Patent ID: 7656872

Claim:
A Layer 2 Tunneling Protocol (L2TP) packet forwarding apparatus to be connected with at least two L2TP Access Concentrators (LACs) via L2TP sessions to receive Point to Point Protocol (PPP) packets each transmitted from one of gateways and forwarded by one of said LACs in the form of an L2TP packet, each of said gateways being connected to one of said LACs and accommodating at least one Local Area network (LAN) belonging to a virtual wide area network, the packet forwarding apparatus comprising: a lookup table including at least one entry which indicates the correspondence of a tunnel ID/session ID pair of an L2TP session to a Virtual Private Network identifier (VPN-ID) corresponding to said virtual wide area network to which a plurality of user terminals are connected through said LANs; and a packet forwarding processing unit which specifies the VPN-ID of a received PPP packet from said lookup table, based on the tunnel ID and the session ID indicated in an L2TP header added to the received PPP packet and which rewrites, if another tunnel ID/session ID pair associated with the same VPN-ID exists in said lookup table, the tunnel ID and the session ID of the L2TP header to said another tunnel ID/session ID pair and forwards the received PPP packet to another LAN of said virtual wide area network through another L2TP session between the L2TP packet forwarding apparatus and one of said LACs, which is specified by said another tunnel ID/session ID pair, in the form of an L2TP packet including said another tunnel ID/session ID pair in its L2TP header.