JP2014164369A - Remote desktop system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which it is difficult to perform remote desktop connection in a remote desktop system performing communication between proxies by UDP, unless uniquely developing recovery and sequence control against packet loss occurrence.SOLUTION: A proxy on a client side receives information for a server device from a client device and transmits the information to a proxy on a server side through a network by TCP communication, and receives information for the client device from the proxy on the server side through the network by the TCP communication and transmits the information to the client device. The proxy on the sever side receives information for the client device from the server device and transmits the information to the proxy on the client side through the network by the TCP communication, and receives information for the server device from the proxy on the client side through the network by the TCP communication and transmits the information to the server device.

Description

  The present invention relates to a remote desktop system, a remote desktop connection method, a proxy device, a proxy method, and a program.

  A remote desktop system that operates a GUI (graphic user interface) of a computer from another device connected through a network is widely adopted. In a remote desktop system, a computer side controlled via a network is called a server device, and a device side operated by a user is called a client device. As a communication protocol suitable for remote desktop connection, there is RDP (Remote Desktop Protocol). This RDP is an application layer protocol.

  On the other hand, as a first related technique related to the present invention, a proxy is provided in each of the server device and the client device for function expansion, and data is exchanged between the server device and the client device via the proxy. It is known (see, for example, Patent Document 1). In the first related technology, an intranet in which a multifunction peripheral as a remote desktop client and a proxy server as a relay device are connected via a bus, a call center terminal device as a remote desktop server, and a proxy as a relay device The server is connected via the Internet.

  In addition, in order to efficiently transfer large volumes of data to remote terminals, UDP (User Datagram Protocol) is connected between proxies, and data is transferred using UDP while performing retransmission control and flow control periodically. Has been proposed as a second related technique related to the present invention (see, for example, Patent Document 2).

JP 2008-270972 A JP 2005-136684 A

  However, in a remote desktop system that performs communication between proxies using UDP, when a packet loss occurs, a command transmitted from the client device to the server device is lost, or conversely, the server device transmits the packet to the client device. Response and screen data are missing. For this reason, remote desktop connection is difficult in a communication environment with many packet losses. Further, in the configuration in which the technique of Patent Document 2 is applied to Patent Document 1 and data transfer is performed using UDP while performing retransmission control and flow control between proxies, recovery and order when packet loss occurs You need to develop your own controls and implement them in the proxy.

  The object of the present invention is the above-described problem, that is, in a remote desktop system that performs communication between proxies by UDP, remote desktop connection is difficult unless recovery and sequence control when packet loss occurs are independently developed. It is to provide a remote desktop system that solves this problem.

A remote desktop system according to a first aspect of the present invention includes:
A remote desktop system in which a server device and a client device are connected via a network,
A client-side proxy connected to the client device;
A server-side proxy connected to the server device and connected to the client-side proxy via the network;
The above client-side proxy
A first communication unit that receives information for the server device from the client device and transmits the information to the server-side proxy through the network by TCP communication;
A second communication unit that receives information for the client device from the server-side proxy through the network by TCP communication and transmits the information to the client device;
The server side proxy
A third communication unit that receives information for the client device from the server device and transmits the information to the client-side proxy through the network by TCP communication;
A fourth communication unit that receives information for the server device from the client-side proxy through the network by TCP communication and transmits the information to the server device.

A remote desktop connection method according to a second aspect of the present invention includes:
A method for remote desktop connection between a server device and a client device via a network,
The client side proxy connected to the client device receives information for the server device from the client device, and transmits the information to the server side proxy connected to the server device through the network by TCP communication,
The server-side proxy receives information for the server device from the client-side proxy through the network via TCP communication, and transmits the information to the server device.
The server-side proxy receives information for the client device from the server device, transmits the information to the client-side proxy through the network by TCP communication,
The client-side proxy receives information for the client device from the server-side proxy through the network by TCP communication, and transmits the information to the client device.

The proxy device according to the third aspect of the present invention is:
A proxy device connected to the server device among the client device and the server device constituting the remote desktop system,
A first communication unit that receives information for the client device from the server device and transmits the information to the client device side through the network by TCP communication;
A second communication unit that receives information for the server device from the client device side through the network by TCP communication and transmits the information to the server device.

The proxy method according to the fourth aspect of the present invention is:
A proxy method executed by a proxy device connected to the server device among a client device and a server device constituting a remote desktop system,
Receive information for the client device from the server device and send it to the client device side through the network by TCP communication,
Information for the server device is received from the client device side through the network by TCP communication and transmitted to the server device.
A program according to the fifth aspect of the present invention is:
A computer constituting a proxy device connected to the server device among the client device and the server device constituting the remote desktop system,
A first communication unit that receives information for the client device from the server device and transmits the information to the client device side through the network by TCP communication;
It functions as a second communication unit that receives information for the server device from the client device side through the network by TCP communication and transmits the information to the server device.

  Since the present invention has the above-described configuration, remote desktop connection can be used in a communication environment in which packet loss frequently occurs without independently developing recovery and order control when packet loss occurs.

It is a block diagram of a 1st embodiment of the present invention. It is a block diagram of the 2nd Embodiment of this invention. It is a block diagram of the 3rd Embodiment of this invention. It is a figure which shows the formula used when changing the size of the socket buffer used for transmission / reception using the data transfer time of a network in the 3rd Embodiment of this invention. It is a flowchart which shows an example of the process of the network state confirmation part of the server side proxy module in the 3rd Embodiment of this invention. It is a flowchart which shows an example of the process of the network state confirmation part of the client side proxy module in the 3rd Embodiment of this invention. It is a principal part block diagram of the 4th Embodiment of this invention. It is a flowchart which shows an example of the process of the communication part in the 4th Embodiment of this invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
Referring to FIG. 1, in a remote desktop system 100 according to the first embodiment of the present invention, a server device 110 and a client device 120 are connected via a network 130. A server-side proxy 140 is interposed between the server device 110 and the network 130, and a client-side proxy 150 is interposed between the client device 120 and the network 130.

  The client side proxy 150 includes a first communication unit 151 and a second communication unit 152. The first communication unit 151 has a function of receiving information for the server device 110 from the client device 120 and transmitting the information to the server-side proxy 140 through the network 130 by TCP communication. The second communication unit 152 has a function of receiving information for the client device 120 from the server-side proxy 140 via the network 130 via TCP communication and transmitting the information to the client device 120.

  The server-side proxy 140 includes a third communication unit 141 and a fourth communication unit 142. The third communication unit 141 has a function of receiving information for the client device 120 from the server device 110 and transmitting the information to the client-side proxy 150 through the network 130 by TCP communication. The fourth communication unit 142 has a function of receiving information for the server apparatus 110 from the client side proxy 150 through the network 130 by TCP communication and transmitting the information to the server apparatus 110.

  The client side proxy 150 may be mounted on either the physically same device as the client device 120 or a different device. The server-side proxy 140 may be mounted on either the physically same device as the server device 110 or a different device.

  Next, the operation of the remote desktop system 100 according to the present embodiment will be described.

