Aggregate congestion control for distributed multimedia applications

Abstract

We consider the problem of applying aggregate congestion control to a class of distributed multimedia applications known as Cluster-to-Cluster (C-to-C) applications. Flows in such an application share a common intermediary path that is the primary source of network delay and packet loss. Using the Coordination Protocol (CP) architecture, we show how aggregate congestion control can be achieved with the following properties: Almost any rate-based, single-flow congestion control algorithm may be applied to make aggregate C-to-C traffic congestion responsive. C-to-C applications may use multiple flow bandwidth shares and still exhibit correct aggregate congestion responsiveness. C-to-C applications may implement complex, application-specific adaptation schemes in which the behavior of individual flows is decoupled from the behavior of the congestion responsive aggregate flow. Bandwidth filtered loss detection (BFLD) is presented as a technique for making single-flow loss detection algorithms work when aggregate traffic uses multiple flowshares. The approach is evaluated using both ns2 simulation and an experimental implementation in Free BSD and Linux. Results demonstrate its success for a wide range of network conditions.