Low-impact call connection request denial

Abstract

A policy enforcement point (PEP) attaches to the edge of a packet-switched network to manage loading when the network nears or exceeds its capacity due to changes in the network, e.g., component failures or incremental growth. Autonomous PEP's at the network's edges provide short-term, application-aware controls on their own that are applied to the corresponding network ingress traffic. Changes become necessary when a network event results in a loss of resilient bandwidth that effects the traffic class under admission control. Or, when an unexpected surge in traffic exceeds the PEP's reserved resources to a particular destination. The resources available across the network are recalculated for minimizing impact on existing sessions or calls, and it informs the PEP's of the new resources available. If the new maximum exceeds the current utilization to that destination, the PEP invokes a local priority drop mechanism to back off the traffic until it is under the new limit. A media gateway handling voice calls can keep all emergency calls up, and then invoke a local algorithm, such as random drop, for the remaining calls until calls to the constrained destination are under the new limit. In the second case, where there is an unexpected surge in demand, the PEP can request from the bandwidth manager additional resources to a particular destination.