  In the remote desktop system 100, various information such as commands necessary for remote operation (hereinafter referred to as information for the server device) is transmitted from the client device 120 to the server device 110. On the other hand, response data to a command, GUI screen data, and the like (hereinafter referred to as information for a client) are transmitted from the server apparatus 110 to the client apparatus 120. In the present embodiment, the information for the server device and the information for the client are transmitted and received as follows.

  Information for the server device is first transmitted from the client device 120 to the client-side proxy 150. When the first communication unit 151 of the client-side proxy 150 receives information for the server device from the client device 120, the first communication unit 151 transmits the information to the server-side proxy 140 through the network 130 by TCP communication. The fourth communication unit 142 of the server side proxy 10 receives information for the server device from the client side proxy 150 through the network 130 by TCP communication, and transmits the information to the server device 110.

  Thus, the information for the server device transmitted from the client device 120 is delivered to the server device 110 via the client side proxy 150, the network 130, and the server side proxy 140. If a packet loss occurs in the network 130, the first communication unit 151 retransmits the packet because it cannot receive the ACK by the TCP communication from the fourth communication unit 142. Thereby, the information for the server device transmitted from the client device 120 is reliably delivered to the server device 110.

  On the other hand, information for the client device is first transmitted from the server device 110 to the server-side proxy 140. When the third communication unit 141 of the server-side proxy 140 receives information for the client device from the server device 110, the third communication unit 141 transmits the information to the client-side proxy 150 through the network 130 by TCP communication. The second communication unit 152 of the client side proxy 150 receives information for the client device from the server side proxy 140 through the network 130 by TCP communication, and transmits the information to the client device 120.

  As a result, the information for the client device transmitted from the server device 110 is delivered to the client device 120 via the server-side proxy 140, the network 130, and the client-side proxy 150. If a packet loss occurs in the network 130, the third communication unit 141 cannot receive an ACK by the TCP communication from the second communication unit 152, and retransmits the packet. Thereby, the information for the client device transmitted from the server device 110 is reliably delivered to the client device 120.

  As described above, according to the present embodiment, when packet loss occurs in communication via a network between proxies, recovery and order control are automatically performed by TCP. Therefore, recovery and order when packet loss occurs are performed. Remote desktop connection can be used in a communication environment where packet loss occurs frequently without developing control independently.

[Second Embodiment]
Referring to FIG. 2, in a remote desktop system 200 according to the second embodiment of the present invention, an information processing device 210 and an information processing device 220 are connected via a network 230.

  The information processing apparatus 210 includes a remote desktop server module 240, a server side proxy module 250, and a TCP communication unit 260. The remote desktop server module 240 is a program module for causing the information processing apparatus 210 to function as a server apparatus in a remote desktop system. The TCP communication unit 260 is a program module for the information processing device 210 to perform TCP communication with other devices such as the information processing device 220 via the network 230. The server side proxy module 250 is a program module interposed between the remote desktop server module 240 and the TCP communication unit 260. Although the server-side proxy module 250 is omitted and the remote desktop server module 240 is basically connected to the TCP communication unit 260, remote desktop connection is basically possible. 250 is interposed.

  The information processing apparatus 220 includes a remote desktop client module 270, a client side proxy module 280, and a TCP communication unit 290. The remote desktop client module 280 is a program module for causing the information processing apparatus 220 to function as a client apparatus in the remote desktop system. The TCP communication unit 290 is a program module for the information processing apparatus 220 to perform TCP communication with other apparatuses such as the information processing apparatus 210 via the network 230. The client side proxy module 280 is a program module interposed between the remote desktop client module 270 and the TCP communication unit 290. Although the client-side proxy module 280 is omitted and the remote desktop client module 270 is connected to the TCP communication unit 270, remote desktop connection is basically possible. However, in order to expand the function on the client side, the client-side proxy module 280 is interposed.

  The client side proxy module 280 includes a communication unit 281 and a communication unit 282.

  The communication unit 281 receives various types of information (information for the server device) such as commands necessary for remote operation from the remote desktop client module 270, and uses the function of the TCP communication unit 290 to perform server communication through the network 230 by TCP communication. The information processing apparatus 210 has a function of transmitting to the information processing apparatus 210. The communication unit 281 includes a reception unit 2811, an intermediate buffer 2812, and a transmission unit 2813.

  The intermediate buffer 2812 is a buffer memory that temporarily stores information for the server device.

  The receiving unit 2811 has a function of storing information for the server apparatus received from the remote desktop client module 270 in the intermediate buffer 2812. The reception unit 2811 includes a reception buffer 28111 and a reception processing unit 28112. The reception buffer 28111 is a buffer for temporarily storing information for the server device sent from the remote desktop client module 270 to the remote desktop server module 240. When the remote desktop client module 270 transmits information for the server device to the remote desktop server module 240, the remote desktop client module 270 writes the information to be transmitted in the reception buffer 28111. The reception processing unit 28112 has a function of reading information written in the reception buffer 28111 and writing it in the intermediate buffer 2812.

  The transmission unit 2813 has a function of transmitting information for the server apparatus stored in the intermediate buffer 2812 to the information processing apparatus 210 through the network 230 by TCP communication using the function of the TCP communication unit 290. The transmission unit 2813 includes a transmission processing unit 28131 and a transmission buffer 28132. The transmission processing unit 28131 has a function of reading out information for the server apparatus accumulated in the intermediate buffer 2812 and writing it in the transmission buffer 28132. Information written in the transmission buffer 28132 is read by the TCP communication unit 290 and transmitted to the information processing apparatus 210 through the network 230.

  For example, the communication unit 281 is configured by one application (process), and the reception buffer 28111 and the transmission buffer 28132 are configured by a socket buffer. Each of the reception unit 2811 and the transmission unit 2813 operates as one thread. For this reason, the reception unit 2811 and the transmission unit 2813 operate independently and in parallel.

  The communication unit 282 receives response data for commands, GUI screen data and the like (information for clients) by TCP communication from the server-side information processing device 210 through the TCP communication unit 290 and the network 230, and the remote desktop client module 270. It has a function to transmit to. The communication unit 282 includes a reception unit 2821, an intermediate buffer 2822, and a transmission unit 2823.

  The intermediate buffer 2822 is a buffer memory that temporarily stores information for the client device.

  The reception unit 2821 has a function of storing information for the client device received from the TCP communication unit 290 in the intermediate buffer 2822. The reception unit 2821 includes a reception buffer 28211 and a reception processing unit 28212. The reception buffer 28211 is a buffer that temporarily stores information for the client device received from the information processing device 210. When the TCP communication unit 290 receives information for the client device from the remote desktop server module 240 of the information processing device 210 via the network 230, the TCP communication unit 290 writes the received information in the reception buffer 28211. The reception processing unit 28212 has a function of reading information written in the reception buffer 28211 and writing it in the intermediate buffer 2822.

  The transmission unit 2823 has a function of transmitting information for the client device stored in the intermediate buffer 2822 to the remote desktop client module 270. The transmission unit 2823 includes a transmission processing unit 28231 and a transmission buffer 28232. The transmission processing unit 28231 has a function of reading out information for the client device accumulated in the intermediate buffer 2822 and writing it in the transmission buffer 28232. Information written in the transmission buffer 28232 is read by the remote desktop client module 270.

