Cache signatures for peer-to-peer cooperative caching in mobile environments

Caching is a key technique for improving data retrieval performance of mobile clients in mobile environments. The emergence of robust and reliable peer-to-peer (P2P) tech-nologies now brings to reality what we call “cooperative caching ” in which mobile clients can access data items from the cache in their neighboring peers. This paper considers a COoperative CAching scheme for mobile systems, called COCA. A cache signature scheme is devised for COCA that provides hints for the mobile clients to determine whether a required data item is cached by their neighboring peers based on their local state. The trade-off between the im-provement in system performance and the overheads of the cache signature scheme in COCA is discussed. The per-formance of COCA with and without the cache signature scheme is evaluated through a number of simulated exper-iments. COCA is shown to be capable of effectively reduc-ing the number of server requests and power consumption, as well as shortening the access latency as the number of neighboring peers increases. The inclusion of cache signa-ture scheme further improves on the access latency. 1