MPLS Working Group Loa Andersson Internet-Draft Utfors AB Informational George Swallow Expiration Date: March 2003 Cisco Systems 18 September, 2002 The MPLS Working Group decision on MPLS signaling protocols Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [RFC2026]. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. For potential updates to the above required-text see: http://www.ietf.org/ietf/1id-guidelines.txt Abstract This document is the documentation of the decision taken by the IETF to focus the efforts on a signalling protocol for traffic engineering applications on "RSVP-TE: Extensions to RSVP for LSP Tunnels" (RFC3209), and consequently discontinue the efforts on "Constraint-Based LSP Setup using LDP" (RFC3212). Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [RFC2119]. INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 2] Contents 1. Introduction ..................................................... 2 1.1 Objectives of document ....................................... 2 1.2 Nomenclature ................................................. 3 2. Background ....................................................... 3 3. CCAMP implementation study ....................................... 4 4. MPLS Working Group discussion .................................... 4 4.1 Phase 1 ...................................................... 4 4.2 IETF process ................................................. 5 4.3 Relationship to other standards organizations ................ 5 4.4 Phase 2 ...................................................... 5 5. MPLS Working Group consensus ..................................... 6 6. Recommendation to the IESG ....................................... 7 7. Security considerations .......................................... 8 8. IANA considerations .............................................. 8 9. References ....................................................... 8 9.1 Normative .................................................... 8 9.2 Non-normative ................................................ 8 1. Introduction 1.1 Objectives of document This document documents the Working group consensus on continuing to develop RFC3209 [RFC3209] as the signalling protocol MPLS signaling for Traffic Engineering application. This document also documents the MPLS working group consensus on not undertaking any further work on the RFC3212 [RFC3212], e.g. there is no plans to progress RFC 3212 beyond proposed standard. No other actions are taken relative the document status of RFC3212 [RFC3212] or RFCs that specifies extensions to RFC3212. INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 3] 1.2 Nomenclature This document uses the term "CR-LDP related working group drafts" to discuss a group of Internet Drafts that has specifies changes or extensions to [RFC3212] and the term "CR-LDP related RFCs" to discuss the group of RFCs that specifies protocol and applicability of [RFC3212]. The CR-LDP related drafts are: draft-ietf-mpls-lsp-query-nn.txt [QUERY] draft-ietf-mpls-te-feed-nn.txt [FEED] draft-ietf-mpls-crldp-unnum-nn.txt [UNNUM] draft-ietf-mpls-ldp-ft-nn.txt [FT] draft-ietf-mpls-generalized-cr-ldp-nn.txt [GEN] draft-ietf-ccamp-gmpls-sonet-sdh-nn.txt [SONET] draft-ietf-ccamp-gmpls-g709-nn.txt [G709] draft-ietf-ccamp-gmpls-sonet-sdh-extensions-nn.txt [SDH] The ¡nn in the filename indicates that this does not only apply to the current version of the document, but to future version as well. CR-LDP related RFCs The CR-LDP related RFCs are: RFC3212, "Constraint-Based LSP Setup using LDP" RFC3213, "Applicability Statement for CR-LDP" RFC3214, "LSP Modification Using CR-LDP" No further updates of the CR-LDP related RFCs, beyond proposed standard are planned. 2. Background Very early (1997) in the MPLS standardization it was clear that a protocol would be needed that would enable providers to setup LSPs that took other information (e.g. various QoS parameters) as input for establishing LSPs. Development of this type of signalling protocol took two different tracks: - extensions to RSVP for setting up MPLS tunnels [RFC3209] - extensions to LDP for setting constraint based LSPs [RFC3212] The motivation for the choice of protocol was in both cases straightforward. Extending RSVP-TE to do in an MPLS environment what it already was doing (handling QoS information and reserving resources) in an IP environment is comprehensible; you only have to add the label INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 4] distribution capability. Extending a native MPLS protocol like LDP, which was designed to do label distribution, to handle some extra TLVs with QoS information is also not revolutionary. The MPLS group never reached a consensus on which way to go. Both protocols were progressed to proposed standard. 3. CCAMP implementation study An implementation survey for signaling protocols within the GMPLS area were published in June 2002 [GMPLS]. The survey did show that there are quite a number of implementations; the survey includes responses from 22 different implementers. The survey also did show that of the 22 responders 21 had implemented the GMPLS signalling based on [RFC3209], while only 3 had implemented based on [RFC3212]. 