  For example, the communication unit 282 is configured by one application (process), and the reception buffer 28211 and the transmission buffer 28232 are configured by a socket buffer. Each of the reception unit 2821 and the transmission unit 2823 operates as one thread. For this reason, the receiving unit 2821 and the transmitting unit 2823 operate independently and in parallel.

  The server side proxy module 250 includes a communication unit 251 and a communication unit 252.

  The communication unit 251 has a function of receiving information for the client from the remote desktop server module 240 and transmitting the information to the information processing apparatus 220 on the client side through the network 230 by TCP communication using the function of the TCP communication unit 260. The communication unit 251 includes a reception unit 2511, an intermediate buffer 2512, and a transmission unit 2513.

  The intermediate buffer 2512 is a buffer memory that temporarily stores information for the client device.

  The receiving unit 2511 has a function of storing information for the client device received from the remote desktop server module 240 in the intermediate buffer 2512. The reception unit 2511 includes a reception buffer 25111 and a reception processing unit 25112. The reception buffer 25111 is a buffer for temporarily storing information for the client device to be sent from the remote desktop server module 240 to the remote desktop client module 270. When the remote desktop server module 240 transmits information for the client device to the remote desktop client module 270, the remote desktop server module 240 writes the information to be transmitted in the reception buffer 25111. The reception processing unit 25112 has a function of reading information written in the reception buffer 25111 and writing it in the intermediate buffer 2512.

  The transmission unit 2513 has a function of transmitting information for the client apparatus stored in the intermediate buffer 2512 to the information processing apparatus 220 through the network 230 by TCP communication using the function of the TCP communication unit 260. The transmission unit 2513 includes a transmission processing unit 25131 and a transmission buffer 25132. The transmission processing unit 25131 has a function of reading out information for the client device accumulated in the intermediate buffer 2512 and writing it in the transmission buffer 25132. The information written in the transmission buffer 25132 is read by the TCP communication unit 260 and transmitted to the information processing apparatus 220 through the network 230.

  For example, the communication unit 251 is configured with one application (process), and the reception buffer 25111 and the transmission buffer 25132 are configured with a socket buffer. Each of the receiving unit 2511 and the transmitting unit 2513 operates as one thread. For this reason, the receiving unit 2511 and the transmitting unit 2513 operate independently and in parallel.

  The communication unit 252 has a function of receiving information for the server device from the information processing device 220 on the client side through the TCP communication unit 260 and the network 230 and transmitting the information for the server device to the remote desktop server module 240. The communication unit 252 includes a reception unit 2521, an intermediate buffer 2522, and a transmission unit 2523.

  The intermediate buffer 2522 is a buffer memory that temporarily accumulates information for the server device.

  The receiving unit 2521 has a function of storing information for the server device received from the TCP communication unit 260 in the intermediate buffer 2522. The reception unit 2521 includes a reception buffer 25211 and a reception processing unit 25212. The reception buffer 25211 is a buffer that temporarily accumulates information for the server device received from the information processing device 220. When the TCP communication unit 260 receives information for the server device from the remote desktop server module 270 of the information processing device 220 via the network 230, the TCP communication unit 260 writes the received information in the reception buffer 25211. The reception processing unit 25212 has a function of reading information written in the reception buffer 25211 and writing it in the intermediate buffer 2522.

  The transmission unit 2523 has a function of transmitting information for the server apparatus stored in the intermediate buffer 2522 to the remote desktop server module 240. The transmission unit 2523 includes a transmission processing unit 25231 and a transmission buffer 25232. The transmission processing unit 25231 has a function of reading information for the server device accumulated in the intermediate buffer 2522 and writing it in the transmission buffer 25232. Information written in the transmission buffer 25232 is read by the remote desktop server module 240.

  For example, the communication unit 252 is configured by one application (process), and the reception buffer 25211 and the transmission buffer 25232 are configured by a socket buffer. Each of the receiving unit 2521 and the transmitting unit 2523 operates as one thread. For this reason, the receiving unit 2521 and the transmitting unit 2523 operate independently and in parallel.

  Next, the operation of the remote desktop system 200 according to the present embodiment will be described.

  In the remote desktop system 200, various information (information for the server device) such as commands necessary for remote operation is transmitted from the remote desktop client module 270 of the information processing device 220 to the remote desktop server module 240 of the information processing device 210. Is done. On the other hand, response data to the command, GUI screen data, etc. (information for the client device) are transmitted from the remote desktop server module 240 of the information processing device 210 to the remote desktop client module 270 of the information processing device 220. In the present embodiment, the information for the server device and the information for the client device are transmitted and received as follows.

  First, the remote desktop client module 270 writes information for the server device in the reception buffer 28111 in the reception unit 2811 of the communication unit 281 of the client side proxy module 280.

  Next, when the information for the server device is accumulated in the reception buffer 28111, the reception processing unit 28112 of the communication unit 281 reads it and writes it in the intermediate buffer 2812.

  Next, when the information for the server device is accumulated in the intermediate buffer 2812, the transmission processing unit 28131 of the transmission unit 2813 of the communication unit 281 reads it and writes it in the transmission buffer 28132.

  Next, when information for the server device is accumulated in the transmission buffer 28132, the TCP communication unit 290 reads the information and transmits it to the remote desktop server module 240 of the information processing device 210 via the network 230 by TCP communication.

  When the TCP communication unit 260 of the information processing device 210 receives the information for the server device transmitted by the TCP communication unit 290, the received information is stored in the reception buffer 25211 in the reception unit 2521 of the communication unit 252 of the server side proxy module 250. Write.

  When the information for the server device is accumulated in the reception buffer 25211, the reception processing unit 25212 of the reception unit 2521 reads the information and writes it in the intermediate buffer 2522.

  When the information for the server device is accumulated in the intermediate buffer 2522, the transmission processing unit 25231 in the transmission unit of the communication unit 252 reads it and writes it in the transmission buffer 25232.

  When the information for the server device is accumulated in the transmission buffer 25232, the remote desktop server module 240 reads the information. Then, the remote desktop server module 240 executes processing according to the read information.

  Through the operation as described above, the information for the server device transmitted from the remote desktop client module 270 is converted into the communication unit 281, the TCP communication unit 290, the network 230, the TCP communication unit 260, and the server side proxy module of the client side proxy module 280. The data is delivered to the remote desktop server module 240 via the communication unit 252 of 250, and server processing corresponding to the information is executed. If a packet loss occurs in the network 230, the TCP communication unit 290 cannot receive an ACK by the TCP communication from the TCP communication unit 260, and retransmits the packet. As a result, information for the server device is reliably delivered from the information processing device 220 to the information processing device 210.

