Distributing files from a single server to multiple clients via cyclical multicasting

• US 7,143,132 B2
• Filed: 05/31/2002
• Issued: 11/28/2006
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Klein, Eitan, Blumfield, Anthony
• Primary Examiner(s): Follansbee, John
• Assistant Examiner(s): Nguyen, Dustin
• Application Number:
  US10/159,468
• Publication Number:
  US 20030225835A1
• Time in Patent Office: 1,642 Days
• Field of Search: 705/50, 725/87, 725/105, 725/112, 725/42, 725/71, 725/91, 725/103, 725/144, 707/104, 707/10, 709/230, 709/203, 709/204, 709/231, 380/255, 455/507
• US Class Current: 709/203
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A method and system are disclosed for reliably distributing file data from a single server to multiple client computers using a cyclical multicast approach. By “cyclical,” it is meant that data is distributed repeatedly onto the network at a certain period. The server transmits metadata asynchronously onto the network via a first communication channel, and file data via a second communication channel. Both data sets are received by one or more client devices operating a data catch module, which listens for metadata and file data from the network via a first and second communication channel. Once the metadata is received, the first channel is disconnected, and the one or more client devices operating the data catch module listen for file data for which the metadata is associated. Any file data not received during one cycle can be received by the client device in a subsequent cycle.

Claims

1. In a network that includes a server maintaining first and second communication channels with each of multiple client devices, a method for cyclically transferring file data from the server to the multiple client devices such that the client devices can determine the completeness of received file data, the method comprising:

creating a set of metadata specifying properties associated with the file data, wherein the properties include at least error correction information for the file data, and wherein the error correction information is configured for use by a client device, after transmission of the file data from the server, to determine the completeness of the file data;

transmitting the set of metadata over the network from the server to the multiple client devices in cycles via the first communication channel, each cycle comprising a full transmission of the set of metadata and being repeated periodically while and until it is determined that no client device of the multiple client devices has not yet received in full the set of metadata; and

transmitting the file data over the network from the server to the multiple client devices in cycles via the second communication channel, each cycle comprising a full transmission of the file data and being repeated periodically while and until it is determined that no client device of the multiple client devices has not yet received in full the file data, and such that the error correction information for determining completeness of the transmitted file data after transmission is transmitted independent of the file data.

2. The method of claim 1 wherein the step of creating a set of metadata includes storing of a metadata table by the server, the metadata table including metadata pertaining to the file data to be transmitted.

3. The method of claim 2 wherein the set of metadata further specifies properties selected from the group consisting of a message identification number, a name designated for the file data, the size of the file data, a cyclic redundancy check value and a message position.

4. The method of claim 1 wherein transmitting the set of metadata further comprises packetizing the metadata into at least one data packet conforming to an IP multicast protocol.

5. The method of claim 4 wherein transmitting the file data further comprises formulating the file data into at least one data packet conforming to an IP multicast protocol.

6. A computer-readable storage medium for performing the computer-executable steps recited in claim 1.

42. A method as recited in claim 1, wherein the method further includes:

determining at least one of the client devices has received in full the set of metadata.

43. A method as recited in claim 1, wherein the method further includes:

determining at least one of the client devices has received in full the file data.

45. A method as recited in claim 1, wherein the multiple client devices can store data on the server.

7. A method for receiving file data from a network by a client device, the client device being communicably linked to the network via first and second communications channels and capable of determining the completeness of the received file data, the method comprising:

at the client device, receiving metadata specifying properties associated with the file data via the first communication channel by listening to a repeated periodic transmission of the metadata over the network;

at the client device, receiving file data via the second communication channel once the metadata is received in its entirety by listening to a repeated periodic transmission of the file data over the network;

after the client device receives the file data, determining, at the client device, whether the file data contains any transmission error, the determination being made according to error correction information specified by the metadata, and wherein the error correction information is received independent of the received file data; and

storing the file data into a memory location that is accessible to the client device if the file data is without error.

8. The method of claim 7 further comprising repeating the steps of receiving, determining and storing if the file data is found to contain errors, the repeating being performed until the file data is received in its entirety without any transmission error.

9. The method of claim 7 further comprising:

closing the first communication channel once the metadata is received by the client device in its entirety; and

closing the second communication channel once the file data is received in its entirety without any transmission error.

10. The method of claim 7 further comprising:

maintaining the first communication channel in an active state, the active state being maintained even once the metadata is received by the client device in its entirety, the first communication channel being usable for listening for the transmission of new metadata over the network; and

receiving new metadata specifying properties associated with new file data via the first communication channel, wherein in response to the new metadata being received the client device aborts receiving the original data.

11. The method of claim 7 wherein receiving the metadata includes establishing a first queue in the client device and in association with the first communication channel, wherein the first queue maintains received metadata until the metadata has been received in its entirety.

12. The method of claim 11 wherein the state of the queue associated with the first communication channel triggers the closing of the first communication channel.

13. The method of claim 7 wherein the step of receiving the file data includes establishing a second queue in the client device and in association with the second communication channel, wherein the second queue maintains the received file data until the file data has been received in its entirety.

14. The method of claim 13 wherein the state of the queue associated with the second communication channel triggers the closing of the second communication channel.

