JP5916224B2 - Device server system using multiple device servers - Google Patents

Description

  The present invention relates to a device server system, and more particularly to a system in which a single client communicates with a plurality of device servers.

  A system (device server system) is known in which a device that is a computer peripheral device can be used from a client connected to the network via a network (Non-Patent Document 1).

Silex Technology Co., Ltd. homepage <http://www.silex.jp/products/usbdeviceserver/sx3000gb.html>

  In the device server system, a command issued by a client device driver is converted into a network packet, which is transmitted from the client to the device server. The device server that has received the packet retrieves the command included in the received network packet and transfers it to the device connected to itself.

  On the other hand, the device server converts the response received from the device into a network packet, and transmits this to the client that is the source of the command.

  In this way, the device server system can use the device from the client via the network.

  The above communication between the client and the device server is usually performed using session type communication (for example, TCP).

  FIG. 1 is an example of an overall system diagram of a device server system. A client 101 and device servers 102, 103, and 104 are connected to a network. Keyboards 105, 106 and 107 and conversion devices 108, 109 and 110 are connected to each device server through a USB interface. Note that monitors 111, 112, and 113 for displaying images are connected to the conversion device by RGB signal cables.

  Each keyboard is simply a device as an input means. On the other hand, each conversion device is a device that converts video data included in a USB signal into RGB, which is a video signal.

  The device server system imitates a device connected to a device server as if it is directly connected to a client. For this reason, it is possible to input data to the client 101 by operating a keyboard connected to each device server, and to display video data output from the client 101 on each monitor. it can.

  When transmitting / receiving data or video data input from the keyboard, a TCP session is generated between the client 101 and each device server, and communication is performed using this session (TCP communication).

  Although there are only three device servers in the figure, the device server system can use more device servers. It is only necessary to secure a TCP session according to the number of device servers.

  However, when video data is transmitted from a client to a device server as shown in FIG. 1, there is a problem regarding network traffic as described below.

  In general, the amount of video data is overwhelmingly large compared to other types of data (for example, commands). Therefore, continuously transmitting video data output from the client 101 to the device server consumes a lot of network traffic. Furthermore, the network traffic to be consumed is independent for each device server, and the traffic increases in proportion to the number of device servers, which effectively limits the number of device servers that can be used depending on the network environment. There was a problem.

  The present invention solves this problem. An object of the present invention is to reduce traffic necessary for communication between a client and a plurality of device servers in a device server system having a plurality of device servers.

  A first aspect of the present invention is a client in a device server system in which a plurality of device servers and clients each connected to a predetermined device are connected to a network, and a predetermined one of the plurality of device servers Session communication means for transmitting / receiving data between the master device server and itself by performing session-type communication with the device server (master device server) of the device, and other device servers other than the master device server among the plurality of device servers (Slave device server) A client having multicast communication means for transmitting the same data by multicast communication as data transmitted from the client to the master device server in the session communication means That.

  Preferably, the client further transmits the transmission data to the master device server not by session communication means but by multicast communication only when the data (transmission data) transmitted from the client to a plurality of device servers is specific. Communication switching means for switching to be performed by the means.

  Preferably, the client further includes an operation mode acquisition means for acquiring an operation mode of a predetermined device connected to the master device server, and an operation mode (operable) in which the predetermined device connected to the slave device server can operate. Operation mode acquisition means for acquiring the operation mode, operation mode acquired by the operation mode acquisition means, and operation mode comparison means for comparing the operation mode acquired by the operation mode acquisition means. When the operation mode acquired by the operation mode acquisition unit is included in the operation mode acquired by the operation mode acquisition unit as a result of the comparison by the unit, the slave device server to which the predetermined device having the operation mode is connected Only the transmission target of the multicast communication means.

  According to a second aspect of the present invention, a plurality of device servers and clients each connected to a predetermined device are clients in a device server system connected to a network, and the predetermined device server and client are connected inside the client. Pseudo-session communication means for performing session-type communication between two devices, and pseudo-session communication for at least two or more device servers among a plurality of device servers only when the pseudo-session communication means is executed The client includes a multicast communication unit that transmits the same data as the data transmitted from the client to a predetermined device server by multicast communication.

