Methods and systems to store state used to forward multicast traffic

• US 8,295,203 B2
• Filed: 04/01/2008
• Issued: 10/23/2012
• 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: Ramakrishnan, Kadangode K., Srivastava, Divesh, Cho, Tae W., Zhang, Yin, Rabinovich, Michael
• Primary Examiner(s): Phunkulh, Bob
• Assistant Examiner(s): Van, Jenkey
• Application Number:
  US12/060,709
• Publication Number:
  US 20090052448A1
• Time in Patent Office: 1,666 Days
• Field of Search: None
• US Class Current: 370/256
• 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 comprising:

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

identifying, by the system, a second node in the first plurality of nodes, wherein the first and second nodes are separated from each other by at least one other node of the first plurality of nodes, wherein identifying the second node includes identifying a sub-tree including a second plurality of nodes that includes the second node and the first node;

communicating, by the system, 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; and

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 and wherein the database comprises map information to map logical node identifiers to physical node identifiers, dissemination tree information, membership tree information comprising information used for communicating multicast traffic over the membership tree, mode transition information used for transitioning from a transient mode to an active mode, and domain information used to communicate multicast traffic across administrative domains.

2. The method of claim 1, wherein the second plurality of nodes are exclusively accessed in the membership tree via the second node.

3. The method of claim 1, comprising identifying, by the system, a third plurality of 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.

4. The method of claim 3, wherein the communicating is responsive to comparing a count of the number of nodes in the third plurality of nodes to a predetermined threshold.

5. The method of claim 4, comprising increasing, by the system, the predetermined threshold to decrease branching in the membership tree and to increase a quantity of state information stored at the second node.

6. The method of claim 4, comprising decreasing, by the system, the predetermined threshold to increase branching in the membership tree and to decrease a quantity of state information that is stored at the second node.

7. The method of claim 3, 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.

8. A system comprising:

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

a memory storing computer instructions; and

a processing device coupled to the memory, wherein the processing device, responsive to executing the computer instructions, performs operations comprising;

identifying a second node in the first plurality of nodes;

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, wherein the first and second nodes are separated from each other by at least one other node of the first plurality of nodes;

identifying a sub-tree including a second plurality of nodes that includes the second node and the first node; and

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 and wherein the database comprises map information dissemination tree information, membership tree information, mode transition information used for transitioning from a transient mode to an active mode, and domain information used to communicate multicast traffic across administrative domains.

9. The system of claim 8, wherein the second plurality of nodes are exclusively accessed in the membership tree via the second node.

10. The system of claim 9, wherein the processing device, responsive to executing the computer instructions, performs operations comprising identifying a third plurality of 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.

11. The system of claim 10, wherein the processing device, responsive to executing the computer instructions, performs operations comprising communicating in response to a comparison of a count of the number of nodes in the third plurality of nodes to a predetermined threshold.

12. The system of claim 11, wherein the processing device, responsive to executing the computer instructions, performs operations comprising increasing the predetermined threshold to decrease branching in the membership tree and to increase a quantity of state information stored at the second node.

13. The system of claim 11, wherein the processing device, responsive to executing the computer instructions, performs operations comprising decreasing the predetermined threshold to increase branching in the membership tree and to decrease a quantity of state information that is stored at the second node.

14. The system of claim 10, 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.

15. A system comprising:

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

a memory storing computer instructions; and

a processor coupled to the memory, wherein the processor, responsive to executing the computer instructions, performs operations comprising;

identifying a second node in the first plurality of nodes;

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, wherein the first and second nodes are separated from each other; and

identifying a sub-tree including a second plurality of nodes that includes the second node and the first node; and

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 and wherein the database comprises map information, dissemination tree information, membership tree information, mode transition information used for transitioning from a transient mode to an active mode, and domain information used to communicate multicast traffic across administrative domains.

16. A non-transitory machine-readable medium storing instructions that, when executed by a machine, cause the machine to perform operations comprising:

receive 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, 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;

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, wherein the first and second nodes are separated from each other by at least one other node of the first plurality of node; and

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 and wherein the information, mode transition information used for transitioning from a transient mode to an active mode, and domain information used to communicate multicast traffic across administrative domains.