ABSTRACT
Ad-hoc network contains a set of wireless nodes without any infrastructure (Access Point/Base station) support. Caching frequently accessed data items in mobile nodes is the effective technique to enhance the communication performance in Mobile Ad-hoc Networks (MANETs). One of the effective techniques to avoid the stale data is cache invalidation, which maintains data consistency between the client cache and the server. This paper discusses the Time-To- Live (TTL) based invalidation. There are basically two types of TTL based schemes namely Fixed TTL and Adaptive TTL. Fixed TTL scheme always set the fixed TTL value for all kind of data item and it also take additional process time for cache invalidation. Adaptive TTL scheme refresh the cache data and reset the TTL. Cache refresh and TTL reset of Adaptive TTL scheme produce some process overhead to the cache node. So this paper proposes a new scheme called Extended Adaptive TTL (Ex-ATTL) in which each 1-hop distance node’s to data cache node maintain a hash table for cache invalidation. The hash table contains data item name as key and TTL as its value. Finally the simulation using Ns-2 is conducted to evaluate the performance of the proposed scheme then it has been compared with fixed TTL and Adaptive TTL schemes
Keywords: MANET, Cache consistency, Cache invalidation, Stale data, TTL value.
