An ELFN-based adaptive probing strategy to improve TCP performance in ad hoc networks

TCP performance degrades considerably in ad hoc network due to its distinguishing characteristics, such as high channel error rate and link failure. Various schemes have been proposed to improve TCP performance in ad hoc network. ELFN (Explicit Link Failure Notification) is one of mechanisms to handle link failures with ceasing TCPpsilas exponential back-off behavior. Though ELFN improves TCP performance considerably, it uses fixed probing technique to check link status. Hence performance of TCP with ELFN depends on probing interval. In this paper, we propose an ELFN-based adaptive probing strategy that eliminates problem due to fixed probing interval. This strategy uses rapid probing initially so as to continue use of channel when link failure is due to channel contention. Our simulation results, using ns-2 simulator, indicate that the adaptive probing can handle link failures in better way, and improves TCP performance considerably.