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ION WG M. Maher Category: internet-draft March 1997 draft-ietf-ion-sig-uni4.0-02.txt Expires: August 25, 1997 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 working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific 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 known "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). 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. Maher [Page 1] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 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. Table of Contents 1. Conventions ............................................... 2 2. Overview .................................................. 3 3. Use of Protocol Procedures ................................ 3 3.1 VC Teardown........................................... 3 4. Overview of Call Establishment Message Content ............ 3 5. Description of Information Elements ....................... 4 5.1 ATM Adaptation Layer Parameters ...................... 4 5.2 Broadband Low Layer Information ..................... 5 5.3 Traffic Management Issues and Related IEs............. 5 5.3.1 ATM Traffic Descriptor ........................ 7 5.3.1.1 Tagging vs. Dropping ................. 7 5.3.2 Traffic Parameter Negotiation .................. 8 5.3.3 Broadband Bearer Capability .................... 8 5.3.4 QoS Parameter .................................. 9 5.3.4.1 Signalling of Individual QoS Parameters 9 5.6 ATM Addressing Information ........................... 9 6. ABR Signalling In More Detail ............................ 9 7. Frame Discard Capability .................................. 10 8. Security Consideration .................................... 10 9. Open Issues ............................................... 10 10. Acknowledgements........................................... 11 11. References ................................................ 11 12. Authors ................................................... 12 Appendix A Sample Signaling Messages ......................... 13 Appendix B Combinations of Traffic Related Parameters ........ 15 1. Conventions The following language conventions are used in the items of specifi- cation in this document: o MUST, SHALL, or MANDATORY -- the item is an absolute requirement of the specification. o SHOULD or RECOMMEND -- this item SHOULD generally be followed for all but exceptional circumstances. o MAY or OPTIONAL -- the item is truly optional and MAY be followed or ignored according to the needs of the implementor. Maher [Page 2] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 2. 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 environments 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 because models for their use in IP over ATM environments have not yet been defined or IP imposes no special requirements on them. 3. Use of Protocol Procedures Section 3 in RFC 1755 introduces requirements of virtual circuit (VC) management intended to prevent VC thrashing, excessive VC consump- tion, and other related problems. This section updates RFC 1755's requirements related to VC teardown. 3.1. VC Teardown In environments running layer 3 (L3) signalling protocols, such as RSVP [RSVP], over ATM, data VCs might correspond to L3 reserved flows (even if the VC is a 'best effort' VC). In such environments it is beneficial for VCs to be torn down only when the L3 reservation has expired. In other words, it is more efficient for the sender of a L3 reserved flow to initiate VC tear-down when the receiver(s) has ceased refreshing the reservation. To support such L3 behavior, sys- tems implementing a Public ATM UNI interface and serving as the _called_ party of a VC, MUST NOT use an inactivity timer to clear connections that are idle for some period of time. 4. 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: Maher [Page 3] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 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 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. 5. 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. 5.1. 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]. Maher [Page 4] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 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]. 5.2. 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) | ---------------------------------------------------------- 5.3. 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 Maher [Page 5] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 not straightforward. This document attempts only to present the required IP to ATM signal- ling 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 system administrators so that they can configure their IP over ATM entities to conform to the varied services that their ATM pro- vider may have sold to them. By definition, IP without IIS cannot be expected to provide a signalling interface that is flexible and allows application specific traffic descriptors. The topic of IP over ATM signalling 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: - CBR - CBR with CLR specified (loss-permitting CBR) - ABR - UBR - real time VBR - non-real time VBR 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, however this note does not provide expli- cit recommendations on their use. 