Performance evaluation of westwood+ TCP over WLANs with local error control
Luigi Alfredo Grieco, Saverio Mascolo · 2004
Link layer error control is widely adopted in wireless LANs (WLANs) to hide the unreliability of the wireless channel to higher level protocols. This allows classic end-to-end congestion control algorithms to achieve acceptable throughput even in the presence of radio links. The present work investigates the performance of Westwood+ and NewReno TCP over a noisy wireless LAN channel. In particular, the effect of local error control persistency on the end-to-end performances of Westwood+ and NewReno TCP is addressed. The investigation has been carried out by using ns-2 computer simulation. Simulation results show that (1) in the presence of uniformly distributed packet losses a well tuned local error control leads both Westwood+ and NewReno TCP to full network utilization; (2) in the presence of bursty losses Westwood+ TCP improves the good-put with respect to NewReno TCP also in the presence of local error control; in particular, Westwood+ TCP requires a smaller number of retransmissions at the link layer than New Reno to achieve full utilization of the wireless channel.