Method and apparatus for virtual overlay networks

• US 7,095,740 B1
• Filed: 06/30/1998
• Issued: 08/22/2006
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Avaya Management L.P. (Avaya Incorporated)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Doraswamy, Naganand, Jagannath, Shantigram, Fredette, Andre
• Primary Examiner(s): LEE, CHI HO A
• Application Number:
  US09/109,343
• Time in Patent Office: 2,975 Days
• Field of Search: 370/389, 370/392, 370/393, 370/400, 370/401, 370/397
• US Class Current: 370/392
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 12/4675 Dynamic sharing of VLAN information amongst network nodes configuration of the network or of network elements H04L41/08
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/54 Organization of routing tables

Abstract

A method and apparatus for directing messages through a network wherein multiple tables for directing messages through the network are maintained and provided. Each table corresponds to a virtual private network and contains routing information specific to that virtual private network. A separate routing table is maintained for each VPN. In one embodiment the messages are forwarded using plain IP forwarding using a route table associated with the VPN. In another embodiment separate forwarding tables using labels are generated for each virtual private network. The messages are forwarded by looking up the label in the table corresponding to the VPN In a third embodiment, a single forwarding table is utilized where the table is built based on separate routing tables for each virtual private network.

Claims

1. A router for routing a packet belonging to a virtual private network (VPN) and having a label that includes a virtual private network identifier (VPN-ID) according to the Multiprotocol Label Switching (MPLS) standard and a forwarding label, the router comprising:

a) a first forwarding table associated with the VPN, from among one or more separate forwarding tables, each forwarding table associated with a different VPN; and

b) a processor for routing the packet based on an association between the VPN-ID), the forwarding label, and the first forwarding table.

2. The router as recited by claim 1 wherein the forwarding table includes a portion of a route table.

3. The router as recited by claim 1 further having a port for transmitting said packet.

4. A method of routing a packet in a network, the packet belonging to a virtual private network (VPN) and having a label that includes a virtual private network identifier (VPN-ID) according to the Multiprotocol Label Switching (MPLS) standard and a forwarding label, the method comprising:

a) maintaining a first forwarding table corresponding to a first virtual private network;

b) maintaining a second forwarding table corresponding to a second virtual private network; and

c) routing the packet based on an association between the VPN-ID, the forwarding label, and one of the first forwarding table and the second forwarding table.

5. The method of claim 4, wherein the VPN-ID is contained in a first label in the header.

6. The method of claim 4, wherein the routing of the packet is based on information in the header.

7. The method of claim 4 wherein the first forwarding table includes a first portion of a route table and the second forwarding table includes a second portion of the route table.

8. The method of claim 7 further comprising:

identifying, from the forwarding table, label switching information for routing the packet to the VPN.

9. The method of claim 4, wherein routing of the packet is based on information in the forwarding table.

10. A network comprising:

a) a first edge router configured to route a packet through a wide area network cloud, the packet belonging to a virtual private network (VPN), having a label that includes a virtual private network identifier (VPN-ID) according to the Multiprotocol Label Switching (MPLS) standard, and a second label identifying forwarding table corresponding to the virtual private network, the forwarding table including a portion of the route table;

b) a backbone router configured to receive the packet and route the packet based on a route table associated solely with the VPN-ID, from among one or more separate route tables, each table associated with a different VPN; and

c) a second edge router configured to receive the packet.

11. The network as recited by claim 10 wherein the label farther includes a forwarding label.

12. The network as recited by claim 10 wherein the backbone router comprises a second route table.

13. A method of routing a packet belonging to a virtual private network (VPN) and having a label that includes a virtual private network identifier (VPN-ID) according to the Multiprotocol Label Switching (MPLS) standard and a forwarding label corresponding to a forwarding table, the method comprising:

a) receiving the packet;

b) identifying a rotting table associated with the VPN from among multiple separate routing tables associated with different VPNs; and

c) facilitating routing of the packet to the VPN.

14. The method of claim 13, wherein the VPN-ID is contained in a first label in the header.

15. The method of claim 13, wherein the routing of the packet is based on information in the header.

16. The method of claim 14 wherein the forwarding table includes a portion of a route table.

17. The method of claim 16 further comprising:

identifying, from the forwarding table, label switching information for routing the packet to the VPN.

18. The method of claim 17, wherein routing of the packet is based on information in the forwarding table.

19. A method of routing a packet belonging to a virtual private network (VPN) and having a label that includes a virtual private network identifier (VPN-ID) according to the Multiprotocol Label Switching (MPLS) standard in a first label in a header, the method comprising:

a) receiving the packet;

b) identifying a route table associated with the VPN from among multiple separate route tables associated with different VPNs;

c) identifying, from a second label, a forwarding table corresponding to the VPN, the forwarding table including a portion of the route table; and

d) facilitating routing of the packet to the VPN.

20. The method of claim 19, wherein the routing of the packet is based on information in the header.

21. The method of claim 19 further comprising:

identifying, from the forwarding table, label switching information for routing the packet to the VPN.

22. The method of claim 21, wherein routing of the packet is based on information in the forwarding table.

23. The method of claim 19 wherein the label includes a forwarding label corresponding to a forwarding table.