  In addition, the communication units 252 and 281 are configured by intermediate buffers 2522 and 2812, and reception units 2521 and 2811 and transmission units 2523 and 2813 that operate independently of each other. A reception operation can be performed without being affected by the transmission operation, and conversely, a transmission operation can be performed without being influenced by the reception operation. For example, in the case of the communication unit 281, even if the communication state of the network 230 deteriorates and the transmission buffer 28132 becomes full and transmission of the transmission unit 2813 temporarily stops, as long as the intermediate buffer 2812 has a free space, the reception unit 2811 Can continue to receive information for the server device from the remote desktop client module 270. Accordingly, it is possible to prevent the operation of the remote desktop client module 270 from being stopped due to the deterioration of the communication state of the network 230.

  Next, an operation for transmitting and receiving information for the client device will be described.

  First, the remote desktop server module 240 writes information for the client device in the reception buffer 25111 in the reception unit 2511 of the communication unit 251 of the server side proxy module 250.

  Next, when the information for the client device is accumulated in the reception buffer 25111, the reception processing unit 25112 of the communication unit 251 reads it and writes it in the intermediate buffer 2512.

  Next, when information for the client device is accumulated in the intermediate buffer 2512, the transmission processing unit 25131 of the transmission unit 2513 of the communication unit 251 reads it and writes it in the transmission buffer 25132.

  Next, when the information for the client device is accumulated in the transmission buffer 25132, the TCP communication unit 260 reads the information and transmits it to the remote desktop client module 270 of the information processing device 220 through the network 230 by TCP communication.

  When the TCP communication unit 290 of the information processing device 220 receives the information for the client device transmitted by the TCP communication unit 260, the received information is stored in the reception buffer 28211 of the reception unit 2821 of the communication unit 282 of the client side proxy module 280. Write.

  When information for the client device is accumulated in the reception buffer 28211, the reception processing unit 28212 of the reception unit 2821 reads it and writes it in the intermediate buffer 2822.

  When the information for the client device is accumulated in the intermediate buffer 2822, the transmission processing unit 28231 in the transmission unit of the communication unit 282 reads the information and writes it in the transmission buffer 28232.

  When the information for the client device is accumulated in the transmission buffer 28232, the remote desktop client module 270 reads the information. Then, the remote desktop server client module 270 executes processing according to the read information.

  Through the operation as described above, the information for the client device transmitted from the remote desktop server module 240 is converted into the communication unit 251, the TCP communication unit 260, the network 230, the TCP communication unit 290, and the server side proxy module of the server side proxy module 250. The data is delivered to the remote desktop client module 270 via the communication unit 282 of the H.280, and client processing corresponding to the information is executed. If a packet loss occurs in the network 230, the TCP communication unit 260 retransmits the packet because it cannot receive the ACK by the TCP communication from the TCP communication unit 290. As a result, information for the client device is reliably delivered from the information processing device 210 to the information processing device 220.

  The communication units 251 and 282 are configured by intermediate buffers 2512 and 2822, and reception units 2511 and 2821 and transmission units 2513 and 2822 that operate independently of each other. A reception operation can be performed without being affected by the transmission operation, and conversely, a transmission operation can be performed without being influenced by the reception operation. For example, in the case of the communication unit 251, even if the communication state of the network 230 deteriorates and the transmission buffer 25132 becomes full and the operation of the transmission unit 2513 temporarily stops, as long as the intermediate buffer 2512 has a free space, the reception unit 2511 Can continue to receive information for the client device from the remote desktop server module 240. Accordingly, it is possible to prevent the operation of the remote desktop server module 240 from being stopped due to the deterioration of the communication state of the network 230.

[Third embodiment]
Referring to FIG. 3, in a remote desktop system 300 according to the third embodiment of the present invention, an information processing device 310 and an information processing device 320 are connected via a network 330.

  The information processing apparatus 310 includes a remote desktop server module 340, a server-side proxy module 350, and a TCP communication unit 360. The remote desktop server module 340 and the TCP communication unit 360 have the same functions as the remote desktop server module 240 and the TCP communication unit 260 in the second embodiment shown in FIG. The server-side proxy module 350 includes a communication unit 351, a communication unit 352, a network state confirmation unit 353, and a window size adjustment unit 354. The communication unit 351 and the communication unit 352 have the same functions as the communication unit 251 and the communication unit 252 in the second embodiment illustrated in FIG. That is, the reception unit 3511, the intermediate buffer 3512, the transmission unit 3513, the reception buffer 35111, the reception processing unit 35112, the transmission processing unit 35131, and the transmission buffer 35132 included in the transmission unit 3513 are included in the communication unit 351. The receiving unit 2511, the intermediate buffer 2512, the transmitting unit 2513, the receiving buffer 25111 included in the receiving unit 2511, the receiving processing unit 25112, and the transmitting unit 2513 included in the communication unit 251 in the second embodiment illustrated in FIG. It has the same functions as the processing unit 25131 and the transmission buffer 25132. The communication unit 352 includes a reception unit 3521, an intermediate buffer 3522, a transmission unit 3523, a reception buffer 35211, a reception processing unit 35212, a transmission processing unit 35231, and a transmission buffer 35232 included in the transmission unit 3523. The receiving unit 2521, the intermediate buffer 2522, the transmitting unit 2523, the receiving buffer 2521 included in the receiving unit 2521, the receiving processing unit 25212, and the transmitting unit 2523 included in the communication unit 252 in the second embodiment illustrated in FIG. It has the same functions as the processing unit 25231 and the transmission buffer 25232.

  The information processing apparatus 320 includes a remote desktop client module 370, a client side proxy module 380, and a TCP communication unit 390. The remote desktop client module 370 and the TCP communication unit 390 have the same functions as the remote desktop client module 270 and the TCP communication unit 290 in the second embodiment shown in FIG. The client side proxy module 380 includes a communication unit 381, a communication unit 382, a network state confirmation unit 383, and a window size adjustment unit 384. The communication unit 381 and the communication unit 382 have the same functions as the communication unit 281 and the communication unit 282 in the second embodiment illustrated in FIG. That is, the reception unit 3811, the intermediate buffer 3812, the transmission unit 3813, the reception buffer 38111, the reception processing unit 38112, the transmission processing unit 38131, and the transmission buffer 38132 included in the transmission unit 3811 are included in the communication unit 381. The receiving unit 2811, the intermediate buffer 2812, the transmitting unit 2813, the receiving buffer 28111 included in the receiving unit 2811, the receiving processing unit 28112, and the transmitting unit 2813 included in the communication unit 281 in the second embodiment illustrated in FIG. It has the same functions as the processing unit 28131 and the transmission buffer 28132. The communication unit 382 includes a reception unit 3821, an intermediate buffer 3822, a transmission unit 3823, the reception unit 3821 includes a reception buffer 38211, a reception processing unit 38212, the transmission unit 3823 includes a transmission processing unit 38231, and a transmission buffer 38232. The receiving unit 2821, the intermediate buffer 2822, the transmitting unit 2823, the receiving buffer 2821 included in the receiving unit 2821, the reception processing unit 28212, and the transmitting unit 2823 included in the communication unit 282 in the second embodiment illustrated in FIG. It has the same functions as the processing unit 28231 and the transmission buffer 28232.

