Computer system with a packet transfer device using a hash value for transferring a content request

• US 20060248195A1
• Filed: 04/26/2006
• Published: 11/02/2006
• Est. Priority Date: 04/27/2005
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Suzuki, Toshiaki, Kataoka, Mikio, Toumura, Kunihiko, Yamamoto, Junji
• Granted Patent: US 7,653,703 B2
• Time in Patent Office: Days
• US Class Current: 709/226
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1021 based on client or server locations
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context

Abstract

An object of this invention is to reduce a calculation amount and required storage capacity of a URL switch by dividing transfer destination determining processing among a plurality of devices. Provided is a computer system including: a plurality of servers; and a packet transfer device, in which: the servers are coupled to the packet transfer device; the packet transfer device is coupled to a client terminal via a network; the packet transfer device receives a content request including a fixed-length hash value that is calculated from a variable-length identifier of the content requested by the client terminal; extracts the hash value from the received content request; and determines, based on the extracted hash value, to which one of the plurality of servers the content request is to be transferred.

Claims

1. A computer system comprising a plurality of servers, and a packet transfer device, wherein:

the servers are coupled to the packet transfer device;

the packet transfer device is coupled to a client terminal via a network;

the packet transfer device;

receives a content request including a fixed-length hash value that is calculated from a variable-length identifier of the content requested by the client terminal;

the packet transfer device extracts the hash value from the received content request; and

the packet transfer device determines, based on the extracted hash value, to which one of the plurality of servers the content request is to be transferred.

2. The computer system according to claim 1, further comprising the client terminal, wherein the client terminal calculates a fixed-length hash value from the variable-length identifier of the requested content, stores the calculated hash value in the content request, and sends the content request to the packet transfer device.

3. The computer system according to claim 1, further comprising a proxy server for receiving a content request from the client terminal, wherein:

the proxy server is coupled to the packet transfer device and to the client terminal;

the client terminal sends, to the proxy server, a content request that includes a variable-length identifier of requested content; and

the proxy server extracts, from the received content request, the variable-length identifier of the requested content, calculates a fixed-length hash value from the extracted identifier, stores the calculated hash value in the content request, and sends the content request to the packet transfer device.

4. The computer system according to claim 3, wherein the proxy server comprises:

an interface unit for receiving the content request from the client terminal; and

a processor for calculating a fixed-length hash value from the variable-length identifier of the requested content and storing the calculated hash value in the content request.

5. The computer system according to claim 1, wherein the client terminal comprises a processor for calculating a fixed-length hash value from the variable-length identifier of the requested content and writing the calculated hash value in a content request packet.

6. The computer system according to claim 1, wherein the packet transfer device comprises:

a processor for extracting a fixed-length hash value that is included in the content request; and

storage unit for storing transfer destination selection information, which includes correspondence between the hash value calculated from the variable-length content identifier and a transfer destination of the content request.

7. The computer system according to claim 6, wherein the processor determines a transfer destination of the content request based on the extracted hash value and the transfer destination selection information, and transfers the content request to the determined transfer destination.

8. The computer system according to claim 6, wherein the processor extracts the hash value from an HTTP header.

9. The computer system according to claim 6, wherein the processor extracts the hash value from a session establishment requesting packet.

10. The computer system according to claim 1, wherein:

the packet transfer device receives, instead of the content request, a session establishment request including a fixed-length hash value that is calculated from a variable-length identifier of content requested by the client terminal; and

the packet transfer device extracts the hash value from the received session establishment request, and determines, based on the extracted hash value, to which one of the plurality of servers the session establishment request is to be transferred.

11. A computer system, comprising:

a packet transfer device;

an origin server;

a cache server; and

a control server, wherein;

the origin server provides content to a client terminal;

the cache server stores content provided by the origin server;

the control server manages the content stored in the cache server;

the packet transfer device receives a content request including a fixed-length hash value that is calculated from a variable-length identifier of the content requested by the client terminal; and

the packet transfer device allocates the content request to the origin server or the cache server based on the hash value that is included in the received content request.

12. The computer system according to claim 11, wherein the control server has cache location information which includes information of content stored in the cache server.

13. The computer system according to claim 11, wherein the cache server comprises:

an interface for receiving a content request from the client terminal; and

a processor for calculating a fixed-length hash value from a variable-length identifier of requested content and storing the calculated hash value in the content request.