Patent ID: 7054319

Claim:
A router connected a core network, a first local area network (LAN) belonging to a first virtual private network (VPN), a second LAN belonging to a second VPN, a third LAN belonging to a third VPN and a fourth LAN belonging to a fourth VPN, comprising: a memory; a first interface for accommodating a first line connected to the first LAN and the second LAN, and for receiving multiplexed IP packets from the first and the second LANs via the first line, the IP packets from the first and the second LANs being encapsulated by a first protocol; a second interface for connected to the core network; means for identifying which of the first VPN and the second VPN to which an IP packet received at the first interface belongs by header information of the first protocol; and means for registering, in the memory, header information of the first protocol as a VPN identifier for identifying which of the first VPN and the second VPN to which an IP packet received from the first line belongs, wherein IP packets from the third and the fourth LANs being encapsulated by a second protocol different from the first protocol.