2.5.6 Multiprotocol Label Switching (mpls)

NOTE: This charter is a snapshot of the 62nd IETF Meeting in Minneapolis, MN USA. It may now be out-of-date.

Last Modified: 2005-01-25


George Swallow <swallow@cisco.com>
Loa Andersson <loa@pi.se>

Routing Area Director(s):

Bill Fenner <fenner@research.att.com>
Alex Zinin <zinin@psg.com>

Routing Area Advisor:

Alex Zinin <zinin@psg.com>

Mailing Lists:

General Discussion: mpls@lists.ietf.org
To Subscribe: https://www1.ietf.org/mailman/listinfo/mpls
Archive: http://cell.onecall.net/cell-relay/archives/mpls/mpls.index.html

Description of Working Group:

The MPLS working group is responsible for standardizing a base
technology for using label switching and for the implementation of
label-switched paths over various packet based link-level
technologies, such as Packet-over-Sonet, Frame Relay, ATM, and
LAN technologies (e.g. all forms of Ethernet, Token Ring, etc.).
This includes procedures and protocols for the distribution of
labels between routers and encapsulation.

The working group is also responsible for specifying the necessary
MIBs for the functionality specified in the base MPLS technology.

The first generation of the MPLS standards are largely complete,
and the current WG work items are:

- procedures and protocols for multicast protocol extensions for
  point-to-multipoint TE, including soft-preemption

- Define requirements and mechanisms for MPLS OAM

- Define an overall OAM framework for MPLS applications

- MPLS-specific aspects of traffic engineering for multi-areas/multi-AS
  in cooperation with the CCAMP WG

- Determine (with CCAMP) what procedures are appropriate for evaluating
  proposals to extend the MPLS and GMPLS protocols, and document these

- Document current implementation practices for MPLS load sharing

The Working Group chairs tracking of the working group documents can be
viewed at http://www.tla-group.com/~mpls/mpls-wg-docs.htm

Goals and Milestones:

Done  Submit documents from original MPLS effort to IESG
Done  Framework for IP multicast over label-switched paths ready for advancement.
Done  LDP fault tolerance specification ready for advancement to Proposed Standard.
Done  Submit Definitions of Managed Objects for MultoiProtocol Label Switching, Label Distribution Protocol (LDP) to the IESG for publication as Proposed Standards
Done  Specification for MPLS-specific recovery ready for advancement.
Done  Submit Multiprotocol Label Switching (MPLS) Forward Equivalency Class-To-Next Hop Label Forwarding Entry Management Information Base to the IESG for publication as Proposed Standards
Done  Submit Multiprotocol Label Switching (MPLS) Label Switching Router (LSR), Management Information Base to the IESG for publication as Proposed Standards
Done  Submit Multiprotocol Label Switching (MPLS) Management Overview to the IESG for publication as Proposed Standards
Done  Submit Definitions of Textual Conventions for Multiprotocol Label Switching (MPLS) Management to the IESG for publication as Proposed Standards
Done  Submit Multiprotocol Label Switching (MPLS) Traffic Engineering Management Information Base to the IESG for publication as Proposed Standards
Done  Submit the Traffic Engineering Link MIB to the IESG for as a Proposed Standard
Done  Submit a specification on Encapsulations to carry MPLS over IP and GRE to the IESG for as a Proposed Standard
Nov 03  Together with CCAMP complete and establish the (G)MPLS change process
Apr 04  Advance MPLS Architecture and MPLS encapsulation to Draft Standard
Apr 04  Submit a specification on Soft Pre-emption of LSP Tunnels to the IESG for publication as a Proposed Standard
Apr 04  Submit specification on LSR Self Test to the IESG for publication as a Proposed Standard
Jul 04  Submit specification on LSP Ping to the IESG for publication as a Proposed Standard
Jul 04  Submit a document defining the scope, requirements, and issues to resolve for setup of P2MP TE LSPs (MPLS and GMPLS)
Aug 04  Submit an OAM Framework Document to the IESG for publication as an Informational RFC
Oct 04  Advance 'Extension to RSVP for LSP Tunnels' to Draft Standard
Nov 04  Submit document(s) specifying protocol extensions, enhancements and mechanisms for setup of P2MP TE LSPs
Nov 04  Submit a BCP on MPLS load sharing to the IESG


