Computing segmented backups using resilient routing layers

Abstract

Hard guarantees on message delivery timeliness and recovery delay from network equipment failures are required by several distributed real-time applications such as video conferencing. In order to meet these requirements many schemes have been proposed to provide solutions by reserving additional resources a priori along a disjoint backup path. One of the approaches in the literature [1] proposes segmented backup, in which backup paths are provided for partial segments of the primary path rather than for its entire length. The advantages of having segmented backups are improved network resource utilization and faster failure-recovery. We found that [1] generates only two backup segments, whatever the length of the primary path, in mesh networks. This is not much better than a disjoint path in terms of resource utilization. We propose a new method for computing segmented backup using the concept of Resilient Routing Layers (RRL) [2]. We compared the performance of our scheme with the scheme proposed in [1] for mesh and other topologies generated using BRITE [5]. We demonstrate that our approach gives better results on parameters like number of backup segments, percentage reuse of primary path and average hop count for failure notification which influence network resource utilization and faster failure-recovery.