A Cross-Layer Approach for TCP Packet Loss Differentiation in Adhoc Networks
Valli S.P, K. M. Mehata · 2015
Transmission Control Protocol (TCP) is a transport layer protocol that is widely used across different types of networks. TCP provides reliable data transfer and the reliability is obtained by retransmitting lost packets. TCP was originally designed for wired networks. However performance of TCP is degraded in wireless networks due to various reasons. TCP has to face new challenges specific to wireless networks such as lossy channels, hidden and exposed stations, path asymmetry, network partitions and route failures and multipath. TCP uses packet loss as the primary means to indicate congestion in the network. However in wireless networks, the loss may be due to a link failure, signal loss, interference or multipath routing. A major drawback in TCP used for wireless networks is its inability to classify and distinguish congestion losses from non-congestion losses. This paper discusses about a technique for classifying packet losses using Explicit Congestion Notification (ECN) and Random Early Detection (RED). This paper also focuses on a cross-layer technique to improve TCP performance whenever congestion is encountered. The enhancement in the performance is measured with the metrics such as throughput and peak queue size. The methodology has been implemented using Qualnet 5.0 simulator.