Patent ID: 7848767

Claim:
A method for routing short message service (SMS) messages in a network in which subscribers have subscriptions of both first and second application layer mobile signaling protocols concurrently and use the same directory number for both application layer mobile signaling protocols, the method comprising: (a) receiving, at a short message service center (SMSC), an SMS message to be delivered to a subscriber of both the first and second application layer mobile signaling protocols concurrently; (b) sending, from the SMSC, a request for SMS routing information in the first application layer mobile signaling protocol, the request for SMS routing information including a directory number corresponding to the subscriber of both the first and second application layer mobile signaling protocols; (c) at a node distinct from a home location register (HLR), a visitor location register (VLR), and the SMSC, receiving the request for SMS routing information and determining whether the subscriber is registered according to the first application layer mobile signaling protocol or the second application layer protocol; and (d) in response to determining that the subscriber is registered according to the first application layer mobile signaling protocol, routing the request for SMS routing information from the node to an HLR of the first application layer mobile signaling protocol.