15. The method of claim 7 wherein the step of determining includes performing a cyclic redundancy check.

16. A computer-readable storage medium for performing the computer-executable steps recited in claim 7.

17. A system for cyclically distributing file data to a plurality of client devices in a manner that allows the client devices to determine the completeness of the distributed file data, the plurality of client devices being communicably linked to a network via a first and second communication channel respectively, the system comprising:

a server for maintaining the file data;

a first communication channel to the network from the server for transmitting metadata to the plurality of devices, the metadata specifying properties associated with the file data, wherein the specified properties include at least error correction information for the file data, and wherein the error correction information is configured to be used by the plurality of client devices, after transmission of the file data, to determine the completeness of the file data;

a second communication channel to the network from the server for transmitting the file data to the plurality of clients devices, and such that the error correction information for determining the completeness of the file data is transmitted independent of the file data transmitted over the second communication channel; and

an executable datacaster hosted by the server for transmitting the metadata and file data in cyclical transmissions over the first and second communication channels respectively, the cyclical transmission for the first channel being repeated periodically upon the completion of a full transmission of the metadata, the cyclical transmission for the second channel being repeated periodically upon the completion of a full transmission of the file data, the cycle period for the transmission of the metadata being independent of the cycle period for the transmission of the file data.

18. The system of claim 17 further comprising a memory location accessible by the server for storing the file data.

19. The system of claim 17 further comprising a queuing mechanism operable by the server for communicating file data over the network.

20. The system of claim 17 wherein the executable datacaster further packages the metadata as one or more data packets.

21. The system of claim 17 wherein the executable datacaster further packages the file data as one or more data packets.

22. The system of claim 17 further comprising a router in communication with the server for cyclically transmitting the metadata and file data via the first and second communication channels, respectively, to the multiple client devices.

23. The system of claim 22 wherein the router is a pragmatic general multicast router.

40. A method as recited in claim 17, wherein the executable datacaster is a standalone executable.

41. A method as recited in claim 40, wherein the executable datacaster is a DLL.

46. A method as recited in claim 22, wherein the router prevents the file data from being transmitted when no client devices are listening for the file data.

24. A system for receiving file data transmitted over a network by a server, the server being communicably linked to the network via first and second communication channels, the file data being distributed by the server in cycles over the second communication channel, the system comprising:

a client device comprising;

a first communication port for detecting the receipt of metadata from the network, the metadata being distributed by the server over the first communication port, the metadata specifying properties associated with the file data, wherein the properties include at least error indicating information for the file data;

a second communication port for detecting the receipt of file data from the network, the file data being distributed by the server over the second communication port, and such that the error indicating information for the file data is received independent of the file data; and

a receiving module for consuming the metadata and the file data as it is received at the first and second communication ports respectively, the receiving module deactivating the first communication port in response to the metadata being received in its entirety, and deactivating the second communication port in response to the file data being received in its entirety, wherein the receiving module uses the error indicating information specified in the metadata to determine whether the file data has been received in its entirety.

25. The system of claim 24 further comprising a memory location for storing the metadata and file data as it is received over the first and second communication ports respectively.

26. The system of claim 24 further comprising a first queuing mechanism in association with the first communication port, the first queuing mechanism indicating when the metadata has been received in its entirety.

27. The system of claim 24 further comprising a second queuing mechanism in association with the second communication port, the second queuing mechanism indicating when the file data has been received in its entirety.

28. The system of claim 24, the client device further comprising an error checking routine for determining whether the received file data contains any errors, wherein in response to the file data containing an error the file data is rejected, wherein in response to the file data not containing an error the file data is stored in the accessible memory location.

29. The system of claim 28 wherein the error checking routine operates according to error indicating information specified by the metadata.

30. The system of claim 24 further comprising a router in communication with the. receiving module for determining when the first and second communication ports are deactivated, the router preventing the transmission of data onto the network by the server when the first and second communication ports are deactivated.

44. A method as recited in claim 24, wherein the entirety of at least one of the set of metadata and the file data is obtained over at least two different cycles.

31. A system for distributing file data over a network to multiple client devices without prior knowledge of the number of client devices or their locations on the network, the system comprising:

means for creating metadata specifying properties associated with the file data, the properties including at least error correction information for the file data, said error correction information being configured for use by a client device, after transmission of the file data, to determine the completeness of the file data;

means for transmitting the metadata over the network in periodic cycles over a first communication channel; and

means for transmitting the file data over the network in periodic cycles over a second communication channel, and such that the error correction information for the file data is transmitted independent of the transmitted file data.

32. The system of claim 31 further comprising means for creating a metadata table, the metadata table including metadata pertaining to the file data to be transmitted over the network.

33. The system of claim 31 wherein said means for transmitting metadata transmits the metadata asynchronously over the first communication channel.

34. A method for transferring primary information to a plurality of recipients, each recipient being capable of using the primary information to perform a desired network or computing task, the primary information being retrieved by each recipient via a primary connection to a network, the method comprising:

multicasting secondary information to the plurality of recipients repeatedly over a secondary connection to the network, each cycle being repeated asynchronously, the secondary information specifying properties associated with the primary information, wherein the properties include at least error correction information for the primary information, wherein the error correction information is configured for use by the recipients, after multicasting the primary data, to determine the completeness of the primary information, and wherein at least one of the plurality of recipients is capable of receiving the secondary information; and

multicasting the primary information to the plurality of recipients repeatedly over the primary connection, wherein at least one of the plurality of recipients is capable of receiving the primary information, and such that the error correction information for determining the completeness of the primary information is multicasted independent of the primary information.

35. The method of claim 34 further comprising retrieving primary information to be transmitted to the plurality of recipients from a memory location.

36. The method of claim 34 wherein the secondary information specifies properties of the primary information selected from the group consisting of a message identification number, a name designated for the primary information, the size of the primary information, an error check value and a position indicator pertaining to the primary information.

37. The method of claim 34 wherein the step of multicasting the secondary information includes formulating the secondary information as one or more data packets conforming to a multicast protocol.

38. The method of claim 34 wherein the step of multicasting the primary information includes formulating the primary information as one or more data packets conforming to a multicast protocol.

39. A computer-readable storage medium for performing the computer-executable steps recited in claim 34.