  • draft-ietf-mpls-lsp-hierarchy-08.txt
  • draft-ietf-mpls-bundle-06.txt
  • draft-ietf-mpls-mgmt-overview-09.txt
  • draft-ietf-mpls-bgp-mpls-restart-04.txt
  • draft-ietf-mpls-rsvp-lsp-fastreroute-07.txt
  • draft-ietf-mpls-lsp-ping-08.txt
  • draft-ietf-mpls-lc-if-mib-04.txt
  • draft-ietf-mpls-in-ip-or-gre-08.txt
  • draft-ietf-mpls-nodeid-subobject-05.txt
  • draft-ietf-mpls-oam-requirements-05.txt
  • draft-ietf-mpls-soft-preemption-03.txt
  • draft-ietf-mpls-telink-mib-07.txt
  • draft-ietf-mpls-lsr-self-test-04.txt
  • draft-ietf-mpls-rsvpte-attributes-04.txt
  • draft-ietf-mpls-explicit-null-02.txt
  • draft-ietf-mpls-rfc3036bis-01.txt
  • draft-ietf-mpls-ecmp-bcp-00.txt
  • draft-ietf-mpls-oam-frmwk-01.txt
  • draft-ietf-mpls-rsvp-te-p2mp-01.txt
  • draft-ietf-mpls-p2mp-sig-requirement-01.txt

    Request For Comments:

    RFC2702 I Requirements for Traffic Engineering Over MPLS
    RFC3031 PS Multiprotocol Label Switching Architecture
    RFC3032 PS MPLS Label Stack Encoding
    RFC3033 PS The Assignment of the Information Field and Protocol Identifier in the Q.2941 Generic Identifier and Q.2957 User-to-user Signaling for the Internet Protocol
    RFC3034 PS Use of Label Switching on Frame Relay Networks Specification
    RFC3035 PS MPLS using LDP and ATM VC Switching
    RFC3036 PS LDP Specification
    RFC3037 PS LDP Applicability
    RFC3038 PS VCID Notification over ATM link for LDP
    RFC3063 E MPLS Loop Prevention Mechanism
    RFC3107 PS Carrying Label Information in BGP-4
    RFC3209 PS RSVP-TE: Extensions to RSVP for LSP Tunnels
    RFC3210 I Applicability Statement for Extensions to RSVP for LSP-Tunnels
    RFC3212 PS Constraint-Based LSP Setup using LDP
    RFC3213 I Applicability Statement for CR-LDP
    RFC3214 PS LSP Modification Using CR-LDP
    RFC3215 I LDP State Machine
    RFC3270 PS MPLS Support of Differentiated Services
    RFC3353 I Framework for IP Multicast in MPLS
    RFC3443 PS Time to Live (TTL) Processing in MPLS Networks (Updates RFC 3032)
    RFC3469 I Framework for MPLS-based Recovery
    RFC3477 PS Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)
    RFC3478 PS Graceful Restart Mechanism for Label Distribution Protocol
    RFC3479 PS Fault Tolerance for the Label Distribution Protocol (LDP)
    RFC3480 PS Signalling Unnumbered Links in CR-LDP (Constraint-Routing Label Distribution Protocol)
    RFC3612 I Applicability Statement for Restart Mechanisms for the Label Distribution Protocol (LDP)
    RFC3811 Standard Definitions of Textual Conventions for Multiprotocol Label Switching (MPLS) Management
    RFC3812 Standard Multiprotocol Label Switching (MPLS) Traffic Engineering Management Information Base
    RFC3813 Standard Multiprotocol Label Switching (MPLS) Label Switching Router (LSR)Management Information Base
    RFC3814 Standard Multiprotocol Label Switching (MPLS) Forwarding Equivalence Class To Next Hop Label Forwarding Entry (FEC-To-NHLFE)Management Information Base
    RFC3815 Standard Definitions of Managed Objects for the Multiprotocol Label Switching, Label Distribution Protocol (LDP)
    RFC3988 E Maximum Transmission Unit Signalling Extensions for the Label Distribution Protocol

    Current Meeting Report

    IETF 62 MPLS WG Meeting March 9, 2005

    Chairs: George Swallow <swallow@cisco.com>
    Loa Andersson <loa@pi.se>

    Scribes: M.Morrow, M. Eubanks

    Agenda Bash

    I. WG Status

    New RFCs:

    RFC 3988 MTU Extensions for LDP
    RFC 4023 Encaps MPLS in IP or GRE

    In IESG Review:

    ietf-mpls-explicit-null (approved)


    A. Farrel - Fast track for RFC process would be welcomed
    for the Bundle draft

    Working Group Drafts

    soft pre-emption (ver -04 in pipe)


    J-P Vasseur - Should publish -04 next week for pre-emption

    mpls over l2tpv3 (new)

    LSP-Ping - Last Call after this meeting

    LSR-Self-Test - Last Call after LSP Ping

    II. Incoming liaisons:

    G.motnni from ITU-T SG 15 (Steve Trowbridge)

    Loa: Apologized for chairs dropping the liaison by accident (thus no response)

    Steve: Genoa meeting, editor MPLS Transport - too much included; transport NNI aspects of MPLS itself as transport technology - was not purpose of the document - should be shorter document and narrower in scope Next meeting is in May (ITU-T)

    Monique: Cisco pointed out problems with draft and liaison needed to be done

    MFA: Liaison Relationship with IETF

    Loa: The IETF already has a liaison relationship with the ATM Forum. The IAB wants to await outcome of proposed merger of ATM Forum and MFA before responding.