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 accommodate varied sites' needs. The principle is that IP over ATM service may be available in different sites by different types of procured 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 pro- visioned. The intent of this document is to specify the use of 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 document. Ideally this Maher [Page 6] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 document could recommend specific values for the various table param- eters that would offer the most sensible IP over ATM service. Nevertheless, it is not possible to mandate specific values given the varied scenarios of procured ATM service. 5.3.1. ATM Traffic Descriptor Even with the newly defined ABR ASC, the most convenient model of IP behavior still corresponds to the best effort capability. If a a site's configuration allows this capability, a user MAY signal for it using the IE's and parameters pertaining to the UBR ATM service category. See Appendix B for the list of IE's and parameters. Although we make no recommendations for signalling ABR service, we note here that in support of ABR service two new subfields have been added in UNI 4.0 to the Traffic Descriptor IE. These fields are the forward and backward 'Minimum Cell Rate' fields. 5.3.1.1. Tagging vs. Dropping The Traffic Descriptor IE contains a 'tagging' subfield used for indicating whether the network is allowed to tag the source's data cells. Tagging in the network may occur during periods of congestion or when the source's traffic has violated the traffic contract for the connection. See Section 4 of [TMGT96] for an explanation of ATM connection conformance and the Usage Parameter Control (UPC) func- tion. UNI 4.0 and TMGT 4.0 define two modes of UBR, UBR.1 which disables tagging and UBR.2 which enables tagging (see Appendix B). In some network environments there is no potential for UBR traffic sources to violate the connection traffic contract because, either the user's terminal equipment supports traffic shaping, or the network does not enforce PCR. In such environments, the user SHOULD specify 'no tag- ging' in the SETUP message (UBR.1). Specifying 'no tagging' indi- cates to the network that cells should be dropped during periods of congestion instead of being randomly marked/tagged as low priority. Cells of packets that the source itself has marked as low priority are dropped first, thereby preserving the source's characterization of the traffic. On the other hand, when the network applies PCR to the UPC function, meaning it enforces PCR, and traffic shaping is not enabled at the source, the source has the potential to violate the traffic contract and SHOULD therefore signal for tagging (UBR.2). Tagging allows the source's non-conforming cells to be tagged and forwarded instead of Maher [Page 7] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 dropped. 5.3.2. 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. 5.3.3. 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 category. The figure below shows the allowable ATC values. 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 | ------------------------------------------------------------- Maher [Page 8] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 5.3.4. 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. 5.3.4.1. Two IEs for 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]). 5.4. 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. 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) | ---------------------------------------------------------- 6. 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. Maher [Page 9] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 Two new IEs have been defined for ABR signalling: o ABR Setup Parameters o ABR Additional Parameters These IEs may be optionally included in a SETUP or CONNECT message. The ABR Setup Parameters IE contains the following subfields: - Forward/Backward ABR Initial 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). 7. Frame Discard Capability The frame discard capability 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 required that they all forward the signalling. 8. Security Considerations The ATM Forum has established an ATM Security sub-working group for the purpose of defining security 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. Maher [Page 10] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 9. 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. 10. Acknowledgements The authors would like to thank the members of the ION working group for their input. 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", Prentice Hall, Upper Saddle River, NJ, specification final- ized July 1996; expected publication, late 1996; available at ftp://ftp.atmforum.com/pub. [UNI94] ATM Forum, "ATM User-Network Interface Specification Version 3.1", Prentice Hall, Upper Saddle River, NJ, 1995 [TMGT96] ATM Forum, "ATM Forum Traffic Management Specification Ver- sion 4.0", Prentice Hall, Upper Saddle River NJ; specification finalized April 1996; expected publication, late 1996; available at ftp://ftp.atmforum.com/pub. [RSVP] R. Braden, L. Zhang, S. Berson, S. Herzog and S. Jamin, "Resource ReSerVation Protocol (RSVP) - Version 1 Functional Specification", Internet Draft, May 1996, <draft-ietf-rsvp-spec- 14.txt> [KATZ96] "NBMA Next Hop Resolution Protocol (NHRP)", Katz, Pisci- tello, Cole, Luciani, draft-ietf-rolc-nhrp-08.txt. Work in Pro- gress. [BRAD89] Braden, R., Editor, "Requirements for Internet Hosts -- Com- munication Layers", RFC 1122, USC/Information Science Institute, October 1989. Maher [Page 11] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 [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. Author's Address Maryann Perez Maher USC/ISI 4350 N. Fairfax