Patent attributes
A user (terminal) is allowed to make an emergency voice-over-Internet Protocol (VoIP) phone call through an access network, such as a wireless local area network (WLAN) using Extensible Authentication Protocol (EAP). The emergency call can be made with or without authentication credentials and is identified by the user's terminal transmitting a Network Access Identifier (NAI) having a user part and/or realm part that indicates the emergency nature of the call, such as e911@e911.com. In response to such an NAI, the caller can be immediately granted limited authentication for the purpose of connecting to an emergency call center. Alternatively, the user (terminal) can be authenticated through networks supporting emergency calls, such as the user's home network, if the terminal indicates to the access network authentication server a preference or requirement for using such networks. The call can be routed to the emergency call center either directly or via one or more intermediary networks, such as networks that support emergency VoIP phone calls.
