JP4175352B2 - Communication device - Google Patents

Description

  The present invention relates to a technique for performing data communication via a communication network, and more particularly to a technique for performing data communication while grasping a bandwidth usable for the data communication.

In a communication network (hereinafter also referred to as “public network”) shared by an unspecified number of users such as the Internet, the bandwidth that can be used for new data communication is performed via the communication network. Depending on the traffic volume of the communication, there are cases where it fluctuates greatly. Under circumstances where sufficient bandwidth cannot be used, the transmitted data may not reach its destination (so-called packet loss). For this reason, when transmitting data that needs to be reliably delivered to the other device, such as high-priority data or important data, the bandwidth available at that time is measured, and the QoS based on the measurement result is measured. It is desirable to perform control so that unintended packet loss does not occur, for example, by delaying transmission of packets with low priority.
As an example of a technique that makes it possible to measure the bandwidth that can be used in a communication network, the techniques disclosed in Non-Patent Document 1, Non-Patent Document 2, and Patent Document 1 and Patent Document 2 (hereinafter referred to as , Also referred to as “prior art”). In these prior arts, data blocks (for example, packets) for bandwidth measurement are transmitted one by one at a predetermined transmission interval by a predetermined number. Then, the transmission interval is compared with the reception interval at the partner device, and when both are substantially the same, the bandwidth corresponding to the transmission interval (that is, the number of transmissions per unit time (the reciprocal of the transmission interval) It is determined that the value obtained by multiplying the data size of the data block for measurement) can be used. If the reception interval is longer than the transmission interval, the bandwidth that can be used at that time is measured by performing the above-described band measurement while narrowing the transmission interval until the two coincide substantially. The
Bprobe and cprobe, http://cs-people.bu.edu/carter/tools/Tool.html,1966 Yuji Oie, Daishi Takahashi, research on evaluation method of Internet characteristic measurement tool, Faculty of Information Engineering, Kyushu Institute of Technology, Department of Electronic Information Engineering, February 2001 JP 2003-87324 A JP 2004-343227 A

By the way, when the above band measurement is performed with the number of measurement data blocks being constant, the time required for transmission of all the measurement data blocks is measured assuming a wide band (that is, measured at a narrow transmission interval). The case where the measurement data block is transmitted) and the case where the measurement is performed assuming a narrow band (that is, the case where the measurement data block is transmitted at a wide transmission interval). Specifically, the time required to perform measurement assuming a narrow band is longer than when performing measurement assuming a wide band.
Also, when performing measurement assuming a wide band, it is desirable to increase the number of measurement data blocks to be transmitted sufficiently, because a slight error in the reception interval has a large effect on the measurement result. When measurement is performed assuming a narrow band, the influence of the reception interval error on the measurement result is not so large, so even if band measurement is performed using a small number of measurement data blocks, there is a special problem. Does not occur.
In addition, the smaller the data size of the data block, the greater the overhead that occurs when routing the data block with a relay device such as a router. Therefore, the data size of the measurement data block is actually transmitted and received on the communication network. If the data size is too small or too large compared to the data size of the data block, the band measurement may not be performed correctly by the overhead.
In other words, when performing bandwidth measurement using a measurement data block, the values of measurement parameters such as the data size of the measurement data block, its transmission interval, and the number of transmissions are set to the actual values of the communication network that is the target of bandwidth measurement. Although it is necessary to set the value according to the usage situation, even if the technique disclosed in each of the above documents is used, this cannot be realized.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique that enables bandwidth measurement in accordance with the use status of a communication network.

The invention according to claim 1 is a communication unit that transmits and receives data blocks according to a predetermined communication protocol via a communication network between a storage unit and a partner device, and a data block transmitted or received by the communication unit. A writing unit for writing the history of the data size to the storage unit, and a measurement data block having a data size that is a value obtained by performing predetermined statistical processing on the history stored in the storage unit is predetermined. The bandwidth that can be used when transmitting a predetermined number of transmission intervals and communicating with the counterpart device via the communication network is defined as the reception interval and the transmission interval of the measurement data block at the counterpart device. And the measurement means used for the measurement and the data size of the measurement data block used for the measurement when the bandwidth is measured by the measurement means. Is stored in the storage means as the data size at the time of the previous measurement, while the difference between the value obtained by performing predetermined statistical processing on the history stored in the storage means and the data size at the time of the previous measurement is a predetermined value. There is provided a communication apparatus comprising: a measurement control unit that controls the measurement unit so that a bandwidth is measured again when a threshold value is exceeded.

