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]