US Patent 7899174 Emergency services for packet networks

The present invention provides a technique for facilitating emergency services via packet networks. Emergency service providers will implement emergency proxies to ensure that proper call setup requests for emergency services are forwarded to the appropriate entities, even if those entities are in overload conditions. The emergency proxies may authenticate and filter call setup requests to ensure that only proper call setup requests are forwarded to help prevent such overload conditions. The emergency proxies may operate solely in a packet network, as well as at the interface between a packet network and a circuit-switched network to assist in call setup requests originating from either the packet network or the circuit-switched network.