Stochastic Analysis of Some Expedited Forwarding Networks

Abstract— We consider stochastic guarantees for networks with aggregate scheduling, in particular, Expedited Forwarding (EF). Our approach is based on the assumption that a node can be abstracted by a service curve, and the input flows are regulated individually at the network ingress. Both of these assumptions are inline with the current definition of EF [1], [2]. We derive bounds to the complementary distributions of the backlog, delay through a single node, and the end-to-end delay. We also give a bound on the lossratio. Our analysis is exact under the given assumptions. Our results should help us to understand the performance of networks with aggregate scheduling, and provide the basis for dimensioning such networks. Keywords— Expedited Forwarding, diffserv, Aggregate Scheduling, Statistical Multiplexing, Stochastic QoS, Service Curve, Packet Scale Rate Guarantee, Queueing, Loss Ratio