METHODS AND SYSTEMS TO STORE STATE USED TO FORWARD MULTICAST TRAFFIC

• US 20090052448A1
• Filed: 04/01/2008
• Published: 02/26/2009
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Srivastava, Divesh, Zhang, Yin, Ramakrishnan, Kadangode K., Rabinovich, Michael, Cho, Tae Won
• Granted Patent: US 8,295,203 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/48 Routing tree calculation

Abstract

Methods and systems are described to store state used to forward multicast traffic. The system includes a receiving module to receive request to add a first node to a membership tree. The membership tree includes a first plurality of nodes associated with a multicast group. The system further includes a processing module to identify a second node in the first plurality of nodes and to communicate a node identifier that identifies the first node over a network to the second node. The node identifier is to be stored at the second node to add the first node to the membership tree. The node identifier is further to be stored in the membership tree exclusively at the second node to enable the second node to forward the multicast traffic to the first node.

Claims

1. A method to store state used to forward multicast traffic, the method comprising:

receiving a request to add a first node to a membership tree including a first plurality of nodes associated with a multicast group;

identifying a second node in the first plurality of nodes; and

communicating a node identifier that identifies the first node over a network to the second node, the node identifier to be stored at the second node to add the first node to the membership tree, the node identifier to be stored in the membership tree exclusively at the second node to enable the second node to forward the multicast traffic to the first node.

2. The method of claim 1, wherein the identifying the second node includes identifying a sub-tree including a second plurality of nodes that includes the second node and the first node.

3. The method of claim 2, wherein the second plurality of nodes are exclusively accessed in the membership tree via the second node.

4. The method of claim 2, further including identifying a third plurality nodes included in the first and second plurality of nodes that are respectively associated with node identifiers used to forward multicast traffic over the membership tree for the multicast group.

5. The method of claim 4, wherein the communicating is responsive to comparing a count of the number of nodes in the third plurality of nodes to a predetermined threshold.

6. The method of claim 4, wherein the first plurality of nodes are included in a base tree that includes a fourth plurality of nodes, wherein the base tree is a k-ary tree, wherein the fourth plurality of nodes are respectively associated with a plurality of logical router identifiers that are generated based on a multicast group identifier associated with the multicast group.

7. The method of claim 1, further including increasing the predetermined threshold to decrease branching in the membership tree and to increase a quantity of state stored at the second node.

8. The method of claim 1, further including decreasing the predetermined threshold to increase branching in the membership tree and to decrease a quantity of state that is stored at the second node.

9. The method of claim 1, wherein the first node is associated with a multicast member that has been added to the multicast group, wherein the multicast member is stored in a database that is managed by a subscription manager that communicates over a network with the first node.

10. A system to store state used to forward multicast traffic, the system comprising:

a receiving module to receive a request to add a first node to a membership tree including a first plurality of nodes associated with a multicast group; and

a processing module to identify a second node in the first plurality of nodes and to communicate a node identifier that identifies the first node over a network to the second node, the node identifier to be stored at the second node to add the first node to the membership tree, the node identifier to be stored in the membership tree exclusively at the second node to enable the second node to forward the multicast traffic to the first node.

11. The system of claim 10, wherein the processing module is to identify a sub-tree including a second plurality of nodes that includes the second node and the first node.

12. The system of claim 11, wherein the second plurality of nodes are exclusively accessed in the membership tree via the second node.

13. The system of claim 12, wherein the processing module is to identify a third plurality nodes included in the first and second plurality of nodes that are respectively associated with node identifiers used to forward multicast traffic over the membership tree for the multicast group.

14. The system of claim 13, wherein the processing module is to communicate in response to a comparison of a count of the number of nodes in the third plurality of nodes to a predetermined threshold.

15. The system of claim 13, wherein the first plurality of nodes are included in a base tree that includes a fourth plurality of nodes, wherein the base tree is a k-ary tree, wherein the fourth plurality of nodes are respectively associated with a plurality of logical router identifiers that are generated based on a multicast group identifier associated with the multicast group.

16. The system of claim 10, wherein the processing module is to increase the predetermined threshold to decrease branching in the membership tree and to increase a quantity of state stored at the second node.

17. The system of claim 10, wherein the processing module is to decrease the predetermined threshold to increase branching in the membership tree and to decrease a quantity of state that is stored at the second node.

18. The system of claim 10, wherein the first node is associated with a multicast member that has been added to the multicast group, wherein the multicast member is stored in a database that is managed by a subscription manager that communicates over a network with the first node.

19. A system to store state used to forward multicast traffic, the system comprising:

a first means for receiving a request to add a first node to a membership tree including a first plurality of nodes associated with a multicast group;

a second means for identifying a second node in the first plurality of nodes and for communicating a node identifier that identifies the first node over a network to the second node, the node identifier to be stored at the second node to add the first node to the membership tree, the node identifier to be stored in the membership tree exclusively at the second node to enable the second node to forward the multicast traffic to the first node.

20. A machine-readable medium storing instructions that, when executed by a machine, cause the machine to:

receive a request to add a first node to a membership tree including a first plurality of nodes associated with a multicast group;

identify a second node in the first plurality of nodes; and

communicate a node identifier that identifies the first node over a network to the second node, the node identifier to be stored at the second node to add the first node to the membership tree, the node identifier to be stored in the membership tree exclusively at the second node to enable the second node to forward the multicast traffic to the first node.