Patent ID: 8565760

Claim:
A method for recovering registration information at a home network, the method comprising: communicating, from the home network, a triggering message to a visited network to initiate registration information recovery; determining, at the visited network in response to the triggering message, a sub-set of subscriber units are associated with the home network; communicating, from the visited network in response to the triggering message, re-registration request messages to the sub-set of subscriber units, wherein each of the re-registration request messages commands a particular one of the sub-set of subscriber units to re-register with the visited network and comprises either: a subscriber unit identifier for that particular subscriber unit, or one or more talk group identifiers for talk groups that the particular subscriber unit is affiliated with; receiving, in response to the communicating the re-registration request messages, register messages from each of the sub-set of subscriber units, wherein each register message comprises registration information including either: a subscriber unit identifier for a particular subscriber unit or talk group identifiers for each talk group that the particular subscriber unit belongs to; communicating, from the visited network, one or more registration request message(s) to the home network, wherein the registration request messages are generated based on the register messages that were received from the sub-set of subscriber units, wherein each registration request message includes the registration information that comprises either a subscriber unit identifier corresponding to a particular one of the sub-set of subscriber units, or one or more talk group identifiers that correspond to a particular one of the sub-set of subscriber units; and restoring the registration information at the home network based on the registration information provided in the one or more registration request message(s).