,|abs|
| Capability | abs |8 or 10| |8 or 10|ab| 8 or10 |10 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | S | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | | | S |
|--------------------|---------------|---------------|---------------|
| Best Effort | | | |
|--------------------|---------------|---------------|---------------|
| Tagging | Y/N | N | N |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | * | * | * |
|--------------------|---------------|---------------|---------------|
| Transit Delay(nt.2)| (note 3) | (note 3) | (note 3) |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | | | |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1) | | | |
+--------------------------------------------------------------------+
Maher, Mankin [Page 17]
INTERNET-DRAFT IP over ATM Signalling - UNI 4.0 Update June 1996
+--------------------------------------------------------------------+
|ATM Service Category| ABR | UBR |
|--------------------|---------------|---------------|---------------|
| Conformance | ABR | UBR.1 | UBR.2 |
|--------------------|---------------|---------------|---------------|
| Bearer Capability | | | |
|--------------------|---------------|---------------|---------------|
| BB Bearer Class | C | X | VP |C | X | VP|C | X | VP|
|--------------------|---------------|--|--------|---|--|--------|---|
| ATM Transfer | | |abs,0,2,|abs| |abs,0,2,|abs|
| Capability | 12 |ab| 8,10 |10 |ab| 8,10 |10 |
|--------------------|---------------|---------------|---------------|
| Traffic Descriptor | | | |
| for a given dir. | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| PCR (CLP=0+1) | S | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0) | | S | S |
|--------------------|---------------|---------------|---------------|
| SCR, MBS (CLP=0+1) | S | | |
|--------------------|---------------|---------------|---------------|
| ABR MCR | (note 6) | | |
|--------------------|---------------|---------------|---------------|
| Best Effort | | S (note 9) | S (note 9) |
|--------------------|---------------|---------------|---------------|
| Tagging | N | N | N |
|--------------------|---------------|---------------|---------------|
| Frame Discard | Y/N | Y/N | Y/N |
|--------------------|---------------|---------------|---------------|
| QoS Classes | 0 | 0 | 0 |
|--------------------|---------------|---------------|---------------|
| Transit Delay(nt.2)| | | |
|--------------------|---------------|---------------|---------------|
| Peak-to-Peak CDV | | | |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0) | | | |
|--------------------|---------------|---------------|---------------|
| CLR (CLP=0+1) | | | |
+--------------------------------------------------------------------+
ab, abs = absent.
Y/N = either "Yes" or "No" is allowed.
Maher, Mankin [Page 18]
INTERNET-DRAFT IP over ATM Signalling - UNI 4.0 Update June 1996
* = allowed QoS class values are a network option. Class 0 is always
for allignement with ITU-T.
^ = (note 5).
See Annex 9 of [TMGT96] for comments on "note"s.
Maher, Mankin [Page 19]
| PAFTECH AB 2003-2026 | 2026-04-22 19:07:58 |