Patent ID: 11252200

Abstract:
Described herein are apparatus and methods for detecting and handling Proxy-Call Session Control Function (P-CSCF) failures. A method may include sending, by a serving-CSCF (S-CSCF), a message to the P-CSCF to check operability. The S-CSCF may mark in a list that the P-CSCF is unavailable if a negative response or no response is received from the P-CSCF and may set a timer to recheck availability of the unavailable P-CSCF. A message is sent by the S-CSCF to a device management system to force a user device to stop using the unavailable P-CSCF and register with a different P-CSCF. The S-CSCF may recheck availability of the unavailable P-CSCF upon expiration of the timer and may remove the unavailable P-CSCF from the list when a positive response is received from the unavailable P-CSCF.