    A. Malis: Merger has to be approved by written vote by both existing orgs and still in progress (end of Mar termination of voting period);

    III. LDP to Draft Standard (Ina Minei)

    New rev since last IETF draft-3036-bis-01

    Removal of host address FEC proved to be a significant change - Thanks E.Rosen and A.Malis for resolution of issue

    There were a lot of responses from the operational survey. Thanks to the participants, and to Scott Bradener for being the anonymizer. A new draft based on the survey results is available: Draft-minei-ldp-opertal-exper-00.txt

    A new version of 3036 bis will be posted soon, and this should be ready for last call.

    There also needs to be an implementation survey, and we will be working on that.

    IV. Pt-to-MP Signalling Req Draft (S.Yakusawa), pt2mp-sig requirement

    Rev -04
    Removed application scenarios
    Remove (and apologized for) offensive remarks about PIM
    Made the choice of signaling protocols less constrained
    Renamed draft "signalling"

    Resolved 3 of the 5 outstanding issues
    1) Variation of LSP parameters is not allowed
    2) transit LSR's can re-optimize a sub tree
    3) clarified case of tree re-merger to prevent egress data duplication

    Two remaining questions and issues:
    1) Can short-term data duplication be tolerated
    2) Absolute limits and design targets
    number of recipients
    number of branch points
    rate of Join / prune
    rate of change of tree topology

    Seisho proposed that the remaining questions be resolved through discussion on the list. Draft to be complete for last call in May or June.

    Loa: Preferable to have ready in May so that a last call can be completed before Paris.

    V. Extensions to G/RSVP-TE for P2MP TE LSP's (D. Papadimitriou)

    Terminology adapted to requirements doc;
    Document structure has been reorganized.

    Open Issues:
    1) Style usage (SE vs FF style)
    2) Review text for re-merge/cross-over conds
    3) Re-optimization (requires consensus whether re-opt may be done on a P2P sub-LSP and / or sub-tree basis)
    4) Pruning (deletion) and sub-ERO compression reorg
    5) Stitching mechanism - c.f. CCAMP


    George: Right now there are 3 different methods for tearing down an LSP. This seems unnecessarily complicated.

    Rahul: Point well taken. As you know, we had a huge number of authors. It needs to be pruned down on the mailing list.

    VI. Detecting P2MP Data Plane Failures (A.Farrell)

    Need simple and efficient mechanisms to detect data plane failures in P2MP MPLS LSPs

    Verification of reception at recipients
    Discovering p2mp topology
    Objective is to build on top of LSP Ping need to introduce RSVP P2MP session sub-TLV

    Revision 01 has not changed very much. The biggest was that we limited the choice of traceroute destinations to all, or one.

    Request for WG

    Rahul: The draft tries to limit the ping to a subset of the recipients?

    Adrian: Sub-set permitted in sub-set 1 or all (target individual recipient or whole tree)

    Rahul: If I have a tree with a thousand egresses then I am not sure that that solves my problem.

    Adrian: Issue is with problem statement - may be need to be a separate draft

    George: Leave it together for now - if it gets too big then separate

    VII. Component Link Recording and Resource Control for GMPLS Link
    Bundles (Zafar Ali)

    This started in CCAMP at IETF 57. People found issues with link bundling. These were discussed and it was decided that this should be pursued by the MPLS WG.

    Motivation : TE Link Bundle resources are identified by TE Link ID, Component interface ID and Label value.

    RFC3209 allows for label recording, component recording would also be useful. RFC3473 allows for label selection; explicit component selection would be useful for applications like LSP splicing and SRLG diversity.

    Therefore the RRO and ERO should carry component IDs.

    We think that there is general agreement on the requirement and the solution, and would like to have it adopted as a WG doc.

    Loa: (after show of hands who read; who believe should be a WG doc) That's pretty good support, so we will take this to the list.

    Loa: Meeting adjourned - see you in Paris

    George Swallow Cisco Systems (978) 936-1398
    1414 Massachusetts Avenue
    Boxborough, MA 01719


    None received.