Drive, Suite 620 Arlington VA 22203 Maher [Page 12] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 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 (xmit IP MTU value) bkw_max_sdu_size_ident 129 bkw_max_sdu_size (recv IP MTU, 0 for disallowing return traffic) 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 if return traffic indicated) spare 0 tagging_bkw 1 (on) tagging_fwd 1 (on if return traffic indicated) 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 10 (nrt-vbr) timing_requirements 10 (timing not required) susceptibility_to_clipping 0 (not susceptible to clipping) spare 0 user_plane_configuration 0 (point_to_point) Maher [Page 13] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 bb_low_layer_information 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 Maher [Page 14] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 Appendix B. Combinations of Traffic Related Parameters This appendix contains a copy of the five tables found in Annex 9 of [UNI96] 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 | O | O | O | |--------------------|---------------|---------------|---------------| | Peak-to-Peak CDV | O | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0)~ | | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0+1)~ | O | | | +--------------------------------------------------------------------+ Maher [Page 15] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 +--------------------------------------------------------------------+ |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)| O | O | O | |--------------------|---------------|---------------|---------------| | Peak-to-Peak CDV | O | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0)~ | | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0+1)~ | O | | | +--------------------------------------------------------------------+ Maher [Page 16] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 +--------------------------------------------------------------------+ |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)| O | O | O | |--------------------|---------------|---------------|---------------| | Peak-to-Peak CDV | O | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0)~ | O | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0+1)~ | | | | +--------------------------------------------------------------------+ Maher [Page 17] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 +--------------------------------------------------------------------+ |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)~ | | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0+1)~ | O | | | +--------------------------------------------------------------------+ Maher [Page 18] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 +--------------------------------------------------------------------+ |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)~ | O | O | O | |--------------------|---------------|---------------|---------------| | CLR (CLP=0+1)~ | | | | +--------------------------------------------------------------------+ Maher [Page 19] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 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 [Page 20] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 O = Optional. May be specified using: - an additional QoS parameter encoded i the Extended QoS parameters information element or the end-to-end transit information element; or, - objectives implied from the QoS class If an Extended QoS Parameters IE is not present in the message, then any value of this parameter is acceptable. If neither the parameter nor the Extended QoS Parameters IE is present, then the objective for this parameter is determined from the QoS class in the QoS Parameter IE. S = Specified. (blank) = Unspecified. * = allowed QoS class values are a network option. Class 0 is always for alignment with ITU-T. ^ = (note 5). ~ = (note 11). Note 1 - Values 0,1,2,4,6, and 8 are not used on transmission but shall be understood on reception. Note 2 - Maximum end-2-end transit delay objectives may only be specified for the forward direction. Note 3 - Maximum end-2-end transit delay objectives may be specified for the ATM Service Category of Non-real Time VBR for reasons of backward compatibility with ITU-T Recommendations. Note 4 - Included for reasons of backward compatibility with UNI 3.1 and ITU-T Recommendations. With these conformance definitions, the CLR commitment is only for the CLP=0 traffic stream. Note 5 - Included to allow switched virtual paths to use the UNI 3.1 conformance definitions. Note 6 - Optional in the user-to-network direction. Specified in the network-to-user direction. Note 7 - This combination should be treated as if the received PCR (CLP=0) parameter were a SCR (CLP=0) parameter and a MBS (CLP=0) parameter with a value of 1. Note 8 - This combination should be treated as if an additional SCR (CLP=0) parameter were received with the same value as a PCR (CLP=0+1) parameter and a MBS (CLP=0) parameter with a value of 1. Note 9 - The best effort parameter applies to both the forward and backward directions. Note 10 - This combination should only be used when the CLR commitment on CLP=0+1 is required versus CLR commitment on CLP=0 traffic, since these combinations are not supported by UNI 3.0/3.1 nor ITU-T Maher [Page 21] INTERNET DRAFT IP over ATM Signalling - UNI 4.0 Update November 1996 Q.2931. Note 11 - In this table the CLR commitment is shown as two entries to indicated explicitly whether the CLR commitment is for the CLP=0 or the CLP=0+1 cells. Maher [Page 22]