1.3 Routing in Mobile Ad Hoc Networks

This paper describes a recent simulation-based evaluation of several unicast routing protocols tailored specifically for mobile ad hoc networks. Four protocols were evaluated: the Wireless Internet Routing Protocol (WIRP), a Link State (LS) algorithm with constrained LS updates, a Distance Vector variant of WIRP, and Temporally Ordered Routing Algorithm (TORA). The goal was to determine how well these routing protocols worked in specific tactical conditions, supporting a given mix of traffic. Factors varied included tactical scenario, network size, and loading. Tactical scenario included different connectivities (e.g., “dense” versus “sparse”) and link fluctuation rates (e.g., “high” versus “low”). Metrics collected included average end-to-end delay per application, path length, total efficiency, and fraction of user messages received. We found that certain protocols performed better in densely connected networks than in sparser networks (e.g., TORA), while some performed better in sparser networks (e.g., LS). One protocol, WIRP, performed well in both types of networks over the scenarios evaluated. Several remaining issues and areas for continued research are identified.