Distributed multicast caching technique

• US 20020103972A1
• Filed: 01/26/2001
• Published: 08/01/2002
• Est. Priority Date: 01/26/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Satran, Julian, Gershinsky, Gidon
• Granted Patent: US 7,240,105 B2
• Time in Patent Office: Days
• US Class Current: 711/119
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1859 adapted to provide push services, e.g. data channels
• CPC Class Codes: H04L 67/2885 Hierarchically arranged intermediate devices, e.g. for hierarchical caching
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A caching arrangement for the content of multicast transmission across a data network utilizes a first cache which receives content from one or more content providers. Using the REMADE protocol, the first cache constructs a group directory. The first cache forms the root of a multilevel hierarchical tree. In accordance with configuration parameters, the first cache transmits the group directory to a plurality of subsidiary caches. The subsidiary caches may reorganize the group directory, and relay it to a lower level of subsidiary caches. The process is recursive, until a multicast group of end-user clients is reached. Requests for content by the end-user clients are received by the lowest level cache, and forwarded as necessary to higher levels in the hierarchy. The content is then returned to the requesters. Various levels of caches retain the group directory and content according to configuration options, which can be adaptive to changing conditions such as demand, loading, and the like. The behavior of the caches may optionally be modified by the policies of the content providers.

Claims

1. A method of transmitting data over a communications network, comprising the steps of:

receiving content from a content provider;

responsive to said content establishing a first group directory in a cache;

transmitting said first group directory from said cache on a data channel to a subsidiary cache;

establishing a second group directory in said subsidiary cache, said second group directory being derived from said first group directory; and

transmitting said second group directory from said subsidiary cache to a multicast group of receivers.

2. The method according to claim 1, wherein said step of transmitting said first group directory is performed using a REMADE protocol.

3. The method according to claim 1, wherein said step of transmitting said first group directory is performed by periodic transmission thereof.

4. The method according to claim 1, wherein said step of transmitting said first group directory is performed in response to a request from a receiver thereof.

5. The method according to claim 1, wherein said step of transmitting said first group directory is performed according to a policy of said content provider.

6. The method according to claim 1, wherein said step of transmitting said second group directory is performed by periodic transmission thereof.

7. The method according to claim 1, wherein said step of transmitting said second group directory is performed in response to a request from a receiver.

8. The method according to claim 1, wherein said step of transmitting said second group directory is performed using a REMADE protocol.

9. The method according to claim 1, wherein said step of transmitting said second group directory is performed according to a policy of said content provider.

10. The method according to claim 1, wherein said content provider comprises a plurality of content providers.

11. The method according to claim 1, wherein said subsidiary cache comprises a plurality of subsidiary caches.

12. The method according to claim 11, wherein said cache and said subsidiary caches are linked together as a hierarchical tree, said cache forming a root of said hierarchical tree.

13. The method according to claim 11, further comprising the steps of:

receiving a transmission request from a member of said group of receivers, wherein said transmission request is responsive to said second group directory; and

responsive to said transmission request, transmitting a data item from said subsidiary cache to said receiver.

14. The method according to claim 1, wherein said first group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said first group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.

15. The method according to claim 1, wherein said second group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said second group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.

17. The computer software product according to claim 16, wherein said step of transmitting said first group directory is performed using a REMADE protocol.

18. The computer software product according to claim 16, wherein said step of transmitting said first group directory is performed by periodic transmission thereof.

19. The computer software product according to claim 16, wherein said step of transmitting said first group directory is performed in response to a request from a receiver.

20. The computer software product according to claim 16, wherein said step of transmitting said first group directory is performed according to a policy of said content provider.

21. The computer software product according to claim 16, wherein said step of transmitting said second group directory is performed by periodic transmission thereof.

22. The computer software product according to claim 16, wherein said step of transmitting said second group directory is performed in response to a request from a receiver.

23. The computer software product according to claim 16, wherein said step of transmitting said second group directory is performed using a REMADE protocol.

24. The computer software product according to claim 16, wherein said step of transmitting said second group directory is performed according to a policy of said content provider.

25. The computer software product according to claim 16, wherein said content provider comprises a plurality of content providers.

26. The computer software product according to claim 16, wherein said subsidiary cache comprises a plurality of subsidiary caches.

27. The computer software product according to claim 26, wherein the method further comprises the steps of:

receiving a transmission request from a member of said group of receivers, wherein said transmission request is responsive to said second group directory; and

responsive to said transmission request, transmitting a data item from said subsidiary cache to said receiver.

28. The computer software product according to claim 26, wherein said cache and said subsidiary caches are linked together as a hierarchical tree, said cache forming a root of said hierarchical tree.

29. The computer software product according to claim 16, wherein said first group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said first group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.

30. The computer software product according to claim 16, wherein said second group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said second group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.

16. A computer software product, comprising a computer-readable medium in which computer program instructions are stored, which instructions, when read by at least one computer, causes said at least one computer to execute a method of transmitting data over a communications network, comprising the steps of:

in a first server receiving content from a content provider;

responsive to said content establishing a first group directory in a cache of said first server;

transmitting said first group directory from said cache on a data channel to a second server having a subsidiary cache;

establishing a second group directory in said subsidiary cache, said second group directory being derived from said first group directory; and

transmitting said second group directory from said subsidiary cache to a multicast group of receivers.

31. A system for transmitting data over a communications network, comprising:

a first server, having a cache therein, receiving content from a content provider, wherein responsive to said content a first group directory is established in said cache by said first server,

a second server, having a subsidiary cache therein, said first group directory being transmitted by said first server from said cache on a data channel to said subsidiary cache, wherein responsive to said first group directory, a second group directory is established in said subsidiary cache by said second server, said second group directory being derived from said first group directory, and said second group directory is transmitted by said second server from said subsidiary cache to a multicast group of receivers.

32. The system according to claim 31, wherein said first group directory is transmitted using a REMADE protocol.

33. The system according to claim 31, wherein said first group directory is transmitted periodically.

34. The system according to claim 31, wherein said first group directory is transmitted in response to a request from a receiver thereof.

35. The system according to claim 31, wherein said first group directory is transmitted according to a policy of said content provider.

36. The system according to claim 31, wherein said second group directory is transmitted periodically.

37. The system according to claim 31, wherein said second group directory is transmitted in response to a request from a receiver.

38. The system according to claim 31, wherein said second group directory is transmitted using a REMADE protocol.

39. The system according to claim 31, wherein said second group directory is transmitted according to a policy of said content provider.

40. The system according to claim 31, wherein said content provider comprises a plurality of content providers.

41. The system according to claim 31, wherein said subsidiary cache comprises a plurality of subsidiary caches.

42. The system according to claim 41, wherein said cache and said subsidiary caches are linked together as a hierarchical tree, said cache forming a root of said hierarchical tree.

43. The system according to claim 41, wherein said second server receives a transmission request from a member of said group of receivers, wherein said transmission request is responsive to said second group directory;

and

responsive to said transmission request, said second server transmits a data item from said subsidiary cache to said receiver.

44. The system according to claim 31, wherein said first group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said first group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.

45. The system according to claim 31, wherein said second group directory comprises a root directory hierarchically linked to a plurality of subdirectories, said subdirectories carrying a list of data items, a subtree of said second group directory being defined by one of said subdirectories and at least one linked subdirectory thereunder.