Patent ID: 7047314

Claim:
In a duplicate address translating system which uses private addresses based on a specific protocol in respective private networks and also connects a plurality of private networks, which permit duplicate assignment of private addresses between respective private networks, with a global network which uses a global address based on said specific protocol, the improvement comprises: an address translating means for performing, in said plurality of private networks, for communications data having identification information for identifying the respective private networks, mutual translation between said plurality of private addresses and said global address with a combination of said identification information and said private addresses, wherein said address translating means comprises; a switching hub which performs, for communications data having VLAN-IDs for identifying virtual LAN groups that are realized inside said plurality of private address networks, switching based on said VLAN-IDs and a duplicate network address translating device which performs, for frames which are to be switched by said switching hub and have private addresses and VLAN-IDs, mutual translation between said private addresses and said global address with a combination of said VLAN-IDs and said private addresses.