A Lightweight ARQ Scheme to Minimize Communication Overhead

Abstract

Due to limited buffer space available at routers, the packets in the Internet gets lost or dropped, especially when the network is congested. Automatic repeat request (ARQ), is an error-control method that uses acknowledgments and timeouts to decide retransmission of messages to achieve reliable data transmission. However, the re-transmission of a lost packet further increases the congestion in the network, and hence the end-to-end delay of other coexisting flows. This paper aims at improving the performance of ARQ schemes by introducing a lightweight re-transmission mechanism called LW-ARQ based on the concept of caching of packets at intermediate routers that are indented to be dropped. To evaluate the performance of proposed LW-ARQ scheme, we chose to implement it over TCP protocol considering that TCP has become a de-facto transport layer protocol standard for the Internet. However, the proposed LW-ARQ scheme can be integrated with any protocol that uses either stop-and-wait or sliding window based ARQ scheme to handle packet losses. On analyzing the results obtained by performing simulations, we found that the proposed LW-ARQ scheme improves the average end-to-end delay performance of the TCP protocol.