IS-IS for IP Internets P. Sarkar, Ed. Internet-Draft H. Gredler Intended status: Standards Track S. Hegde Expires: August 18, 2014 H. Raghuveer Juniper Networks, Inc. S. Litkowski B. Decraene Orange February 14, 2014 Advertising Per-node Admin Tags in IS-IS draft-psarkar-isis-node-admin-tag-01 Abstract This document describes an extension to IS-IS protocol [ISO10589], [RFC1195] to add an optional operational capability, that allows tagging and grouping ofthe nodes in an IS-IS domain. This allows simple management and easy control over route and path selection, based on local configured policies. This document describes the protocol extensions to disseminate per- node admin-tags in IS-IS protocols. 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 RFC 2119 [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 August 18, 2014. Sarkar, et al. Expires August 18, 2014 [Page 1] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 Copyright Notice Copyright (c) 2014 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 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. Administrative Tag . . . . . . . . . . . . . . . . . . . . . . 3 3. TLV format . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Per-node Admin Tag sub-TLV . . . . . . . . . . . . . . . . 3 3.2. Ordering of tags . . . . . . . . . . . . . . . . . . . . . 4 4. Applications . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Sarkar, et al. Expires August 18, 2014 [Page 2] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 1. Introduction This document provides mechanisms to advertise per-node administrative tags in the IS-IS Link State PDU [RFC1195]. In certain path-selection applications like for example in traffic- engineering or LFA [RFC5286] selection there is a need to tag the nodes based on their roles in the network and have policies to prefer or prune a certain group of nodes. 2. Administrative Tag For the purpose of advertising per-node administrative tags within IS-IS, a new sub-TLV to the IS-IS Router Capability TLV-242 that is defined in [RFC4971] is proposed. Because path selection is a functional set which applies both to TE and non-TE applications the same has not added as a new sub-TLV in the Traffic Engingineering TLVs [RFC5305]. An administrative Tag is a 32-bit integer value that can be used to identify a group of nodes in the IS-IS domain. The new sub-TLV specifies one or more administrative tag values. An IS-IS node advertises the set of groups it is part of in the specific IS-IS level. As an example, all PE-nodes may be configured with certain tag value, whereas all P-nodes are configured with a different tag value in. The new sub-TLV defined will be carried inside the IS-IS Router Capability TLV-242 (defined in [RFC4971]) in the Link State PDUs originated by the router. Link State PDUs [ISO10589] has level-wise (i.e. L1 or L2) flooding scope. Choosing the flooding scope to flood the group tags are defined by the policies and is a local matter. Once a group tag is decided in a specific level the same will be inserted in the administrative tag sub-TLV in the Link State PDU for the same level. Implementations should allow configuring both a 'global' and 'per-level' admin tag. In the absence of a specific admin tag configuration for a specific level the global admin tag should be copied in to the LSP PDU for the same level. 3. TLV format 3.1. Per-node Admin Tag sub-TLV The new Administrative Tag sub-TLV, like other ISIS Capability sub- TLVs, is formatted as Type/Length/Value (TLV)triplets. Figure 1 below shows the format of the new sub-TLV. Sarkar, et al. Expires August 18, 2014 [Page 3] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Administrative Tag #1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Administrative Tag #2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Administrative Tag #N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : TBA Length: A 8-bit field that indicates the length of the value portion in octets and will be a multiple of 4 octets dependent on the number of tags advertised. Value: A sequence of multiple 4 octets defining the administrative tags. Figure 1: IS-IS per-node Administrative Tag sub-TLV The 'Per-node Admin Tag' sub-TLV may be generated more than once by an originating router. This MAY happen if a node carries more than 63 per-node admin groups and a single sub-TLV does not provide sufficient space. As such occurence of the 'Per-node Admin Tag' sub- TLV does not cancel previous announcements, but rather is cumulative. 3.2. Ordering of tags The semantics of the tag order are implementation-dependent. There is no implied meaning to the ordering of the tags that indicates a certain operation or set of operations that need to be performed based on the ordering. Each tag SHOULD be treated as an independent identifier that MAY be used in policy to perform a policy action. Whether or not tag A precedes or succeeds tag B SHOULD not change the meaning of the tag set. 4. Applications Increased deployment of Loop Free Alternates (LFA) [RFC5286] has Sarkar, et al. Expires August 18, 2014 [Page 4] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 exposed some limitations. A recent draft on Operation management of Loop Free Alternates [I-D.ietf-rtgwg-lfa-manageability] proposes refinements to address those limitations. One of the proposed refinements is to be able to group the nodes in IGP domain with administrative tags and engineer the alternate paths based on configured policies. The proposal in this document helps provide the capability to advertise group tags within IS-IS protocol and perform policy based LFA selection. The policies configured on each node can then make use of these tags to prefer or prune LFAs via certain group of nodes. 5. Security Considerations This document does not introduce any further security issues other than those discussed in [ISO10589] and [RFC1195]. 6. IANA Considerations IANA maintains the registry for the Router Capability sub-TLVs. IS-IS Administrative Tags will require one new type code for the sub- TLV defined in this document. 7. Acknowledgments 8. References 8.1. Normative References [ISO10589] "Intermediate system to Intermediate system intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode Network Service (ISO 8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2. Informative References [I-D.ietf-rtgwg-lfa-manageability] Litkowski, S., Decraene, B., Filsfils, C., and K. Raza, "Operational management of Loop Free Alternates", Sarkar, et al. Expires August 18, 2014 [Page 5] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 draft-ietf-rtgwg-lfa-manageability-00 (work in progress), May 2013. [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990. [RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, July 2007. [RFC5286] Atlas, A. and A. Zinin, "Basic Specification for IP Fast Reroute: Loop-Free Alternates", RFC 5286, September 2008. [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008. Authors' Addresses Pushpasis Sarkar (editor) Juniper Networks, Inc. Electra, Exora Business Park Bangalore, KA 560103 India Email: psarkar@juniper.net Hannes Gredler Juniper Networks, Inc. 1194 N. Mathilda Ave. Sunnyvale, CA 94089 US Email: hannes@juniper.net Shraddha Hegde Juniper Networks, Inc. Electra, Exora Business Park Bangalore, KA 560103 India Email: shraddha@juniper.net Sarkar, et al. Expires August 18, 2014 [Page 6] Internet-Draft Advertising Per-node Admin Tags in IS-IS February 2014 Harish Raghuveer Juniper Networks, Inc. Electra, Exora Business Park Bangalore, KA 560103 India Email: hraghuveer@juniper.net Stephane Litkowski Orange Email: stephane.litkowski@orange.com Bruno Decraene Orange Email: bruno.decraene@orange.com Sarkar, et al. Expires August 18, 2014 [Page 7]