Internet Draft Sriganesh Kini Expires : April 2001 Muralidharan Kodialam <draft-kini-ospf-lsp-restoration-00.txt> T.V.Lakshman - Bell Labs Curtis Villamizar - Avici Systems Open Shortest Path First (OSPF) protocol extensions for Label Switched Path restoration draft-kini-ospf-lsp-restoration-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. 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 Traffic engineering using MPLS involves the setting up of label switched paths (LSP) possibly with explicit routing and with bandwidth guarantees (for label switched paths). The reliability of these LSPs can be increased by providing a backup LSP onto which traffic can be switched upon failure of an element in the path of the active LSP. Backup LSPs can be routed in a way that bandwidth can be shared between backup links of more than one active path while still guaranteeing recoverability for a set of failures. This sharing greatly increases the network efficiency, thereby increasing the number of LSPs that can be carried while maintaining guarantees. Algorithms which can route such recoverable LSPs while using only aggregate network usage information are being developed. To route the active LSP and the (possibly shared) backup LSP, the topology information of the network is needed and this can be provided by a link state routing protocol like OSPF. This document describes the encoding of the additional information within the link state advertisement (LSA) of OSPF to enable routing of shared backup paths. S. Kini, et al Expires April, 2001 [Page 1]
Internet Draft draft-kini-ospf-lsp-restoration-00.txt November 2000 1. Introduction The concept of sharing links along backup paths is explained in [4]. OSPF (as described in [2]) is a link state protocol that can provide topology information about the network. Extensions to OSPF to enable traffic engineering are described in [1]. This document proposes further TE extensions to OSPF. These extensions provide aggregate information useful to calculate shared backup paths. 2. Extensions to the Type 10 LSA The opaque LSA [5] Type 10 (with area flooding scope) is used to convey traffic engineering capabilities [1]. The semantic content of the extensions proposed here are essentially identical to the corresponding extensions to IS-IS [3]. The extensions described here add more information about a link to the Type 10 LSA. New sub-TLVs are defined for the link TLV (section 2.4.2 of [1]). All sub-TLVs defined in this document are optional. Sub-TLV Type Length (octets) Name x1 4*8 link bandwidth allocated for active paths with backup x2 4*8 link bandwidth allocated for active paths without backup x3 4*8 link bandwidth allocated for backup paths Note : Only logical numbers (x1, .. x3) are used to describe the sub-TLV. Actual values can be assigned when this document is made a working group document. 2.1 Sub-TLV x1 : Link bandwidth allocated for active paths with backup This sub-TLV contains the bandwidth that is reserved on this link for active paths that have backup paths. The link bandwidths allocated for active paths is encoded in 32 bits in IEEE floating point format. The units are bytes (not bits!) per second. 2.2 Sub-TLV x2 : Link bandwidth allocated for active paths without backup This sub-TLV contains the bandwidth that is reserved on this link for active paths that do not have a backup. The link bandwidths allocated for active paths without a backup is encoded in 32 bits in IEEE floating point format. The units are bytes (not bits!) per second. 2.3 Sub-TLV x3 : Link bandwidth allocated for backup paths This sub-TLV contains the bandwidth that is allocated to backup paths. S. Kini, et al Expires April, 2001 [Page 2]
Internet Draft draft-kini-ospf-lsp-restoration-00.txt November 2000 The link bandwidths allocated for backup paths is encoded in 32 bits in IEEE floating point format. The units are bytes (not bits!) per second. 3. Security Considerations This document raises no new security issues for OSPF. 4. IANA Considerations The responsible Internet authority (presently called IANA) should assign values to x1, x2 and x3. 5. Acknowledgments The authors would like to thank Vishal Sharma and Roch Guerin for their comments on this work. 6. References [1] Katz, D., Yeung, M., "Traffic engineering extensions to OSPF", Internet Draft <draft-katz-yeung-ospf-traffic-01.txt>, November 1999. [2] Moy, J,, "OSPF Version 2" RFC 2328, April 1998. [3] Kini, S., et al, "Intermediate System to Intermediate System (IS-IS) protocol extensions for Label Switched Path restoration" Work in progress, Internet Draft <draft-kini-isis-lsp-restoration-00.txt>, November 2000. [4] Kini. S., et al, "Shared backup Label Switched Path restoration", Work in progress, Internet Draft <draft-kini-restoration-shared- backup-00.txt>. November 2000. [5] Coltun. R., "The OSPF Opaque LSA Option", RFC2370. July 1998. 7. Author's Addresses Sriganesh Kini Lucent Technologies, Bell Labs High Speed Networks Research Department Room 4C-526, 101 Crawfords Corner Road Holmdel, NJ 07733-3030 Phone : 732 949 6418 Email : kini@dnrc.bell-labs.com Muralidharan Kodialam Lucent Technologies, Bell Labs High Speed Networks Research Department Room 4D-525, 101 Crawfords Corner Road Holmdel, NJ 07733-3030 S. Kini, et al Expires April, 2001 [Page 3]
Internet Draft draft-kini-ospf-lsp-restoration-00.txt November 2000 Phone : 732 949 6296 Email : muralik@dnrc.bell-labs.com T.V.Lakshman Lucent Technologies, Bell Labs High Speed Networks Research Department Room 4D-531, 101 Crawfords Corner Road Holmdel, NJ 07733-3030 Phone : 732 949 4778 Email : lakshman@dnrc.bell-labs.com Curtis Villamizar Avici Systems Email : curtis@avici.com Full Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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." S. Kini, et al Expires April, 2001 [Page 4]