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Versions: 00 01 02 03 04 05 06 07 08 09 10 11 RFC 6165

Network Working Group                                        A. Banerjee
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                                 D. Ward
Expires: August 13, 2011                                Juniper Networks
                                                        February 9, 2011


                Extensions to IS-IS for Layer-2 Systems
                       draft-ietf-isis-layer2-11

Abstract

   This document specifies the Intermediate System to Intermediate
   System (IS-IS) extensions necessary to support link state routing for
   any protocols running directly over Layer-2.  While supporting this
   concept involves several pieces, this document only describes
   extensions to IS-IS.  Furthermore, the Type, Length, Value pairs
   (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

   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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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 August 13, 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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  TLV Enhancements to IS-IS  . . . . . . . . . . . . . . . . . .  4
     2.1.  Multi Topology aware Port Capability TLV . . . . . . . . .  4
     2.2.  The MAC-Reachability TLV . . . . . . . . . . . . . . . . .  4
   3.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11






























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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 Intermediate System to Intermediate System
   (IS-IS) [IS-IS] [RFC 1195], 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.

   Each Intermediate System (IS) advertises one or more IS-IS Link State
   Protocol Data Units (PDUs) with routing information.  Each Link State
   PDU (LSP) is composed of a fixed header and a number of tuples, each
   consisting of a Type, a Length, and a Value.  Such tuples are
   commonly known as TLVs.  In this document we specify a set of TLVs to
   be added to [IS-IS] 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.
























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2.  TLV Enhancements to IS-IS

   This section specifies the enhancements for the TLVs that are needed
   in common by Layer-2 technologies.

2.1.  Multi Topology aware Port Capability TLV

   The Multi-Topology aware Port Capability (MT-PORT-CAP) is an IS-IS
   TLV type 143, and has the following format:

   +-+-+-+-+-+-+-+-+
   | Type=MTPORTCAP|                  (1 byte)
   +-+-+-+-+-+-+-+-+
   |   Length      |                  (1 byte)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |R|R|R|R|  Topology Identifier  |  (2 bytes)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                sub-TLVs         (variable bytes)              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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

   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 4-bits, MUST be sent as zero and 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-PORT-CAP TLV value contains sub-TLVs formatted as
      described in [RFC 5305].  They are defined in the technology
      scoped documents.

   The MT-PORT-CAP TLV may occur multiple times, and is carried within a
   IS-IS Hello (IIH) PDU.

2.2.  The MAC-Reachability TLV

   The MAC-Reachability (MAC-RI) TLV is IS-IS TLV type 147 and has the
   following format:









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   +-+-+-+-+-+-+-+-+
   | 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 147 (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: (4-bits) MUST be sent as zero and 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 Link State PDU (LSP).  This
   TLV can be carried multiple times in an LSP and in multiple LSPs.  It
   MUST contain only unicast addresses.  The manner in which these TLVs
   are generated by the various Layer-2 routing technologies, and the



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   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.













































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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.














































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4.  Security Considerations

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















































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5.  IANA Considerations

   This document specifies the definition of a set of new IS-IS TLVs,
   the Port-Capability TLV (type 143), and the MAC-Reachability TLV
   (type 147) that needs to be reflected in the IS-IS TLV code-point
   registry.

                                         IIH  LSP  SNP
   MT-Port-Cap-TLV (143)                  X    -    -
   MAC-RI TLV  (147)                      -    X    -









































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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.

   [RFC 5305]
              Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", 2008.

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-01, 2010.

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




















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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
































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