According to a second aspect of the present invention, in the communication device according to the first aspect, a plurality of different data sizes are written in advance in the storage means for the measurement data block, and are associated with each data size. The number of measurement data blocks to be transmitted to the measurement unit is measured when the measurement unit performs bandwidth measurement with a predetermined measurement accuracy using the measurement data block having the data size. It is written for each accuracy, and the measurement control means uses a value obtained by subjecting the history stored in the storage means to a predetermined statistical process as a data size, and the data size and a predetermined measurement accuracy The number of measurement data blocks corresponding to the above is specified with reference to the storage content of the storage means, and the measurement data having the data size of the value Using the lock only that number and controls the measurement unit to re-measure the bandwidth.

In another aspect of the present invention, in a program that causes a computer device to execute transmission / reception of a data block according to a predetermined communication protocol with a counterpart device via a communication network, the computer device transmits or receives the data block via the communication network. A storage function for storing a history of the data size of the data block, and a predetermined transmission interval for a measurement data block whose data size is a value obtained by performing predetermined statistical processing on the history stored by the storage function The number of transmissions determined in advance is compared, and the bandwidth that can be used when communicating with the counterpart device via the communication network is compared with the reception interval of the measurement data block at the counterpart device and the transmission interval. It is also possible to provide a program characterized by realizing a measurement function for measurement.
According to such a program, it becomes possible to give the same function as the communication apparatus according to the present invention to a general computer apparatus that performs data communication via a communication network.

  According to the present invention, the data size of the measurement data block used when performing the band measurement can be set to the data size of the data block transmitted / received via the communication network by the time when the measurement is to be performed. Thus, there is an effect that it becomes possible to perform bandwidth measurement in accordance with the use situation of the communication network.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
(A. Configuration)
FIG. 1 is a diagram illustrating a configuration example of a communication system 10 including relay apparatuses 200A and 200B, which is an embodiment of a communication apparatus according to the present invention. As shown in FIG. 1, the communication system 10 includes a communication network 100, which is a public network such as the Internet, and LANs (Local Area Networks) 300A and 300B. The LAN 300A is connected via a relay device 200A. The LAN 300B is connected to the communication network 100, and the LAN 300B is connected to the communication network 100 via the relay device 200B.
Hereinafter, when it is not necessary to distinguish between the relay apparatuses 200A and 200B, they are referred to as “relay apparatus 200”. Similarly, the LANs 300A and 300B are denoted as “LAN300” when it is not necessary to distinguish between them.

  The relay device 200 is, for example, a router, and receives a data block (that is, a packet) transmitted from the communication network 100 according to a predetermined communication protocol (“IP” in the present embodiment). When the packet is addressed to a communication device accommodated in the LAN 300 connected to the device, the packet is transferred to the destination according to the predetermined communication protocol. In the present embodiment, a case where the relay apparatus 200 is a router will be described. However, the relay apparatus 200 is a gateway (that is, a communication apparatus that performs relay processing while performing mutual conversion between the communication protocol in the communication network 100 and the communication protocol in the LAN 300). Of course, it may be.

FIG. 2 is a block diagram illustrating an example of a hardware configuration of the relay apparatus 200.
As shown in FIG. 2, the relay device 200 includes a control unit 210, a user interface (hereinafter “UI”) unit 220, a first communication interface (hereinafter “IF”) unit 230, 2 includes a communication IF unit 240, a storage unit 250, and a bus 260 that mediates data exchange between these components.

  The control unit 210 is, for example, a CPU (Central Processing Unit), and executes a program stored in a storage unit 250 (to be described later) to control the operation of other components. The control unit 210 also functions as a time measuring unit that performs a time measuring operation according to an operation clock supplied from a clock generator (not shown).

