Patent ID: 7177636

Claim:
A radio terminal controlling apparatus, comprising: first receiving means for, from a radio terminal having a first communication interface for connecting to a cellular network and a second communication interface for connecting to an Internet protocol network, receiving a location registration request sent via said second communication interface; storing means for storing a correspondence between identification information on said radio terminal and an IP address based on said received location registration request; converting means for, in the case where said location registration request is not in compliance with a standard of said cellular network, converting the location registration request into a location registration message in compliance therewith; first sending means for sending to the cellular network the location registration message in compliance with the standard of said cellular network; determination means for determining whether or not the identification information on the radio terminal which is a subject of a search is stored in said storing means; and search request means for, in the case where it is determined that the identification information on said radio terminal which is the subject of the search is not stored in said storing means, sending a search request including the identification information on the radio terminal which is the subject of the search to another radio terminal controlling apparatus.