Patent ID: 7447221

Claim:
A communication apparatus to be used between a first communication group including one or two or more communication terminals that perform communications by a first type of communication protocol and a second communication group including one or two or more communication terminals that perform communications by a second type of communication protocol capable of embedding address information for use in the first communication group, comprising: a first storage unit, in which a destination address to the first communication group or the second communication group, and tunnel identification information for identifying attribute information of a route specified by address information for use in the first communication group when a packet transmitted from the second communication group via the first communication group to another second communication group is encapsulated by the address information for use in the first group and passed through the first communication group, are registered; a destination retrieval unit which makes retrieval as to whether or not a destination address extracted from the received packet is registered in the first storage unit; a second storage unit, in which communication enable/disable information indicating whether or not the route on the first communication group, the route being designated by using the tunnel identification information, is constructible by a private address or whether or not the route is constructible by a global address, is registered; an encapsulation processing unit which extracts the address information for use in the first communication group from the destination address to encapsulate the packet; and a control unit which makes control as to whether or not the encapsulation is to be performed in accordance with the communication enable/disable information of the second storage unit.