Congestion control based on flow-state-dependent dynamic priority scheduling

The existing congestion control mechanism in the current Internet use is based on TCP congestion control mechanism, which is the key to the success of the Internet. However the TCP´s end-to-end congestion control mechanism and the router assistant mechanism active queue management (AQM), such as random early detection (RED), cannot cope with flows that are unresponsive to congestion notification or non-TCP-compatible flows which are responsive but more aggressive than TCP. Unresponsive or non-TCP compatible flows could even cause congestion collapse. In this paper, a new mechanism is presented, namely source aware congestion control (SACC) based on a packet scheduling algorithm called flow-state-dependent dynamic priority scheduling (FDPS), which performs traffic monitoring, marking and scheduling at routers. Extensive simulation experiments are conducted based on ns-2 to examine SACC behaviour and evaluate its performance in a variety of scenarios. The numerical results illustrate that the proposed scheme can differentiate services and resolve congestion by gracefully discarding packets from non-conformant and best effort flows when unresponsive flows exist.