NPP: A Facility Based Computation Framework for Restoration Routing Using Aggregate Link Usage Information

Bandwidth Sharing with Primary Paths for Protection Routing in an MPLS Network

“…In local protection, the node which diverts traffic from the primary path to the backup path-called the Point of Local Repair (PLR)-is a node that is immediately upstream the failed facility. It is well-known that MPLS local protection meets the requirements of real-time applications with recovery times comparable to those of SONET rings [1], [2], [4], [6]. In this paper, we focus on local protection while emphasizing that the idea of sharing with primary paths can also be used with other protection routing frameworks that may not use local protection.…”

“…2 The primary goal in protection routing is to maximize the bandwidth sharing among paths that will not be activated simultaneously. A number of schemes and frameworks have previously been studied for sharing bandwidth along the backup paths [1], [4], [10]. To the best of our knowledge, none of the existing schemes have considered sharing with the primary paths.…”

“…Under this model, we setup local backup paths that provide protection against the failure of a single network element, either a node or a link. Towards this end, we recollect the definitions of the two types of backup paths from [1] and [7]. Definition 1: A next-hop path that spans a link (i, j) 3 is a backup path which: a) originates at node i, b) merges with the primary LSP(s) at node j, and c) is activated only when {i, j} fails providing protection for one or more primary LSPs that traverse (i, j) and terminate at node j.…”

“…In this paper, we use the single element protection fault model described in [1] and [11]. Under this model, we setup local backup paths that provide protection against the failure of a single network element, either a node or a link.…”

“…A desirable characteristic of a protection routing framework is minimal latency in switching the traffic onto backup paths This work was supported in part by a grant from Cisco Systems under the University Research Program, Chonbuk National University, KOSEF through OIRC project, and IITA. 1 The term facility refers to either a node or a bidirectional link.…”