ROUTER, METHOD FOR USING CACHE WHEN CONTENT SERVER IS UNREACHABLE, AND PROGRAM

• US 20130275619A1
• Filed: 01/16/2012
• Published: 10/17/2013
• Est. Priority Date: 01/19/2011
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yagyu, Tomohiko
• Granted Patent: US 9,444,724 B2
• Time in Patent Office: Days
• US Class Current: 709/239
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

Provided is a router to acquire a content, even when accessibility to a server is impossible due to a network failure. The router comprises: a unit for storing content data included in a content reply message transmitted from a content server; a unit for, when the content server becomes unreachable, broadcasting, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router; and a unit for replying a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information.

Claims

1. A router comprising:

means for storing content data included in a content reply message transmitted from a content server;

means for, when the content server becomes unreachable, broadcasting, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router; and

means for replying a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information.

2. The router according to claim 1, further comprising:

means for setting the guidance information in the own router and transferring the MBC setting request message to another router, when the MBC setting request message is received.

3. The router according to claim 1, wherein, when the MBC setting request message is received from a plurality of routers, the guidance information is set in the own router based on the MBC setting request message in which the number of hops is minimum.

4. The router according to claim 1, wherein a broadcasting range of the MBC setting request message is a range of a predetermined number of hops.

5. The router according to claim 1, wherein the content data stored in the own router is retained at least until an access pass to the content server recovers.

6. The router according to claim 1, wherein the MBC setting request message includes a content ID, the number of hops, and the upper limit number of transfers.

7. The router according to claim 1, wherein the guidance information includes a content ID, the number of hops, a downstream node, and a registration time.

8. A cache using method when a content server is unreachable, comprising steps of:

storing, as a cache, content data included in a content reply message transmitted from a content server;

when the content server becomes unreachable, broadcasting, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router; and

replying a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information.

9. A non-transitory computer-readable medium on which recorded is a program causing a computer to function as a router comprising:

means for storing content data included in a content reply message transmitted from a content server;

means for, when the content server becomes unreachable, broadcasting, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router; and

means for replying a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information.

10. A system for accessing a content, comprising:

a server for storing a content data;

a first router comprising;

means for storing content data included in a content reply message transmitted from a content server;

means for, when the content server becomes unreachable, broadcasting, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router; and

means for replying a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information; and

one or more second routers included in the other routers;

comprising;

means for transferring the content request message to the first router in accordance with the guidance information.

11. A method for accessing a content, comprising the steps of:

causing a first router to store, as a cache, content data included in a content reply message transmitted from a content server;

causing the first server, when the content server becomes unreachable, to broadcast, to other routers, an MBC setting request message configured to set guidance information in the other routers, the guidance information being used, when a content request message which requests the content server for the content data is transmitted from a content request node, to transfer the content request message to the own router;

causing one or more second routers included in the other routers to transfer the content request message to the first router in accordance with the guidance information; and

causing the first server to reply a content reply message including the stored content data, when the content request message used to request the content server for the content data is transferred in accordance with the guidance information.