FAULT TOLERANT REAL TIME COMMUNICATION IN MULTIHOP NETWORKS USING SEGMENTED BACKUP

Many distributed real-time applications demand guarantees on the message delivery latency and the recovery delay from component failures in multi hop networks. So special schemes have been proposed to provide timely recovery for real-time communications in multihop networks. These schemes reserve additional network resources (spare resources) a priori along a backup channel that is disjoint with the primary. Upon a failure in the primary channel, its backup is activated, making the real-time connection dependable. In this paper we propose a new method of providing backups called segmented backups, in which backup paths are provided for partial segments of the primary path rather than for its entire length as is done in the earlier methods. In order to provide backups we use three protocols: 1) routing protocol, to determine the primary as well as the backup paths; 2) reservation protocol, to reserve resources efficiently along these paths; and 3) recovery protocol, to recover from any failure. We present the recovery protocol as a simple extension to the Internet Engineering Task Force (IETF)- recommended resource reservation protocol, RSVP. Using above protocols we can offer: 1) improved network resource utilization; 2) higher average call acceptance rate; 3) better quality-of-service guarantees on propagation delays and failure-recovery times; and 4) increased flexibility to control the level of fault tolerance of each connection separately.