Abstract

Part 6: New Testing Methods; International audience; In this paper, we focus on Mobile Ad-hoc Networks (MANETs) with non-uniform node density distribution such as Vehicular Ad-hoc Networks (VANETs) and Delay Tolerant Networks (DTNs), and propose a technique for protocol testing and performance evaluation. In such MANETs, node density varies depending on locations and time, and it dynamically changes every moment. In the proposed method, we designate node density distributions and their dynamic variations in a target area. Then, we construct a graph called TestEnvGraph where all node density distributions are treated as its nodes and they are connected by edges whose weights denote differences of two node density distributions. We specify a set of edges to be tested in the graph, formulate a problem for efficiently reproducing all the given node density distributions and their dynamic variations as a rural postman problem, find its solution and use it as the order of reproduction of designated node density distributions and their variations. Protocol testing is carried out by reproducing node density distributions in the derived order. We have designed and developed a method and its tool for mobility generation on MANETs, which can reproduce any designated node density distribution and its dynamic variations in a target area. From our experiments for a VANET protocol, we have shown that our method can give a similar trend in network throughput and packet loss rates compared with realistic trace based protocol testing. Document type: Part of book or chapter of book

Abstract

The TCP protocol exhibits poor performance in multi-hop Mobile Ad Hoc Networks (MANETs). The ultimate reason for this is that MANETs behave in a significantly different way from traditional wired networks (like the Internet) for which the TCP protocol was originally designed. In particular, route failures and route changes due to node mobility may be frequent events in MANETs. Furthermore, congestion phenomena in MANETs are essentially different from traditional wired networks. In this paper we propose a novel transport protocol for MANETs. Unlike other proposals, our protocol is not a modification of the TCP but is specifically tailored to the characteristics of the MANET environment. It is able to manage efficiently route changes and route failures. Furthermore, it includes a completely re-designed congestion control mechanism. Finally, it is designed in such a way to reduce as much as possible the number of useless retransmissions. This is extremely important since retransmissions consume energy. Document type: Part of book or chapter of book