ISIS WG Internet Draft Jean-Philippe Vasseur Stefano Previdi Cisco Systems Document: draft-vasseur-isis-link-attr- 00.txt Expires: August 2004 February 2004 Definition of an IS-IS Link Attribute sub-TLV draft-vasseur-isis-link-attr-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [i]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This document proposes the definition of a sub-TLV called ôlink- attributeö carried within the TLV 22 and used to flood some link characteristics. Conventions used in this document 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 [ii]. Vasseur and Previdi Expires û August 2004 [Page 1] draft-vasseur-isis-link-attr-00.txt February 2004 Table of contents 1. Introduction...................................................2 2. Link-attributes sub-TLV format.................................2 3. Interoperability with routers non supporting this capability...3 4. Security considerations........................................3 5. Intellectual Property Considerations...........................3 6. Acknowledgments................................................4 7. References.....................................................4 Normative references..............................................4 Informative references............................................4 8. Author's Addresses.............................................4 1. Introduction [IS-IS] specifies the IS-IS protocol (ISO 10589) with extensions to support IPv4 in [IS-IS-IP]. A router advertises one or several Link State Protocol data units which are composed of variable length tuples called TLVs (Type-Length-Value). [IS-IS-TE] defines a set of new TLVs whose aims are to add more information about links characteristics, increase the range of IS-IS metrics and improve the encoding of IS-IS prefixes. This document defines a new sub-TLV named ôLink-attributesö carried within the extended IS reachability TLV (type 22) specified in [IS- IS-TE]. 2. Link-attributes sub-TLV format The link-attribute sub-TLV is carried within the TLV 22 and has a format identical to the TLV format used by the Traffic Engineering Extensions for IS-IS [IS-IS-TE]: 1 octet of sub-type, 1 octet of length of the value field of the sub-TLV followed by a 16 set of bit flags. The Link-attribute sub-type is 19 (to be assigned by IANA) and has a length of 2 octets bit mask. This sub-TLV is OPTIONAL and MUST appear at most once. The following bits are defined: Vasseur and Previdi Expires û August 2004 [Page 2] draft-vasseur-isis-link-attr-00.txt February 2004 0x01: ôLocal Protection Availableö. When set, this indicates that the link is protected by means of some local protection mechanism (e.g [FRR]). 0x02: ôLocal protection in useö. When set, this indicates that the local protection for the link in question is currently active. Such link characteristics has several applications such as constrained shortest path computation for a Traffic Engineering Label Switched (TE LSP) path, triggering of specific actions in the context of IS-IS SPF computation. 0x04: ôLink excluded from local protection pathö. When set, this link SHOULD not be included in any computation of a repair path by any other router in the routing area. 3. Interoperability with routers non supporting this capability There is no interoperability issue as a router not supporting the link-attribute sub-TLV MUST just silently ignore this sub-TLV. 4. Security considerations No new security issues are raised in this document. 5. Intellectual Property Considerations The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. The IETF has been notified of intellectual property rights claimed in regard to some or all of the specification contained in this Vasseur and Previdi Expires û August 2004 [Page 3] draft-vasseur-isis-link-attr-00.txt February 2004 document. For more information consult the online list of claimed rights. 6. Acknowledgments The authors would like to thank Mike Shand for his comments. 7. References Normative references [RFC] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels," RFC 2119. [IS-IS] "Intermediate System to Intermediate System Intra-Domain Routeing Exchange Protocol for use in Conjunction with the Protocol for Providing the Connectionless-mode Network Service (ISO 8473)", ISO 10589. [IS-IS-IP] Callon, R., RFC 1195, "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990. [IS-IS-TE] H. Smit, T. Li, ôIs-IS extensions for traffic engineeringö, draft-ietf-isis-traffic, work in progress. Informative references [FRR] Ping Pan, et al, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute-03.txt, December 2003. 8. Author's Addresses Jean-Philippe Vasseur CISCO Systems, Inc. 300 Beaver Brook Boxborough, MA 01719 USA Email: jpv@cisco.com Stefano Previdi CISCO Systems, Inc. Via Del Serafico 200 00142 - Roma ITALY Email: sprevidi@cisco.com Vasseur and Previdi Expires û August 2004 [Page 4] draft-vasseur-isis-link-attr-00.txt February 2004 Full Copyright Statement Copyright (C) The Internet Society (2004). All Rights Reserved. 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