Recovery of established emergency calls

摘要

A system, method and apparatus for re-establishing a call received at a public safety answering point are described. A Session Initiation Protocol (SIP) call establishment request is received at an emergency call answer node. The call establishment request has an indication of a previously established emergency call to re-establish. The emergency call answer node searches a call recovery queue for a previously received call establishment request having a matching indication for the previously established emergency call to re-establish. The emergency call answer node bridges a call leg for the received call establishment request and a call leg for the previously received call establishment request having the matching indication for the previously established emergency call to re-establish when a match is found.

主权项

1. A method of re-establishing a call received at a public safety answering point comprising:
receiving an emergency call establishment request at a Session Initiation Protocol (SIP) proxy, the call originating from caller device; directing, from the SIP proxy, establishment of a call leg for the emergency call between a first emergency call answer node and an emergency call operator workstation; directing, from the SIP proxy, establishment of a call leg for the emergency call between the first emergency call answer node and an emergency call gateway; detecting at the SIP proxy a failure of the first emergency call answer node during the emergency call from the caller device wherein detecting the failure of the first emergency call answer node at the SIP proxy comprises:
using a heartbeat signal between the first emergency call answer node and the SIP proxy; andmonitoring a real-time transport protocol (RTP) stream between the first call answer node and the operator workstation; causing, with the SIP proxy, transmittal of one of the call establishment request or the previously received call establishment request to a second emergency call answer node; receiving the SIP call establishment request at the second emergency call answer node, the call establishment request having an indication of a previously established emergency call to re-establish; searching at the second emergency call answer node a call recovery queue at the second emergency call answer node for a previously received call establishment request having a matching indication for the previously established emergency call to re-establish; and bridging at the second emergency call answer node a call leg for the received call establishment request and a call leg for the previously received call establishment request having the matching indication for the previously established emergency call to re-establish when a match is found.