ATM virtual path self-healing based an a new path restoration protocol

Abstract

Many studies have many studies have been conducted using ATM technology to implement B-ISDN. These have shown that ATM virtual path (VP) technology, due to its fast cross-connect system, can be used to achieve rapid restoration for a distributed control mesh-type restoration system. The signaling channel using operations and maintenance (OAM) cells further improves restoration time because of the high bandwidth available to the OAM cells in an ATM VP network. Within the framework of logical channel protection scheme, self-healing restoration can be provided at two different schemes: path restoration and line restoration. Path restoration restores the end to end logical channel (i.e. finds an alternative logical channel), and line restoration restores demands carried by the failed link. We propose a new three-phase distributed VP self-healing scheme using path restoration protocol to achieve high restoration ratio, with an average restoration time of around 1-second, and less spare capacity assignments due to more efficient usage of them in the network. An empirical study based on a real metropolitan LATA mesh network shows that, under the condition of assigning sufficient VPs between the same source and destination, the three-phase path restoration protocol has superior performance compare to the existing two-phase line restoration protocol over a number of networks with randomly generated VP assignments and spare capacity assignments. This empirical study also shows that restoration times of the proposed path restoration protocol are mostly around 1 second which is well suited for metropolitan LATA mesh networks.