Round-trip Time Variation in SmoothTCP in the Face of Spurious Errors

In this paper, we review the definition of a variant of TCP, called SmoothTCP, and describe one of its versions which uses ICMP-SQ messages as its primary control metric. This version of SmoothTCP is intended to be used in environments subject to spurious errors, such as in wireless networks. We evaluate the behavior of this version of SmoothTCP by comparing it with the behavior of Standard TCP in simulated environments with and without spurious errors. When there are no spurious errors, Standard TCP inherently drops packets and suffers large variations in the congestion window size causing large variations in round-trip time. In the case of spurious errors, Standard TCP encounters wide round-trip time variations around the retransmitted packet that was lost due to a spurious error. In both cases, SmoothTCP exhibits better performance with respect to round-trip time variation.