Throttling

In the case of signaling storms, the IPFE provides a configurable parameter which limits the IPFE's throughput rate and prevents the maxing out of its CPU. Throttling causes the IPFE to drop packets in order to keep the load from overwhelming the IPFE. The packet/second rate limit implementation creates an even dropping of packets that would cause client TCP/SCTP stacks to withhold their rates to just below the threshold, as happens when there is an overloaded router in the path. Throttling is on per-local-port bases, for example, each local port (such as 3868) is apportioned the configured amount.