4. MPLS Working Group discussion 4.1 Phase 1 The report prompted questions if it was motivated to have two different protocols for the same things. The discussion was brought to the MPLS Working Group at the meeting in Yokohama July 2002. After discussion at the meeting it was decided to "bring this to the list" and also invite comments from the other Sub-IP Area Working Groups. The question sent to the list was formulated as: "As there are issues with having two similar standards (potentially diverging), and it generates duplicate work in several IETF working groups, the question was asked whether we should make CR-LDP informational (which still make it available and possible to work with) and progress only RSVP-TE on the standards track." The response to this was largely positive, but some problems were immediately pointed out: - there are non-IETF standards which reference RFC3212. Taking CR-LDP off the standards track would cause un-necessary problems for those organisations and should be done only after co-ordinating with those organizations - there is, e.g. in RFC2026 [RFC2026], no documented process according to which a document on the standards track may be move to a status that is non-standards track INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 5] Each of these arguments is by themselves strong and would have led to some reformulation of the proposal to move CR-LDP to informational. Moreover, in combination it was clear that the original proposal was not viable. On the other hand the support for actually keeping CR-LDP as alive an IETF alternative to RSVP-TE is extremely small. 4.2 IETF process The current IETF process for managing changes in RFC status does not include any information on how to move an existing standard track RFC to a non-standard track status. It has been show that such actions have been previously taken e.g. RFCs 2673 and 2874 were moved from Proposed Standard to Experimental. Though the cases are not exactly parallel to the MPLS signalling case it shows that the IESG are prepared to take such decisions given that the arguments are sufficiently strong. 4.3 Relationship to other standards organizations The relationship with other standard organizations is a corner stone in the IETF work. We are dependent on their work and they need us; each has their own area of expertise. It is therefore necessary that both sides handle their standards documentation in such a way that no unnecessary updates or revisions are introduced simply by sloppy handling of documents. Consequently we need to keep CR-LDP referenceable, i.e. on the standards track, for the foreseeable future. The implication of this is not that we need to progress it further, or need to undertake further work in the area. One implication however is that standards organizations which reference the document, need to be notified of our decision so that they (at their own leisure) can change their references to more appropriate documents. It is also expected that they notify us when they no longer have normative references to CR-LDP. 4.4 Phase 2 Based on the feed back from this first discussion the question to the working group were reformulated as: "Should the MPLS WG focus its efforts on a signaling protocol for traffic engineering applications on RSVP-TE, and hence the WG effort with CR-LDP be discontinued? This would not involve any change in document status for CR-LDP, nor would it hinder continued individual contributions in the CR-LDP space. It would involve a change in the MPLS WG charter to reflect this." INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 6] It was pointed out that "nor would it hinder continued individual contributions" is too weak. We actually discourage, while it is not prohibited, continued work in the CR-LDP area. That is the whole point with taking this decision. It was also pointed out that while it is quite acceptable to not accept further working group documents, it would also be appropriate to take the existing CR-LDP related working group documents through the process to proposed standard or informational as intended. This is applicable to the following documents, since much of the work has already been completed on them: -in MPLS WG -- draft-ietf-mpls-lsp-query-nn.txt draft-ietf-mpls-te-feed-nn.txt draft-ietf-mpls-crldp-unnum-nn.txt draft-ietf-mpls-ldp-ft-nn.txt - in CCAMP WG -- draft-ietf-mpls-generalized-cr-ldp-nn.txt draft-ietf-ccamp-gmpls-sonet-sdh-nn.txt draft-ietf-ccamp-gmpls-g709-01.txt draft-ietf-ccamp-gmpls-sonet-sdh-extensions-nn.txt Some of the documents listed above are not in themselves be extensions to CR-LDP, but in one way or another are deemed to be "equally applicable to CR-LDP". For those documents it will be fully appropriate to progress them to beyond proposed standard in the future. RFCs that are extensions to CR-LDP, i.e. RFCs 3213 and 3214 will remain proposed standard documents. After this a good consensus quickly formed along those lines. Close to 90% of the people participating discussion said that they support or at least accept this outcome of the working group discussion. 