Optimizing Cached Route Time-to-Live in Mobile Ad-Hoc Networks

As reactive routing protocols take advantage of using recently active routes in the route cache, determining appropriate cached route Time-To-Live plays an important role in reducing the routing overhead by avoiding misrouting overhead caused by route errors. In this paper, an analytical model is presented for quantifying the bandwidth necessary to facilitate routing. Then, a numerical model for determining the optimal cached route Time-To-Live is derived to minimize the reactive routing overhead depending on network mobility and data traffic load. We show that cached route Time-To-Live should be set far shorter than that commonly seen in or recommended for simulations to save bandwidth. This paper provides a valuable insight into the fundamental limits of routing performance in MANETs in response to mobility.