Patent ID: 8761817

Claim:
A method comprising: receiving a request, by a network device and from a user, to deliver a short messaging service (SMS) message, to another user, wherein the other user is roaming; sending, to a first device and by the network device, a user registration query; receiving, from the first device and by the network device, a user registration response, wherein the user registration response indicates whether the other user, in which the SMS message is to be delivered, is registered with zero networks, one network, or two networks; forwarding, by the network device, the SMS message associated with the request, via at least one of the one network or the two networks, when the user registration response indicates that the other user is registered with at least one of the one network or the two networks; and sending to a second device, by the network device, another user registration query, when the user registration response indicates that the other user is registered with zero networks.