Networking Working Group JP. Vasseur, Ed. Internet-Draft Cisco Systems, Inc Expires: November 16, 2006 May 15, 2006 A Link-Type sub-TLV to convey the number of Traffic Engineering Label Switch Paths signalled across a link draft-ietf-mpls-number-0-bw-te-lsps-00 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. This Internet-Draft will expire on November 16, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract Several Link-type sub-TLVs have been defined for OSPF and ISIS in the context of MPLS Traffic Engineering in order to convery some link characteristics such as the available bandwidth, traffic enginering metric, adminstrative group and so on. There are various circumstances where it would be useful to also know the number of unconstrained Traffic Engineering Label Switched Path(s) (TE LSP). This document specifies a new Link-type Traffic Engineering sub-TLV used to advertise the number of unconstrained TE LSP(s) signalled Vasseur Expires November 16, 2006 [Page 1]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 across a specific link. 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]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Protocol extensions . . . . . . . . . . . . . . . . . . . . . . 4 3.1. ISIS . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Elements of procedure . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . . . 7 Vasseur Expires November 16, 2006 [Page 2]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 1. Introduction Several Link-type sub-TLVs have been defined for OSPF and ISIS (see [I-D.ietf-isis-te-bis] and [RFC3630]) in the context of MPLS Traffic Engineering in order to advertise various link characteristics such as the available bandwidth, traffic enginering metric, adminstrative group and so on. There are various circumstances where it would be useful to also know the number of unconstrained Traffic Engineering Label Switch Path(s) (TE LSP). It is not uncommon to deploy MPLS Traffic Engineering for the sake of fast recovery with MPLS TE Fast Reroute (see [RFC4090]). In this case, a common deployment model consists of deploying a full mesh of unconstrained TE LSPs between a set of LSRs and protect these TE LSPs thanks to pre-established backup tunnels against link, SRLG and/or node failures. When a set of unconstrained TE LSPs is deployed, various algorithms can be designed so as efficiently load balance the traffic carried by such unconstrained TE LSPs provided that the number of unconstrained TE LSPs traversing each link in the network is known. As currently defined in [RFC3630] and [I-D.ietf-isis-te-bis] the information related to the number of unconstrained TE LSP(s) is not available. Note that the specification of load balancing algorithms is outside of the scope of this document and merely listed for the sake of illustration of the motivation for gathering such information. Furthermore, the knowledge of the number of unconstrained TE LSPs signalled across each link can be used for other purposes (e.g. management, ...). This document specifies a new Link-type Traffic Engineering sub-TLV used to indicate the number of unconstrained TE LSP signalled across a specific link. 2. Terminology Terminology used in this document LSR: Label Switch Router. TE LSP: MPLS Traffic Engineering Label Switched Path. Backup tunnel: the TE LSP that is used to backup up one of the many TE LSPs in many-to-one backup (as defined in [FAST-REROUTE]). Unconstrained TE LSP: A TE LSP signalled with a bandwidth requirement equal to 0. Vasseur Expires November 16, 2006 [Page 3]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 3. Protocol extensions A new Sub-TLV named NB-O-BW-LSP is defined that specifies the number of unconstrained TE LSPs signalled across a link. 3.1. ISIS The NB-0-BW-LSP TLV is OPTIONAL and MUST appear at most once within the extended IS reachability TLV (type 22) specified in [ISIS-TE]. The NB-0-BW-LSP consists of: Type (1 octet): To be assigned by IANA (Recommended value = 19) Length (1 octet): 4 Value (4 octets): field value that comprises the number of unconstrained TE LSP(s) signalled across the link. 3.2. OSPF The NB-0-BW-LSP is OPTIONAL and MUST appear at most once within the Link TLV (Type 2) that is itself carried within the Traffic Engineering LSA specified in [OSPF-TE]. The NB-0-BW-LSP consists of: Type (2 octets): To be assigned by IANA (Recommended value = 19) Length (2 octets): 4 Value (4 octets): field value that comprises the number of unconstrained TE LSP(s) signalled across the link. 4. Elements of procedure An implementation may decide to implement a dual-thresholds mechanism so as to trigger the origination of an updated OSPF LSA or ISIS LSP. Similalry to other MPLS Traffic Engineering link characteristics, LSA/LSP origination trigger mechanisms are outside of the scope of this document. 5. IANA Considerations IANA will assign a new code point for the newly defined ISIS sub-TLV (NB-0-BW-LSP) carried within the TLV 22 (suggested value =19) IANA will assign a new code point for the newly defined OSPF sub-TLV (NB-0-BW-LSP) carried within the Link TLV (Type 2) of the Traffic Vasseur Expires November 16, 2006 [Page 4]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 Engineering LSA (suggested value=19). 6. Security Considerations This document raises no new security issues for IS-IS and OSPF. 7. Acknowledgements The author would want to thank Kenji Kumaki, Alberto Tempia, Jean- Louis Le Roux and Matt Meyer for their useful inputs. 8. References 8.1. Normative References [I-D.ietf-isis-te-bis] Li, T. and H. Smit, "IS-IS extensions for Traffic Engineering", draft-ietf-isis-te-bis-00 (work in progress), September 2005. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. 8.2. Informative References [RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May 2005. Vasseur Expires November 16, 2006 [Page 5]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 Author's Address JP Vasseur (editor) Cisco Systems, Inc 1414 Massachusetts Avenue Boxborough, MA 01719 USA Email: jpv@cisco.com Vasseur Expires November 16, 2006 [Page 6]
Internet-Draft draft-ietf-mpls-number-0-bw-te-lsps-00 May 2006 Intellectual Property Statement 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 this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity 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. 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Vasseur Expires November 16, 2006 [Page 7]