  The network state confirmation unit 353 of the server side proxy module 350 and the network state confirmation unit 383 of the client side proxy module 380 transmit and receive test data for investigating the congestion state of the network 330 through the network 330, thereby processing the information processing apparatus. It has a function of investigating the congestion status of the network 330 regarding the route from 310 to the information processing device 320. In this embodiment, the data transfer time is used as an index indicating the congestion status of the network 330. Specifically, the network state confirmation unit 353 writes the test data describing the current time as the transmission time in the transmission buffer 35132, thereby using the TCP communication unit 360 to transmit the test data via the network 330 and the TCP communication unit 390. Is transmitted from the server-side proxy module 350 to the reception buffer 38211 of the client-side proxy module 380. The network state confirmation unit 383 extracts the test data from the reception buffer 38211, and calculates the data transfer time from the transmission buffer 35132 to the reception buffer 38211 from the difference between the transmission time described in the test data and the current time. Then, the network state confirmation unit 383 notifies the calculated data transfer time to the window size adjustment unit 384 of its own module. Further, the network state confirmation unit 383 writes the response data describing the calculated data transfer time in the transmission buffer 38132, thereby using the TCP communication unit 390 to send the response data to the client side proxy via the network 330 and the TCP communication unit 360. The data is transmitted from the module 380 to the reception buffer 35211 of the server side proxy module 350. The network state confirmation unit 353 extracts the response data from the reception buffer 35211 and notifies the window size adjustment unit 354 of the data transfer time described in the response data.

  In order to avoid delaying the transmission of information for the client device by transmitting the test data, the network state confirmation unit 353 determines that the amount of information for the client device waiting for transmission in the server-side proxy module 350 is less than or equal to the threshold value. Send test data at a certain timing. In order to avoid delaying the transmission of information for the server device by transmitting the response data, the network state confirmation unit 383 determines that the amount of information for the server device waiting for transmission in the client side proxy module 380 is a threshold value. Response data is transmitted at the following timing.

  The window size adjustment units 354 and 384 have a function of adjusting the TCP window size used for transmission / reception from the TCP communication unit 360 to the TCP communication unit 390 according to the notified data transfer time. For example, if the data transfer time is shortened by enlarging the TCP window size, the enlargement adjustment is continued. If the data transfer time is lengthened by enlarging the TCP window size, the reduction adjustment is performed. Further, if the data transfer time is shortened by adjusting the TCP window size to be reduced, the reduction adjustment is performed continuously. If the data transfer time is increased by reducing the TCP window size, the enlargement adjustment is performed.

  In the present embodiment, the window size is adjusted using a socket mechanism in which the window size is determined in accordance with the change in the size of the socket buffer used for transmission and reception. The change in the size of the socket buffer follows the formula shown in FIG.

In the formula shown in FIG. 4, X _n is the measured data transfer time now, X _n-1 is the previous measured data transfer time, a is a positive constant, C _n is increased or decreased amount of the current socket buffer, C _{n -1} is the previous increase / decrease amount of the socket buffer. When the increase / decrease amount of the socket buffer is smaller than a certain amount, the increase / decrease adjustment is not performed, and it is not adopted as the nth measurement data. The socket buffer size has a positive minimum value, and the initial value uses a preset default value.

  Next, the operation of the remote desktop system 300 according to the present embodiment will be described. Of the operations of the remote desktop system 300 according to the present embodiment, the operations other than the network state confirmation units 353 and 383 and the window size adjustment units 354 and 384 are the remote desktop system 200 according to the second embodiment shown in FIG. Is the same as the operation. Hereinafter, operations of the network state confirmation units 353 and 383 and the window size adjustment units 354 and 384 will be described.

  When the remote desktop client module 370 and the remote desktop server module 340 can communicate with each other through the client side proxy module 380, the TCP communication unit 390, the network 330, the TCP communication unit 360, and the server side proxy module 350. The network state confirmation unit 353 of the server side proxy module 350 starts executing the processing shown in FIG. 5 at a predetermined period (for example, several minutes), and the network state confirmation unit 383 of the client side proxy module 380 6 is started.

  When activated, the network state confirmation unit 353 of the server side proxy module 350 determines whether or not the intermediate buffer 3512 is empty (S301). This process is an example of a process for determining whether or not the amount of information for the client device waiting for transmission in the server side proxy module 350 is equal to or less than a threshold value. If the intermediate buffer 3512 is not empty, the processing shown in FIG. 5 is terminated. If the intermediate buffer 3512 is empty, the test data describing the current time as the transmission time is written into the transmission buffer 35132 (S302). Then, it is monitored whether response data for the test data arrives at the reception buffer 35211 (S303).

  The test data written in the transmission buffer 35132 is transmitted from the information processing apparatus 310 to the information processing apparatus 320 through the network 330 by the TCP communication unit 360, received by the TCP communication unit 390, and received in the reception buffer 38211 of the client side proxy module 380. Written.

  The network state confirmation unit 383 of the client side proxy module 380 constantly monitors the arrival of the test data in the reception buffer 38211 (S311). When the test data arrives at the reception buffer 38211, the network state confirmation unit 383 extracts the data (S312), and calculates the difference between the transmission time described in the test data and the current time as the data transfer time (S313). Next, the network status confirmation unit 383 writes the calculated data transfer time in the response data (S314), and writes the response data to the transmission buffer 38132 when the intermediate buffer 3812 is empty (YES in S315) (S316). The processing in step S315 is an example of processing for determining whether or not the amount of information for the server device waiting for transmission in the client side proxy module 380 is equal to or less than a threshold value. The network state confirmation unit 383 notifies the calculated data transfer time to the window size adjustment unit 384 (S317). Then, the network state confirmation unit 383 returns to the process of step S311.

  The response data written in the transmission buffer 35182 is transmitted from the information processing apparatus 320 to the information processing apparatus 310 via the network 330 by the TCP communication unit 390, received by the TCP communication unit 360, and received in the reception buffer 35211 of the server side proxy module 350. Written.

  When the response data arrives at the reception buffer 35211 (YES in S303), the network state confirmation unit 353 of the server-side proxy module 350 extracts it (S304) and sets the data transfer time described in the response data to the window size adjustment unit 354. (S305). Then, the network state confirmation unit 353 finishes the process illustrated in FIG.

  The window size adjustment unit 354 changes the size of the transmission buffer 35132 of the transmission unit 3513 based on the expression shown in FIG. 4 according to the data transfer time notified from the network state confirmation unit 353. Further, the window size adjustment unit 384 changes the size of the reception buffer 38211 of the reception unit 3821 based on the formula shown in FIG. 4 according to the data transfer time notified from the network state confirmation unit 383. The transmission buffer 35132 and the reception buffer 38211 are socket buffers. The size of the socket buffer can be changed using a socket API option. Then, the size of the TCP window is changed by changing the size of the buffer used by the socket for transmission and reception.

  As described above, according to the present embodiment, the same effects as those of the second embodiment can be obtained, and the following effects can be obtained.

  Since the congestion state of the network 330 is periodically checked and the TCP window size is adjusted based on the check result, communication can be performed dynamically with an optimal window size.

