Improving of TCP Performance Evaluation in Mobile Ad Hoc Networks

Wireless Mobile Ad-hoc networks offer challenges to TCP’s congestion control mechanism related to its inability of distinguishing between losses induced by congestion and others types of losses. The performance of transport layer protocols will be a key factor in the successful extension of internet application and services to Mobile Ad-Hoc networks (MANETs). This paper uses fixed RTO interval. The TCP is the most commonly used transport for the internet, so providing a high level performance in MANETs is of particular importance. While TCP has been extensively tuned for wire line networks, in its correct form TCP does not perform well when used in MANETs. One of the services provided by transport layer protocols is to turn IP’s best effort level of service into a reliable packet delivery service. IP packets may be dropped, reordered, or duplicated on the way from sender to receiver. By contrast the TCP enables applications to establish reliable, full-duplex connection. TCP includes a flow controls scheme by which the receiver can limit the rate at which the sender transmits data. TCP also implements a congestion control mechanism of to keep TCP sender from over loading the network and possible causing congestion collapse. We evaluated its performance under variety of network conditions running different class of routing protocols: DSR and AODV are reactive and DSDV is proactive. Our performance study shows the effect of different factors in isolation and in combination with each other on the TCP performance and the impact of routing protocol design approaches in the TCP stability.