Content Synchronization in a File Sharing Environment

• US 20080005188A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Heron, Alexandra K., Wu, Yunnan, Li, Jin, Chou, Philip A., Huang, Cheng, Teodosiu, Dan, Schwartz, Eyal, Spivey, John T.
• Granted Patent: US 7,953,785 B2
• Time in Patent Office: Days
• US Class Current: 707/201
• CPC Class Codes: G06F 16/176 Support for shared access to files; File sharing support
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: G06F 16/1834 implemented based on peer-to-peer networks, e.g. gnutella p2p communication protocols H04L67/104

Abstract

Content synchronization in a file sharing environment is described. A node in a circle share maintains a version vector that represents that node'"'"'s knowledge of file synchronization events. Version vector data may be transmitted between nodes of the circle share via a presence service in the form of short notification messages. The version vector data is compared to identify one or more nodes to be synchronized. A resource-aware overlay representing the circle share is computed, and is used to initiate communication to determine which of the available nodes with which to synchronize will provide the most synchronization value to other nodes in the circle share.

Claims

1. A method, implemented at least in part by a computer, comprising:

determining an overlay graph representation of connections between a plurality of nodes within a peer-to-peer file sharing network based, at least in part, on at least one of;

a sharing relationship between individual ones of the plurality of nodes, a presence status associated with at least one of the plurality of nodes, or a published capability associated with at least one of the plurality of nodes; and

selecting first and second nodes to be synchronized via the peer-to-peer file sharing network, wherein the first and second nodes are selected from the plurality of nodes based at least in part on the overlay graph.

2. The method as recited in claim 1, wherein the second node is selected based at least in part on an anticipated utility of the synchronization.

3. The method as recited in claim 2, wherein the anticipated utility of the synchronization is based at least in part on an anticipated ability of the second node to redistribute file events that will be transmitted to the second node from the first node via the synchronization.

4. The method as recited in claim 3, wherein the anticipated ability of the second node to redistribute file events is based on at least one of an upload bandwidth associated with the second node or a connection type associated with the second node.

5. The method as recited in claim 1, wherein the overlay graph comprises at least one of a structured overlay graph or a distributed hash table (DHT) overlay graph.

6. The method as recited in claim 1, wherein the overlay graph representation is determined based, at least in part, on a resource associated with one of the plurality of nodes.

7. The method as recited in claim 6, wherein the resource comprises at least one of a network proximity, a download bandwidth, an upload bandwidth, a network connection type, or a network connection speed.

8. The method as recited in claim 1, wherein selecting the first and second nodes to be synchronized further comprises:

maintaining at the first node, first and second version vectors representing events associated with files shared by the plurality of nodes, wherein the first version vector represents events that have been applied to files maintained by the first node and the second version vector represents events that have been applied to files maintained by the second node; and

when a comparison of the first and second version vectors indicates that synchronization between the first and second nodes may be warranted, transmitting a form of the first version vector from the first node to the second node.

9. The method as recited in claim 8, wherein the events associated with the files comprises at least one of creation of a new file, deletion of a shared file, or a modification to a shared file.

10. The method as recited in claim 8, wherein the form of the first version vector is transmitted via a presence service as a short notification message.

11. The method as recited in claim 10, wherein the presence service is configured to automatically notify the second node when the first node logs on to the peer-to-peer network.

12. The method as recited in claim 8, wherein the form of the first version vector that is transmitted comprises at least one of a hash of a collection of file events or a high watermark generated based on a collection of file events, such that the high watermark indicates for each node the most recent event, of which, the first node is aware.

13. The method as recited in claim 8, further comprising:

maintaining at the second node, a third version vector representing events that have been applied to files maintained by the second node; and

when a comparison of the transmitted form of the first version vector and a form of the third version vector indicates that synchronization between the first and second nodes is warranted, synchronizing the first and second nodes via a direct peer-to-peer connection between the first and second nodes.

14. The method as recited in claim 13, wherein the comparison of the transmitted form of the first version vector and the form of the third version vector comprises a comparison of version vector high watermarks.

15. The method as recited in claim 14, wherein, in an event that the version vector high watermarks are identical, the comparison further comprises a comparison of a hash of the first version vector and a hash of the third version vector.

16. A synchronization negotiation manager comprising:

a version vector store configured to maintain a version vector that identifies shared file events, of which a particular node is aware;

a dynamic overlay generator configured to generate an overlay that represents connections between nodes and resources of the respective nodes of a group defined within a peer-to-peer network; and

a synchronization partner selection module configured to analyze the version vector and the overlay to select a synchronization partner.

17. The synchronization negotiation manager as recited in claim 16, further comprising a high watermark generator configured to generate a high watermark of the version vector that indicates a most recent shared file event of which the particular node is aware.

18. The synchronization negotiation manager as recited in claim 16, further comprising a hash generator configured to generate a hash of the version vector.

19. One or more computer-readable media comprising computer-executable instructions that, when executed, cause a computing system to:

receive at a first node of a peer-to-peer group, presence-based data indicating that second and third nodes of the peer-to-peer group are online;

receive at the first node, version vector data respectively associated with the second and third nodes, the version vector data representing one or more file synchronization events that are respectively available from the second and third nodes;

compare the version vector data associated with the second and third nodes with version vector data associated with the first node to determine whether synchronization between the first and second nodes is warranted and whether synchronization between the first and third nodes is warranted;

generate a resource-aware overlay representing characteristics of and connections between nodes of the peer-to-peer group; and

when synchronization between the first and second nodes and the first and third nodes is warranted, analyze the resource-aware overlay to select either the second or third node for synchronization.

20. The one or more computer-readable media as recited in claim 19, further comprising computer-executable instruction that, when executed, cause the computing system to analyze the resource-aware overlay to determine which of the second and third nodes has a greater likelihood of being a more efficient synchronization partner based, at least in part, on the second and third nodes'"'"' respective ability to redistribute file synchronization events to be received from the first node.