Data communication apparatus and data communication method

• US 20030093488A1
• Filed: 05/03/2002
• Published: 05/15/2003
• Est. Priority Date: 11/15/2001
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Yasuhiro, Yoshida, Hiroshi
• Granted Patent: US 7,043,558 B2
• Time in Patent Office: Days
• US Class Current: 709/213
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0862 with prefetch
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: H04N 21/2183 Cache memory caches in web servers or browsers G06F16/9574; intermediate storage and caching in data networks H04L67/568
• CPC Class Codes: H04N 21/23106 involving caching operations prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand

Abstract

The present invention aims to embody a cache server which can provide the service of the same quality as a media server. A client sends a delivery request for a streaming delivery of a specific media file to a media server, and a cache checking unit of the cache server checks if the requested media file is stored in a cache file storing unit as a cache file. If it is stored, a file streaming delivering unit performs the streaming delivery to the client using the cache file. If not stored, the cache checking unit transfers the delivery request to the media server, and the media server performs the streaming delivery, and in parallel with the streaming delivery, at the cache server, a media file obtaining unit obtains the requested media file from the media server and stores the requested media file in the cache file storing unit.

Claims

1. A data communication apparatus for performing communication between a terminal device requesting streaming delivery of information data and a delivering apparatus holding at least one information data file containing at least one piece of information data and performing the streaming delivery of the information data requested by the terminal device, the data communication apparatus comprising:

a file caching unit available to store any piece of the information data file;

a delivery request receiving unit for receiving a delivery request of the streaming delivery of specific information data from the terminal device;

a data checking unit for checking if the information data file containing requested information data of which the streaming delivery is requested by the delivery request is stored in the file caching unit, and sending the delivery request to the delivering apparatus if the information data file containing the requested information data is not stored in the file caching unit;

a file transmission requesting unit for sending a file transmission request for requesting a transmission of requested information data file containing the requested information data out of the information data file held by the delivering apparatus if the requested information data file containing the requested information data is not stored in the file caching unit;

a file receiving unit for receiving the requested information data file sent from the delivering apparatus in response to the file transmission request, and

wherein the file caching unit stores the requested information data file received by the file receiving unit.

2. The data communication apparatus of claim 1 further comprising a data delivering unit performing the streaming delivery of the requested information data to the terminal device from the file caching unit if the information data file containing the requested information data is stored in the file caching unit.

3. The data communication apparatus of claim 1 further comprising:

a communication rate checking unit for checking a communication rate available for receiving the requested information data file by the file receiving unit; and

a communication rate setting unit for setting the communication rate used for receiving the requested information data file by the file receiving unit based on the available communication rate checked by the communication rate checking unit, and

wherein the file receiving unit receives the requested information data file at the communication rate set by the communication rate setting unit.

4. The data communication apparatus of claim 1,

wherein the data communication apparatus is connected to the delivering apparatus though plural communication channels,

the data communication apparatus further comprising a communication channel selecting unit for selecting a communication channel used for receiving the requested information data file by the file receiving unit, and

wherein the file receiving unit receives the requested information data file using the communication channel selected by the communication channel selecting unit.

5. The data communication apparatus of claim 1 further comprising a delivery request counting unit for counting a number of transmission of the delivery request for each of the requested information data each time the data checking unit sends the delivery request to the delivering apparatus, and

wherein the file transmission requesting unit sends the file transmission request to the delivering apparatus only for the requested information data of which the number of transmission counted by the delivery request counting unit exceeds a predetermined threshold value.

6. The data communication apparatus of claim 1 further comprising a communication rate dynamically setting unit for dynamically setting a communication rate used for receiving the requested information data file by the file receiving unit when the file receiving unit receives the requested information data file, and

wherein the file receiving unit receives the requested information data file at the communication rate dynamically set by the communication rate dynamically setting unit.

7. The data communication apparatus of claim 2, wherein, when the delivery request receiving unit receives the delivery request for the requested information data from a new terminal device before the file caching unit finishes storing the requested information data file, the data delivering unit performs the streaming delivery of the requested information data to the new terminal device from the file caching unit after the requested information data file has been stored in the file caching unit.

8. The data communication apparatus of claim 2 further comprising:

an information data receiving unit for receiving the requested information data of which the streaming delivery is performed from the delivering apparatus to the terminal device; and

an information data caching unit for storing the requested information data received by the information data receiving unit, and

wherein, when the delivery request receiving unit receives the delivery request for the requested information data from a new terminal device before the information data caching unit finishes storing the received requested information data, the data delivering unit performs the streaming delivery of the received requested information data to the new terminal device sequentially from a part of the received requested information data, which has been already stored in the information data caching unit,.

9. The data communication apparatus of claim 8 further comprising a data deleting unit for deleting duplicated information data stored in the information data caching unit when the information data in the file caching unit and the information data in the information data caching unit are duplicated.

10. A data communication method for performing communication between a terminal device for requesting streaming delivery of information data and a delivering apparatus holding at least one information data file containing at least one piece of information data and performing the streaming delivery of the information data requested by the terminal device, the method comprising:

recording any piece of the information data file;

receiving a delivery request of the streaming delivery of specific information data from the terminal device;

checking if the information data file containing requested information data of which the streaming delivery is requested by the delivery request is recorded by the recording;

sending the delivery request for requesting the streaming delivery of the requested information data to the delivering apparatus if the information data file containing the requested information data is not recorded by the recording;

sending a file transmission request for requesting a transmission of requested information data file containing the requested information data out of the information data file held by the delivering apparatus if the requested information data file containing the requested information data is not stored by the recording;

receiving the requested information data file sent from the delivering apparatus in response to the file transmission request, and

wherein the recording records the requested information data file received by the receiving.