In-band multicast signaling using LDP

• US 20070104194A1
• Filed: 11/04/2005
• Published: 05/10/2007
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, Ijsbrand, Eckert, Toerless, Meylor, John
• Granted Patent: US 7,852,841 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• 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 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/60 Router architectures

Abstract

A mechanism is provided by which a transport tree identifier can be generated using one or more identifiers for a multicast datastream. The transport tree identifier can then be used in the process of building a transport tree across a transport network. A transport network egress router can receive a request to join a multicast datastream from a downstream node outside of the transport network. The information contained in the join message that identifies the desired multicast datastream can be encoded in the transport tree identifier. The transport tree identifier can be related to one or more of a multicast group destination address, a multicast datastream source address, and a broadcast domain identifier.

Claims

1. A method comprising:

generating a transport tree identifier using one or more identifiers for a multicast datastream; and

transmitting a transport tree building message, wherein

the transport tree building message comprises the transport tree identifier.

2. The method of claim 1 further comprising:

receiving a message to join a multicast group, wherein

the message to join comprises one or more of a multicast source address and a multicast group address.

3. The method of claim 1 further comprising:

identifying a root router in a transport network, wherein

the root router is upstream toward a source of the multicast datastream;

transmitting the transport tree building message to an upstream next hop router,

wherein

the upstream next hop router is toward the root router.

4. The method of claim 1, wherein

the transport tree identifier identifies a transport tree spanning a transport network from an ingress router to an egress router.

5. The method of claim 4 wherein the transport network comprises a multiprotocol label switching (MPLS) network.

6. The method of claim 5 wherein the transport tree building message comprises:

a label distribution protocol (LDP) message.

7. A method comprising:

receiving a transport tree building message for a transport tree comprising a transport tree identifier;

generating an identifier for a multicast datastream using the transport tree identifier; and

associating the multicast datastream with the transport tree.

8. The method of claim 7 wherein the transport tree identifier comprises:

information related to one or more of a multicast source address, a multicast group address, and a broadcast domain identifier.

9. The method of claim 7 further comprising:

transmitting a request to receive the multicast datastream to a neighbor network node,

wherein

the neighbor network node is upstream toward a source of the multicast datastream.

10. A router element comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to transmit a transport tree building message, wherein

the transport tree building message comprises a transport tree identifier;

a switch fabric comprising a plurality of ports, wherein

each of the plurality of ports is coupled to a corresponding one of the plurality of network line cards, and

a first port is coupled to the first network line card; and

a processor coupled to the switch fabric, wherein the processor is configured to

generate the transport tree identifier using one or more identifiers for a multicast datastream.

11. The router element of claim 10 further comprising:

a second network line card of the plurality of network line cards coupled to a broadcast domain and configured to receive a message to join a multicast group, wherein

the message to join comprises one or more of a multicast source address and a multicast group address.

12. The router element of claim 10, wherein

the first network line card is coupled to a transport network, wherein

the transport tree identifier identifies a transport tree spanning the transport network from an ingress router to the router element.

13. A router element comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to receive a transport tree building message for a transport tree, wherein

the transport tree building message comprises a transport tree identifier;

a switch fabric comprising a plurality of ports, wherein

each of the plurality of ports is coupled to a corresponding one of the plurality of network line cards, and

a first port is coupled to the first network line card; and

a processor coupled to the switch fabric, wherein the processor is configured to

generate an identifier for a multicast datastream using the transport tree identifier; and

associate the multicast datastream with the transport tree.

14. The router element of claim 13 wherein the transport tree identifier comprises:

information related to one or more of a multicast source address, a multicast group address, and a broadcast domain identifier.

15. The router element of claim 13 further comprising:

a second line card configured to transmit a request to receive the multicast datastream to a neighbor network node, wherein

the neighbor network node is upstream toward a source of the multicast datastream.

16. An apparatus comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to transmit a transport tree building message, wherein

the transport tree building message comprises a transport tree identifier;

a switch fabric comprising a plurality of ports, wherein

each of the plurality of ports is coupled to a corresponding one of the plurality of network line cards, and

a first port is coupled to the first network line card; and

means for generating the transport tree identifier using one or more identifiers for a multicast datastream.

17. An apparatus comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to receive a transport tree building message for a transport tree, wherein

the transport tree building message comprises a transport tree identifier;

a switch fabric comprising a plurality of ports, wherein

each of the plurality of ports is coupled to a corresponding one of the plurality of network line cards, and

a first port is coupled to the first network line card; and

means for generating an identifier for a multicast datastream using the transport tree identifier; and

means for associating the multicast datastream with the transport tree.