Active Route Cache Optimization for Ad hoc Networks
Nikhil I. Panchal, Nael Abu‐Ghazaleh · 2002
In mobile Ad hoc networks, the topology of the network is constantly changing as nodes move in and out of each others range. Routing must maintain required paths in such an environment with an acceptable overhead. On demand routing protocols maintain paths only when they are requested by flooding the request through the network at great cost. Caches are used to reduce the frequency of flooding. We quantify the benefits and drawbacks of maintaining caches (vs. doing a full search every time). We show that caching can have undesirable side effects including inefficiencies due to stale paths, and the use of low quality paths even when significantly shorter paths become available. Based on these observations, we investigate optimizations to the caching of the Dynamic Source Routing (DSR) algorithm including path verification, periodic scoped searches to discover shorter paths, and selective pruning of cached paths. With active cache management we have a new class of Ad Hoc routing algorithms that is proactive but only on paths that are in use. We believe that these techniques are general and can be applied to other on-demand routing protocols.