CACHE SHARING AMONG BRANCH PROXY SERVERS VIA A MASTER PROXY SERVER AT A DATA CENTER

• US 20120166572A1
• Filed: 03/02/2012
• Published: 06/28/2012
• Est. Priority Date: 10/21/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Burckart, Erik J., Cammarata, John P., Ivory, Andrew J., Shook, Aaron K.
• Granted Patent: US 8,880,634 B2
• Time in Patent Office: Days
• US Class Current: 709/213
• CPC Class Codes: G06F 13/00 Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units interface circuits for specific input/output devices G06F3/00 ; multiprogram control therefor G06F9/46; multiprocessor systems G06F15/16
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• 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 67/5682 Policies or rules for updating, deleting or replacing the stored data

Abstract

A method for cache sharing among branch proxy servers. A branch proxy sever receives a request for accessing a resource at a data center. The branch proxy server creates a cache entry in its cache to store the requested resource if the branch proxy server does not store the requested resource. Upon creating the cache entry, the branch proxy server sends the cache entry to a master proxy server at the data center to transfer ownership of the cache entry if the master proxy server did not store the resource in its cache. When the resource becomes invalid or expired, the master proxy server informs the appropriate branch proxy servers storing the resource to purge the cache entry containing this resource. In this manner, the master proxy server ensures that the cached resource is synchronized across the branch proxy servers storing this resource.

Claims

1. A method for cache sharing among branch proxy servers, the method comprising:

receiving a request by a first proxy server in a branch office to access a resource at a data center;

transmitting a request to a second proxy server at said data center to determine if said resource is located in a cache of said second proxy server in response to said first proxy server not storing said resource in its cache;

creating a cache entry in said cache of said first proxy server to store said resource in response to said second proxy server not storing said resource in its cache; and

sending said cache entry to said second proxy server to transfer ownership of said cache entry to said second proxy server.

2. The method as recited in claim 1 further comprising:

fetching said resource by said first proxy server in response to said second proxy server not storing said resource in its cache.

3. The method as recited in claim 1 further comprising:

receiving said resource by said first proxy server from said second proxy server in response to said second proxy server storing said resource in its cache.

4. The method as recited in claim 1 further comprising:

receiving said cache entry by said second proxy server from said first proxy server; and

storing said cache entry in said cache of said second proxy server.

5. The method as recited in claim 4 further comprising:

informing said first proxy server to purge said cache entry in response to said resource at said cache entry being one of invalid and expired.

6. The method as recited in claim 4 further comprising:

informing one or more proxy servers at one or more branch offices to purge a cache entry storing said resource in response to said resource at said cache entry being one of invalid and expired.