Optimal bridging over MPLS / IP through alignment of multicast and unicast paths

• US 20070025277A1
• Filed: 12/07/2005
• Published: 02/01/2007
• Est. Priority Date: 08/01/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Farinacci, Dino, Sajassi, Ali, Alvarez, Daniel, Zwiebel, John
• Granted Patent: US 8,169,924 B2
• Time in Patent Office: Days
• US Class Current: 370/256
• 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 45/26 Route discovery packet

Abstract

A provider edge (PE) node of a network operates to send a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node; and receive a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Claims

1. A method of operation for a provider edge (PE) node of a network, comprising:

sending a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node; and

receiving a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path.

2. The method of claim 1 wherein the network comprises an Internet Protocol (IP) network.

3. The method of claim 2 wherein the trace path message is sent in accordance with the Protocol Independent Multicast (PIM) protocol.

4. A method of operation for a provider edge (PE) node of a network, comprising:

receiving a trace path message sent over the network from a source PE node, the trace path message recording a list of intermediate nodes of a unicast path from the source PE node to the PE node;

terminating the trace path message; and

issuing a join message to build a branch of a multicast tree, the join message using the list to propagate to the source PE node through the intermediate nodes such that the branch of the multicast tree is aligned with the unicast path.

5. The method of claim 4 wherein the network comprises an Internet Protocol (IP) network.

6. The method of claim 4 wherein the join message is issued in accordance with the Protocol Independent Multicast (PIM) protocol.

7. The method of claim 4 wherein network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

8. A provider edge (PE) node comprising:

a port for connection with a network; and

a processing unit operable to send a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node, the processing unit being further operable to receive a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path.

9. The PE node of claim 8 wherein the network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

10. The PE node of claim 8 wherein the unicast path comprises a point-to-point tunnel.

11. A provider edge (PE) node comprising:

a port for connection with a network; and

a processing unit operable to receive a trace path message sent over the network from a source PE node, the trace path message recording a list of intermediate nodes of a unicast path from the source PE node to the PE node, the processing unit being further operable to terminate the trace path message and issue a join message to build a branch of a multicast tree, the join message using the list to propagate to the source PE node through the intermediate nodes such that the branch of the multicast tree is aligned with the unicast path.

12. A provider edge (PE) node comprising:

a port for connection with a network; and

means for receiving a trace path message sent over the network from a source PE node, the trace path message recording a list of intermediate nodes of a unicast path from the source PE node to the PE node, the means also for terminating the trace path message and issuing a join message to build a branch of a multicast tree, the join message using the list to propagate to the source PE node through the intermediate nodes such that the branch of the multicast tree is aligned with the unicast path.

13. A provider edge (PE) node comprising:

a port for connection with a network; and

means for sending a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node, the means also for receiving a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path.

14. A computer program product comprising a computer useable medium and computer readable code embodied on the computer useable medium, execution of the computer readable code causing the computer program product to configure a provider edge (PE) node to:

send a trace path message over a network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node; and

receive a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path.

15. The computer program product of claim 14 wherein the network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

16. The computer program product of claim 14 wherein the trace path message is sent in accordance with the Protocol Independent Multicast (PIM) protocol.

17. A computer program product comprising a computer useable medium and computer readable code embodied on the computer useable medium, execution of the computer readable code causing the computer program product to configure a provider edge (PE) node to:

receive a trace path message sent over a network from a source PE node, the trace path message recording a list of intermediate nodes of a unicast path from the source PE node to the PE node;

terminate the trace path message; and

issue a join message to build a branch of a multicast tree, the join message using the list to propagate to the source PE node through the intermediate nodes such that the branch of the multicast tree is aligned with the unicast path.

18. The computer program product of claim 17 wherein the network comprises an Internet Protocol (IP) network.

19. The computer program product of claim 17 wherein the join message is issued in accordance with the Protocol Independent Multicast (PIM) protocol.

20. The computer program product of claim 17 wherein network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

21. A system for alignment of a multicast distribution tree and unicast paths over a network, comprising:

a plurality of receiver provider edge (PE) nodes; and

a source provider edge (PE) node operable to send trace path messages over the network, each trace path message recording a list of intermediate nodes of a unicast path from the source PE node to a corresponding one of the receiver PE nodes,

wherein each receiver PE node is operable to initiate a join message for building the multicast distribution tree, the join message being sent back to the source PE node upon receiving the trace path message, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of the multicast distribution tree is aligned with the unicast path.

22. A method of operation for a service provider (SP) network, comprising:

creating a plurality of unicast paths from a source node to a corresponding plurality of receiver nodes;

sending, by the source node, trace path messages over the network, each trace path message recording a list of intermediate nodes of one of the unicast paths from the source node to a corresponding one of the receiver nodes,

sending, by each receiver node, a join message for building a multicast distribution tree, the join message being sent back to the source node upon receipt of the trace path message, the join message using the list to propagate to the source node through the intermediate nodes such that a branch of the multicast distribution tree is aligned with the corresponding unicast path.