Methods, devices and software for merging multicast groups in a packet switched network

• US 20040252690A1
• Filed: 06/16/2003
• Published: 12/16/2004
• Est. Priority Date: 06/16/2003
• Status: Active Grant

• Current Assignee: National University of Singapore
• Original Assignee: National University of Singapore
• Inventors: Koh, Kwang Yong, Pung, Hung Keng
• Granted Patent: US 7,532,622 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 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04W 4/08 User group management

Abstract

In a method of merging and disbanding multicast groups in a packet switch network multicast groups may be merged at edge routers. Merging and disbanding of multicast groups may be controlled by a designated computing device (referred to as connection managers) on each sub-network. Connection managers across sub-networks may communicate with each other to ensure merge and disband messages are properly distributed. Connection managers may optionally be interconnected hierarchically. Connection managers or other computing devices may optionally act as proxies for merged groups to ensure traffic for merged groups is directed to a sub-network.

Claims

1. A method of merging first and second multicast groups in a packet switched computer network comprising a plurality of sub-networks, comprising

receiving a request to merge said first and second multicast groups at a computing device, operable to receive requests to merge multicast groups from multiple hosts on said network;

dispatching a request from said computing device to merge said first and second multicast groups to an edge router connecting one sub-network to other sub-networks, thereby signalling said edge router to duplicate data in packets for said first group to members of said second group in said one sub-network.

2. The method of claim 1, further comprising maintaining indicators of memberships in multicast groups of said multiple hosts at said computing device.

3. The method of claim 2, further comprising monitoring requests to join multicast groups, originated at said multiple hosts.

4. The method of claim 1, wherein said computing device is on said one sub-network, and wherein said method further comprises joining said second multicast group at said computing device to act as a proxy for said second multicast group on said one sub-network.

5. The method of claim 1, further comprising dispatching a request to merge said first and second multicast groups to other computing devices, each of said other computing devices operable to receive requests to merge other multiple hosts on said network.

6. The method of claim 5, wherein said request to merge said first and second multicast groups is dispatched to said other computing devices, by way of a multicast connection.

7. The method of claim 5, further comprising passing a request to merge said first and second multicast groups to a higher level computing device, said higher level computing device interconnecting multiple of said other computing devices to provide requests to merge multicast groups.

8. The method of claim 1, further comprising

receiving a request to merge other multicast groups at said computing device from another computing device, said another computing device operable to receive requests to merge groups from other multiple hosts on said network;

responsive thereto dispatching a request from said computing device to merge said other multicast groups to said edge router connecting said one sub-network to other sub-networks.

9. The method of claim 1, further comprising

receiving a request to disband merger of said first and second multicast groups at said computing device;

dispatching a request from said computing device to disband merger of said first and second multicast groups to said edge router connecting said sub-network to other sub-networks, thereby signalling said edge router to cease duplicating data in packets for members of said first multicast group to members of said second multicast group in said one sub-network.

10. The method of claim 1, further comprising maintaining a list of merged groups at said computing device.

11. The method of claim 10, further comprising updating said list to reflect merger of said first and second multicast groups.

12. The method of claim 5, wherein said multicasts have been established using an IGMP protocol.

13. The method of claim 1, further comprising authenticating an originator of said request to merge to ensure said request to merge originates with an authorized computing device.

14. The method of claim 1, wherein said receiving comprises receiving said request to merge from a computing device belonging to said first multicast group.

15. The method of claim 1, wherein said receiving comprises receiving said request to merge from a computing device belonging to neither said first or said second multicast group.

16. The method of claim 1, wherein said computing device is on said one sub-network, and wherein said method further comprises having a computing device on said one sub-network act as a proxy for said second multicast group on said one sub-network.

17. Computer readable medium, storing processor readable instructions loadable at said computing device within said network, adapting said computing device to perform the method of claim 1.

18. A computing device, comprising a processor and processor readable memory, said processor readable memory storing instructions adapting said computing device to perform the method of claim 1.

19. A method of operating an edge router connecting a sub-network to a packet switched network, comprising:

maintaining a list of merged multicast groups at said edge router;

duplicating data in packets destined for members of one of said groups on said sub-network, to provide said data to members of a merged group on said sub-network, based on said list.

20. The method of claim 19, further comprising updating said list in response to requests received from a computing device on said sub-network.

21. The method of claim 20, wherein said requests comprise requests to merge established multicast groups, or disband merged groups.

22. The method of claim 21, wherein said method comprises adding at least one entry to said list in response to a requests to merge established multicast groups.

23. The method of claim 22, wherein said method comprises deleting an entry of said list in response to a requests to disband established multicast groups.

24. The method of claim 23, further comprising deleting an entry of said list after expiry of a time-out period.

25. The method of claim 20, further comprising adding destination addresses to packets destined for said members of a merged group on said sub-network.

26. The method of claim 20, including a time-to-live value of two or less in said packets destined for said members of said merged group on said sub-network.

27. The method of claim 22, further comprising adding multiple entries to said list to merge groups already merged with a particular group in response to a requests to merge said particular group with another multicast group, thereby merging said groups already merged with said another multicast group.

28. The method of claim 27, further comprising removing said multiple entries from said list in response to a requests to disband merger of said particular group with said another multicast group.

29. Computer readable medium, storing processor readable instructions loadable at a router within a communications network, that adapt said router to perform the method of claim 19.

30. A router comprising a processor and processor readable memory, said processor readable memory storing instructions adapting said computing device to perform the method of claim 19.