  The UI unit 220 notifies the operation manager of the relay device 200 (for example, the network administrator of the LAN 300 to which the relay device 200 is connected) the communication address of the partner device that is the destination of the measurement packet, and the above-described measurement parameters ( Settings such as the initial value of the data size of the measurement packet, the number of measurement packets used for bandwidth measurement, etc., and whether or not the control unit 210 executes the bandwidth measurement processing characteristic of the communication apparatus according to the present invention It is for letting you do. More specifically, the UI unit 220 includes a display unit (not shown) including a liquid crystal display and its drive circuit, and an operation unit (not shown) such as a keyboard, and a screen for prompting the above settings. Is displayed on the display unit under the control of the control unit 210, or data representing the setting contents input by the operation manager operating the operation unit is delivered to the control unit 210.

The first communication IF unit 230 and the second communication IF unit 240 are both NICs (Network Interface Cards), and are connected to different communication networks. Specifically, the first communication IF unit 230 of the relay device 200A is connected to the communication network 100, and the second communication IF unit 240 of the relay device 200A is connected to the LAN 300A. On the other hand, the first communication IF unit 230 of the relay device 200B is connected to the communication network 100, and the second communication IF unit 240 of the relay device 200B is connected to the LAN 300B.
The first communication IF unit 230 and the second communication IF unit 240 receive a packet transmitted via a communication network to which each of the first communication IF unit 230 and the second communication IF unit 240 is connected, and deliver the packet to the control unit 210. The packet is sent to the communication network to which each packet is connected. In this embodiment, information for distinguishing from a packet for data transmission / reception (hereinafter referred to as a data packet) is written in the header portion of the measurement packet transmitted / received for bandwidth measurement.

As illustrated in FIG. 2, the storage unit 250 includes a volatile storage unit 251 and a nonvolatile storage unit 252.
The volatile storage unit 251 is a RAM (Random Access Memory), and is used as a work area by the control unit 210 operating according to a program. Specifically, various data set by the operation manager in the initial setting are written in the volatile storage unit 251. The volatile storage unit 251 stores the data size of the data packet every time the control unit 210 performs a data packet transfer from the communication network 100 to the LAN 300 or a data packet transfer from the LAN 300 to the communication network 100. A history table (hereinafter referred to as transfer history) in which the reception time of the data packet is registered in association with each other is stored. Although details will be described later, the stored contents of the transfer history are used when determining the data size of the measurement packet.
On the other hand, the nonvolatile storage unit 252 includes a ROM (Read Only Memory) or a hard disk. The nonvolatile storage unit 252 stores in advance a program for causing the control unit 210 to perform a bandwidth measurement operation characteristic of the communication apparatus according to the present invention, and also stores a management table shown in FIG. Yes. As shown in FIG. 3, in this management table, a measurement packet to be transmitted when performing band measurement using a measurement packet having the data size in association with data representing the data size of the measurement packet. Is stored for each measurement accuracy. For example, the management table shown in FIG. 3 indicates that 20 measurement packets should be transmitted when performing high-accuracy bandwidth measurement using a measurement packet having a data size of 256 bytes.
The above is the configuration of the relay device 200.

(B. Operation)
Next, an operation performed by the control unit 210 in accordance with a program stored in the nonvolatile storage unit 252 will be described. In the operation example described below, the relay device 200A is set to perform band measurement characteristic of the communication device according to the present invention, and the relay device 200B is set as described above. Shall not.

FIG. 4 is a flowchart showing the flow of the band measurement operation performed by the control unit 210.
As shown in FIG. 4, the control 210 operating according to the program first determines whether or not the setting for performing the band measurement is made (step SA100), and the determination result is “Yes”. If it is, execution of initial setting for performing bandwidth measurement according to the present invention is prompted (step SA110). Conversely, if the determination result in step SA100 is “No”, normal packet transfer processing is executed.

