Internet DRAFT - draft-manral-isis-trill-multi-topo

draft-manral-isis-trill-multi-topo




TRILL Working Group                                       Vishwas Manral
INTERNET-DRAFT                                       Hewlett-Packard Co.
Intended status: Proposed Standard                       Donald Eastlake
Expires: December 21, 2012                                  Mingui Zhang
                                                                  Huawei
                                                           Ayan Banerjee
                                                           Cisco Systems
                                                           June 22, 2012


  Multiple Topology Routing Extensions for Transparent Interconnection
                        of Lots of Links (TRILL)
               draft-manral-isis-trill-multi-topo-04.txt


Abstract

   This document describes optional extensions to the TRILL protocol's
   use of IS-IS (Intermediate System to Intermediate Systems). These
   extensions support multiple topologies (MT) within the same TRILL
   campus and protocol instance of IS-IS.


Status of This Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.  Distribution of this document is
   unlimited.  Comments should be sent to the TRILL working group
   mailing list <rbridge@postel.org>.

   Internet-Drafts are working documents of the Internet Engineering
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   The list of current Internet-Drafts can be accessed at
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Table of Contents

      1. Introduction............................................3
      2. Terminology.............................................3

      3. TLV Enhancements for Multiple Topology..................4
      4. Multi-Topology Changes to Appointed Forwarders..........5

      5. Security Considerations.................................6
      6. IANA Considerations.....................................6
      7. Acknowledgements........................................6

      8. References..............................................7
      8.1 Normative References...................................7
      8.2 Informative References.................................7





































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1. Introduction

   Maintaining Multiple Topologies (MT) in an Rbridge campus requires
   extensions to the base TRILL protocol use of IS-IS [ISIStrill].
   These extensions change the packet encoding on the wire.  This
   document describes such extensions so that multiple topologies can be
   supported as described in [RFC5120].



2. 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 [RFC2119].

   IS-IS: Intermediate-System to Intermediate-System

   LSP: Link State Protocol Data Unit (PDU)

   Rbridge: Routing Bridge

   SPF: Shortest Path First Algorithm

   TRILL: Transparent Interconnection with Lots of Links

   TLV: Type, Length and Value

























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3. TLV Enhancements for Multiple Topology

   Currently the Router Capability TLV is specified in [RFC4971].  For
   TRILL, many sub-TLV's are specified as being carried in the Router
   Capability TLV which carries information only for a single Topology.

   The following extensions are required to TRILL use of IS-IS to
   support multi-topology:

   1. The Nicknames sub-TLV, Trees sub-TLV, Tree Identifiers sub-TLV,
      Trees Used Identifiers sub-TLV, and VLAN Group sub-TLV, MAY be
      encapsulated in the MT-CAP TLV (TLV #144) [ISISieee].

   2. The Multi-Topology TLV [RFC5120] MAY be advertized in the TRILL
      LAN Hellos and RBridge LSPs.  It will contain topology identifiers
      for one or more topologies in which the Rbridge is participating.
      An RBridge is considered MT aware as long at it advertises at
      least one MT TLV in its LSP.

   3. The MTU sub-TLV [ISIStrill] MAY occur in the MT ISN TLV #222
      [RFC5120] as well as in the Extended IS Reachability TLV #22.

   4. The Topology Mapping (TOPO-MAP) sub-TLV, which occurs within a
      Router Capapbilities TLV (TLV #242) for MT Aware RBridges [trill-
      mt] is specified below. This sub-TLV may occur more than once in
      the same or in multiple Router Capapbilities TLVs.

         +-+-+-+-+-+-+-+-+
         |Type = TOPO-MAP|                  (1 byte)
         +-+-+-+-+-+-+-+-+
         |   Length      |                  (1 byte)
         +-+-+-+-+-+-+-+-+
         |    RESV   |TAS|                  (1 byte)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |R| ABR |      Topology 1       |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |R| ABR |      Topology 2       |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |  . . .
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |R| ABR |      Topology N       |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         o  Type: Router Capability sub-TLV Type, set to TBD (TOPO-MAP).

         o  Length: 1 + 2*n where n is the number of topology to
            topology mapping entries.

         o  RESV: Five reserved bits, must be sent as zero and ignored
            on receipt.


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         o  TAS: Topology Abbreviation Size as apecified in [trill-mt].

         o  R: Reserved bit. must be sent as zero and ignored on
            receipt.

         o  ABR, Topology: Each 2-byte mapping entries specifies that
            ABR is the abbreviation for the 12-bit topology number
            given.



4.  Multi-Topology Changes to Appointed Forwarders

   The TRILL IS-IS DRB election protocol is a bit different from Layer-3
   IS-IS as described in [RFCadj].  The DRB corresponds to the DIS
   (Designated Intermediate System) and is responsible for specifing the
   Designated VLAN for communication between the RBridges on the Link
   [RFCtrill]. As in [RFC5120], there is only one DRB on a link.

