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Network Working Group                                  Rahul Aggarwal
Internet Draft                                         Kireeti Kompella
Expiration Date: March 2004                            Juniper Networks

      Advertising a Router's Local Addresses in OSPF TE Extensions

                draft-raggarwa-ospf-te-node-addr-00.txt


1. 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.


2. Abstract

   This document describes procedures that enhance OSPF Traffic
   Engineering (TE) extensions for advertising a router's local
   addresses.  This is needed to enable other routers in a network to
   compute traffic engineered MPLS LSPs to a given router's local
   addresses.  Currently, the only addresses belonging to a router that
   are advertised in TE LSAs are the router's local addresses on links
   enabled for TE, and the Router ID.











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3. Motivation

   In some cases it is desirable to setup, constrained shortest path
   first (CSPF) computed MPLS TE LSPs, to local addresses of a router
   that are not currently advertised in the TE LSAs i.e. loopback and
   non-TE interface addresses.

   For instance in a network carrying VPN and non-VPN traffic, its often
   desirable to use different MPLS TE LSPs for the VPN traffic and the
   non-VPN traffic. In this case one loopback address may be used as the
   BGP next-hop for VPN traffic while another may be used as the BGP
   next-hop for non-VPN traffic. Its also possible that different BGP
   sessions are used for VPN and non-VPN services. Hence two separate
   MPLS TE LSPs are desirable, one to each loopback address.

   However currently routers in an OSPF network can only use CSPF to
   compute MPLS TE LSPs to the router ID or the local addresses of TE
   enabled links, of a remote router. This restriction arises because
   OSPF TE extensions [OSPF-TE, OSPFv3-TE] only advertise the router ID
   and the local addresses of TE enabled links, of a given router. Other
   routers in the network can populate their traffic engineering
   database (TED) with these local addresses belonging to the
   advertising router. However they cannot populate the TED with other
   local addresses of the advertising router i.e. loopback and non-TE
   interface addresses. OSPFv2 stub links in the router LSA [OSPFv2],
   provide stub reachability information to the router but are not
   sufficient to learn all the local addresses of a router. The same
   problem exists with intra-prefix LSAs in OSPFv3 [OSPFv3].

   For the above reasons this document proposes an enhancement to OSPF
   TE extensions to advertise the local addresses of a node.


4. A Potential Solution

   A potential solution would be to advertise a TE link TLV for each
   local address, possibly with a new link type.  However, this is
   inefficient, as the only meaningful information is the address.
   Furthermore, this would require implementations to process these TE
   link TLVs differently from others; for example, the TE metric is
   normally considered a mandatory sub-TLV, but would have no meaning
   for a local address









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5. Proposed Solution

   The proposed solution is to advertise the local addresses of a router
   in a new node attribute TLV, in the OSPF TE LSA. It is anticipated
   that a node attribute TLV will also prove more generally useful.


5.1. Node Attribute TLV

   The node attribute TLV carries the attributes associated with a
   router. The TLV type is TBD and the length is variable. It contains
   one or more sub-TLVs. This document defines the following sub-TLVs:

     1. Node IPv4 Local Address sub-TLV
     2. Node IPv6 Local Address sub-TLV

   The node IPv4 local address sub-TLV has a type of 1 and contains one
   or more local IPv4 addresses. It has the following format:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              1                |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          IPv4 Address 1                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                               .                               .
      .                               .                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          IPv4 Address n                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The length is set to 4 * n where n is the number of local addresses
   included in the sub-TLV.

   The node IPv6 local address sub-TLV has a type of 2 and contains one
   or more local IPv6 addresses. It has the following format:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              2                |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         IPv6 Address 1                        |
      |                                                               |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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      .                               .                               .
      .                               .                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         IPv6 Address n                        |
      |                                                               |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--

   The length is set to 16 * n where n is the number of local addresses
   included in the sub-TLV.


6. Security Considerations

   This document does not introduce any further security issues other
   than those discussed in [OSPF-TE, OSPFv3-TE].


7. IANA Considerations

   The Node Attribute TLV type has to be IANA assigned from the range 3
   - 32767 as specified in [OSPF-TE].


8. Acknowledgments

   We would like to thank Nischal Sheth for his contribution to this
   work. We woud also like to thank Jean Philippe Vasseur for his
   comments.


9. References


   [OSPF]         Moy, J., "OSPF Version 2", RFC 2328, April 1998.

   [RFC]          Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.

   [OSPF-TE]      D. Katz, K. Kompella, D. Yeung, "Traffic Engineering
                  Extensions to OSPF version 2", RFC 3630,
                  September 2003.

   [OSPFv3]       R. Coltun, D. Ferguson, J. Moy, "OSPF for IPv6",
                  RFC 2740.

   [OSPFv3-TE]    K. Ishiguro, T. Takada, "Traffic Engineering



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                  Extensions to OSPF version 3",
                  draft-ietf-ospf-ospfv3-traffic-01.txt.

   [OSPF-TE-MESH] J. P. Vasseur, P. Psenak, "OSPF Traffic Engineering
                  Capability TLVs",
                  draft-vasseur-mpls-ospf-te-cap-00.txt.


10. Author Information


   Rahul Aggarwal
   Juniper Networks
   1194 North Mathilda Ave.
   Sunnyvale, CA 94089
   Email: rahul@juniper.net

   Kireeti Kompella
   Juniper Networks
   1194 North Mathilda Ave.
   Sunnyvale, CA 94089
   Email: kireeti@juniper.net





























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