  According to a third aspect of the present invention, a client in a device server system in which a plurality of device servers and clients each connected to a predetermined device are connected to a network is designated as a predetermined device among the plurality of device servers. Session communication means for transmitting and receiving data between the master device server and itself by performing session-type communication with the server (master device server), among other device servers, other device servers (slave devices) excluding the master device server Program that functions as a multicast communication means for transmitting the same data as the data transmitted from the client to the master device server in the session communication means by using multicast communication. .

  Preferably, the program further transmits the transmission data to the master device server only when the data (transmission data) transmitted from the client to the plurality of device servers from the client is specific, instead of the session communication means. It is made to function as a communication switching means for switching to be performed by the multicast communication means.

  Preferably, the program further includes an operation mode acquisition means for acquiring an operation mode of a predetermined device connected to the master device server by the client, and an operation mode (operation of the predetermined device connected to the slave device server). Operation mode acquisition means for acquiring the operation mode), the operation mode acquired by the operation mode acquisition means, and the operation mode comparison means for comparing the operation mode acquired by the operation mode acquisition means. When the operation mode acquired by the operation mode acquisition unit is included in the operation mode acquired by the operation mode acquisition unit as a result of the comparison by the unit, the slave device server to which the predetermined device having the operation mode is connected Only the transmission target of the multicast communication means That.

  According to a fourth aspect of the present invention, a client in a device server system in which a plurality of device servers each connected to a predetermined device and a client are connected to a network is connected to a predetermined device server inside the client. In the pseudo session communication means, the pseudo session communication means for performing the session-type communication in the pseudo, the pseudo session communication means is directed to at least two device servers among the plurality of device servers only when the pseudo session communication means is executed. Is a program that functions as multicast communication means for transmitting the same data as that transmitted from a device to a predetermined device server by multicast communication.

  According to the present invention, when data is transmitted from a client to a plurality of device servers in a device server system, the data transmitted by session-type communication, which is communication of a conventional device server system, is duplicated and multicasted. Send to multiple device servers via communication. As a result, it is possible to significantly reduce the traffic consumed compared to the case where a plurality of session type communications are used.

Embodiments according to the present invention will be described below with reference to the drawings. Unless otherwise noted, elements having the same number in the drawings indicate the same thing.
[Example 1]
[System overview]

FIG. 1 is an example of an overall system diagram according to the present invention. Since the details are as described above, the description is omitted.
[Data transmission according to the present invention]

  FIG. 2 is an example of data transmission according to the present invention. The configuration of the device server system is the same as that described in FIG.

  A feature of data transmission in the present invention is that multicast communication is used for communication between the device server and the client in addition to TCP communication which is conventional session type communication. For example, communication between the client 101 and the device server 102 uses TCP communication, and communication between other device servers, that is, the device server 103 and the device server 104 uses multicast communication.

  Since the communication between the client 101 and the device server 102 uses TCP communication, the communication with the client 101 is bidirectional communication. That is, not only communication from the client 101 to the device server 102 but also communication from the device server 102 to the client 101 can be performed. For example, input from the keyboard 105 can be transmitted to the client 101.

  On the other hand, since communication between the client 101 and the device servers 103 and 104 is multicast communication, the communication is one-way communication from the client 101 to each device server. Therefore, data input from the keyboard 106 and the keyboard 107 is not transmitted to the client 101.

As described above, the feature of data transmission in the present invention is that not only TCP communication but also TCP communication and multicast communication are used together.
[Connection request processing task 1]

  FIG. 3 shows a part of the operation flow of the client 101. This is for establishing a connection between the device server and the client 101, that is, TCP communication. This connection may be triggered by either the client 101 or the device server, but in this embodiment, the connection is attempted from the device server to the client 101.

