Caching techniques for streaming media

• US 7,076,544 B2
• Filed: 04/08/2002
• Issued: 07/11/2006
• Est. Priority Date: 04/08/2002
• Status: Expired due to Fees

• Current Assignee: eTotalSource, Inc., Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Douceur, John R., Heckerman, David E., Katz, Ariel, Goodman, Joshua, Friedel, Guy, Sagiv, Yifat
• Primary Examiner(s): Najjar, Saleh
• Assistant Examiner(s): Baturay, Alicia
• Application Number:
  US10/104,679
• Publication Number:
  US 20030217113A1
• Time in Patent Office: 1,555 Days
• Field of Search: 709/223, 709/226, 709/229, 709/231, 718/104, 711/100, 711/118, 711/113, 711/136, 711/159
• US Class Current: 709/223
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A streaming media caching mechanism and cache manager efficiently establish and maintain the contents of a streaming media cache for use in serving streaming media requests from cache rather than from an original data source when appropriate. The cost of caching is incurred only when the benefits of caching are likely to be experienced. The caching mechanism and cache manager evaluate the request count for each requested URL to determine whether the URL represents a cache candidate, and further analyze the URL request rate to determine whether the content associated with the URL will be cached. In an embodiment, the streaming media cache is maintained with a predetermined amount of reserve capacity rather than being filled to capacity whenever possible.

Claims

1. At a proxy server communicably linked to a first network and communicably linked to a second network, the first network including at least one client computer and the second network including at least one server computer, a method of caching streaming media content from a server computer at the proxy server to facilitate more efficient client computer access to the streaming media content, the method comprising:

receiving a request for streaming media content from a client computers included in the first network, the request directed to a server computer in the second network, the request corresponding to a resource identifier that identifies streaming media content maintained by the server computer;

determining that the number of requests for the identified streaming media content satisfies a threshold indicative of the streaming media content being a candidate for caching at the proxy server, the determination based on analysis of the received request and on analysis of one or more previously received requests for the identified streaming media content from client computers in the first network, the one or more previously received requests being received at the proxy server prior to the received request being received at the proxy server;

in response to the threshold being satisfied, calculating a request rate for the resource identifier based on the number of ticks of an adaptive global clock that occurred between reception of the first previously received request and reception of the received request, the ticks of the adaptive global clock accruing at different rates according to the level of network activity at the network proxy;

determining that the calculated request rate is greater than the request rate for at least one resource identifier corresponding to streaming media content previously cached at the proxy server; and

caching the requested streaming media content at the proxy server.

2. The method according to claim 1, wherein the resource identifier is a URL, and wherein the second network is a wide area network.

3. The method according to claim 2, wherein the wide area network comprises the Internet, and the first network comprises a local area network.

4. The method according to claim 1, wherein determining that the number of requests for the identified streaming media content satisfies a threshold further comprises:

ascertaining whether the received request for the streaming media content is the first request from any of the at least one client computers; and

adding the selected resource identifier to a list of previously requested resource identifiers if the received request is the first request for the selected streaming media content, wherein each resource identifier in the list is associated with an identity of a client computer previously requesting content associated with that resource identifier.

5. The method according to claim 4, further comprising:

determining via the list of previously requested resource identifiers whether the requesting client computer is the same as any client computer previously requesting the streaming media content;

incrementing the number of requests by a first predetermined value if the requesting client computer is not the same as any client computer previously requesting the streaming media content; and

incrementing the number of requests by a second predetermined value if the requesting client computer is the same as a client computer previously requesting the streaming media content, whereby the number of requests identifies a count value representing the number of times that the selected streaming media content has been requested by any of the at least one client computers.

6. The method according to claim 1, further comprising:

comparing the number of requests to a predetermined count threshold;

determining that the selected streaming media content is a cache candidate based on the number of requests exceedings the predetermined count threshold; and

checking the cache to determine how the cache is to be adjusted to store the streaming media content.

7. A proxy server for communicating between a local area network and a wide area network comprising:

one or more processors;

system memory;

one or more computer storage media having stored thereon a non-streaming media proxy and cache module for proxying requests for non-streaming media content from nodes of the local area network and responses thereto from nodes of the wide area network, and for establishing and maintaining a cache for retrievably storing requested non-streaming media content; and

one or more computer storage media having stored thereon a streaming media proxy and cache module comprising;

a proxy module for proxying requests from nodes of the local area network for streaming media content and responses thereto from nodes of the wide area network;

a streaming media cache for retrievably and selectively storing requested streaming media content; and

a cache manager for establishing and maintaining the contents of the streaming media content cache, wherein the cache manager determines when to add streaming media content to the cache, the cache manager configured to;

determine that the number of requests for streaming media content satisfy a threshold indicative of the streaming media content being a candidate for caching at the proxy server, the determination based on analysis of received requests for the identified streaming media content from nodes in the local area network; and

in response to a threshold being satisfied, calculate a request rate for a corresponding resource identifier based on the number of ticks of an adaptive global clock that occurred between reception of received requests for the streaming media content, the ticks of the adaptive global clock accruing at different rates according to the level of network activity at the proxy server such that ticks of the global adaptive clock represent different amounts of time relative a standard world clock depending on the level of network activity;

determine that a calculated request rate is greater than the request rate for at least one resource identifier corresponding to streaming media content previously cached at the proxy server.

8. A computer program product for use at a proxy server communicably linked to a first network and communicably linked to a second network, the first network including at least one client computer and the second network including at least one server computer, the computer program product for implementing a method of caching streaming media content from a server computer at the proxy server to facilitate more efficient client computer access to the streaming media content, the computer program product comprising one or more computer storage media having stored thereon computer-executable instructions that, when executed by a processor, cause the proxy server to perform the following:

receive a request for streaming media content from a client computer included in the first network, the request directed to a server computer in the second network, the request corresponding to a resource identifier that identifies streaming media content maintained by the server computer;

determine that the number of requests for the identified streaming media content satisfies a threshold indicative of the streaming media content being a candidate for caching at the proxy server, the determination based on analysis of the received request and on analysis of one or more previously received requests for the identified streaming media content from client computers in the first network, the one or more previously received requests being received at the proxy server prior to the received request being received at the proxy server;

in response to the threshold being satisfied, calculate a request rate for the resource identifier based on the number of ticks of an adaptive global clock that occurred between reception of the first previously received request and reception of the received request, the ticks of the adaptive global clock accruing at different rates according to the level of network activity at the network proxy;

determine that the calculated request rate is greater than the request rate for at least one resource identifier corresponding to streaming media content previously cached at the proxy server; and

cache the requested streaming media content at the proxy server.