Congruent forwarding paths for unicast and multicast traffic

• US 20070025276A1
• 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 7,855,950 B2
• Time in Patent Office: Days
• US Class Current: 370/256
• CPC Class Codes: H04L 12/1836 with heterogeneous network architecture
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• 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 45/16 Multipoint routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A mechanism that provides congruent forwarding paths for unicast and multicast data traffic over a service provider core network includes issuing, by a receiver edge node, a request to join a multicast tree structure. A unicast path from the receiver edge node to a source node of the provider network is then established using a special message that contains an identifier. The identifier allows the unicast path through the core network to be aligned with the multicast tree structure. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

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

issuing a request to join a multicast tree structure; and

issuing a message used to build a unicast path from the PE node to a source node of the network in accordance with a protocol, the message containing an identifier utilized to align the unicast path with the multicast tree structure.

2. The method of claim 1 wherein the network comprises an Internet Protocol (IP) network, and the protocol comprises the Protocol Independent Multicast (PIM) protocol.

3. The method of claim 1 wherein the identifier comprises an IP address.

4. The method of claim 1 wherein the identifier comprises a multicast group destination address.

5. The method of claim 1 wherein network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

6. A provider edge (PE) node comprising:

a port for connection with a network; and

a processing unit operable to issue a first message to join a multicast tree routed to a source PE node over the network, and to issue a second message to establish a unicast path between the PE node and the source PE node path aligned to the multicast tree through the network, the first and second messages being issued in accordance with a protocol, the second message including information identifying a route of the multicast tree through the network.

7. The PE node of claim 6 wherein the network comprises a Multi-protocol label switching (MPLS)/Internet Protocol (IP) network.

8. The PE node of claim 7 wherein the unicast path comprises a point-to-point tunnel.

9. The PE node of claim 6 wherein the information comprises a multicast group destination address.

10. The PE node of claim 6 wherein the multicast tree identifier comprises a Media Access Control (MAC) address.

11. A provider edge (PE) node comprising:

a port for connection with a network; and

means for issuing a first message to join a multicast tree routed to a source PE node over the network, and for issuing a second message to establish a unicast path between the PE node and the source PE node path aligned to the multicast tree through the network, the first and second messages being issued in accordance with a protocol, the second message including information identifying a route of the multicast tree through the network.