5. MPLS Working Group consensus In a message to the working group (date) the working groups chairs found that consensus had been reached on: - that the MPLS WG needs to focus its efforts on RSVP-TE (RFC 3209) as protocol for traffic engineering signalling. INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 7] - that the Working Group effort on CR-LDP should be discontinued. - that the WG charter should be updated to reflect this. - that CR-LDP (RFC 3212) will remain a proposed standard. - that RFCs 3213 and 3214, that is closely related to CR-LDP will remain proposed standard. - that existing Working Group drafts related to or updating/changing CR-LDP will be progressed through the standards process to proposed standard or informational RFCs as appropriate. - that "the existing cr-ldp working group documents" are: draft-ietf-mpls-lsp-query-nn.txt draft-ietf-mpls-te-feed-nn.txt draft-ietf-mpls-crldp-unnum-nn.txt draft-ietf-mpls-ldp-ft-nn.txt draft-ietf-mpls-generalized-cr-ldp-nn.txt draft-ietf-ccamp-gmpls-sonet-sdh-nn.txt draft-ietf-ccamp-gmpls-g709-nn.txt draft-ietf-ccamp-gmpls-sonet-sdh-extensions-nn.txt - that the IETF will take on no new Working Group documents related to CR-LDP. - that the IETF will entertain no efforts to promote CR-LDP beyond proposed standard. - that individual contributions to CR-LDP area are not prohibited, but discouraged. - that a message will be sent to the relevant standards organizations notifying them of this change of focus on MPLS signaling protocols. 6. Recommendation to the IESG Based on the consensus in the MPLS working group we recommend the IESG to: - confirm the MPLS Working Group decision to discontinue work on CR- LDP and focus on RSVP-TE as signaling protocol for traffic engineering applications for MPLS - refrain from entertaining work that intends to progress RFC-3212 or related RFCs beyond proposed standard INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 8] - review the IETF process with respect to management of documents that needs to be moved from standards track to any other status - publish this document as Informational RFC 7. Security considerations This document only discusses a refocusing of the MPLS Working Group work and consequently brings no new security considerations. 8. IANA considerations This document brings no IANA considerations. 9. References 9.1 Normative [RFC2026] Bradner, S. "The Internet Standards Process -- Revision 3", RFC 2026, October 1996. [RFC2119] Bradner, S. "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC3212] Jamoussi, B. et.al., "Constraint-Based LSP Setup using LDP" RFC3212, January 2002. [RFC3209] Awduche, D. et.al., "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC3209, December 2001. 9.2 Non-normative [RFC3213] Jamoussi, B. et.al., "Applicability Statement for CR-LDP", RFC3213, Jan 2002 [RFC3214] Jamoussi, B. et.al., "LSP Modification Using CR-LDP" RFC3213, Jan 2002 INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 9] [GMPLS] Rekhther,Y and Berger,L, "Generalized MPLS Signaling - Implementation Survey" http://www.ietf.org/IESG/Implementations/MPLS-SIGNALING- Implementation.txt , June 2002. [QUERY] Ashwood-Smith P. and A. Paraschiv, "Multi Protocol Label Switching Label Distribution Protocol Query MessageDescription" draft-ietf- mpls-lsp-query-04.txt, Internet Draft, Work in Progress, May 2002. [FEED] Jamoussi, B. et.al., "Improving Topology Data Base Accuracy with LSP Feedback in CR-LDP", draft-ietf-mpls-te-feed-04.txt, Internet Draft, Work in progress, May 2002. [UNNUM] Rekhter, Y., et.al., "Signalling Unnumbered Links in CR-LDP", draft- ietf-mpls-crldp-unnum-07.txt, Internet Draft, Work in Progress, July 2002. [FT] Farrel, A., et.al., "Fault Tolerance for the Label Distribution Protocol (LDP)", draft-ietf-mpls-ldp-ft-nn.txt, Internet draft, Work in Progress, Sep 2002. [GEN] Ashwood-Smith, P. and Berger, L. (eds) "Generalized MPLS Signaling - CR-LDP Extensions", draft-ietf-mpls-generalized-cr-ldp-07.txt, Internet draft, Work in Progress, Aug 2002. [SONET] Mannie, E and Papadimitriou, D., "Generalized Multiprotocol Label Switching Extensions forSONET and SDH Control" draft-ietf-ccamp- gmpls-sonet-sdh-06.txt, Internet draft, Work in Progress, Aug 2002. [G709] Papadimitriou, D. (ed), "Generalized MPLS Signalling Extensionsfor G.709 Optical Transport Networks Control" draft-ietf-ccamp-gmpls- g709-nn.txt, Internet draft, Work in Progress, June 2002. [SDH] "Generalized Multiprotocol Label Switching Extensions to ControlNon- Standard SONET and SDH Features" draft-ietf-ccamp-gmpls-sonet-sdh- extensions-nn.txt Authors contacts: INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02 Andersson Expires March 2003 [Page 10] Loa Andersson Utfors AB Box 525 SE-169 29 Solna Sweden email: loa.andersson@utfors.se George Swallow Cisco Systems, Inc. 250 Apollo Drive Chelmsford, MA 01824 Voice: +1 978 244 8143 email: swallow@cisco.com INTERNET-DRAFT draft-andersson-mpls-sig-decision-01.txt 18.09.02