A method of routing a short message to a user device is described. An SMSC sends a routing request to a HLR or HSS of the terminating user. The HLR or HSS has static provisioning settings for users and relays the request according to these settings. The HLR or HSS relays the request to the IP-SM-GW, which dynamically determines if the terminating user has attached to an IMS network and decides accordingly on onward routing of the message over circuit switched or IMS network elements.
