DualRTT: detecting spurious timeouts in wireless mobile environments

Retransmission ambiguity, arising from delay spikes in a wireless mobile environment, results in poor TCP performance. Eifel improves the performance of TCP by using the timestamp option, which requires additional header bytes, resulting in increased overhead in bandwidth constrained wireless networks. Moreover, the destination needs to support the timestamp option. In this paper, we propose a new algorithm, called DualRTT, which increases the performance of TCP in the presence of delay spikes, without requiring any additional header bytes. It requires changes only at the sender, and hence is easier to deploy in the existing Internet infrastructure. It also does not require the destination to support the TCP timestamp option. Results show that DualRTT increases the performance of TCP, and also achieves a higher transport layer efficiency than previous algorithms.