A Study on the Performance of Wireless-cum-Wired Network Using Different TCP Flavors

Kansham Modar Maring Mr., North Eastern Regional Institute of Science and Technology
Prof. Md. Anwar Hussain Mr., North Eastern Regional Institute of Science and Technology

Abstract

In this thesis entitled, A Study On the Performance of Wireless-cum-Wired Network Using Different TCP Flavors", the objective is to focus on the TCP performance study in hybrid network consisting of wired and wireless network. The Transmission Control Protocol (TCP) which was designed primarily for reliable wire line networks has packet loss which is mainly because of network congestion. The TCP congestion avoidance mechanisms attribute packet loss to congestion in the network. Subsequently, congestion avoidance mechanisms are triggered. These measures are targeted to reduce the load on intermediate links. In the wireless scenario, however, packet loss is primarily because of bit errors and hand overs, which gets mistaken as an indication of network congestion. The resulting measures taken by TCP lead to degradation of throughput. In this paper, the hybrid network so designed consists of two base stations, BS0 and BS1 respectively in cluster 1 and 2. It consists of four wired nodes and six mobile nodes in each cluster. The wireless nodes are interconnected by a wire line which serves as the backbone network. The comparative result of performance for different network scenarios both for Drop Tail and RED are studied using TCP Reno, TCP Vegas and TCP New Reno. The Comparison of performance both in RED and Drop Tail is studied using different TCP flavors. The comparative study on performance under different error rates, link capacity and mobility rates are presented in this paper. The packets are sent from different nodes at different times. The two level hierarchical routing is used to reduce the routing table and calculation time. The window size management is observed for all the TCP connections. Transmission control protocol (TCP) plays an important role in designing a network's performance. Its use in wireless networks has exposed several inadequacies in its operation. I have presented the results of simulation using the network simulator NS-2. Using the network animator (NAM) the packet movements and packet drops are shown.