Active Congestion Control (ACC)

The Active Congestion Control project is applying Active Networking techniques to feedback congestion control. Feedback congestion control is a very effective system for sharing network bandwidth when the bandwidth delay product of the network is low, but loses its effectiveness in high bandwidth-delay networks. Using Active Networking techniques ACC seeks to increase the range over which feedback is effective.

ACC allows internal network nodes to take action immediately in times of congestion, as opposed to endpoint congestion control systems that require all action to be taken at endpoints. It takes time for an endpoint to deduce that there is a problem and to take corrective action. By taking action at the congested node, ACC avoids that delay.

The goals of the project are to implement congestion controls based on this idea and measure their performance improvement. Initial simulations described below show that ACC congestion controls can improve performance by as much as 18%.

The project is designing congestion controls both in simulation, using the VINT ns simulator, and by implementing an ACC enabled transport protocol in the ARP project's ASP Execution Environment.

The transport protocol we have chosen to implement is RDP, described in RFC 908, and RFC 1151. The protocol is currently running and integrated with ASP, with congestion control being added.

The following documents describe our work:

T. Faber,"ACC: Active Congestion Control," IEEE Network, IEEE, May/June 1998, pp. 61-65. ( html, ps, pdf)
T. Faber, "An Implementation of the Reliable Data Protocol for Active Networking", internal draft, html, ps, pdf)
An overview of both ACC and ARP, delivered at the DARPA Active Nets Workshop on 15 Apr 99 (ps - 1 slide/page, ps - 4 slides/page)
A discussion of how ACC and ARP are related, delivered at the DARPA Active Nets Team 2 review (ps - 1 slide/page, ps - 4 slides/page)

Here is the source code for a modified version of ns (based on ns2.1b5) that supports ACC and for scripts that create figures similar to those in the paper above.

This page written and maintained by Ted Faber [email protected]).
Please mail me any problems with, or comments about this page.