  In step 301, it is determined whether or not a connection request transmitted from the device server has been received. As a result, if it is received, the process proceeds to the next step, and if not, the determination is repeated.

  In step 302, it is determined whether a master exists. Here, the master is a device server that has already established a connection by TCP communication, and determines whether or not it exists. The present invention aims at minimizing TCP communication with the device server, and therefore sets an upper limit on the number of device servers that can be connected by TCP. In this embodiment, there is one device server that can be a master. As a result of the determination, if the master already exists, the process proceeds to step 303, and if not, the process proceeds to step 304.

  In step 303, a response is sent to the source device server of the connection request received in step 301 that the device server is a slave. That is, since there is already a master device server, it is notified and recognized to the connection request source device server that it is a slave. When the device server recognizes itself as a slave, it receives the multicast communication described later, and processes it in the same way as in normal TCP connection without discarding it.

  In step 304, a response is sent to the connection request source device server received in step 301 that the device server is the master. In other words, since there is no master, the connection request source device server is notified and recognized as a master.

  In step 305, the client 101 and the device server establish a connection capable of TCP communication. This enables bidirectional communication between the client 101 and the device connected to the device server.

As described above, the connection request processing task 1 is a task for determining whether the device server that has transmitted the connection request operates as a master or a slave.
[Data transmission task]

  FIG. 4 is a part of the operation flow of the client 101. In particular, this is a flow when data is transmitted from the client 101 to the device server.

  In step 401, it is determined whether there is data to be transmitted. That is, it is determined whether there is data (for example, video data) to be transmitted to the device server. As a result of the determination, if data exists, the process proceeds to the next step, and if not, the determination is repeated.

  In step 402, it is determined whether a slave exists. That is, it is determined whether there is a slave device server as well as the master device server. As a result of the determination, if there is a slave, the process proceeds to steps 403 and 404; otherwise, the process proceeds only to step 404.

  In step 403, data is transmitted to the slave by multicast communication. Depending on the network environment, there are cases where the multicast communication reaches only a device server that is certified as a slave among a plurality of device servers, and a case where it reaches all device servers. Due to the characteristics of multicast communication, only those that have been approved as slaves are originally reached. However, this requires a dedicated network hub, so in the case of a network environment where this network hub does not exist, Reach all device servers. In this case, as described above, only the device server that is a slave processes this multicast communication.

  In step 404, data is transmitted to the master by TCP communication.

As described above, when a slave exists, data is transmitted to the slave by multicast communication in addition to the TCP communication to the master. On the other hand, when only the master exists, only TCP communication is used. Since communication transmitted from the master to the slave is multicast communication, only constant traffic is generated regardless of the number of slaves. For this reason, the greater the number of slaves, the greater the effect of reducing traffic according to this embodiment.
[Example 2]

The previous embodiment is based on the premise that the conversion devices connected to each device server and further the monitors ahead have the same capability. However, in practice, for example, monitors of the same ability are not always connected. The corresponding resolution varies from monitor to monitor. In this embodiment, such a case will be described.
[Connection request task 2]

  FIG. 5 shows a connection request task according to this embodiment. The difference from the previous embodiment is steps 501, 502 and 503. Since other steps are the same, description thereof is omitted.

  In step 501, a resolution is requested from the device server that transmitted the connection request, in this case, the device server that is a candidate for the slave. Specifically, this is information on resolution at which a monitor connected to the slave device server can operate. The information obtained can be single or multiple.

  In step 502, it is determined whether or not the resolution has been received. If it has been received, the next step proceeds. If not, the determination is repeated.

  In step 503, it is determined whether the received resolution (one or more) includes a resolution used by the monitor connected to the master. In other words, it is determined whether the resolution used by the master monitor can be used (supported) by the slave monitor.

  As a result of the determination, if it is supported, the process proceeds to step 303, a response that it is a slave is returned, and if not, the process returns to step 301. In other words, if there is no common point between the resolution of the slave and the resolution of the master, the device server that sent the connection request cannot become a slave. As a result, in the multicast transmission performed in step 403, only slaves having a common point with the master with respect to the resolution are targeted for transmission.

