Department of Computer Science & Engineering

Traditionally, capacity on the Internet has been allocated between competing flows through a distributed fairness calculation implemented by end-to-end congestion control protocols like TCP. Increasingly, however, network operators are deploying fair queuing and other forms of router-based enforcement mechanisms to prevent greedy or misbehaving end points from consuming more than their fair share of the network’s capacity. In environments where fairness is enforced by the network itself, it seems worthwhile to reconsider the role of the congestion control protocol. In particular, we ask if it might be both safe and sensible in the long term for self-interested senders to send at rates that exceed the capacity of the network. Through simulation, we identify and quantify the source of inefficiency in this regime, which we term zombie packets. Surprisingly, we show that such aggressive mechanisms are not only tenable in a wide variety of network structures, but, combined with effective use of erasure coding, they can avoid creating zombie packets and achieve throughputs that approach optimal.

Pre-2018 CSE ID: CS2013-0998