  Test data for investigating the congestion status of the network 330 at the timing when the amount of information for the client device waiting for transmission in the server-side proxy module 350 is equal to or less than the threshold (for example, when the intermediate buffer 3512 is empty). Thus, it is possible to prevent the transmission of information for the client apparatus from being delayed due to the process of investigating the congestion status of the network 330.

  Response data to the test data for investigating the congestion status of the network 330 at the timing when the amount of information for the server device waiting for transmission in the client side proxy module 380 is equal to or less than the threshold (for example, the timing when the intermediate buffer 3812 is empty). By transmitting to the network 330, it is possible to prevent the transmission of information for the server apparatus from being delayed due to the process of investigating the congestion status of the network 330.

  In the present embodiment, the data transfer time from the transmission buffer 35132 to the reception buffer 38211 is used as an index indicating the congestion status of the network 330, but another index may be used. For example, the round trip time that is the sum of the data transfer time from the transmission buffer 35132 to the reception buffer 38211 and the return data transfer time from the transmission buffer 38132 to the reception buffer 35211 may be used as an index.

  In this embodiment, the congestion state of the network 330 related to the route from the TCP communication unit 360 to the TCP communication unit 390 is investigated, and the TCP window size used for transmission / reception from the TCP communication unit 360 to the TCP communication unit 390 is adjusted. . However, instead of or together with this, the congestion status of the network 330 regarding the route from the TCP communication unit 390 to the TCP communication unit 360 is investigated, and the TCP used for transmission / reception from the TCP communication unit 390 to the TCP communication unit 360 is checked. You may adjust the window size. For that purpose, instead of the network state confirmation unit 383 in FIG. 3, a network state confirmation unit having the same function as the network state confirmation unit 353 is used, or the functions of the network state confirmation unit 383 and the network state confirmation unit 353 are used. 3 is used, and instead of the network state confirmation unit 353 in FIG. 3, a network state confirmation unit having the same function as the network state confirmation unit 383 is used, or the network state confirmation unit 353 and the network A network status confirmation unit having the function of the status confirmation unit 383 may be used. Further, instead of the window size adjustment unit 354 in FIG. 3, a window size adjustment unit having the same function as the window size adjustment unit 384 is used, or the functions of the window size adjustment unit 354 and the window size adjustment unit 384 are provided. The window size adjustment unit is used, and instead of the window size adjustment unit 384 in FIG. 3, a window size adjustment unit having the same function as the window size adjustment unit 354 is used, or the window size adjustment unit 384 and the window size adjustment are used. A window size adjustment unit having the function of the unit 354 may be used.

[Fourth Embodiment]
Referring to FIG. 7, the communication unit 451 in the server-side proxy module used in the remote desktop system 400 according to the fourth embodiment of the present invention receives information for clients from the remote desktop server module 440, The function of the TCP communication unit 460 is used to transmit to the client side through the network by TCP communication. That is, the communication unit 451 corresponds to the communication unit 351 in the third embodiment shown in FIG.

  The communication unit 451 includes a reception unit 4511, an intermediate buffer 4512, and a transmission unit 4513. Among them, the reception unit 4511, the reception buffer 45111 and the reception processing unit 45112 that constitute it, and the intermediate buffer 4512 are the reception unit 3511 shown in FIG. 3, the reception buffer 35111 and the reception processing unit 35112 that constitute it, and the intermediate buffer 3512. Has the same function.

  The transmission unit 4513 includes a transmission processing unit 45131, a transmission buffer 45132, a transmission order determination unit 45133, a duplicate screen image deletion unit 45134, a screen generation unit 45135, and a screen storage unit 45136. Among these, the transmission buffer 45132 has the same function as the transmission buffer 35132 shown in FIG.

  The transmission order determination unit 45133 determines the transmission order of the information stored in the intermediate buffer 4512, that is, the information received by the communication unit 451 from the remote desktop server module 440 and not yet transmitted to the client side proxy module through the TCP communication unit 460. Has a function to determine. The transmission order determining unit 45133 determines the transmission order based on the type of information and the priority determined in advance for the type.

  Information exchanged between the Remote Desktop Server Module and Remote Desktop Client Module includes audio data, storage data, printer data, clipboard data, smart card data, key data such as screen data, keyboard and mouse event data, There is serial port data, other PnP device data, and user-defined data. These are classified into several types and given priority. For example, the highest priority is assigned to screen data and keyboard / mouse event data, the next highest priority is assigned to audio data, and the lowest priority is assigned to others.

  The transmission order determining unit 45133 determines the type of each piece of information stored in the intermediate buffer 4512, and rearranges the information in the intermediate buffer 4512 in order of priority according to the priority corresponding to the determined type. In remote desktop connection using the RDP protocol, an RDP protocol header is added to information exchanged between the remote desktop server module and the remote desktop client module, and the type of information is confirmed by analyzing the RDP protocol header. be able to. The rearrangement is performed so that higher-priority type information can be read from the transmission processing unit 45131 with higher priority. Information of the same priority is arranged in the order of arrival at the intermediate buffer 4512.

The transmission order determining unit 45133 may have a function of deleting information having a priority level equal to or lower than the threshold from the intermediate buffer 4512 as well as determining the transmission order. This deletion function may be effective only when the free space of the intermediate buffer 4512 is equal to or less than a predetermined threshold.

  The duplicate screen image deletion unit 45134 is based on the screen image stored in the intermediate buffer 4512, that is, the screen image that the communication unit 451 has received from the remote desktop server module 440 and has not yet transmitted to the client side proxy module through the TCP communication unit 460. , And has a function of deleting overlapping portions.

  In general, in remote desktop connection, in order to reduce the transfer amount, a screen image of a rectangular area including an updated area in the server screen is transmitted to the client side. At this time, if the same area is repeatedly updated, the screen image of the same rectangular area is transmitted many times. Now, when the screen image of a certain rectangular area changes from the screen image A to the screen image B and further changes to the screen image C, the three screen images of the screen image A, the screen image B, and the screen image C are displayed in the remote desktop. The data is accumulated in the intermediate buffer 4512 from the server module 440 through the communication unit 4511. Under a good communication environment, the screen image that has arrived at the intermediate buffer 4512 is immediately transferred to the transmission buffer 45132 by the transmission processing unit 45131 and transmitted to the client side through the TCP communication unit 460. Multiple screen images of the area are not stored. However, when the communication environment deteriorates and the transmission buffer 45132 is full, a plurality of screen images of the same rectangular area are accumulated in the intermediate buffer 4512. If such a situation is left unattended, the intermediate buffer 4512 will eventually become full, leading to a situation where information for a new client device cannot be received from the remote desktop server module 440. Therefore, the duplicate screen image deletion unit 45134 monitors whether or not a plurality of screen images related to the same rectangular area are accumulated in the intermediate buffer 4512, and if found, the time is older (the arrival time at the intermediate buffer is older). ) Delete the screen image from the intermediate buffer 4512. For example, when the screen image B and the screen image C are stored in the intermediate buffer 4512, the screen image B is deleted from the intermediate buffer 4512. As a result, the rectangular area on the client side suddenly changes from the screen image A to the screen image C so that frame-by-frame feeding is performed, but an inconvenient situation due to a lack of an empty area in the intermediate buffer 4512 can be avoided. .

