Open Shortest Path First (OSPF) protocol extensions for Label Switched Path restoration
draft-kini-ospf-lsp-restoration-00

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.

Authors

Sriganesh Kini
Murali Kodialam
T. V. Lakshman
Curtis Villamizar

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