Emergency services for packet networks

Abstract

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.

What is claimed is: 
     
         1 . A method of controlling access to an emergency service, comprising:
 receiving a communication session initiation request from an originator, the communication session initiation request requesting initiation of a communication session with a terminating element associated with the emergency service;   determining whether the originator is authorized to initiate the communication session;   when the originator is determined to be authorized to initiate the communication session:
 providing an indication that the originator is authorized to initiate the communication session in the communication session initiation request; and 
 forwarding the communication session initiation request including the indication toward the terminating element associated with the emergency service; 
 at least one of the receiving of the communication session initiation request and the forwarding of the communication session initiation request being via a packet network. 
   
     
     
         2 . The method of  claim 1 , comprising, when the originator is determined not to be authorized to initiate the communication session, not forwarding the communication session initiation request toward the terminating element associated with the emergency service. 
     
     
         3 . The method of  claim 1 , comprising, when the originator is determined to be authorized to initiate the communication session, creating emergency information for the communication session initiation request, wherein providing an indication that the originator is authorized to initiate the communication session in the communication session initiation request comprises adding the emergency information to the communication session initiation request. 
     
     
         4 . The method of  claim 1 , wherein the providing an indication that the originator is authorized to initiate the communication session in the communication session initiation request comprises carrying the indication in a header of the communication session initiation request. 
     
     
         5 . The method of  claim 1 , wherein the providing an indication that the originator is authorized to initiate the communication session in the communication session initiation request comprises carrying the indication in at least one parameter of the communication session initiation request. 
     
     
         6 . The method of  claim 1 , comprising determining whether the originator is authorized to initiate the communication session only when at least one network resource required to forward the communication session initiation request toward the terminating element or the terminating element is in an overload condition. 
     
     
         7 . The method of  claim 5 , when the originator is determined not to be authorized to initiate the communication session, not forwarding the communication session initiation request toward the terminating element associated with the emergency service. 
     
     
         8 . The method of  claim 7 , comprising providing a response to the originator when not forwarding the communication session initiation request toward the terminating element associated with the emergency service, the response indicating that the communication session initiation request has not been forwarded. 
     
     
         9 . The method of  claim 1 , comprising registering originators authorized to initiate communication sessions with the emergency service in response to received registration messages. 
     
     
         10 . The method of  claim 9 , wherein determining whether the originator is authorized to initiate the communication session comprises determining whether the originator is registered. 
     
     
         11 . The method of  claim 1 , comprising:
 selecting a priority level of a plurality of priority levels for association with the communication session initiation request; and   providing an indication of the selected priority level in the communication session initiation request.   
     
     
         12 . The method of  claim 1 , wherein the originator is a user of an originating device. 
     
     
         13 . The method of  claim 1 , wherein the originator is an originating device. 
     
     
         14 . The method of  claim 1 , wherein received communication session initiation request is a Session Initiation Protocol (SIP) invite message. 
     
     
         15 . The method of  claim 14 , wherein the SIP invite message is received via a packet network. 
     
     
         16 . The method of  claim 1 , wherein the forwarded communication session initiation request is a Session Initiation Protocol (SIP) invite message, and the SIP invite message is forwarded via packet network. 
     
     
         17 . The method of  claim 16 , wherein the Indication comprises information in a header of the forwarded communication session initiation request, the information indicating that the forwarded communication session initiation request is associated with an emergency communication session. 
     
     
         18 . The method of  claim 16 , wherein the Indication comprises information in at least one parameter of the forwarded communication session initiation request, the information indicating that the forwarded communication session initiation request is associated with an emergency communication session. 
     
     
         19 . The method of  claim 1 , wherein received communication session initiation request is an Initial Address Message (IAM) requesting setup of a circuit switched communication session. 
     
     
         20 . The method of  claim 19 , wherein the IAM is received via circuit switched communication network. 
     
     
         21 . The method of  claim 1 , wherein the forwarded communication session initiation request is an Initial Address Message (IAM) forwarded via a circuit switched communication network. 
     
     
         22 . The method of  claim 21 , wherein the Indication comprises emergency parameters in the IAM message. 
     
     
         23 . The method of  claim 1 , comprising encrypting the indication in the communication session initiation request before forwarding the communication session initiation request toward the terminating element. 
     
     
         24 . The method of  claim 1 , wherein the communication session initiation request is a request for a communication session of a type selected from the group consisting of data, audio, voice and video. 
     
     
         25 . The method of  claim 1 , performed at an emergency proxy connected to the packet network. 
     
     
         26 . The method of  claim 25 , wherein the emergency proxy is implemented at a gateway between a packet network and a circuit-switched communication network.