Convergence Time Evaluation of Algorithms in MANETs

Since the advent of wireless communication, the need for mobile ad hoc networks has been growing exponentially. This has opened up a Pandora’s Box of algorithms for dealing with mobile ad hoc networks, or MANETs, as they are generally referred to. Most attempts made at evaluating these algorithms so far have focused on parameters such as throughput, packet delivery ratio, overhead etc. An analysis of the convergence times of these algorithms is still an open issue. The work carried out fills this gap by evaluating the algorithms on the basis of convergence time. Algorithms for MANETs can be classified into three categories: reactive, proactive, and hybrid protocols. In this project, we compare the convergence times of representative algorithms in each category, namely Ad hoc On-Demand Distance Vector (AODV)-reactive, Destination Sequence Distance Vector protocol (DSDV)-proactive, and Temporally Ordered Routing Algorithm (TORA)-hybrid. The algorithm performances are compared by simulating them in ns2. Tcl is used to conduct the simulations, while perl is used to extract data from the simulation output and calculate convergence time. The design of the experiments carried on is documented using Unified modeling Language. Also, a user interface is created using perl, which enables the user to either run a desired simulation and measure convergence time, or measure the convergence time of a simulation that has been run earlier. After extensive testing, it was found that the two algorithms AODV and DSDV are suited to opposite ends of the spectrum of possible scenarios. AODV was observed to outperform DSDV when the node density was low and pause time was high (sparsely populated very dynamic networks), while DSDV performed better when the node density was high and pause time was low (densely populated, relatively static networks). The implementation of TORA in ns2 was found to contain bugs, and hence analysis of TORA was not possible. Future enhancements include rectifying the bugs in TORA and performing convergence time analysis of TORA as well. Also, a system could be developed which can switch between protocols in real time if it is found that another protocol is better suited to the current network environment.