   However, the DRB also handles all native frames being ingressed from
   or egressed to the like, as it chooses, or may appoint other RBridges
   on the link Appointed Forwarder [RFCaf] for one or more VLANs.
   Appointed Forwarders are per topology. The appointed forwarder sub-
   TLV is already a part of the MT-PORT-CAP TLV, which is Multi-Topology
   Aware.



























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5. Security Considerations

   The extensions to TRILL use of IS-IS specified herein add no new
   Security Considerations beyond those already present with multi-
   topology IS-IS and TRILL.  See [RFC5120] for IS-IS multi-topology
   security considerations.  See [RFCtrill] for TRILL base protocol
   security considerations.



6. IANA Considerations

   IANA is requested to update the subregistry of the IS-IS TLV Code
   points Registry which shows permitted occurrence of sub-TLVs within
   TLVs #22, #141, and #222 to show that the MTU sub-TLV is permitted in
   TLV #222 as well as in TLV #22.

   IANA is requested to assign sub-TLV numbers within the MT-CAP TLV
   (TLV #144) [ISISieee] for the Nicknames sub-TLV, Trees sub-TLV, Tree
   Identifiers sub-TLV, Trees Used Identifiers sub-TLV, and VLAN Group
   sub-TLV [ISIStrill].  Noting that there is no conflict between the
   numbers of these sub-TLVs within the Router Capabilities TLV #242 and
   with any other number so far assigned within the MT-CAP TLV, it is
   requested that these sub-TLVs be assigned the same number within the
   MT-CAP TLV as they have within the Router Capabilities TLV #242.

   IANA is request to assign a sub-TLV number within the Router
   Capabilities TLV (TV #242) for the TOPO-MAP sub-TLV.



7. Acknowledgements

   The authors would like to thank Meenakshi Kaushik and Dinesh Dutta.


















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8. References

   Normative and informative references for this document are given
   below.



8.1 Normative References

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

   [RFC4971] - Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
         System to Intermediate System (IS-IS) Extensions for
         Advertising Router Information", RFC 4971, July 2007.

   [RFC5120] - Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
         Topology (MT) Routing in Intermediate System to Intermediate
         Systems (IS-ISs)", RFC 5120, February 2008.

   [RFCtrill] - R. Perlman, D. Eastlake, D. Dutt, S. Gai, and A.
         Ghanwani, "RBridges: Base Protocol Specification", draft-ietf-
         trill-rbridge-protocol-16.txt, in RFC Editor queue.

   [ISIStrill] - D. Eastlake, A. Banerjee, D. Dutt, R. Perlman, A.
         Ghanwani, "TRILL Use of IS-IS", draft-ietf-isis-trill-05.txt,
         work in progress.

   [RFCadj] - D. Eastlake, R. Perlman, A. Ghanwani, D. Dutt, V. Manral,
         "RBridges: Adjacency", draft-ietf-trill-adj, work in progress.

   [ISISieee] - D. Fedyk, P. Ashwood-Smith, "IS-IS Extensions Supporting
         IEEE 802.1aq Shortest Path Bridging", draft-ietf-isis-ieee-
         aq-05.txt, in RFC Editor queue.

   [RFCaf] - Perlman, R., D. Eastlake, Y. Li, A. Banerjee, H. Fangwei,
         "RBridges: Appointed Forwarders", draft-ietf-trill-rbridge-
         af-04, work in progress.

   [trill-mt] - Perlman, R., D. Eastlake, M. Zhang, A. Banerjee, V.
         Manral, "RBridges: Multiple Topology TRILL", draft-eastlake-
         trill-rbridge-multi-topo-00.txt, work in progress.



8.2 Informative References

         None.




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Authors' Addresses

   Vishwas Manral
   Hewlett-Packard Co.
   19111 Pruneridge Ave.
   Cupertino, CA 95014 USA

   Phone:  1-408-447-0000      
   Email: vishwas.manral@hp.com


   Donald Eastlake 3rd
   Huawei Technologies (USA)
   155 Beaver Street
   Milford, MA 01757 USA

   Phone: 1-508-333-2270      
   Email: d3e3e3@gmail.com


   Mingui Zhang
   Huawei Technologies Co.,Ltd
   HuaWei Building, No.3 Xinxi Rd., Shang-Di
   Information Industry Base, Hai-Dian District,
   Beijing, 100085 P.R. China

   Email: zhangmingui@huawei.com


   Ayan Banerjee
   Cisco Systems
   170 West Tasman Drive
   San Jose, CA 95134 USA

   Email: ayabaner@cisco.com

















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