Patent ID: 9345060
Filing Date: 2016-05-17
CPC Classification: H04W

Claim Text:
1. In a communication system comprising a first radio access network (RAN) configured to serve user equipment devices (UEs) according to a first air interface protocol, a second RAN configured to serve UEs according to a second air interface protocol, and a network node through which voice over Internet Protocol (VoIP) signaling packets normally flow between the first RAN and a VoIP call server on a packet-switched network, a method comprising: detecting by the node (i) that a UE served by the first RAN is attempting VoIP call setup to a call destination, and (ii) failure of the VoIP call setup, wherein detecting that the UE is attempting the VoIP call setup and failure of the VoIP call setup comprises receiving a request to establish a dedicated VoIP bearer for the UE and detecting failure to set up the dedicated VoIP bearer, wherein the node is a gateway that provides connectivity between the first RAN and the packet-switched network, and wherein the dedicated VoIP bearer is between the UE and the gateway; and responsive to the detecting, signaling by the node to invoke setup of an alternate call between the UE and the call destination via the second RAN.