RED tuning for TCP performance on the mobile ad hoc networks

Mobile ad hoc networks (MANET) does not need the fixed base station to process the link operation. In the past several years, many researchers have focused on studies of routing protocol over the MANET. Currently, the pervasion of Internet causes TCP as the standard transmission protocol for most of the networking applications. The RED is one of congestion avoidance methods in TCP. Due to the unconstrained movement of the mobile nodes, TCP is unable to notice network congestion or link down to activate related controls on the MANET. The network will search and establish a new transmission path, when an unwarned link down occurs on the MANET. The average queue length of RED will be longer than MinThreshold, if the link re-establishment costs too much of time. Then, it will invoke the sender to perform relative congestion control. Hence, it may degrade the TCP performance before the link reestablish completely. The main purpose of this paper is to adjust related RED parameters for evaluating the performance through the simulation on the MANET. Consequently, we did propose the tuning strategies in RED to improve the TCP performance based on final simulation results.