Last Modifield: 03/25/2002
The Internet Traffic Engineering Working Group defines, develops, specifies, and recommends principles, techniques, and mechanisms for traffic engineering in the internet. The working group also serves as a general forum for discussing improvements to IETF protocols to advance the traffic engineering function.
The primary focus of the tewg is the measurement and control aspects of intra-domain internet traffic engineering. This includes provisioning, measurement and control of intra-domain routing, and measurement and control aspects of intra-domain network resource allocation. Techniques already in use or in advanced development for traffic engineering include ATM and Frame Relay overlay models, MPLS based approaches, constraint-based routing, and traffic engineering methodologies in Diffserv environments. The tewg describes and characterizes these and other techniques, documents how they fit together, and identifies scenarios in which they are useful.
The working group may also consider the problems of traffic engineering across autonomous systems boundaries.
The tewg interacts with the common control and measurement plane working group to abstract and define those parameters, measurements, and controls that traffic engineering needs in order to engineer the network.
The tewg also interacts with other groups whose scopes intersect, e.g. mpls, is-is, ospf, diffserv, ippm, rap, rtfm, policy, rmonmib, disman, etc.
The work items to be undertaken by TE WG encompass the following categories:
- BCP documents on ISP uses, requirements, desires (TEBCPs)
- Operational TE MIB (TEMIB)
- Document additional measurements needed for TE (TEM)
- TE interoperability & implementation informational notes (TEIMP)
- Traffic Engineering Applicability Statement (TEAPP)
For the time being, it also is covering the area of verification that diffserv is achievable in traffic engineered SP networks. This will entail verification and review of the Diffserv requirements in the the WG Framework document and initial specification of how these requirements can be met through use and potentially expansion of existing protocols.
|Done||Solicit TEBCP drafts concerning requirements, approaches, lessons learned from use (or non use) of TE techniques in operational provider environments.|
|Done||Review and comment on operational TEMIB|
|Done||TEBCPs submitted for WG comment|
|Done||Comments to TEBCP authors for clarifications|
|Done||First draft of TEAPP|
|Done||First draft of TEM|
|Done||TE Framework Draft to AD/IESG for review.|
|Done||Drafts available for E-LSP and L-LSP Diffserv TE|
|Done||Another update of operational TEMIB draft|
|Done||All comments back on TE Diffserv requirements|
|Done||Submit revised TEBCPs and REAPP to AD/IESG for review|
|OCT 01||Submit TEM draft for AD review|
|OCT 01||Progress operational TE MIB to AD review|
|NOV 01||Any necessary protocol extensions for Diffserv TE sent to protocol relevant WGs for review.|
|JAN 02||Progress Diffserv TE E-LSP and L-LSP Diffserv TE drafts together to AD/IESG for review|
|RFC3272||I||Overview and Principles of Internet Traffic Engineering|
|RFC3346||I||Applicability Statement for Traffic Engineering with MPLS|
---------------------------------------- -------------------- Internet Traffic Engineering WG - IETF 55 November 20, 2002 Atlanta o) Agenda and WG Update Document status since last meeting. TE Applicability RFC3346 Survivability and Hierarchy RFC3386 IGP as second metric RFC-ED CW BCP RFC-ED TEWG MIB no status Diffserv TE Requirements IESG Diffserv TE Protocol no status Diffserv Bandwidth models no status TE Measurement no status o) TEWG MIB - Kireeti Issue is how to define a hop (Textual Convention for hops) Going to define TCs for HOPs in MPLS WG TC MIB, reference them in TEWG MIB Jerry Ash: It would be prefereable to merge the MPLS WG MIB and the TEWG MIB, service providers would prefer to have one as opposed to two mibs. Kireeti: They serve different purposes, so they can stay separate. Jim: So TEWG mib will include reference into MPLS WG mib Kireeti: Just the MPLS TC MIB, which can proceed independent of LSR MIB, or other MIBS in MPLS WG (Loa confirmed) o) Diffserv TE (proto) - Francois Bandwidth constraint models and protocol drafts have been split. Really no recent comments on "protocol", most discussion is on BC models. Drafts define the BC models Changes of proto-01 -> proto-02 - move RSVP-TE appendix into section of text - CR-LDP appendix removed - cleanup for IESG Outstanding issues on 02 - mostly clarity issues, seem resolved. Next steps? - Most of room feel that the protocol draft is ready to "freeze" so WG last call on list after -03 issued. o) BC models - Francois Requirements - operates well w/ or w/o preemption - efficient use of bandwidth - isolation across