Rate and delay controlled core networks: An experimental demonstration

Growing demand for streaming, voice and interactive gaming applications emphasize the importance of quality of service (QoS) provisioning in the Internet, particularly the need for maximum end-to-end delay guarantee. Current methods of QoS provisioning have either scalability concerns or cannot guarantee end-to-end delay with acceptable packet loss unless bandwidth is over-provisioned. While low jitter guarantee is required for streaming applications, maximum end-to-end delay is also required for VoIP and interactive games. We propose, analyze the stability and demonstrate the viability of three combined rate and end-to-end delay controls. The stability analysis is done on a fluid network model with greedy flows showing that all controls are globally asymptotically stable without information time lags and one of them is also globally asymptotically stable with arbitrary time lags; however it substantivally under-utilizes the network. Another control, which numerically demonstrates stability with arbitrary time lags, is implemented in edge and core routers of our WAN-in-Lab with long haul links. The prototype implementation confirms its viability and its advantage over the Differentiated Service architecture. The viability of the two other controls is shown by detailed NS2 packet-based simulations of an eight-node real core network.