Reactive Routing Protocols

The reactive routing protocols discover the route between the nodes only if it is needed. The commonly used reactive routing protocols are Dynamic Source Routing (DSR), Ad hoc On Demand Distance Vector (AODV), Temporally Ordered Routing Algorithm(TORA), Associativity Based Routing (ABR), and Signal Stability Routing (SSR). The route discovery process is initiated only if the source node does not already have a valid route to the destination in its route cache. The routes in the route cache are periodically updated. The reactive routing protocol reduces control overhead and power consumption as it establishes routes only in on-demand fashion.

Problem

Individual Performance of the each Reactive Routing Protocol should be evaluated in various network scenarios and also comparative analysis is also required to identify the suitable routing protocol for specific network condition.

Solution in NS2

  • In NS2, operation of the individual routing protocols can be visualized in network animation and performance of the routing protocol can be traced out using trace file records.

  • The strength of the routing algorithm reveals under the condition of network mobility. It can be evaluated by setting the mobility scenario in the network simulation. The ns~\indep-utils\cmu-scen-gen\setdest.cc file is available in ns2 to generate the mobile scenario for varying number of nodes, pause time and speed.

  • Performance comparison between reactive routing protocols can be done and illustrated in x-graph in ns2.

  • Performance metrics such as a packet delivery ratio, Routing overhead, throughput, end to end delay and packet loss can be obtained by processing the trace file using AWK script.

  • Based on the results obtained using NS2, appropriate routing protocol can be selected that performs better in specific network scenario. Reactive routing protocol is suitable for large network.