To lessen the load and working resources without being restrained on communications with other apparatus in a communication network using the IPv6.
The IPv6 communication system has a repeater 400 between the same link network 800 and a compact terminal 500. The repeater 400 stores IPv6 addresses of a router 100, terminals 200, 300 and the compact terminal 500, related to their link layer addresses one to one. It detects whether the IPv6 address of the compact terminal 500 and the IPv6 address of the terminal are doubled, using neighbor retrieving packets of the IPv6. If a doubled address is detected, the repeater forms a new IPv6 address and stores it related to the IPv6 address of the compact terminal 500. Thus the repeater 400 executes the neighbor retrieval and the routing over the same link network 800 by the IPv6 communication instead of the compact terminal 500.
Hiroshi Shimura
Michio Nagai