Congestion-resilient TCP

Abstract

In response to the advent of publicly-accessible high bandwidth links, we explore a potential resiliency enhancement to TCP that makes use of extra bandwidth to do forward error correction using the exclusive-or binary operation. We implement this XOR-Packets enhancement in the FreeBSD network stack and show that it guarantees the ability to reconstruct any single packet loss without the need for retransmission. Furthermore, in the unlikely best case, up to a third of the TCP stream can be lost without the need for retransmissions. We test our scheme against FreeBSD's default NewReno implementation with and without Selective Acknowledgment and find that our enhancement's goodput scales better than both for large stream sizes in high network congestion conditions.