A method is provided for facilitating recovery from the failure of a P-CSCF within an IP multimedia Subsystem network. A gateway, such as a GGSN, monitors signals arriving at the gateway from the P-CSCF and provides an indication if the monitored signals become unacceptable, for example because of an interruption in the signals. The gateway responds by signalling the unavailability of the P-CSCF to user equipment, which was associated with the P-CSCF during a previous registration with the IMS network. In response, for example, the user equipment affected by the failure may request re-registration with the IMS network using a different available P-CSCF.