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Internet Engineering Task Force (IETF)                       A. BanerjeeRequest for Comments: 6165                                 Cisco SystemsCategory: Standards Track                                        D. WardISSN: 2070-1721                                         Juniper Networks                                                              April 2011Extensions to IS-IS for Layer-2 SystemsAbstract   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 is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6165.Banerjee & Ward              Standards Track                    [Page 1]

RFC 6165                      Layer-2-IS-IS                   April 2011Copyright Notice   Copyright (c) 2011 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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   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 Contents1. Overview ........................................................21.1. Terminology ................................................32. TLV Enhancements to IS-IS .......................................32.1. Multi-Topology-Aware Port Capability TLV ...................32.2. The MAC-Reachability TLV ...................................43. Acknowledgements ................................................54. Security Considerations .........................................55. IANA Considerations .............................................56. References ......................................................66.1. Normative References .......................................66.2. Informative References .....................................61.  Overview   There are a number of systems (for example, [RBRIDGES], [802.1aq],   and [OTV]) that use Layer-2 addresses carried in a link state routing   protocol, specifically Intermediate System to Intermediate System   [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.   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 areBanerjee & Ward              Standards Track                    [Page 2]

RFC 6165                      Layer-2-IS-IS                   April 2011   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 document   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 inRFC 2119 [RFC2119].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 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 [RFC5305].  They are defined in the technology-      specific documents.Banerjee & Ward              Standards Track                    [Page 3]

RFC 6165                      Layer-2-IS-IS                   April 2011   The MT-PORT-CAP TLV may occur multiple times and is carried within an   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:   +-+-+-+-+-+-+-+-+   | 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 Media Access Control (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.Banerjee & Ward              Standards Track                    [Page 4]

RFC 6165                      Layer-2-IS-IS                   April 2011   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   manner in which 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 and with appropriate next-   hop information as derived from the advertising IS.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 Port-Capability TLV (type 143) and the MAC-Reachability TLV   (type 147).  They are listed in the IS-IS TLV codepoint registry.                                         IIH  LSP  SNP   MT-Port-Cap-TLV (143)                  X    -    -   MAC-RI TLV  (147)                      -    X    -Banerjee & Ward              Standards Track                    [Page 5]

RFC 6165                      Layer-2-IS-IS                   April 20116.  References6.1.  Normative References   [IS-IS]    ISO/IEC 10589:2002, Second Edition, "Intermediate System              to Intermediate System Intra-Domain Routing Information              Exchange Protocol for use in Conjunction with the Protocol              for Providing the Connectionless-mode Network Service              (ISO 8473)", 2002.   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and              dual environments",RFC 1195, December 1990.   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic              Engineering",RFC 5305, October 2008.6.2.  Informative References   [802.1aq]  "Standard for Local and Metropolitan Area Networks /              Virtual Bridged Local Area Networks / Amendment 8:              Shortest Path Bridging, Draft IEEE P802.1aq/D1.5", 2008.   [OTV]      Grover, H., Rao, D., and D. Farinacci, "Overlay Transport              Virtualization", Work in Progress, October 2010.   [RBRIDGES]              Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.              Ghanwani, "RBridges: Base Protocol Specification", Work              in Progress, March 2010.Banerjee & Ward              Standards Track                    [Page 6]

RFC 6165                      Layer-2-IS-IS                   April 2011Authors' Addresses   Ayan Banerjee   Cisco Systems   170 W. Tasman Drive   San Jose, CA  95138   USA   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.netBanerjee & Ward              Standards Track                    [Page 7]