One document matched: draft-manral-isis-trill-multi-topo-00.txt

Network Working Group                                     V. Manral, Ed.
Internet-Draft                                       Hewlett-Packard Co.
Intended status: Standards Track                             D. Eastlake
Expires: November 17, 2011                                        Huawei
                                                             A. Banerjee
                                                           Cisco Systems
                                                            May 16, 2011


  Multi Topology Routing Extensions for Transparent Interconnection of
                         Lots of Links (TRILL)
                 draft-manral-isis-trill-multi-topo-00

Abstract

   This document describes an optional extensions to the TRILL protocol.
   The extensions uses Intermediate System to Intermediate Systems
   (IS-IS) as the control plane, to support multiple topologies (MT)
   within the same TRILL protocol instance of IS-IS.  It describes how
   to run Multiple Independent TRILL topologies, within a single IS-IS
   domain.

Requirements Language

   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].

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 November 17, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the



Manral, et al.          Expires November 17, 2011               [Page 1]

Internet-Draft       TRILL Multi Topology Extensions            May 2011


   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
   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.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  TLV enhancement for Multitopology . . . . . . . . . . . . . . . 3
   4.  Multi-Topology changes to Routing . . . . . . . . . . . . . . . 4
   5.  Multi-Topology changes to Appointer Forwarders  . . . . . . . . 4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5



























Manral, et al.          Expires November 17, 2011               [Page 2]

Internet-Draft       TRILL Multi Topology Extensions            May 2011


1.  Introduction

   Maintaining Multiple topologies in an Rbridge campus require
   extensions to the base TRILL protocol and its use of IS-IS.  These
   extensions change the packet encoding on the wire as well as the SPF
   calculation.  This document describes all such extensions so that
   multiple topologies can be supported as described in [RFC5120].


2.  Terminology

   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


3.  TLV enhancement for Multitopology

   Currently the Router Capability TLV is specified in [RFC 4971].  For
   TRILL all global sub-TLV's are carried in the Router Capability TLV.
   The Router Capability TLV carries information only for a single
   Topology.

   Besides a CAPABILITY TLV MUST have a Router ID that is a 32-bit
   number.  The ID MUST be unique within the IS-IS area.  However there
   is no requirement for a Router ID in TRILL IS-IS.

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

   1.  The Nickname sub-TLV, Trees sub-TLV, the Tree Identifiers sub-TLV
   and the VLAN Group sub-TLV, MAY be encapsulated in the MT-CAP TLV
   [ISISieee].

   2.  The Multi-Topology TLV [RFC5120] MAY be advertized in the TRILL
   LAN Hellos.  It will contain one or more MT's the Rbridge is
   participating in.

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



Manral, et al.          Expires November 17, 2011               [Page 3]

Internet-Draft       TRILL Multi Topology Extensions            May 2011


4.  Multi-Topology changes to Routing

   or unicast, the Multi-Topology SPF routing calculations will be done
   spearately for each topology.  The ingress RBridge and each transit
   RBridge forwarding a unicast frame addressed to a know destination
   will forward the frame in a particular topology.  The method by which
   such known unicast frames are classified as belonging to a particular
   topology is beyond the scope of this document.

   Multi-destination frames (broadcast, multicast, and unicast to an
   unkown destination) are sent over a distribution tree but each
   distribution tree is calculated for a single topology.  Thus, the
   ingress RBridge for a multi-destination frame is the only RBridge
   that must classify that frame as being in a particular topology as
   part of the process of deciding which tree to distribute it over.
   The method by which the ingress RBridge makes this determination is
   beyond the scope of this document.

   Should the information being advertised in the link state by the
   RBridge with the highest priority to be a tree root appear to specify
   that the same tree (i.e., same nickname) be calculated in more than
   one topology, that tree is only calculated in the lowest numbered of
   those topologies.  If it is desired to have two distribution trees
   rooted at the same RBridge in different topologies, then that RBridge
   must be allocated at least two nicknames (a capability already preent
   in TRILL) so that different nicnames can be used for the different
   topology trees.

   The sub-TLV's, if any, present in the Router Capability TLV will be
   used for MT#0 calculations, only if the information is not there for
   MT#0 in the MT-CAP-TLV.


5.  Multi-Topology changes to Appointer Forwarders

   The TRILL-ISIS election protocol is a bit different from Layer-3
   IS-IS.  The DRB is responsible for specifing the designated VLAN for
   communication between the Rbridges on the Link.

   The DRB algorithm is changed such that there is an appointed VLAN
   forwarder for each of the topologies for each VLAN.  The appointed
   forwarder sub-TLV is already a part of the MT-PORT-CAP TLV, which is
   Multi-Topology Aware.


6.  Security Considerations

   The extensions to TRILL use of IS-IS specified herein add no new



Manral, et al.          Expires November 17, 2011               [Page 4]

Internet-Draft       TRILL Multi Topology Extensions            May 2011


   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.


7.  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
   [ISISieee] for the Trees sub-TLV, the Tree Identifiers 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.

   It is further suggested that the sub-registries for Router
   Capabilities TLV #242 and the MT-CAP TLV [TRILLisis] might be
   combined in the style of the existing IANA sub-registry for sub-TLVs
   of TLVs #22, #141, and #222.  While there would be some duplication
   of sub-TLV numbers in such a combined registry, there would be no
   duplication within a particular TLV because, where there are two sub-
   TLVs with the same number, one is limited to the Router Capability
   TLV and the other is limited to the MT-CAP TLV.

   IANA is requested to allocate a value in the IS-IS Multi-Topology ID
   Values registry as follows:

   TBD TRILL multicast routing topology


8.  Acknowledgements

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












Manral, et al.          Expires November 17, 2011               [Page 5]

Internet-Draft       TRILL Multi Topology Extensions            May 2011


9.  References

9.1.  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.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, October 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-04.txt, work
          in progress.

   [ISISieee]

9.2.  Informative References



















Manral, et al.          Expires November 17, 2011               [Page 6]

Internet-Draft       TRILL Multi Topology Extensions            May 2011






Authors' Addresses

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

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


   Donald Eastlake
   Huawei
   155 Beaver Street
   Milford, MA  01757
   USA

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


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

   Email: ayabaner@cisco.com




















Manral, et al.          Expires November 17, 2011               [Page 7]