  The state of resolution comparison will be described with reference to FIG. The resolution at which the device server that sent the connection request (that is, the slave candidate) can operate is listed on the left side of the figure. On the other hand, the resolution at which the master is operating is displayed on the right side of the figure. In the case of the upper diagram, since the resolution of 1280 × 1024, in which the master is operating, is included in the operable resolution of the slave candidate, it is determined that support is possible. On the other hand, in the case of the lower diagram, since the resolution of 1800 × 1600 at which the master is operating is not included in the operable resolution of the slave candidate, it is determined that support is not possible.

  Note that different monitor resolutions mean different operation modes of the conversion device. For example, even if the conversion device itself is the same, the operation mode differs if the resolution of the monitor is different. Therefore, in practice, it is determined whether or not to be a slave according to the operation mode of the conversion device.

According to this embodiment, whether or not a predetermined device server should be a slave can be determined based on the capability of the device connected to the predetermined device server. Thereby, in the device server system in which a plurality of device servers exist, the utilization efficiency of each device server can be improved. In other words, a device server determined to be unsuitable for a slave can be a master or a slave for different purposes.
[Example 3]

  In the embodiments so far, TCP communication which is session type communication is used for communication between the client and the master, and multicast communication is used for the slave. In this embodiment, when the data to be transmitted is specific, TCP communication is not used for communication with the master, but multicast communication is used.

  As already described, multicast communication is one-way communication unlike TCP communication. For this reason, in general, it is used for transmission of video or audio data that is often allowed to have some packet loss. In this embodiment, using this characteristic, when the data transmitted from the client is video or audio data, only the multicast communication is used without using the TCP communication. In other words, transmission toward the master is switched from TCP communication to multicast communication.

  This switching means switching to multicast communication on the assumption that TCP communication already exists. In other words, multicast communication is not used when TCP communication is not used. As described in step 305 in FIG. 3, in order to use the device server system, a connection operation between the client and the device connected to the device server is required. Since this connection requires bidirectional communication, TCP communication is used. However, since it is not always necessary to use TCP communication after connection, as shown in this embodiment, only when the transmission data is specific, it is switched to multicast communication instead of existing TCP communication. That is why.

  Thereby, the network traffic consumed by TCP communication can be suppressed. Of course, when transmitting / receiving data other than video or audio data, communication is performed using a TCP communication session.

  Note that the type of data transmitted by multicast communication is not limited to video and audio data, and can be determined flexibly according to the type of actual data. For example, even if it is other than video and audio data, it can be transmitted by multicast communication when it is determined that packet lost or the like is acceptable data.

According to the present embodiment, since it is possible to use multicast communication for communication with the master in a specific case, it is possible to reduce traffic related to TCP communication used for the master. If bidirectional communication with the master is required, TCP communication can be restored. In this case, the traffic related to TCP communication is consumed in addition to multicast communication.
[Other Embodiments]

  In the embodiments so far, master and slave exist as device server types. However, the device server system according to the present invention can be realized without using a master as an entity.

  The means is to virtually perform TCP communication with the master inside the client. Specifically, a virtual master is generated inside the client and TCP communication with the master is performed in a pseudo manner (pseudo TCP communication is performed). Since the pseudo TCP communication is completed inside the client, no actual traffic occurs.

  As an actual operation, actual TCP communication and pseudo TCP communication may be appropriately switched based on a predetermined trigger. On the other hand, it is possible to transmit data to the device server using only the multicast communication by using only the pseudo TCP communication without using the actual TCP communication from the time when the communication with the device server is started.

