Enhanced Service Discovery Protocol for MANET by Effective Cache Management

With the increasing pervasiveness of the mobile nodes, service discovery has become inevitable. In the resource constrained mobile nodes, caching is being used to reduce the access cost. The enhanced service discovery protocol presented in this paper is a combination of cache placement, cache discovery, cache consistency and replacement algorithms. The overheard service information is cached by the coordinator nodes of each geographical area to reduce the discovery delay. A light weight cache discovery algorithm that uses a minimum spanning tree is proposed. The cache consistency is maintained in a soft state. Cache replacement is done based on a weight value that is calculated using the recency, frequency and cost factors. An M/G/1/∞ non-preemptive queuing model is proposed to analyse the cache replacement performance. The extensive simulation results performed to demonstrate the effectiveness of the proposed enhanced service discovery protocol in terms of reduction in the service discovery delay and number of cache replacements. The replacement scheme proposed has increased the cache hit ratio.