POSITION INFORMATION FOR VOIP EMERGENCY CALLS: Originating from a Wireless Metropolitan Access Network

摘要

This article describes a mechanism to provide location information about users of a wireless metropolitan access network to trusted and authorized third parties. A case of particular interest is that of providing emergency centers with the location of the VoIP caller. The location information is obtained from the wireless access points using SNMP polling, and stored in a location server. The outbound SIP proxy server requests the user's location and includes it in the SIP invite message when the callee is an emergency center.