draft-ietf-isis-link-attr-02.txt October 2006 ISIS WG Internet Draft Jean-Philippe Vasseur Stefano Previdi Cisco Systems Document: draft-ietf-isis-link-attr-02.txt Expires: April 2007 October 2006 Definition of an IS-IS Link Attribute sub-TLV draft-ietf-isis-link-attr-02.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 defines a sub-TLV called "Link-attributes" 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 [RFC]. Vasseur and Previdi [Page 1] draft-ietf-isis-link-attr-02.txt October 2006 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. IANA considerations ...........................................3 6. Intellectual Property Considerations ..........................3 7. Acknowledgments ...............................................4 8. References ....................................................4 8.1 Normative references .........................................4 8.2 Informative references .......................................4 9. Authors' Addresses ............................................4 Full Copyright Statement .........................................5 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 optimize the encoding of IS-IS prefixes. This document defines a new sub-TLV named "Link-attributes" 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 sub-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 the value field, in this case, a 16 bit flags field. The Link-attribute sub-type is 19 (to be assigned by IANA) and has a length of 2 octets. This sub-TLV is OPTIONAL and MAY appear at most once for a single IS neighbor. If a received LSP contains more than one Link-Attribute Sub-TLV, an implementation MAY decide to consider only the first encountered instance. Vasseur and Previdi [Page 2] draft-ietf-isis-link-attr-02.txt October 2006 The following bits are defined: Local Protection Available (0x01). When set, this indicates that the link is protected by means of some local protection mechanism (e.g [FRR]). Link excluded from local protection path (0x02). When set, this link SHOULD not be included in any computation of a repair path by any other router in the routing area. The triggers for setting up this bit are out of the scope of this document. 3. Interoperability with routers non supporting this capability 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. IANA considerations IANA will assign a new codepoint for the link-attribute sub-TLV defined in this document and carried within TLV 22. Suggested value is 19 (to be assigned by IANA). 6. Intellectual Property Considerations The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement Vasseur and Previdi [Page 3] draft-ietf-isis-link-attr-02.txt October 2006 this standard. Please address the information to the IETF at ietf-ipr@ietf.org. 7. Acknowledgments The authors would like to thank Mike Shand and Les Ginsberg for their useful comments. 8. References 8.1 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, "IS-IS extensions for traffic engineering", RFC 3784. 8.2 Informative references [FRR] Ping Pan, et al, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May 2005. 9. Authors' Addresses Jean-Philippe Vasseur Cisco Systems, Inc. 1414 Massachusetts Avenue 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 [Page 4] draft-ietf-isis-link-attr-02.txt October 2006 Full Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Vasseur and Previdi [Page 5]