Inter-cache protocol for improved WEB performance

• US 5,787,470 A
• Filed: 10/18/1996
• Issued: 07/28/1998
• Est. Priority Date: 10/18/1996
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sibal, Sandeep, Shur, David Hilton, DeSimone, Antonio
• Primary Examiner(s): Swann, Tod R.
• Assistant Examiner(s): TZENG, FRED
• Application Number:
  US08/733,485
• Time in Patent Office: 648 Days
• Field of Search: 395/440, 395/445, 395/446, 395/447, 395/448, 395/451, 395/468, 395/471, 395/621, 395/200.53, 395/473, 395/608, 395/610, 395/200.3, 395/200.31, 395/200.32 , 395/200.43, 395/200.46, 395/200.48, 395/200.55, 395/200.6
• US Class Current: 711/124
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

On the Internet, different caches may contain copies of objects that have been copied from originating servers when they were accessed by users. Interconnected caches may have different objects stored thereon that might at some time be requested by a client terminal that is connected to a cache other than the one on which the object is stored. Rather than awaiting a request for a particular object and then querying each neighbor cache to determine whether a copy of the requested object is stored thereon, and then downloading the requested object if it is found, information about the contents of the neighbor caches is exchanged between these caches so that when a request for an object is received, the object can be retrieved from the cache in which it is stored. In the alternative, the object may be retrieved from the originating server if, for example, the object stored in a cache is stale based on the date and time it was last modified in the cache.

Claims

1. In a system comprising at least a first and a second interconnected Web caches on a packet data network, which each stores Web objects that can be retrieved by a plurality of client terminals connected to either Web cache, the Web objects stored in the first and second Web caches being copies of Web objects received from Web servers connected on the packet data network, a method comprising the steps of:

receiving a signal at the second Web cache from the first Web cache that is indicative of a request for information relating to Web objects stored in the second Web cache; and

transmitting a signal from the second Web cache to the first Web cache that provides the requested information relating to Web objects stored in the second Web cache.

2. The method of claim 1 further comprising the steps of:

receiving a request for a copy of a Web object stored in the second Web cache from the first Web cache in response to receiving the information relating to Web objects stored in the second Web cache; and

providing a copy of the requested Web object to the first Web cache in response to the request for a copy of the Web object in the second Web cache.

3. The method of claim 1 wherein the signal requesting information relating to Web objects stored in the second Web cache is received asynchronous with a request for a copy of a Web object by a client terminal connected to either the first or second Web cache.

4. The method of claim 1 wherein the requested information relating to Web objects stored in the second Web cache comprises information relating to what Web objects are stored in the second Web cache.

5. The method of claim 1 wherein the requested information relating to Web objects stored in the second Web cache comprises information relating to the time a Web object was modified in the second Web cache.

6. The method of claim 5 wherein the requested information relating to Web objects stored in the second Web cache further comprises information relating to the size of a Web object in the second Web cache.

7. The method of claim 1 wherein the step of receiving a signal at the second Web cache from the first Web cache that is indicative of a request for information relating to Web objects stored in the second Web cache comprises the step of receiving a registration request for information relating to when Web objects are modified in the second Web cache.

8. The method of claim 7 wherein the signal transmitted from the second Web cache to the first Web cache that provides the requested information relating to Web objects stored in the second Web cache is transmitted when a Web object is modified in the second Web cache.

9. The method of claim 7 wherein the signal transmitted from the second Web cache to the first Web cache that provides the requested information relating to Web objects stored in the second Web cache is transmitted on a periodic basis.

10. The method of claim 1 wherein the signal received at the second Web cache from the first Web cache that is indicative of a request for information relating to Web objects stored in the second Web cache comprises information on a set of Web objects that have been modified in the first Web cache, and the signal from the second Web cache to the first Web cache that provides the requested information relating to Web objects stored in the second Web cache comprises information on a set of Web objects that have been modified in the second Web cache.

11. In a system comprising at least a first and a second interconnected Web caches on a packet data network, which each stores Web objects that can be retrieved by a plurality of client terminals connected to either Web cache, the objects stored in the first and second Web caches being copies of Web objects received from Web servers connected on the packet data network, a method comprising the steps of:

receiving at the second Web cache from the first Web cache information relating to Web objects that have been modified in the first Web cache,

updating state-information stored at the second Web cache relating to Web objects stored in the first Web cache in response to the information received from the first Web cache relating to Web objects that have been modified in the first Web cache; and

transmitting information to the first Web cache from the second Web cache relating to those Web objects in the second Web cache that have been modified in the second Web cache after those Web objects have been modified in the first Web cache in accordance with the updated state information relating to Web objects stored in the first Web cache.

12. In a system comprising a first Web cache, a second Web cache and at least one other Web cache, the first, second and at least one other Web cache being interconnected on a packet data network, each Web cache storing Web objects that can be retrieved by a plurality of client terminals connected to any Web cache, the Web objects stored in the first, second and the at least one other Web caches being copies of Web objects received from Web servers connected on the packet data network, a method comprising the steps of:

receiving at the second Web cache from the first Web cache information relating to Web objects that have been modified in the first Web cache and information that the first Web cache has on Web objects that have been modified in all other Web caches in the system;

updating state-information stored at the second Web cache relating to Web objects stored in the first Web cache and all other Web caches in the system in response to the information received from the first Web cache relating to Web objects that have been modified in the first Web cache and information that the first Web cache has on Web objects that have been modified in all other Web caches in the system; and

transmitting to the first Web cache from the second Web cache, information relating to those Web objects in the second Web cache that have been modified in the second Web cache and information that the second Web cache has relating to Web objects that have been modified in all other Web caches, in accordance with the updated state-information stored at the Web second cache relating to Web objects stored on all Web caches.