Toward a Loss-Free Packet Transmission via Network Coding

Abstract

Network coding promises significant benefits in network performance, especially in lossy environment. As the Transmission Control Protocol (TCP) forms the central part of the Internet protocol, it is necessary to find out the way that makes these benefits compatible with TCP. This chapter introduces a new mechanism for TCP based on network coding which only requires minor changes to the protocol to achieve incremental deployment. The center of the scheme is transmitting linear combination of original packets in the congestion window and simultaneously generating redundant combinations to mask random losses from TCP. Original packets in the congestion window can be deleted even before it is decoded at the receiver side, since the receiver acknowledges the degree of combinations instead of packet itself. Thus, all the original packets can be obtained once enough combinations are collected. Simulation results show the scheme achieves much higher throughput than original TCP in lossy network. Though it still seems far from being deployed in the real network, it has finished the first step in taking the concept of NC into practice.