Transparent PSTN failover

摘要

Novel tools and techniques for implementing Transparent PSTN Failover. In some embodiments, a VoIP switch might receive a call request for connection between a calling party at a calling telephone number (“TN”) and a called party at a called TN. Based on a determination that connection via a session border controller (“SBC”) between the VoIP switch and an Internet Protocol (“IP”) gateway has been lost, the VoIP switch might route the call request to a PSTN redirect TN through the PSTN. One of the Class 5 switch of the PSTN or the IP gateway might replace the redirect TN with the called TN, based on a determination that the redirect TN represents a PSTN failover. The IP gateway may then route the call request to an IP PBX for terminating (establishing) the call connection between calling party and called party, without interception by an operator, receptionizt, or auto attendant.

主权项

1. A method for implementing transparent PSTN Failover, comprising:
receiving, with a Voice over Internet Protocol (“VoIP”) switch, a first Session Initiation Protocol (“SIP”) invite from an originating telephone at a calling telephone number (“TN”) associated with a calling party for establishing a call connection between the calling party and a called party at a called TN of a destination telephone at a customer premises; determining, with the VoIP switch, whether communication via a session border controller (“SBC”) between the VoIP switch and an Internet Protocol private branch exchange (“IP PBX”) associated with the called TN has been lost, prior to establishing the call connection; based on a determination that communication between the VoIP switch and the IP PBX has been lost, sending, with the VoIP switch, a second SIP invite to a voice gateway, based on a redirect TN associated with the customer premises; sending, with the voice gateway, call information that is associated with the redirect TN to a Class 5 switch of a public switched telephone network (“PSTN”); sending, with the Class 5 switch of the PSTN, the call information to an IP gateway over a primary rate interface (“PRI”), wherein the call information sent to the IP gateway over a data channel of the PRI comprises the calling TN, the called TN, and the redirect TN; receiving, with the IP gateway, the call information; determining, with the IP gateway, whether the call information indicates that the inbound call from the PSTN is a failover call, based on a determination that the redirect TN is associated with a PSTN failover; based on a determination that the inbound call is a failover call, replacing, with the IP gateway, the redirect TN with the called TN in a header of a third SIP invite associated with the redirect TN, to generate a fourth SIP invite associated with the called TN; sending, with the IP gateway, the fourth SIP invite to the IP PBX; establishing, with the IP PBX, the call connection between the originating telephone at the calling TN and the destination telephone at the called TN, without interception by an operator, a receptionist, or an auto attendant.