US Patent 7924812 Domain and service based update messaging

A communication network comprising a plurality of domains, a first location server of a first domain of the plurality of domains, and a first gateway coupled to the first location server and configured to interwork communications between the first domain and a second domain of the plurality of domains wherein the plurality of domains provide a plurality of services. The first gateway, responsive to a first status change associated with a first service of the plurality of services provided by the second domain, transfers a first update message to the first location server wherein the first update message indicates the first gateway, the first status change, the second domain, and the first service. The first location server, responsive to receiving the first update message, processes the first update message to determine a third domain of the plurality of other domains that provides the first service and transfers a second update message to a second location server of the third domain wherein the second update message indicates the first gateway, the first status change, the second domain, and the first service.