Patent ID: 7689234

Claim:
A method, with a short message service center operating in a wireless communication system comprising a plurality of wireless devices, for transmitting at least one short messaging service message to at least one wireless device, the method comprising: receiving at least one short message service message request associated with a short message service message destined for reception by a wireless device; locally maintaining, prior to receiving the request, registration information indicating whether the wireless device is registered with a registrar associated with a session initiation protocol network for communicating over a packet data network; determining, based on the locally maintained information, whether the wireless device is registered with the registrar; transmitting, in response to the request and with the determination that the wireless device is registered with the registrar, the short message service message to the wireless device through the session initiation protocol network communicating over the packet data network; determining if the transmission through the packet data network was successful; and transmitting, in response to the transmission being unsuccessful, the short message service message to the wireless device through a circuit services network.