Self-Protecting Multipaths – A Simple and Resource-Efficient Protection Switching Mechanism for MPLS Networks

Abstract

Abstract. In this paper we propose the concept of an end-to-end (e2e) SelfProtecting Multi-Path (SPM) as a protection switching mechanism that may be implemented, e.g., in Multiprotocol Label Switching (MPLS) networks. In case of local outages, resilient networks redirect the traffic from a failed link over an e2e backup path to its destination. In this case, Quality of Service (QoS) can only be provided if sufficient extra capacity is available. If backup capacity can be shared among different backup paths, multi-path routing allows for considerable savings regarding this extra capacity. The SPM consists of disjoint paths that carry the traffic bothin normal operation mode and during local outages. If a partial path is affected by a network failure, the traffic is just distributed to the remaining working paths. This structure is easy to configure and the switching to failure mode operation is simple since no signalling is required. Based on analytical results, we show that Ioad balancing of the traffic across the disjoint paths can reduce the required backup capacity significantly. The backup performance depends strongly on the network topology, and the SPM outperforms simple Open Shortest Path First (OSPF) rerouting by far.

The Efficiency of Traffic Engineering with Regard to Link Failure Resilience

“…all single link failures are considered in the following examples. Then our aim is to secure the network against the set of failures, such that all traffic demands can be carried through the network in each relevant failure case [19].…”

“…A corresponding link upgrade strategy is described in Section 6 with an example showing the long term results and a discussion of main properties and their implications. Alternative approaches for the treatment of failure scenarios and for resilient transport over MPLS networks have also been studied by [18,19]. We start with a description of the TE-Scout tool including a summary of the algorithms and basic evaluation examples for traffic engineering and load balancing in Sections 2-4.…”

Resilient Multi-path Routing Based on a Biological Attractor Selection Scheme

“…Other papers have dealt with improving the performance by sharing any unused other paths between different users. Approaches to MPLS [15] and WDM networks [16] have been proposed where the backoff capacity is shared, resulting in a better performance especially when supporting quality of service sensitive applications.…”

Overview of resilience mechanisms based on multipath structures

“…Recently, several resilience mechanisms have been proposed in literature taking advantage of multipath structures to reduce either the maximum link utilization ρ E,S max of existing network or the network costs: protection cycles (pcycles) [1], demand-wise shared protection [2], low overhead protection for Ethernet over SONET transport (PESO) [3], optimum backup capacity sharing in packet-switched networks [4], self-protecting multipaths [5], the distributed, responsive, and stable online traffic engineering protocol TeXCP [6], the optimized equal-cost multipath (ECMP) shortest path routing [7]- [9], the adaptive multipath (AMP) [10], and dynamic traffic engineering based on wardrop routing policies (RE-PLEX) [11]. TeXCP, AMP, and REPLEX are not resilience mechanisms in a narrow sense but dynamic traffic engineering algorithms based on multipath structures.…”