Network address converting apparatus and storage medium therefor

Claim 2

A network address converting apparatus according to Claim 1, comprising: data analyzing means 11 which receives data transmitted between said external host server 1 and a client 6 or 7 and analyzes the type, the destination, and the sender of said data; IP address assigning means 12 which, if said data analyzing means 11 determines that said received data is an Internet IP address assignment request signal sent from said external host server 1, selects one of a plurality of Internet IP addresses stored in advance in said IP address assigning means 12 and assigns the selected Internet IP address to the client which is requested to be assigned an Internet IP address by said Internet IP address assignment request signal; address conversion table producing means 13 for producing an address conversion table in such a manner that each time said IP address assigning means 12 assigns an Internet IP address to a client 6 or 7, said address conversion table producing means 13 stores in a relational fashion said Internet IP address assigned to said client and the client's address defined in said local network 4; and address conversion means which, each time said IP address assigning means 12 assigns an Internet IP address to a client 6 or 7, sends the assigned Internet IP address to the sender of said Internet IP address assignment request signal, and which, if said data analyzing means 11 determines that said received data is addressed to the Internet IP address assigned to said client, converts the Internet IP address designating the destination of said data to the corresponding address defined in said local network 4 by referring to said address conversion table.

Claim 3

A network address converting apparatus for converting a source address or a destination address included in data transmitted between an external host server 1 connected to the Internet 2 and a mobile terminal 23 within a radio communication network system, said radio communication network system including a plurality of subnetworks 20-1 to 20-3 each including at least one mobile terminal 23 and at least one wireless server 21-1, 21-2, or 21-3 connected via radio communication to said at least one mobile terminal 23, said mobile terminal 23 being movable among said plurality of subnetworks 20-1 to 20-3, each wireless server 21-1, 21-2, or 21-3 storing and managing the Internet IP address of a wireless server 21-1, 21-2, or 21-3 which controls a subnetwork in which one or more mobile terminals, for which the wireless server serves as the home server, are currently located, said network address converting apparatus being characterized in that: said network address converting apparatus is provided for each said wireless server 21-1, 21-2, or 21-3; and said network address converting apparatus operates in such a manner that: when an inquiry signal about the current location of a particular mobile terminal is sent from an external host server 1 to a home server of said particular mobile terminal, if said network address converting apparatus receives said inquiry signal, it notifies said external host server 1 of the Internet IP address of the wireless server 21-1, 21-2, or 21-3 which controls a subnetwork in which said particular mobile terminals is currently located; when an assignment request signal requesting assignment of an Internet IP address to said particular mobile terminal is received from said external host server 1, said network address converting apparatus assigns an Internet IP address to said particular mobile terminal and notifies said external host server 1 of said assigned Internet IP address; and when data addressed to said assigned Internet IP address is received from said external host server 1, said network address converting apparatus converts the destination of the received data to said particular mobile terminal's address defined in the subnetwork in which said particular mobile terminal is currently located.

Claim 4

A network address converting apparatus according to Claim 3, comprising: data analyzing means 11 which receives data transmitted between said mobile terminal and said external host server 1 connected to the Internet 2 and analyzes the type, the destination, and the sender of said data; current location retrieving and notifying means 15 which, if said data analyzing means 11 determines that said received data is an inquiry signal about the current location of a particular mobile terminal sent from said external host server 1, searches the mobile terminals stored in the respective wireless servers 21-1, 21-2, and 21-3 and the Internet IP addresses of wireless servers 21-1 to 21-3 controlling subnetworks 20-1 to 20-3 in which the respective terminals are currently located so as to detect the Internet IP address of the wireless server which controls the subnetwork in which said particular mobile terminal is currently located, and sends the detected Internet IP address to the sender of said inquiry signal; IP address assigning means 12 which, if said data analyzing means 11 determines that said received data is an Internet IP address assignment request signal sent from said external host server 1, selects one of a plurality of Internet IP addresses stored in advance in said IP address assigning means 12 and assigns the selected Internet IP address to the mobile terminal which is requested to be assigned an Internet IP address by said Internet IP address assignment request signal; address conversion table producing means 13 which, each time said IP address assigning means 12 assigns an Internet IP address to a mobile terminal 23, stores in a relational fashion said Internet IP address assigned to said mobile terminal and the mobile terminal's address defined in the subnetwork in which said mobile terminal is located; and an address converter 14 which, each time said IP address assigning means 12 assigns an Internet IP address to a mobile terminal, sends the assigned Internet IP address to the sender of said Internet IP address assignment request signal, and which, if said data analyzing means 11 determines that the received data is addressed to the destination designated by the Internet IP address assigned to said mobile terminal, refers to said address conversion table and converts the Internet IP address designating the destination of said data to the corresponding address defined in said subnetwork.

Claim 5

A computer readable storage medium storing a network address conversion program executed by a computer to convert a source address or a destination address included in data transmitted between an external host server 1 connected to the Internet 2 and a client 6 or 7 within a local network 4, said network address conversion program including: a first step in which, when an assignment request signal requesting assignment of an Internet IP address to a particular client within said local network 4 is received from said external host server 1, an Internet IP address is assigned to said particular client, and said assigned Internet IP address is sent to said external host server 1; and a second step in which, if data addressed to the destination designated by the Internet IP address assigned in said first step is received, the destination at said received data is converted to said particular client's address defined in said local network 4.