Caching Strategies for Dynamic Source Routing in Mobile Ad Hoc Networks

The dynamic source routing (DSR) protocol usually utilizes route caching to reduce the routing overhead and route discovery latency. For caches to be effective, the protocol needs to adapt to the frequent topology changes. In this paper, we propose two mechanisms to improve cache correctness and route stability. The first is the RERR-enhance mechanism in which a broken link message is sent to all nodes that had cached the broken link. The second mechanism is the hierarchical link cache structure accompanied with a link stability measurement. The cache in each node falls into two tiers: the primary cache and the secondary cache. The node selects a route from the primary cache first, based on link stability, to provide stable transmission. The proposed mechanism can decrease the routing overhead and end-to-end delay, compared to DSR with path caches and with link-maxLife, an adaptive timeout mechanism for link caches.