PERFORMANCE STUDY OF TCP/IP, IN A MOBILE ENVIRONMENT

Abstract

A mobile environment is based on wireless media, which is highly error prone. This leads to a higher data loss and increased delays in transmission. Moreover packets are also lost while the network learns to route data to a mobile host.TCP/IP interprets such delays and losses as signs of network congestion and start off algorithms, which will allow the network to recover from the current crisis. These algorithms actually constrict the data source, and the data transfer rates are brought down substantially, as a precautionary measure. The network recovery, is again, a slow process.Even though the routers are equipped with up to date information, regarding the location of the mobile host, in a few milliseconds, normal throughput levels are not achieved until several milliseconds. Thus, the packet losses and delays caused due to mobility, triggers a false alarm to the transport protocols and they consequently throttle their transmission, further degrading the performance of the network. This thesis, studies the actual degradation in the performance of the TCP/iP, in such a mobile environment. The work accurately models the essential features of TCP and Mobile 1P protocols. Features of TCP implemented are, connection establishment using a three way handshake, effective retransmission of unacknowledged data, dynamic window flow, reorganization of out of sequence data, discarding of duplicated data, and Van Jacobson's Congestion Control algorithm. The Mobile 1.P implemented here, is based on the specifications given by the mobile-IP working group, supported by the IETF. A further optimization has also been incorporated into the Mobile IP, to improve its performance.