Performance of the Selfhealing Network* Protocol with Random Individual Link Failure Times

摘要

The Selfhealing Network (SHN) is a parallel asynchronous distributed protocol which organizes the pool of spare links in a network into the pattern of k-shortest link disjoint paths between any two nodes of the network.When applied to the span restoration problem it operates autonomously in real time,in a single iteration,with no database requirements.The protocol effects a process of network-wide contention amongst multiple concurrent flooding processes and is specifically designed to exploit a highly parallel form of physical-layer interaction that is possible amongst DCS machines embedded within the transport network.Previous studies [1,2,3] tested the protocol [4] on nearly 1800 individual span-cutting experiments including models of the Telecom Canada network to year 2005 using methodology detailed in [5].Results showed that with suitable implementation the protocol;(a) produces all paths of the ideal k-shortest paths restoration solution in one iteration,(b) restores any span failure in the Telecom Canada network in under 1.5 seconds,(c) performs 1:N protection switching in 40 msec,and,(d) performs effectively with dual simultaneous and dual time-concatenated failures.Now we report the behavior of the SHN protocol when presented with a random series of individual fiber failures,as opposed to a "guillotine" (i.e.,simultaneous) model of a cable cut.The most significant results are:(a) verification of the protocolunder complex failure stimuli,(b) a finding of pre-deployment effects which reduce the elapsed outage time of most individual paths when failures occur in a time distributed manner.This paper is abstracted from technical reports prepared under Telecom Canada research project 90-16 [6].