Data transfer scheme using caching and differential compression techniques for reducing network load

Abstract

In a data transfer scheme using a caching technique and/or a compression technique which is capable of reducing the network load of a network connecting between data transfer devices, correspondences between data and their names are registered at the data transfer devices and the corresponding names are transferred, instead of transferring the data, for those data for which the correspondences are registered, so that it is possible to reduce the amount of transfer data among the data transfer devices. Even when the name corresponding to the data is not registered so that it is impossible to transfer the corresponding name instead of transferring the data, it is possible to reduce the amount of transfer data among the data transfer devices by transferring the compressed data in which this data is expressed in a compressed form by utilizing the name corresponding to the registered reference data.

1 - 26 . (canceled) 
   
   
       27 . A server side proxy device for relaying a communication between a server device and a client side proxy device which relays data transmitted by the server device by setting a client device as a destination, the server side proxy device comprising:
 a storing unit configured to store first data received from the server device and transmitted to the client side proxy device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   a reception unit configured to receive second data transmitted by the server device by setting the client device as a destination; and   a transmission unit configured to transmit a difference data indicating a difference of the second data with respect to the first data and an identification information indicating that it is the difference data, by setting the client deice as a destination.   
   
   
       28 . The server side proxy device of  claim 27 , wherein the transmission unit is also configured to transmit the first data and the fingerprint to the client side proxy device, if the fingerprint is not stored in the storing unit when the first data is received. 
   
   
       29 . The server side proxy device of  claim 27 , further comprising a registration unit configured to register the first data and the fingerprint in correspondence into the storing unit, except when the first data is null. 
   
   
       30 . The server side proxy device of  claim 27 , wherein the server side proxy device is connected to the server device through a local area network. 
   
   
       31 . A client side proxy device for relaying a communication between a client device and a server side proxy device which relays data transmitted by a server device by setting the client device as a destination, the client side proxy device comprising:
 a storing unit configured to store first data received from the server side proxy device and transmitted to the client device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   a reception unit configured to receive a difference data indicating a difference of second data with respect to the first data and an identification information indicating that it is the difference data, for which the client device is set as a destination; and   a transmission unit configured to generate the second data by using the first data and the difference data, and transmit the second data by setting the client device as a destination.   
   
   
       32 . The client side proxy device of  claim 31 , further comprising a registration unit configured to register the first data and the fingerprint in correspondence into the storing unit, when the first data and the fingerprint are received from the server side proxy device. 
   
   
       33 . The client side proxy device of  claim 31 , wherein the client side proxy device is connected to the client device through a local area network. 
   
   
       34 . A data transfer method at a server side proxy device for relaying a communication between a server device and a client side proxy device which relays data transmitted by the server device by setting a client device as a destination, the data transfer method comprising:
 storing first data received from the server device and transmitted to the client side proxy device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   receiving second data transmitted by the server device by setting the client device as a destination; and   transmitting a difference data indicating a difference of the second data with respect to the first data and an identification information indicating that it is the difference data, by setting the client deice as a destination.   
   
   
       35 . A data transfer method at a client side proxy device for relaying a communication between a client device and a server side proxy device which relays data transmitted by a server device by setting the client device as a destination, the data transfer method comprising:
 storing first data received from the server side proxy device and transmitted to the client device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   receiving a difference data indicating a difference of second data with respect to the first data and an identification information indicating that it is the difference data, for which the client device is set as a destination; and   generating the second data by using the first data and the difference data, and transmitting the second data by setting the client device as a destination.   
   
   
       36 . A storage medium having computer readable program codes embodied therein for causing a computer to function as a server side proxy device for relaying a communication between a server device and a client side proxy device which relays data transmitted by the server device by setting a client device as a destination, the computer readable program codes include:
 a first computer readable program code for causing said computer to store first data received from the server device and transmitted to the client side proxy device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   a second computer readable program code for causing said computer to receive second data transmitted by the server device by setting the client device as a destination; and   a third computer readable program code for causing said computer to transmit a difference data indicating a difference of the second data with respect to the first data and an identification information indicating that it is the difference data, by setting the client deice as a destination.   
   
   
       37 . A storage medium having computer readable program codes embodied therein for causing a computer to function as a client side proxy device for relaying a communication between a client device and a server side proxy device which relays data transmitted by a server device by setting the client device as a destination, the computer readable program codes include:
 a first computer readable program code for causing said computer to store first data received from the server side proxy device and transmitted to the client device, and a fingerprint generated by applying a hash function to the first data, in correspondence, such that the fingerprint functions as a name of the first data;   a second computer readable program code for causing said computer to receive a difference data indicating a difference of second data with respect to the first data and an identification information indicating that it is the difference data, for which the client device is set as a destination; and   a third computer readable program code for causing said computer to generate the second data by using the first data and the difference data, and transmit the second data by setting the client device as a destination.