Internet Draft
MPLS WG                                                    Loa Andersson
Internet Draft                                            Bilel Jamoussi
Expiration Date: February 2000                     Nortel Networks Corp.

                                                           Muckai Girish
                                           SBC Technology Resources Inc.

                                                             Tom Worster
                                                                   Nokia

                                                            October 1999


                          MPLS Capability Set

                     draft-loa-mpls-cap-set-01.txt



Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of 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.

Abstract

   Several protocols might be used for Label Distribution in an MPLS
   network, e.g. Label Distribution Protocol (LDP), including the part
   of LDP described in Constraint-Based LSP Setup using LDP, the BGP-4
   and RSVP.

   The functionality defined in those protocols are to some extent
   overlapping, but also complementary. This document specifies a
   number of MPLS Capability sets that can be used to define what is
   needed from an MPLS implementation in order to interwork with other
   implementations. The number of Capability sets might change in the
   future.

Andersson, et. al.                                            [Page 1]
Internet Draft           MPlS Capability Set             October, 1999



Table of Contents

   Abstract ..........................................................1
   Table of Contents .................................................2
   1. Introduction ...................................................2
   2. Overview .......................................................2
   3. MPLS Capability set ............................................3
   4. Protocol and functional components .............................3
   5. Defined MPLS Capability set ....................................3
   5.1 MPLS Capability set #1 ........................................4
   5.2 MPLS Capability set #2 ........................................4
   5.3 MPLS Capability set #3 ........................................4
   5.4 MPLS Capability set #4 ........................................5
   5.5 MPLS Capability set #5 ........................................5
   5.6 MPLS Capability set #6 ........................................5
   5.7 MPLS Capability set #7 ........................................5
   5.8 MPLS Capability set #8 ........................................5
   5.9 MPLS Capability set #9 ........................................5
   5.10 MPLS Capability set #42 ......................................6
   5.11 Future extensibility .........................................6
   6. Security .......................................................6
   7. Acknowledgements ...............................................6
   8. References .....................................................6

1. Introduction

   The set of documents that constitute the MPLS standard, as it is
   being specified by the MPLS Working Group of IETF, offers several
   ways of setting up Label Switched Paths (LSP) for a number of
   applications, including support for traffic engineering and Virtual
   Private Networks.

   The Label Distribution Protocol (LDP) has been developed by the MPLS
   WG for the explicit task of doing Label Distribution. Other
   protocols, already in existence and originally developed for other
   purposes, have been adapted or extended to support Label
   Distribution.

   This draft addresses unicast functionality only, multicast is for
   further study.

2. Overview

   It has been frequently noted that the functionality supported by the
   most of the specifications of how you do Label Distribution, for
   most applications, are richer than necessary. MPLS implementations
   implementing parts of one specification or a mix of parts from
   several specifications will be viable.



Andersson, et. al.          February 2000                     [Page 2]
Internet Draft           MPlS Capability Set             October, 1999

   As all implementations won't support all of the specified mechanisms
   for Label distribution specified in the MPLS standard. This
   introduces the requirement of a tool for describing the compliance
   between MPLS implementations.

3. MPLS Capability set

   This draft introduces the MPLS Capability set as a method of
   specifying the compliance of an implementation to the set of MPLS
   specifications and to other implementations. This draft gives an
   overview of what is needed, in terms of protocols and mechanism, to
   support the MPLS capability sets.

4. Protocol and functional components

   The following functional and protocol component are available in the
   protocols  developed for and/or extended to do label distribution,
   [1], [2], [3] and [4]. All the specification listed below are worked
   on by the MPLS WG, and is still work in progress.

      Carrying Label Information in BGP-4 [1]

      Defines mechanisms for:
         - assigning labels to BGP routes

      Constraint based routing with LDP (CR-LDP) [2]

      Defines mechanisms for:
         - explicit routed LSPs
         - LSP set up with defined QoS

      Label Distribution Protocol (LDP) [4]

      Defines mechanisms for:
         - basic LDP mechanisms
            - LDP neighbor detection
            - LDP session initiation, maintenance and termination
            - loop detection
         - modes of  label distribution defined in [5]
            - Downstream Unsolicited Independent Control
            - Downstream Unsolicited Ordered Control
            - Downstream On Demand Independent Control
            - Downstream On Demand Ordered Control

      Extensions to RSVP for LSP Tunnels [3]

      Defines mechanisms for:
         - explicit routed LSPs
         - dynamic distribution of labels (hop-by-hop mechanism)

5. Defined MPLS Capability set


Andersson, et. al.          February 2000                     [Page 3]
Internet Draft           MPlS Capability Set             October, 1999

   An MPLS Capability set defines the set of components that has to be
   supported by an implementation claiming compatibility with the
   capability set. Currently there are 10 Capability sets defined.
   Although there sometimes/frequently is an obviously a relationship
   between the Capability set and an intended use, this draft doesn't
   state the intended use of or the application possible to support by
   the capability set.

   The intention is instead to give a reference framework that offers a
   possibility to classify compatibility of MPLS implementations.  The
   Capability sets is atomic, i.e. it is not possible for an
   application to be compliant to part of a capability set. However it
   is possible for an application to be compliant with one or more
   capability sets.

5.1 MPLS Capability set #1

   MPLS Capability set #1 includes the following components:

         - LDP basic mechanisms
            - LDP neighbor detection
            - LDP session initiation, maintenance and termination
         - CR-LDP strict explicit routed LSPs

   This Capability set supports explicit routed LSP set up, but does
   not allow loosely routed segments on an explicit route. Note that
   this capability set do not require the loop detection mechanism.