  In the above description, a plurality of screen images related to the same rectangular area are exemplified as overlapping screen images, but the present invention is not limited to this. For example, a screen image related to a certain rectangular area and a screen image that is later than that and that includes the previous rectangular area may be recognized as overlapping screen images.

  The screen generation unit 45135 generates a screen image of the entire desktop screen of the server using the screen image stored in the intermediate buffer 4512, that is, the screen image received by the communication unit 451 from the remote desktop server module 440, and the screen storage unit 45136. The method for generating the screen image of the desktop screen using the screen image can use the same method as the method of generating the screen image of the desktop screen of the server from the received screen image in the remote desktop client module. The screen generation unit 45135 updates the screen image of the server desktop screen stored in the screen storage unit 45136 each time a new screen image is stored in the intermediate buffer 4512 by the reception processing unit 45112.

  The screen generation unit 45135 also calculates the total amount of screen images stored in the intermediate buffer 4512, that is, the total amount of screen images received by the communication unit 451 from the remote desktop server module 440 and not yet transmitted to the client side proxy. And a function of calculating the total amount of screen images of the server desktop screen stored in the screen storage unit 45136. Further, the screen generation unit 45135 compares the calculated total amounts, and if the total amount of screen images stored in the intermediate buffer 4512 exceeds the total amount of screen images of the desktop screen stored in the screen storage unit 45136. For example, the transmission processing unit 45131 is instructed to transmit a screen image stored in the screen storage unit 45136, and has a function of deleting all screen images stored in the intermediate buffer 4512 from the intermediate buffer 4512.

  The transmission processing unit 45131 has a function of reading out information for the client device accumulated in the intermediate buffer 4512 and writing it in the transmission buffer 45132. The transmission processing unit 45131 has a function of reading a screen image from the screen storage unit 45136 and writing it in the transmission buffer 45132 when receiving the above instruction from the screen generation unit 45135.

  Next, the operation of this embodiment will be described. Of the operations of the remote desktop system 400 according to the present embodiment, operations other than the communication unit 451 are the same as those of the third embodiment. Below, operation | movement of the communication part 451 is demonstrated with reference to the flowchart of FIG.

  The transmission processing unit 45131 monitors whether the intermediate buffer 4512 is empty, that is, whether information for the client device is accumulated (S401). When information for the client device is accumulated in the intermediate buffer 4512, the transmission unit 4513 performs the following operation.

  First, the transmission order determination unit 45133 determines the type of each piece of information stored in the intermediate buffer 4512, sorts the information in the intermediate buffer 4512 in order of priority according to the priority corresponding to the determined type, Information having the following priorities is deleted from the intermediate buffer 4512 (S402).

  Next, the overlapping screen image deletion unit 45134 deletes the overlapping portion from the screen image stored in the intermediate buffer 4512 (S403).

  Next, the screen generation unit 45135 generates a screen image of the desktop screen of the server using the screen image stored in the intermediate buffer 4512 and stores it in the screen storage unit 45136 (S404). Next, the screen generation unit 45135 calculates and compares the total amount of screen images stored in the intermediate buffer 4512 and the total amount of screen images of the server desktop screen stored in the screen storage unit 45136 (S405). . The subsequent processing differs depending on the comparison result.

  If the total amount of screen images stored in the intermediate buffer 4512 does not exceed the total amount of desktop screen images stored in the screen storage unit 45136, the transmission processing unit 45131 determines whether or not the transmission buffer 45132 has a free space. (S406), if there is a vacancy, information for the client device is read from the intermediate buffer 4512 and written to the transmission buffer 25132 (S407). Then, the process returns to step S401. If there is no space in the transmission buffer 45132, the transmission processing unit 45131 skips step S407 and returns to the process of step S401.

  On the other hand, if the total amount of screen images stored in the intermediate buffer 4512 exceeds the total amount of desktop screen images stored in the screen storage unit 45136, the screen generation unit 45135 stores in the intermediate buffer 4512. All the screen images are deleted from the intermediate buffer 4512, and the transmission processing unit 45131 is instructed to transmit the screen images stored in the screen storage unit 45136 (S408). The transmission processing unit 45131 checks whether or not the transmission buffer 45132 has a space (S409), and if there is no space, waits until a space is available. If there is a vacancy, the screen image of the desktop screen is read from the screen storage unit 45136 and written in the transmission buffer 25132 (S410). Then, the process returns to step S401. When the information for the client device is stored in the transmission buffer 45132, the TCP communication unit 460 reads the information and transmits it to the information processing device in which the remote desktop client module exists by TCP communication through the network.

  As described above, according to the present embodiment, the same effects as those of the third embodiment can be obtained, and the following effects can be obtained.

  By rearranging the information in the order of priority in the intermediate buffer 4512 using the transmission order determination unit 45133, it becomes possible to preferentially transmit a screen image having a high priority over other data having a low priority. Thus, it is possible to improve the response drop of the remote desktop connection in a situation where the communication environment is worsened as information is accumulated in the intermediate buffer 4512.

  By using the overlapping screen image deletion unit 45134 to delete the overlapping portion from the screen image stored in the intermediate buffer 4512, the remote environment in a situation where the communication environment is getting worse as information is accumulated in the intermediate buffer 4512 It can improve the response drop of desktop connection.

  When the total amount of screen images stored in the intermediate buffer 4512 exceeds the total amount of desktop screen images generated based on the screen generation unit 45135, the intermediate buffer 4512 stores the screen image. Situations where all screen images are deleted and the generated desktop screen screen image is sent instead, so that the intermediate buffer 4512 becomes full and information for a new client device cannot be received from the remote desktop server module 440 Can be avoided.

[Other embodiments]
Although the present invention has been described with reference to some embodiments, the present invention is not limited to the above embodiments, and various other additions and modifications can be made. For example, a configuration in which any one or any two of the transmission order determination unit 45133, the duplicate screen image deletion unit 45134, and the screen generation unit 45135 is omitted from the configuration of the fourth embodiment. Included in the form.

