Layer two and layer three virtual private network support in a network device

1 . A network device for processing data on a data network, the network device comprising:

a port interface, in communication with a plurality of ports, configured to receive a data packet from a data network and to send a processed data packet to an egress port of the plurality of ports;

a memory management unit, in communication with the port interface and controlling a memory; and

a search engine, in communication with the port interface and the memory management unit, configured to perform searches of lookup tables and to return search results to assist in modifying the received data packet to produce the processed data packet;

wherein the port interface is configured to assign a virtual forwarding instance (VFI) identifier for the data packet when received and configured to perform appropriate encapsulation of the processed data packet based on the VFI identifier.

2 . The network device according to claim 1 , wherein the port interface is configured to assign the VFI identifier based upon at least one of an ingress port and a virtual local area network indicator for the data packet.

3 . The network device according to claim 1 , wherein the port interface is configured to assign the VFI identifier when the data packet is a layer two switched data packet.

4 . The network device according to claim 1 , wherein the port interface is configured to add a virtual channel label or a Multi-protocol Label Switching label to the processed data packet.

5 . The network device according to claim 1 , wherein port interface is configured to maintain an old Quality-of-Service of the received data packet for the processed data packet through encapsulation.

6 . A method for processing data in a network device, the method comprising the steps of:

receiving a data packet at one port of a plurality of ports;

assigning a virtual forwarding instance (VFI) identifier for the received data packet;

storing the received data packet and the attached pointer by a memory management unit in a memory;

retrieving the received data packet and the attached pointer from the memory;

searching lookup tables using the attached pointer;

obtaining search results;

modifying the received data packet to form a processed data packet based on the search results;

performing appropriate encapsulation of the processed data packet based on the VFI identifier; and

forwarding processed data to an egress port of the plurality of ports.

7 . The method according to claim 6 , wherein the step of assigning the VFI identifier is based upon at least one of an ingress port and a virtual local area network indicator for the data packet.

8 . The method according to claim 6 , wherein the step of assigning the VFI identifier is performed when the data packet is a layer two switched data packet.

9 . The method according to claim 6 , wherein the step of performing appropriate encapsulation comprises adding a virtual channel label or a Multi-protocol Label Switching label to the processed data packet.

10 . The method according to claim 6 , wherein the step of performing appropriate encapsulation comprises maintaining an old Quality-of-Service of the received data packet for the processed data packet through encapsulation.

11 . A network device for processing data, the network device comprising:

port means for receiving a data packet at one port of a plurality of ports and sending a processed data packet to an egress port of the plurality of ports;

VFI means for assigning a virtual forwarding instance (VFI) identifier for the received data packet;

memory means for storing the received data packet and the attached pointer in a memory and retrieving the received data packet and the attached pointer from the memory;

searching means for lookup tables using the attached pointers and obtaining search results;

modifying means for modifying the received data packet to form a processed data packet based on the search results; and

encapsulation means for performing appropriate encapsulation of the processed data packet based on the VFI identifier.

12 . The network device according to claim 11 , wherein the VFI means is configured to assign the VFI identifier based upon at least one of an ingress port and a virtual local area network indicator for the data packet.

13 . The network device according to claim 11 , wherein the VFI means is configured to assign the VFI identifier when the data packet is a layer two switched data packet.

14 . The network device according to claim 11 , wherein the encapsulation means comprises means for adding a virtual channel label or a Multi-protocol Label Switching label to the processed data packet.

15 . The network device according to claim 11 , further comprising means for maintaining an old Quality-of-Service of the received data packet for the processed data packet through encapsulation.