Thereby, in the device server system according to the present invention, data can be transmitted to all slaves by multicast without using a master as an entity. As a result, the traffic actually generated can be limited to that necessary for multicast communication. That is, the TCP communication traffic to the master can be reduced.
[Summary]

According to the present invention, when data is transmitted from a client to a plurality of device servers in a device server system, the data transmitted by session-type communication, which is communication of a conventional device server system, is duplicated and multicasted Send to multiple device servers via communication. As a result, it is possible to significantly reduce the traffic consumed compared to the case where a plurality of session type communications are used.

Overall system diagram Data transmission in the present invention Connection request processing task 1 Data transmission task Connection request processing task 2 Resolution comparison

403 Multicast communication 404 TCP communication

Claims (8)

A plurality of device servers and clients each connected to a predetermined device are clients in a network-connected device server system,
Session communication means for transmitting and receiving data between the master device server and itself by performing session-type communication with a predetermined device server (master device server) among the plurality of device servers;
Multicasting the same data as the data transmitted from the client to the master device server in the session communication means toward the other device servers (slave device servers) other than the master device server among the plurality of device servers A multicast communication means for transmitting by communication;
With client.
The client further includes:
Only when the data (transmission data) transmitted from the client to the plurality of device servers is specific, the transmission data is transmitted to the master device server not by the session communication means but by the multicast communication means. Communication switching means for switching
The client of claim 1, comprising:
The client further includes:
An operation mode acquisition means for acquiring an operation mode of a predetermined device connected to the master device server;
Operable mode acquisition means for acquiring an operation mode (operable mode) in which a predetermined device connected to the slave device server can operate;
An operation mode comparison unit that compares the operation mode acquired by the operation mode acquisition unit with the operation mode acquired by the operation mode acquisition unit;
With
When the operation mode acquired by the operation mode acquisition unit is included in the operation mode acquired by the operation mode acquisition unit as a result of the comparison by the operation mode comparison unit, a predetermined device including the operation mode is connected Only the slave device server that has been sent is subject to transmission by the multicast communication means.
The client according to claim 1 or 2.
A plurality of device servers and clients each connected to a predetermined device are clients in a network-connected device server system,
Pseudo session communication means for performing pseudo session type communication with a predetermined device server in the client;
Only when the pseudo session communication means is being executed, the pseudo session communication means transmits from the client to the predetermined device server toward at least two of the plurality of device servers. Multicast communication means for transmitting the same data as the data to be transmitted by multicast communication;
With client.
A client in a device server system in which a plurality of device servers and clients each connected to a predetermined device are connected to a network,
Session communication means for transmitting and receiving data between the master device server and itself by performing session type communication with a predetermined device server (master device server) among the plurality of device servers;
Multicasting the same data as the data transmitted from the client to the master device server in the session communication means toward the other device servers (slave device servers) other than the master device server among the plurality of device servers Multicast communication means to send by communication,
Program to function as.
The program further transmits the transmission data to the master device server only when the data (transmission data) transmitted from the client to the plurality of device servers is specific. Rather than communication switching means for switching to be performed by the multicast communication means,
The program according to claim 5, which functions as: The program further includes an operation mode acquisition means for acquiring an operation mode of a predetermined device connected to the master device server by the client,
Operable mode acquisition means for acquiring an operation mode (operable mode) in which a predetermined device connected to the slave device server can operate;
An operation mode comparison unit that compares the operation mode acquired by the operation mode acquisition unit with the operation mode acquired by the operation mode acquisition unit;
Function as
When the operation mode acquired by the operation mode acquisition unit is included in the operation mode acquired by the operation mode acquisition unit as a result of the comparison by the operation mode comparison unit, a predetermined device including the operation mode is connected Only the slave device server that has been sent is subject to transmission by the multicast communication means.
The program according to claim 5 or 6.
A client in a device server system in which a plurality of device servers and clients each connected to a predetermined device are connected to a network,
Pseudo session communication means for performing session type communication with a predetermined device server in the client in a pseudo manner;
Only when the pseudo session communication means is being executed, the pseudo session communication means transmits from the client to the predetermined device server toward at least two of the plurality of device servers. Multicast communication means for transmitting the same data as the transmitted data by multicast communication,
Program to function as.