Benefit of Higher Priority for National Security / Emergency Preparedness Calls In Signaling System Number 7 Jansen Szeto GTE Government Systems Charles Krafthofer GTE Government Systems

Signaling System Number 7 (SS7) is a packet switched network protocol for signaling call set-up (and teardown) in the Public Switched Network (PSN). SS7 includes priorities for different types of signaling messages that determine how the messages are handled during conditions of severe signaling network congestion. Simulation results of modeling the behavior of the SS7 congestion control mechanism indicate that significant improvement in the likelihood of completing National Security / Emergency Preparedness (NS/EP) calls is gained by assigning the SS7 Initial Address Message (IAM) of NS/EP calls a priority of one and the IAM of Plain Old Telephone Service (POTS) calls a lower priority of zero, even while keeping all other SS7 messages associated with call set-up their normal priorities.