Access Layer-2 Virtual Private Network From Layer-3 Virtual Private Network

An apparatus for accessing a layer-2 virtual private network (L2VPN) from a layer-3 virtual private network (L3VPN) on a network device, the apparatus comprising:

• a processor and a non-transitory storage medium storing machine readable instructions that are executable by the processor to:
• receive a L3VPN packet of which an egress label edge router (LER) is the network device;
• acquire an adjacency index of an adjacency entry in an adjacency table according to a destination IP address of an inner IP datagram from the L3VPN packet,
• wherein an adjacency entry in the adjacency table includes a pseudo wire (PW) extended index corresponding to a L2VPN to be accessed;
• acquire a PW extended index of a PW extended entry in a PW extended table and a private network layer-2 header for the inner IP datagram from the adjacency entry having the adjacency index,
• wherein a PW extended entry in the PW extended table includes a public network label, a private network label, a public network layer-2 header and a physical egress interface for a L2VPN to be accessed;
• encapsulate the inner IP datagram into a L2VPN packet by using the private network layer-2 header acquired from the adjacency entry having the adjacency index and the public network label, the private network label and the public network layer-2 header in the PW extended entry having the PW extended index;
• and
• transmit the L2VPN packet through the physical egress interface in the PW extended entry having the PW extended index.

A non-transitory storage medium storing machine readable instructions, wherein by executing the machine readable instructions with a processor of a network device, the processor is caused to:

• receive a L3VPN packet of which an egress label edge router (LER) is the network device;
• acquire an adjacency index of an adjacency entry in an adjacency table according to a destination IP address of an inner IP datagram from the L3VPN packet,
• wherein, an adjacency entry in the adjacency table includes a pseudo-wire (PW) extended index corresponding to a L2VPN to be accessed;
• acquire a PW extended index of a PW extended entry in a PW extended table and a private network layer-2 header for the inner IP datagram from the adjacency entry having the adjacency index,
• wherein, a PW extended entry in the PW extended table includes a public network label, a private network label, a public network layer-2 header and a physical egress interface for a L2VPN to be accessed;
• encapsulate the inner IP datagram into a L2VPN packet by using the private network layer-2 header acquired from the adjacency entry having the adjacency index and the public network label, the private network label and the public network layer-2 header in the PW extended entry having the PW extended index;
• and
• transmit the L2VPN packet through the physical egress interface in the PW extended entry having the PW extended index.