Abstract: The throughput of TCP suffer when it used in mobile ad hoc networks. This is a direct consequence of TCP wrongly attributing packet losses due to link failures (a consequence of mobility) to congestion. While this problem causes an overall degradation of throughput, it especially affects connections with a large number of hops where link failures are more likely. Thus, short connections enjoy an unfair advantage over long connections. Moreover, if the MAC protocol defined in the IEEE 802.11 standard is used, the problems make worse due to the capture effect induced by this protocol, leading to a larger degree of unfairness and a further degradation of throughput. In this study, we develop a scheme which we call SecSplit TCP. This scheme separates the functionalities of TCP congestion control and reliable packet delivery. For any TCP connection, certain nodes along the route take up the role of being proxies for that connection. The proxies buffer packets upon receipt and administer rate control. The buffering enables dropped packets to be recovered from the most recent proxy. Introducing proxies, we emulate shorter TCP connections and can thereby achieve as shown by our simulations, the use of proxies decreases the problems described, i.e., it improves the total throughput by as much as 30% in typical scenarios-grid view-(straight movement of nodes) it reduces unfairness significantly. When comparing the performance of the two protocols, we infer that SecSplit-TCP outperforms Split-TCP by 50% in terms of delay, 4% in terms of delivery ratio, 60% in terms of drop and 48% in terms of throughput. We conclude that incorporating TCP proxies is beneficial in terms of improving the security TCP performance in mobile adhoc networks.
P.S. Sujith Kumar and J. Frank Vijay, 2017. WTLS SecSplit-TCP Proxy Based Protocol for MANET. Asian Journal of Information Technology, 16: 588-591.