Stochastic analysis of some Expedited Forwarding networks

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 in line with EF. For a service curve node, we derive bounds on the complementary distributions of the steady-state backlog and backlog as seen by packet arrivals. We also give a bound on the long-run loss ratio for a service curve node where the buffer size is too small to guarantee loss-free operation. For a packet scale rate guarantee node, we use the delay from the backlog bound to obtain a probabilistic bound on the delay. 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.