Connection Management in Peer-to-Peer Content Distribution Clouds

• US 20080294779A1
• Filed: 12/04/2006
• Published: 11/27/2008
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Costa, Manuel, Miller, John, Gkantsidis, Christos, Rodriguez, Pablo Rodriguez, Ranson, Stuart
• Granted Patent: US 7,849,196 B2
• Time in Patent Office: Days
• US Class Current: 709/226
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/1085 involving dynamic management of active down- or uploading connections

Abstract

A topology management process is implemented which involves removing or “tearing down” connections between nodes in certain situations in order to try to replace those connections with more optimal ones. Idle connections are torn down unless those are in a “notify” state; a notify state being one in which a request for content has been made to a neighbour but that neighbour has no available content as yet. Idle connections in a notify state are torn down only if they remain idle for a longer time than that required before an idle connection is torn down. To avoid problems caused by clusters of node forming and of loners being unable to join the cloud, network churn algorithms are taught. These involve requiring nodes to drop connections when specified conditions are met. Relative content distribution between connections is monitored and this information used to influence selection of those connections to drop.

Claims

1. A method of managing connections at a node in a peer-to-peer content distribution cloud, said method comprising:

(i) monitoring traffic on connections at the node for a specified first time period;

(ii) allocating, as being in a notify state, any idle connections at the node over which content has been requested from a neighbor but is not present at that neighbor; and

(iii) tearing down any connections at the node which have been idle for at least that specified first time period and which are not in a notify state.

2. A method as claimed in claim 1 which further comprises:

tearing down any connections at the node which have been in a notify state for at least a second specified time period which is longer than the first time period.

3. A method as claimed in claim 2 wherein said second time period is about twice as long as the first time period.

4. A method as claimed in claim 3 wherein said first time period is between about 3 and 7 minutes.

5. A method as claimed in claim 3 which further comprises:

specifying a minimum number of connections required by the node in order to be part of the peer-to-peer content distribution cloud, and

allowing the number of connections at the node to fall below the minimum in specified situations.

6. A method as claimed in claim 5 which further comprises:

specifying a maximum number of connections required by the node in order to be part of the peer-to-peer content distribution cloud, and

allowing the number of connections at the node to exceed the maximum in specified situations.

7. A method as claimed in claim 6 wherein said step (i) of monitoring traffic on connections at the node further comprises obtaining information about relative content distribution over those connections.

8. A method as claimed in claim 7 which further comprises:

once every specified interval, selecting one of the connections at the node and tearing down that connection.

9. A method as claimed in claim 8 wherein said connection is selected in a substantially random manner from at least a subset of the connections at the node.

10. A method as claimed in claim 9 wherein said step (i) of monitoring traffic on connections at the node further comprises obtaining information about relative content distribution over those connections;

and wherein said subset of the connections at the node excludes the connection where the monitored relative content distribution over that connection is the lowest.

11. A method as claimed in claim 10 wherein said subset of the connections at the node excludes the connection where the monitored relative content distribution over that connection is the highest.

12. A method as claimed in claim 11 wherein said subset further excludes the connection where the monitored relative content distribution over that connection is the second highest.

13. A node in a peer-to-peer content distribution cloud said node comprising:

(i) a plurality of connections to other nodes in the cloud;

(ii) a monitor arranged to monitor traffic on connections at the node for a specified first time period;

(iii) an allocator arranged to allocate as being in a notify state any idle connections at the node over which content has been requested from a neighbor but is not present at that neighbor; and

(iv) a processor arranged to tear down connections at the node which have been idle for at least that specified first time period and which are not in a notify state.

14. A node as claimed in claim 13 wherein the processor is further arranged to tear down any connections at the node which have been in a notify state for at least a second specified time period which is longer than the first time period.

15. A node as claimed in claim 13 wherein said processor is further arranged, once every specified interval, to select one of the connections at the node and tear down that connection.

16. One or more device-readable media with device-executable instructions for performing steps at a node connected in a peer-to-peer content distribution cloud, said steps comprising:

monitoring traffic on connections at the node for a specified first time period;

allocating as being in a notify state any idle connections at the node over which content has been requested from a neighbor but is not present at that neighbor; and

tearing down any connections at the node which have been idle for at least that specified first time period and which are not in a notify state.

17. One or more device-readable media as claimed in claim 16 wherein said steps further comprise tearing down any connections at the node which have been in a notify state for at least a second specified time period which is longer than the first time period.

18. One or more device-readable media as claimed in claim 16 wherein said steps further comprise, once every specified interval, selecting one of the connections at the node and tearing down that connection.

19. One or more device-readable media as claimed in claim 18 wherein said connection is selected in a substantially random manner from at least a subset of the connections at the node.

20. One or more device-readable media as claimed in claim 19 wherein said step of monitoring traffic on connections at the node further comprises:

obtaining information about relative content distribution over those connections; and

wherein said subset of the connections at the node excludes the connection where the monitored relative content distribution over that connection is the lowest.