Network Working Group                                        A. Banerjee
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                                 D. Ward
Expires: March 30, May 27, 2011                                   Juniper Networks
                                                      September 26,
                                                       November 23, 2010

                Extensions to IS-IS for Layer-2 Systems
                       draft-ietf-isis-layer2-07
                       draft-ietf-isis-layer2-08

Abstract

   This document specifies the IS-IS extensions necessary to support
   link state routing to any protocols running directly over layer 2.
   While supporting this concept involves several pieces, this document
   only describes extensions to IS-IS.  Furthermore, the TLVs described
   in this document are generic layer 2 additions and specific ones as
   needed are defined in the IS-IS technology specific extensions.  We
   leave it to the systems using these IS-IS extensions to explain how
   the information carried in IS-IS is used.

Status of this Memo

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   This Internet-Draft will expire on March 30, May 27, 2011.

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Table of Contents

   1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  TLV Enhancements to IS-IS  . . . . . . . . . . . . . . . . . .  4
     2.1.  The MAC-Reachability TLV . . . . . . . . . . . . . . . . .  4
     2.2.  Multi Topology aware Port Capability TLV . . . . . . . . .  5
   3.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  6
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     6.1.  Normative References . . . . . . . . . . . . . . . . . . .  9
     6.2.  Informative References . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10

1.  Overview

   There are a number of systems (for example, [RBRIDGES], [802.1aq],
   [OTV]) that use layer 2 addresses carried in a link state routing
   protocol, specifically IS-IS [IS-IS] [RFC1195], to provide true layer
   2 routing.  In almost all the technologies mentioned above, classical
   Layer 2 packets are encapsulated with an outer header.  The outer
   header format varies across all these technologies.  This outer
   header is used to route the encapsulated packets to their
   destination.

   In this document we specify a set of TLVs to be added to [IS-IS]
   level 1 PDUs, to support these proposed systems.  The TLVs are
   generic layer 2 additions and specific ones as needed are defined in
   the IS-IS technology specific extensions.  This draft does not
   propose any new forwarding mechanisms using this additional
   information carried within IS-IS.

1.1.  Terminology

   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.

2.  TLV Enhancements to IS-IS

   In this section we specify the enhancements for the TLVs that are
   needed in common by Layer-2 technologies.

2.1.  The MAC-Reachability TLV

   The MAC-Reachability (MAC-RI) TLV is IS-IS TLV type 141 and has the
   following format:

   +-+-+-+-+-+-+-+-+
   | Type= MAC-RI  |                  (1 byte)
   +-+-+-+-+-+-+-+-+
   |   Length      |                  (1 byte)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Topology-Id/ Nickname       |  (2 bytes)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Confidence  |                  (1 byte)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  RESV |      VLAN-ID          |  (2 bytes)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MAC (1)    (6 bytes)                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   .................                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MAC (N)    (6 bytes)                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  Type: TLV Type, set to 141 (MAC-RI).

   o  Length: Total number of bytes contained in the value field given
      by 5 + 6*n bytes.

   o  Topology-Id/Nickname : Depending on the technology in which it is
      used, this carries the topology-id or nickname.  When this field
      is set to zero this implies that the MAC addresses are reachable
      across all topologies or across all nicknames of the originating
      IS.

   o  Confidence: This carries an 8-bit quantity indicating the
      confidence level in the MAC addresses being transported.  Whether
      this field is used, and its semantics if used, are further defined
      by the specific protocol using Layer-2-IS-IS.  If not used, it
      MUST be set to zero on transmission and be ignored on receipt.

   o  RESV: Must be sent as zero on transmission and is ignored on
      receipt.

   o  VLAN-ID: This carries a 12-bit VLAN identifier that is valid for
      all subsequent MAC addresses in this TLV, or the value zero if no
      VLAN is specified.

   o  MAC(i): This is the 48-bit MAC address reachable from the IS that
      is announcing this TLV.

   The MAC-RI TLV is carried in a standard Level 1 link state PDU.  It
   MUST contain only unicast addresses.  The manner in which these TLVs
   are generated by the various Layer 2 systems, routing technologies, and the
   manner they are consumed are detailed in the technology specific
   documents.

   In most of the technologies, these MAC-RI TLVs will translate to
   populating the hardware with these entries with appropriate next-hop
   information as derived from the advertising IS.

2.2.  Multi Topology aware Port Capability TLV

   The Multi Topology aware Port Capability (MT-PORT-CAP) is an IS-IS
   TLV type 143 [TBD], and 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Type=MT PORTCAP| Length        |R|R|R|R|  Topology Identifier  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            sub-TLVs                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  Type: TLV Type, set to MT-PORT-CAP TLV 143 [TBD].

   o  Length: Total number of bytes contained in the value field,
      including the length of the sub-TLVs carried in this TLV.

   o  R: Reserved, MUST be sent as zero on transmission and is ignored
      on receipt.

   o  Topology Identifier: MT ID is a 12-bit field containing the MT ID
      of the topology being announced.  This field when set to zero
      implies that it is being used to carry base topology information.

   o  sub-TLVs: The MT aware Port Capabilities TLV value contains sub-
      TLVs formatted as described in [RFC5305].  They are defined in the
      technology scoped documents.

   The MT-PORT-CAP TLV may occur multiple times, and is carried only
   within a IIH PDU.

3.  Acknowledgements

   The authors would like to thank Peter Ashwood-Smith, Donald E.
   Eastlake 3rd, Dino Farinacci, Don Fedyk, Les Ginsberg, Radia Perlman,
   Mike Shand, and Russ White for their useful comments.

4.  Security Considerations

   This document adds no additional security risks to IS-IS, nor does it
   provide any additional security for IS-IS.

5.  IANA Considerations

   This document specifies the definition of a set of new IS-IS TLVs,
   the MAC-Reachability TLV (type 141), and the Port-Capability TLV
   (type 143) that needs to be reflected in the IS-IS TLV code-point
   registry.

                                         IIH  LSP  SNP
   MAC-RI TLV  (141)                      -    X    -

   MT-Port-Cap-TLV (143)                  X    -    -

   IANA SHOULD manage the remaining space using the IETF Review method
   [RFC 5226].

6.  References

6.1.  Normative References

   [IS-IS]    ISO/IEC 10589:2002, Second Edition, "Intermediate System
              to Intermediate System Intra-Domain Routing Exchange
              Protocol for use in Conjunction with the Protocol for
              Providing the Connectionless-mode Network Service (ISO
              8473)", 2002.

   [RFC 1195]
              Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and
              Dual Environments", 1990.

6.2.  Informative References

   [IEEE 802.1aq]
              "Standard for Local and Metropolitan Area Networks /
              Virtual Bridged Local Area Networks / Amendment 9:
              Shortest Path Bridging, Draft IEEE P802.1aq/D1.5", 2008.

   [OTV]      Grover, H., Farinacci, D., and D. Rao, "OTV: Overlay
              Transport Virtualization", draft-hasmit-otv-00, 2010.

   [RBRIDGES]
              Perlman, R., Eastlake, D., Dutt, D., Gai, S., and A.
              Ghanwani, "RBridges: Base Protocol Specification", 2010.

Authors' Addresses

   Ayan Banerjee
   Cisco Systems
   170 W Tasman Drive
   San Jose, CA  95138
   US

   Email: ayabaner@cisco.com

   David Ward
   Juniper Networks
   1194 N. Mathilda Ave.
   Sunnyvale, CA  94089-1206
   USA

   Phone: +1-408-745-2000
   Email: dward@juniper.net