A method for performing initial registration is provided. The method includes receiving a server timeout message, the server timeout message including at least a field set to a value equal to a value received during a first registration. The method further includes initiating restoration procedures by performing an initial registration.

A method for performing initial registration is provided. The method includes receiving a server timeout message, the server timeout message including at least a field set to a value equal to a value received during a first registration. The method further includes initiating restoration procedures by performing an initial registration.

An apparatus for wireless communication of a user equipment (UE) is disclosed. The apparatus may include a memory and at least one processor coupled to the memory. The at least one processor may be configured to receive a paging signal associated with an mobile terminating (MT) internet protocol (IP) multimedia subsystem (IMS) voice session. The at least one processor may be further configured to send a session initiation protocol (SIP) message in response to the paging signal. The at least one processor may be further configured to receive a second SIP message indicating SIP failure. The at least one processor may be further configured to determine whether the second SIP message indicates a network failure or a global failure. The at least one processor may be further configured to establish a connection with a different RAT network when the second SIP message indicates a network failure or a global failure.

An apparatus for wireless communication of a user equipment (UE) is disclosed. The apparatus may include a memory and at least one processor coupled to the memory. The at least one processor may be configured to receive a paging signal associated with an mobile terminating (MT) internet protocol (IP) multimedia subsystem (IMS) voice session. The at least one processor may be further configured to send a session initiation protocol (SIP) message in response to the paging signal. The at least one processor may be further configured to receive a second SIP message indicating SIP failure. The at least one processor may be further configured to determine whether the second SIP message indicates a network failure or a global failure. The at least one processor may be further configured to establish a connection with a different RAT network when the second SIP message indicates a network failure or a global failure.

In an example embodiment, a solution that allows a PBX to utilize bridged mobile or desktop applications for collaboration and softphone use is provided. The solution works in conjunction with existing hardwired PBX devices without requiring additional hardware such as an edge router to be integrated with the PBX hardware. Incoming calls are able to ring a user's hardwired device, such as a desk phone at an office, while simultaneously ring mobile device or desktop applications (apps). App users can place outbound PSTN calls and dial PBX extensions just as if they were using their hardwired device. Additionally, PSTN services are utilized from the existing PBX rather than bypassing the existing PBX, which makes tracking and billing more straightforward. A Session Initiation Protocol (SIP) tie trunk is used between the existing PBX and a software bridge controller.

In an example embodiment, a solution that allows a PBX to utilize bridged mobile or desktop applications for collaboration and softphone use is provided. The solution works in conjunction with existing hardwired PBX devices without requiring additional hardware such as an edge router to be integrated with the PBX hardware. Incoming calls are able to ring a user's hardwired device, such as a desk phone at an office, while simultaneously ring mobile device or desktop applications (apps). App users can place outbound PSTN calls and dial PBX extensions just as if they were using their hardwired device. Additionally, PSTN services are utilized from the existing PBX rather than bypassing the existing PBX, which makes tracking and billing more straightforward. A Session Initiation Protocol (SIP) tie trunk is used between the existing PBX and a software bridge controller.

In a LTE network user devices can access voice application service via Voice over LTE (VoLTE) and Voice over WiFi (VoWiFi). To detect faults in the data link associated with an evolved packet data gateway for providing access by the user device to the LTE network from a non-trusted network which will affect VoWiFi capability, a packet data gateway monitors the status of ePDG and if a fault is detected, the user device is notified that it should connect to voice services via VoLTE.

In a LTE network user devices can access voice application service via Voice over LTE (VoLTE) and Voice over WiFi (VoWiFi). To detect faults in the data link associated with an evolved packet data gateway for providing access by the user device to the LTE network from a non-trusted network which will affect VoWiFi capability, a packet data gateway monitors the status of ePDG and if a fault is detected, the user device is notified that it should connect to voice services via VoLTE.

A technique for enabling signaling message correlation in a telecommunication network is disclosed. A method implementation of the technique is performed by a network node in the telecommunication network and includes receiving a first signaling message as part of a signaling procedure among a plurality of network nodes in the telecommunication network, the first signaling message being transmitted using a first signaling protocol and including a correlation identifier being propagated along a message flow of the signaling procedure, and triggering transmitting a second signaling message as part of the signaling procedure using a second signaling protocol different from the first signaling protocol, wherein the correlation identifier of the first signaling message is incorporated into the second signaling message for further propagation.

A technique for enabling signaling message correlation in a telecommunication network is disclosed. A method implementation of the technique is performed by a network node in the telecommunication network and includes receiving a first signaling message as part of a signaling procedure among a plurality of network nodes in the telecommunication network, the first signaling message being transmitted using a first signaling protocol and including a correlation identifier being propagated along a message flow of the signaling procedure, and triggering transmitting a second signaling message as part of the signaling procedure using a second signaling protocol different from the first signaling protocol, wherein the correlation identifier of the first signaling message is incorporated into the second signaling message for further propagation.