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Versions: (draft-gulrajani-pim-hello-intid) 00 01 RFC 6395

Network Working Group                                       S. Gulrajani
Internet-Draft                                                 S. Venaas
Intended status: Standards Track                           cisco Systems
Expires: December 9, 2011                                   June 7, 2011


                  An Interface ID Hello Option for PIM
                   draft-ietf-pim-hello-intid-01.txt

Abstract

   This document defines a new PIM Hello option to advertise an
   interface identifier that can be used by PIM protocols to uniquely
   identify an interface of a neighboring router.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   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."

   This Internet-Draft will expire on December 9, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Requirements Notation  . . . . . . . . . . . . . . . . . .  3
   2.  Interface Identifier Option  . . . . . . . . . . . . . . . . .  4
     2.1.  Local Interface Identifier . . . . . . . . . . . . . . . .  4
     2.2.  Router Identifier  . . . . . . . . . . . . . . . . . . . .  4
   3.  Message Format . . . . . . . . . . . . . . . . . . . . . . . .  6
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   6.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11




































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1.  Introduction

   This document defines a new option for use in PIM Hello messages
   [RFC4601] to carry an Interface Identifier.  A router generates
   identifiers for each of its PIM enabled interfaces such that each
   interface has a different identifier.  The identifiers can optionally
   be generated such that they are unique within, e.g., an
   administrative domain.

   An example where this Interface Identifier can be used is with PIM
   PORT [I-D.ietf-pim-port], where a single Transport connection is used
   between two routers that have multiple interfaces connecting them.
   If these interfaces have unnumbered or IPv6 Link local addresses, the
   Interface Identifier included in the PORT Join/Prune message will
   identify which interface the message is associated with.  For PIM
   PORT the Router Identifier is not needed, and it can be set to zero.

1.1.  Requirements Notation

   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 [RFC2119].





























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2.  Interface Identifier Option

   The Interface Identifier option is used to identify which interface
   of a neighboring router a PIM Hello [RFC4601] is sent on.  This
   allows PIM protocols to refer to, or identify, a particular interface
   on a neighboring router.

   The Interface Identifier option need only be included in PIM Hello
   messages if the router supports protocols that require it.  An
   implementation MAY choose to always include it.  How exactly the
   Interface Identifier is used, and the uniqueness requirements, is
   left to the specifications of the PIM protocols that make use of it.
   It is assumed that different protocols may have different minimum
   requirements for stability and uniqueness of the interface
   identifier, but that they have no maximum requirement.  When
   specified, these protocols should indicate what their minimum
   requirements are.

   The Interface Identifier consists of 64 bits.  The lower 32 bits form
   a Local Interface Identifier, and the high 32 bits a Router
   Identifier.

2.1.  Local Interface Identifier

   The 32 bit Local Interface Identifier is selected such that it is
   unique among the router's PIM enabled interfaces.  That is, there
   MUST NOT be two PIM interfaces with the same Local Interface
   Identifier.  While an interface is up, the Identifier MUST always be
   the same once it has been allocated.  If an interface goes down and
   comes up, the router SHOULD use the same Identifier.  Many systems
   make use of an ifIndex [RFC1213], which can be used as a Local
   Interface Identifier.

   The Local Interface Identifier MUST be non-zero.  The reason for
   this, is that some protocols may want to only optionally refer to an
   Interface using the Interface Identifier Hello option, and use the
   value of 0 to show that it is not referred to.  Note that the value
   of 0 is not a valid ifIndex as defined in [RFC1213].

2.2.  Router Identifier

   The 32 bit Router Identifier may be used to uniquely identify the
   router.  It may be selected to be unique within some administrative
   domain, or possibly globally unique.  The requirements for the scope
   in which it needs to be unique depend on the protocol that utilizes
   this.  A router implementation MAY choose an IPv4 unicast address
   assigned to the router as the Router Identifer, but MUST allow the
   identifier to be configured manually.  Protocols such as BGP



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   [RFC4271] and OSPFv2 [RFC2328] are other protocols making use of 32
   bit identifiers for routers.  One may use the same identifier to
   construct the Interface Identifier option, provided it meets the
   stability and uniqueness requirements of protocols making use of this
   option.

   The value 0 has a special meaning for the Router Identifier.  It
   means that no Router Identifier is used.  If a router only supports
   protocols that require the Interface Identifier to be unique for one
   router (only making use of the Local Interface Identifier), then the
   implementation MAY set the Router Identifier to zero.








































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3.  Message Format

   Option Type: Interface Identifier


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Type = 31           |         Length = 8            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                       Router Identifier                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                   Local Interface Identifier                  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Allocated Hello Type values can be found in [HELLO-OPT].

   Length:   In bytes for the value part of the Type/Length/Value
      encoding.  The Interface Identifier will be 8 bytes long.

   Router Identifier:   The Router Identifier is a 4 byte identifier
      uniquely identifying the router within some scope.  It MAY be 0
      when no protocols require a Router Identifier.

   Local Interface Identifier:   The Local Interface Identifier is a 4
      byte identifier that is unique among all PIM enabled interfaces on
      a router.























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4.  Security Considerations

   The Interface Identifier is included in PIM Hello messages.  See
   [RFC4601] for security considerations regarding PIM Hello messages.
   In particular, PIM Hello messages may be forged, and may include an
   arbitrary Interface Identifier, or the Interface Identifier may be
   intentionally omitted.  The effects of this depend on how the
   Interface Identifier is used by other protocols.











































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5.  IANA Considerations

   IANA has temporarily assigned the value 31 for the Interface
   Identifier Hello option defined in this document.  IANA is requested
   to make this assignment permanent.














































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6.  Acknowledgments

   The authors thank Yiqun Cai, Heidi Ou, Liming Wei, Gorry Fairhurst,
   Bharat Joshi and Bill Atwood for providing valuable feedback.















































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7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4601]  Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
              "Protocol Independent Multicast - Sparse Mode (PIM-SM):
              Protocol Specification (Revised)", RFC 4601, August 2006.

7.2.  Informative References

   [HELLO-OPT]
              IANA, "PIM Hello Options", PIM-HELLO-OPTIONS per
              RFC4601 http://www.iana.org/assignments/pim-hello-options,
              March 2007.

   [I-D.ietf-pim-port]
              Farinacci, D., Wijnands, I., Venaas, S., and M. Napierala,
              "A Reliable Transport Mechanism for PIM",
              draft-ietf-pim-port-06 (work in progress), March 2011.

   [RFC1213]  McCloghrie, K. and M. Rose, "Management Information Base
              for Network Management of TCP/IP-based internets:MIB-II",
              STD 17, RFC 1213, March 1991.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.




















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Authors' Addresses

   Sameer Gulrajani
   cisco Systems
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: sameerg@cisco.com


   Stig Venaas
   cisco Systems
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: stig@cisco.com

































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