US Patent 7072346 Network and edge router

In network for forming a VPN on a shared network and communicating via the VPN, a core network of the VPN is formed by an MPLS network, access networks for accessing the core network are formed by VLANs, and edge routers are provided between the MPLS network and VLANs for interfacing the MPLS network and the VLANs. A transmit-side edge router converts a packet, which enters from a VLAN, to an MPLS packet and transmits this MPLS packet to the MPLS network, A receive-side edge router converts the MPLS packet, which has been received from the MPLS network, to a VLAN packet and directs the VLAN packet to a VLAN that belongs to the same VPN as that of a VLAN on the transmit side.