5.2 MPLS Capability set #2

   MPLS Capability set #2 includes the following components:
         - LDP basic mechanisms
         - CR-LDP explicit routed LSPs
         - modes of  label distribution defined in [5]
            - Downstream On Demand Ordered Control

   This Capability set supports explicit routing and allows loosely
   routed segments of an explicit route.

5.3 MPLS Capability set #3

   MPLS Capability set #3 includes the following components:

         - LDP basic mechanisms
         - CR-LDP explicit routed LSPs
         - CR-LDP LSP set up with QoS
         - modes of  label distribution defined in [5]
            - Downstream On Demand Ordered Control

   This Capability set supports explicit routing and allows loosely
   routed segments of an explicit route.


Andersson, et. al.          February 2000                     [Page 4]
Internet Draft           MPlS Capability Set             October, 1999

5.4 MPLS Capability set #4

   MPLS Capability set #4 includes the following components:
         - LDP basic mechanisms
         - All the modes of label distribution defined in [5]

   This Capability set is label distribution as defined in [4].

5.5 MPLS Capability set #5

   MPLS Capability set #5 includes the following components:
         - LDP basic mechanisms
         - All the modes of label distribution defined in [5]
         - CR-LDP explicit routed LSPs
         - CR-LDP LSP set up with QoS

   This Capability set is label distribution as defined in [4] and
   [2] combined.

5.6 MPLS Capability set #6

   MPLS Capability set #6 includes the following components:
         - LDP basic mechanisms
         - Downstream unsolicited independent control

   This Capability set emulates the behavior of a legacy best effort IP
   network.

5.7 MPLS Capability set #7

   MPLS Capability set #7 includes the following components:
         - RSVP explicit routed LSPs
         - RSVP based dynamic distribution of labels

   This Capability set is label distribution as defined in [3].

5.8 MPLS Capability set #8

   MPLS Capability set #8 includes the following components:
         - RSVP explicit routed LSPs
         - LDP basic mechanisms
         - All the modes of label distribution defined in [5]

   This Capability set gives explicit routed LSPs and a hop-by-hop
   mechanism.

5.9 MPLS Capability set #9

   MPLS Capability set #9 includes the following components:
         - Assigning label to BGP routes as defined in [1].



Andersson, et. al.          February 2000                     [Page 5]
Internet Draft           MPlS Capability Set             October, 1999

   This Capability set could be used with any of capability set 1
   through 7, and will in that case give a possibility to support
   network hierarchy. It could also be used alone.

5.10 MPLS Capability set #42

   MPLS Capability set #42 includes all of the components listed in
   section 4 of this draft.

   An LSR claiming 42 compliance should, with proper configuration, be
   able to inter work with any other LSR compliant with any of the
   capability sets.

5.11 Future extensibility

   The number or capability sets are not static, but might be increased
   or reduced as required, e.g. if the number of protocols
   specification that defines label distribution changes. If there is a
   need for any Capability set that has not been specified here it will
   be added. Likewise, if any of the defined Capabilities sets fall out
   of use it will be removed.

6. Security

   This draft does not introduce any new security issues to the various
   label distribution protocols.

7. Acknowledgements

   We would like to thank the members of the MPLS working group of the
   IETF, whose input and scrutiny of this document has been invaluable.

8. References

   1 Y. Rehkter and E. Rosen, "Carrying Label Information in BGP-4"
   , work in progress, August 1998.

   2 B. Jamoussi et. al., "Constraint-Based LSP Setup using LDP"
    work in progress, October 1999.

   3 D. Awduche, L. Berger, D. Gan, T. Li, G. Swallow,
   V Srinivasan, "Extensions to RSVP for LSP Tunnels", < draft-ietf-
   mpls-rsvp-lsp-tunnel>, work in progress, October 1999.

   4 L. Andersson et al., "LDP specification",
   , work in progress, October 1999.

   5 E. Rosen, A. Viswanathan, R. Callon,"Multiprotocol Label Switching
   Architecture", < draft-ietf-mpls-arch>, work in progress, September
   1999.



Andersson, et. al.          February 2000                     [Page 6]
Internet Draft           MPlS Capability Set             October, 1999


9. Author's Addresses

   Loa Andersson                     Muckai K Girish
   Nortel Networks Corp.             SBC Technology Resources,
   S:t Eriksgatan 115                4698 Willow Road
   PO Box 6701                       Pleasanton, CA 94588
   113 85 Stockholm                  Phone: (925) 598-1263
   Tel: +46 8 508 835 00             Fax:   (925) 598-1321
   Fax: +46 8 508 835 01             Mgirish@tri.sbc.com
   Loa_andersson@nortelnetworks.com


   Tom Worster                       Bilel Jamoussi
   Nokia                             Nortel Networks Corp.
   3 Burlington Woods Dr.            600 Technology Park Drive
   Suite 250                         Billerica, MA 01821
   Burlington MA 01803 USA           USA
   +1 617 247 2624                   phone: +1 978-288-4506
   Tom.worster@nokia.com             Jamoussi@nortelnetworks.com                                                                                                                                 


Full Copyright Statement

   "Copyright (C) The Internet Society (date). All Rights Reserved.
   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
      revoked by the Internet Society or its successors or assigns.












Andersson, et. al.          February 2000                     [Page 7]