Abstract

Ad-hoc Wireless Local Area Networks (WLANs) are becoming very attractive and useful in many kinds of communication and networking applications. This is due to their efficiency, simplicity (in installation and use), relatively low cost, and availability. Unfortunately, Internet application performance over wireless links is disappointing due to wireless impairments that adversely affect higher layers, specifically TCP and UDP which are the de facto standards for connection oriented and connectionless transport layer protocol, respectively. This work analyzes how TCP and UDP (individually and together) perform in an IEEE 802.11 WLAN consisting of several non-mobile nodes. The focus is on performance evaluation in terms of throughput, delay, jitter, and packet loss ratio at the transport layer. Based on the obtained results, suggestions and recommendations are made which can help improve the performance in such scenarios. These include packet size optimization, effect of RTS/CTS scheme, TCP versions, effect of loading the network with UDP traffic, and MAC buffer size optimization, among other things. File transfer and Constant Bit Rate (CBR) applications are simulated, and the simulations are done using the Network Simulator Version 2 software.