DESCRIPTION OF SYMBOLS 100 ... Remote desktop system 110 ... Server apparatus 120 ... Client apparatus 130 ... Network 140 ... Server side proxy 141 ... 3rd communication part 142 ... 4th communication part 150 ... Client side proxy 151 ... 1st communication part 152 ... 1st 2 Communication Department

Claims (25)

A remote desktop system in which a server device and a client device are connected via a network,
A client-side proxy connected to the client device;
A server-side proxy connected to the server device and connected to the client-side proxy via the network;
The client-side proxy is
A first communication unit that receives information for the server device from the client device and transmits the information to the server-side proxy through the network by TCP communication;
A second communication unit that receives information for the client device from the server-side proxy through the network by TCP communication and transmits the information to the client device;
The server side proxy
A third communication unit that receives information for the client device from the server device and transmits the information to the client-side proxy through the network by TCP communication;
A remote desktop system comprising: a fourth communication unit that receives information for the server device from the client side proxy through the network by TCP communication and transmits the information to the server device. The third communication unit is
An intermediate buffer;
A reception processing unit that stores the information received from the server device in the intermediate buffer;
The remote desktop system according to claim 1, further comprising: a transmission processing unit that operates independently of the reception processing unit, reads the information stored in the intermediate buffer, and transmits the information to the client-side proxy. The server side proxy
When the amount of information for the client device waiting for transmission existing in the third communication unit is equal to or less than a threshold value, test data for investigating the congestion status of the network is exchanged with the client-side proxy through the network. A network status confirmation unit for transmitting and receiving to determine the network congestion status;
The remote desktop system according to claim 1, further comprising: a window size adjusting unit that controls a window size of the TCP communication according to the determined congestion status of the network. The third communication unit is
A transmission order determining unit that determines a transmission order of information for the client device waiting for transmission existing in the communication unit based on a type of the information and a priority predetermined for the type. The remote desktop system according to any one of 1 to 3. The third communication unit is
5. The remote desktop system according to claim 1, further comprising a duplicate screen image deletion unit that deletes a duplicate screen image from a plurality of screen images for the client device waiting for transmission existing in the communication unit. The third communication unit is
A screen image of the desktop screen of the server device is generated using the screen image received from the server device, and the total amount of screen images for the client device waiting for transmission existing in the communication unit is the screen screen of the generated desktop screen The screen generation unit according to claim 1, further comprising: a screen generation unit that deletes a screen image for the client device waiting for transmission and transmits the generated screen image of the desktop screen when the total amount of images is exceeded. Remote desktop system. A method for remote desktop connection between a server device and a client device via a network,
A client-side proxy connected to the client device receives information for the server device from the client device, and transmits the information to the server-side proxy connected to the server device through the network by TCP communication.
The server-side proxy receives information for the server device from the client-side proxy through the network by TCP communication, and transmits the information to the server device.
The server side proxy receives information for the client device from the server device, and transmits the information to the client side proxy through the network by TCP communication.
A remote desktop connection method in which the client-side proxy receives information for the client device from the server-side proxy through the network by TCP communication and transmits the information to the client device. A proxy device connected to the server device among a client device and a server device constituting a remote desktop system,
A first communication unit that receives information for the client device from the server device and transmits the information to the client device through the network by TCP communication;
A proxy device comprising: a second communication unit that receives information for the server device from the client device side through the network by TCP communication and transmits the information to the server device. The first communication unit is
An intermediate buffer;
A reception processing unit that stores the information received from the server device in the intermediate buffer;
The proxy device according to claim 8, further comprising: a transmission processing unit that operates independently of the reception processing unit, reads the information stored in the intermediate buffer, and transmits the information to the client device side. When the amount of information for the client device waiting for transmission existing in the first communication unit is equal to or less than a threshold value, test data for investigating the congestion status of the network is transmitted to the client device side through the network. A network status confirmation unit for transmitting and receiving to determine the network congestion status;
10. The proxy device according to claim 8, further comprising: a window size adjustment unit configured to control a window size of the TCP communication according to the determined congestion status of the network. The first communication unit is
A transmission order determining unit that determines a transmission order of information for the client device waiting for transmission existing in the communication unit based on a type of the information and a priority predetermined for the type. The proxy device according to any one of 8 to 10. The first communication unit is
The proxy device according to claim 8, further comprising: a duplicate screen image deletion unit that deletes a duplicate screen image from a plurality of screen images for the client device waiting for transmission existing in the communication unit. The first communication unit is
A screen image of the desktop screen of the server device is generated using the screen image received from the server device, and the total amount of screen images for the client device waiting for transmission existing in the communication unit is the screen screen of the generated desktop screen The screen generation unit according to any one of claims 8 to 12, further comprising: a screen generation unit that deletes a screen image for the client device waiting for transmission and transmits the generated screen image of the desktop screen when the total amount of images is exceeded. Proxy device. A proxy method executed by a proxy device connected to the server device among a client device and a server device constituting a remote desktop system,
Receive information for the client device from the server device and send it to the client device side through the network by TCP communication,
A proxy method for receiving information for the server device from the client device side through the network by TCP communication and transmitting the information to the server device. In receiving and transmitting information for the client device,
The operation of accumulating the information received from the server device in an intermediate buffer and the operation of reading the information accumulated in the intermediate buffer and transmitting the information to the client device side are performed in parallel independently. Proxy method. When the amount of information for the client device waiting to be transmitted is equal to or less than a threshold value, test data for investigating the congestion status of the network is transmitted / received to / from the client device side through the network, and the congestion status of the network Judging
The proxy method according to claim 14 or 15, wherein a window size of the TCP communication is controlled according to the determined congestion status of the network. The proxy method according to any one of claims 14 to 16, wherein a transmission order of information for the client device waiting for transmission is determined based on a type of the information and a priority predetermined for the type. 18. The proxy method according to claim 14, wherein duplicate screen images are deleted from a plurality of screen images for the client device waiting for transmission. When the screen image received from the server device is used to generate a screen image of the desktop screen of the server device, and the total amount of screen images for the client device waiting for transmission exceeds the total amount of the screen image of the generated desktop screen The proxy method according to claim 14, wherein a screen image for the client apparatus waiting for transmission is deleted, and the generated screen image of the desktop screen is transmitted. A computer constituting a proxy device connected to the server device among a client device and a server device constituting a remote desktop system,
A first communication unit that receives information for the client device from the server device and transmits the information to the client device through the network by TCP communication;
A program for functioning as a second communication unit that receives information for the server device from the client device side through the network by TCP communication and transmits the information to the server device. The first communication unit is
An intermediate buffer;
A reception processing unit that stores the information received from the server device in the intermediate buffer;
The program according to claim 20, further comprising: a transmission processing unit that operates independently of the reception processing unit, reads the information stored in the intermediate buffer, and transmits the information to the client device side. The computer,
When the amount of information for the client device waiting for transmission existing in the first communication unit is equal to or less than a threshold value, test data for investigating the congestion status of the network is transmitted to the client device side through the network. A network status confirmation unit for transmitting and receiving to determine the network congestion status;
The program according to claim 20 or 21, wherein the program functions as a window size adjustment unit that controls a window size of the TCP communication according to the determined congestion status of the network. The first communication unit is
A transmission order determining unit that determines a transmission order of information for the client device waiting for transmission existing in the communication unit based on a type of the information and a priority predetermined for the type. The program according to any one of 20 to 22. The first communication unit is
The program according to any one of claims 20 to 23, further comprising a duplicate screen image deletion unit that deletes a duplicate screen image from a plurality of screen images for the client device waiting for transmission existing in the communication unit. The first communication unit is
A screen image of the desktop screen of the server device is generated using the screen image received from the server device, and the total amount of screen images for the client device waiting for transmission existing in the communication unit is the screen screen of the generated desktop screen The screen generation unit according to any one of claims 20 to 24, further comprising: a screen generation unit that deletes a screen image for the client device waiting for transmission and transmits the generated screen image of the desktop screen when the total amount of images is exceeded. program.

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