Cache channel at network nodes to pass request and data or pointer to shared buffer

• US 6,366,952 B2
• Filed: 03/16/2001
• Issued: 04/02/2002
• Est. Priority Date: 06/03/1992
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: Network Caching Technology LLC
• Inventors: Pitts, William Michael
• Primary Examiner(s): Kim, Kenneth S.
• Application Number:
  US09/811,331
• Publication Number:
  US 20010011300A1
• Time in Patent Office: 382 Days
• Field of Search: 709/213, 709/219, 709/217
• US Class Current: 709/217
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: H04L 67/288 Distributed intermediate devices, i.e. intermediate devices for interaction with other intermediate devices on the same level
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/565 Conversion or adaptation of application format or content adding application control or application functional data H04L67/561
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5681 Pre-fetching or pre-delivering data based on network characteristics
• 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]

Abstract

A network of digital computers includes Network Distributed Cache (“NDC”) sites. Each NDC site includes an NDC that has an NDC buffer. One of the NDC sites receives a request to access data in a stored dataset. The receiving NDC checks its NDC buffer for a projected image of requested data. If the NDC buffer lacks the requested data, and if the NDC site is not the NDC server terminator site for the requested data, the NDC site transmits the request to an NDC site that is closer to the NDC server terminator site. When a requesting NDC site and the request receiving NDC site having a projected image of the requested data both have this NDC buffers located in a shared memory, the NDC site having the data transmits to the requesting NDC a pointer to a location in its NDC buffer for the data.

Claims

1. In a network of digital computers that includes a plurality of Network Distributed Cache (“

NDC”

) sites, each NDC site including an NDC that has an NDC buffer, a method used in projecting through an NDC client terminator site an image of a stored dataset that is accessed through an NDC server terminator site, the network including a pair of NDC sites both of which can access a shared memory, the method comprising the steps of;

(a) a first one of said pair of NDC sites receiving via the network a request to access data in the stored dataset, the request to access data being initially transmitted from a client site to the NDC client terminator site;

(b) the NDC of the first NDC site checking the NDC buffer thereof to determine if a projected image of data requested from the stored dataset is already present there;

(c) if the NDC buffer of the first NDC site does not contain a projected image of all data requested from the stored dataset, and if the first NDC site is not the NDC server terminator site for the stored dataset, and if a second one of said pair of NDC sites is closer to the NDC server terminator site for the stored dataset than the first NDC site, the NDC of the first NDC site transmitting a request for data from the stored dataset downstream to the second NDC site;

(d) if the NDC buffer of the second NDC site, which is located in the shared memory, does not contain a projected image of all data requested from the stored dataset by the first NDC site, and if the second NDC site is the NDC server terminator site for the stored dataset, the NDC of the second NDC site accessing the stored dataset to project an image of the requested data into the NDC buffer of the second NDC site;

(e) if the NDC buffer of the second NDC site does not contain a projected image of all data requested from the stored dataset by the first NDC site, and if the second NDC site is not the NDC server terminator site for the stored dataset, the NDC of the second NDC site transmitting a request for data from the stored dataset downstream to an NDC site of the network that is closer to the NDC server terminator site for the stored dataset than the second NDC site to effect projection of an image of the requested data upstream into the NDC buffer of the second NDC site;

(f) when the NDC buffer of the second NDC site contains a projected image of all data requested from the stored dataset by the first NDC site, the NDC of the second NDC site transmitting to the first NDC site a pointer to a location in the NDC buffer of the second NDC site which contains the requested data;

(g) the first NDC site, upon receiving from the second NDC site the pointer to the location in the NDC buffer of the second NDC site which contains the requested data, returning from the NDC buffer of the second NDC site an image of the requested data upstream toward the client site that initially requested access to data from the stored dataset.