STUDY OF TCP PERFORMANCE IMPROVEMENT IN MOBILE AD HOC NETWORKS USING FEEDBACK SCHEME

Abstract

Ad hoc wireless networks consist of mobile nodes interconnected by mobile nodes interconnected by multihop communication path. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of the networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unstable. Transport protocols like TCP, which have been designed for reliable fixed network, misinterprets this packet loss as congestion and invoke congestion control algorithms, leading to unnecessary retransmission and loss of throughput. To avoid this is a feedback scheme (TCP-F) has been proposed in the literature. In this the router which detects link failure (called Failure Point), will then explicitly send a Route Failure Notification (RFN) packet to the source. The source then invalidates its timers and stops sending packets. When the Failure Point or the router in between source and the Failure Point finds any alternative route for that destination, it will inform the source by sending a Route Reestablishment Notification (RRN) packet to the source. In the present dissertation simulation is performed to study the improvement & performance of TCP-F. Furthermore a modification is suggested wherein the incoming packets are buffered when the router receives an RFN packet. The performance of this scheme is also studied.