MOBILITY WITHIN A PACKET-SWITCHED TELEPHONY NETWORK

摘要

According to an embodiment of the present invention, a system is provided that includes a cellular network, a Public Switched Telephone Network (PSTN) and a mobile IP-telephony network (MIPTN). Both the cellular network and the MIPTN include a Home Function and one or more visited Functions. MIPTN subscribers can roam within the MIPTN. Also, a Gateway Function interfaces the PSTN and the MIPTN to allow roaming between the cellular network and the MIPTN. The Gateway Function performs a dynamic mapping function between PSTN/cellular addresses (e.g., in E.164 format) and MIPTN addresses (e.g., IP addresses) to allow registration and call delivery for subscribers roaming between the cellular network and the MIPTN. A similar type of Gateway Function also allows Short Message Service (SMS) messages to be delivered over the MIPTN as well.