Performance Enhancement of the Temporally-Ordered Routing Algorithm

The Temporally-Ordered Routing Algorithm (TORA) is a highly adaptive distributed routing algorithm used in Mobile Ad hoc Networks (MANET) that is able to provide multiple loop-free routes to a destination. TORA is very dependent on the services provided by the Internet MANET Encapsulation Protocol (IMEP) to effectively carry out its three main functions: Route Creation, Route Maintenance, and Route Erasure. However, TORA does not scale well in networks with a large number of traffic connections compared to other MANET protocols. We performed a comprehensive analysis into the workings of IMEP to determine which behaviour of IMEP leads to the poor performance of TORA and narrowed down the problem in IMEP. We suggested two approaches to improve the operations of IMEP: by increasing the maximum number of object block message retransmissions and by using a random RETRANS PERIOD. In addition, two different variations of TORA were developed to solve some of its performance problems: the network localization approach and selective node participation approach. The IMEP modifications and TORA variations resulted in an overall improvement in terms of packet delivery, routing overhead and packet latency in a variety of network scenarios.