End-to-end acknowledgments for indirect TCP over wireless internetworks

The Internet today is evolved from traditional networks made up of fixed hosts and links. Consequently, protocols for Internet communications, such as TCP, are designed to perform well over fixed networks. The next generation Internet will likely incorporate wireless links and mobile hosts. Characteristics of wireless networks such as higher bit error rates and host mobility result in degraded end-to-end TCP performance. Indirect TCP (I-TCP) has been proposed as an alternative to end-to-end TCP to improve performance. However, the protocol violates the end-to-end semantics of TCP acknowledgments. We propose a modification to I-TCP to maintain the end-to-end semantics, by delaying acknowledgments to the sender until correct reception of the corresponding data at the end host TCP receiver is verified. Preliminary simulation results indicate that our modified I-TCP with end-to-end acknowledgments does not compromise the performance gain obtained by I-TCP. Rather, a slight performance increase is seen at low bit error rates