Traffic Shaping via Congestion Signals Delegation

This paper presents a new architecture that enables a set of clients to enforce traffic shaping policies among them through the delegation of congestion signals. When congestion-aware Internet flows share a bottleneck link, they compete for bandwidth and must respond to congestion signals promptly by decreasing their throughput. For clients running real-time applications (e.g., gaming, streaming), this may impose strict limitation on their achievable throughput over short time-scales. To that end, this paper presents an architecture, whereby a set of TCP connections (we refer to them as the Stunts) sacrifice/trade their performance on behalf of another TCP connection (we refer to it as the Free) by picking up a delegated subset of the congestion signals and reacting to them in lieu of the Free connection. This gives the Free connection just enough freedom to meet specific throughput requirements as requested by the application running on top, without affecting the level of congestion in the network. We present numerical model and analysis, which we validate by extensive simulation as well as through a pluggable module implementation for the Linux kernel. Keywords-Service-oriented architecture; TCP; Congestion Control; Traffic Shaping; Control Theory;