CTs - protection against QoS degradation - simple 3 documented models - russian dolls model (RDM) (Francois) - maximum allocation model (MAM) (Lai) - maximum allocation w/ reservation (MAR) (Ash) Comparison of models [see presentation] Propose to document not only one model but rather to document two models. Propose that these two documented models be RDM and MAM. Noted that there really aren't outstanding issues on Russian Doll model. o) Maximum allocation with reservation (MAR) - Jerry [see presentation] Jerry recommended that the MA model be the default BC model and that the RD model be an optional BC model (should be used only when preemption is also used). Jerry also recommended that we continue to study possible extensions to MA, such as MAR, to improve performance. o) Maximum allocation model and comparison - Waisum [see presentation] Draft is a comparison of MAM and RDM. At some rates of signaling and load, MAM provides less blocking probability for some classes (e.g. service isolation) Proposes to have MAM as default model. o) Discussion on BC models - General Lots of discussion on this. It was pointed out that if we do have a normative reference to a BC model, it must be standards track. Others (modular) might be informational, experimental, or standards track (need to determine track here). However, we have multiple BC models on the table here, and the requirements document says there must be a default BC model for implementation. So the question becomes: Is "one" of these the default? Or both? Or maybe should neither really be required, they proceed non-standard until operational experience shows what people really use (and thus should be required for implementation). Some discussion and opinions, but breaking up the question: Must there be at least one normative reference from the protocol draft to a BC model [show of hands says "yes"] Must there be one and only one required bc model? Or is more than one required bc model ok. [hands are split] o) Discussion on DSTE protocol drafts and how to proceed Obviously going to IESG, the proto draft must proceed with any normative referred to bc models. However, we have to first involve other WGs (OSPF, ISIS, MPLS). Some discussion on whether to hold off until conclusion on bc models prior to involving other WGs. Bert indicated that since we are going to WG last call on proto, just send some heads up to the other lists. So we will send a heads up to other WGs shortly after IETF 55 and again when WG last call starts (on proto). If any feel the bc model is relevant to how their WG (e.g OSPF, ISIS, MPLS) evaluates the protocol, they can raise that issue. We will send another reminder when the BC model issue is resolved. o) Inter AS requirements [see presentation] Discussion on if TEWG is right place for these types of requirements, show of hands indicated it was and there was no objection. Bert confirmed that was his understanding of where these would be too. Also, show of hands indicated it is about time to take this type of requirements work on. o) TE Measurement draft Specific measurements - Use of node-pair measurements - Stats of carried load -v- performance - record/detect label-binding changes (e.g. topology changes) Next steps? Propose that it is WG item against charter item and it is ready for WG last call. Discussion: Most agree this is an important charter item. Question is to whether this draft has sufficient review to proceed. Merike Kaeo (IPPM WG Chair) stated that the need for consistent measurement methods is obviously important, but after having read the draft, it wasn't clear if that had been achieved [note: this is the original issue w/ -02 discussed in Minneapolis]. Jerry again stated his support for this moving forward. Although there were not many people in room who had read the draft, Bert asked who would read this if WG last call was raised, and most raised there hand. So it will go forward for WG last call, if there are folks with issues with it, they will need to raise their concern. It is also important to make sure it has had thorough WG review, so there will be an attempt by Ed to make sure it's not proceeding to IESG w/o only minimal review. o) DSTE link bundle options Augments DS-TE protocols, but DS-TE protocols (or requirements) don't depend on it. There seemed to be folks who indicated in audience that they use link-bundles and want to do DS-TE so this is relevant work. As to WG item, Chairs decided to hold off for now. Issue: If we complete the core work for Diffserv TE, does further work on DSTE protocol happen here or somewhere else? o) Wrapup Sub-IP lives (for now). There are question in terms of where TEWG heads as it finishes up its current charter. A dormant period? Or turn into a more long-term concept group (w/o becoming a research group)?