In step SA110, control unit 210 of relay apparatus 200A (hereinafter referred to as control unit 210A) first causes UI unit 220 to display a screen for prompting execution of the initial setting. The operation manager who visually recognizes this screen can input various data such as measurement parameters and data representing desired measurement accuracy by appropriately operating the operation unit of the UI unit 220. The data input in this way is transferred from the operation unit of the UI unit 220 to the control unit 210A, and is written into the volatile storage unit 251 by the control unit 210. Thereby, the initial setting is completed.
On the other hand, the control unit 210 (hereinafter referred to as the control unit 210B) of the relay device 200B executes the conventional packet transfer process because the determination result in step SA100 is “No”. Here, “conventional packet transfer processing” is written in the header of a data packet when the data packet is received via either the first communication IF unit 230 or the second communication IF unit 240. The destination address is referred to determine whether or not the packet should be transmitted from the other communication IF unit. If the determination result is “Yes”, the packet is transferred to the other communication IF unit. On the other hand, when the determination result is “No”, the packet is discarded. In addition, when the measurement unit 210B receives the measurement packet via the communication network 100, the control unit 210B also executes a process of measuring the reception interval and returning the measurement result to the transmission source of the measurement packet.

In step SA120 executed subsequent to step SA110, control unit 210A performs band measurement according to the measurement parameters set in step SA110. Specifically, the control unit 210 communicates the measurement packet having the data size set in step SA110 through the first communication IF unit 230 at a predetermined transmission interval by the number set in step SA110. When it is transmitted to the network 100 and the reception interval is notified from the counterpart device (in this embodiment, the relay device 200B), the communication interval 100 is compared with the transmission interval by comparing the reception interval with the transmission interval. The bandwidth that can be used when communicating with the partner device is measured, and data representing the measurement result (that is, the bandwidth that can be used at that time) is written in the volatile storage unit 251 and stored. The measurement result written in the volatile storage unit 251 in this way is used when determining the transfer rate (that is, the data packet transmission interval) when transferring the data packet to the counterpart device.
Then, control unit 210A determines whether or not the packet has been received by either first communication IF unit 230 or second communication IF unit 240 (step SA130), and when the determination result is “Yes”. 5 performs the packet transfer process shown in FIG. 5 for the received data packet (step SA140). If the determination result is “No”, the process of step SA130 is performed until the determination result is “Yes”. Repeatedly.

FIG. 5 is a flowchart showing a flow of a packet transfer operation performed by the control unit 210A.
As shown in FIG. 5, the control unit 210A analyzes the data packet delivered from either the first communication IF unit 230 or the second communication IF unit 240, and the data packet passes through the other communication IF unit. It is determined whether the data packet is to be transferred to the destination (step SB100).
If the determination result in step SB100 is “No”, the controller 210 discards the received data packet (step SB110) and ends the packet transfer operation. Conversely, if the determination result in step SB100 is “Yes”, the data size of the received data packet and its reception time are registered in the transfer history described above (step SB120), and then the data packet is described above. At the transmission interval corresponding to the bandwidth measured in step SA120, the data is transferred to the other communication IF unit and transferred to the destination (step SB130). Of course, when transferring a data packet, the header portion may be appropriately rewritten as necessary.

Returning to FIG. 4, when completing the above-described packet transfer operation, control unit 210 </ b> A determines whether or not it is necessary to perform band measurement again with reference to the history (step SA <b> 150). Specifically, the control unit 210A calculates an average value (for example, an arithmetic average) of data sizes of data packets transferred up to that time with reference to the transfer history described above, and the average value and the previous bandwidth measurement It is determined whether or not the difference from the data size of the measurement packet used when performing the measurement exceeds a predetermined threshold, and if it exceeds the threshold, it is determined that the band measurement needs to be performed again To do.
In the present embodiment, the case where the average value is calculated with reference to all the data sizes stored in the transfer history has been described. However, the average value is calculated for a predetermined number of data packets transferred most recently. Of course, it is good. In addition, when the number of data sizes stored in the transfer history does not reach the predetermined number, it may be determined that it is not necessary to perform band measurement again.

When the determination result in step SA150 is “No” (that is, when it is determined that it is not necessary to perform band measurement again), control unit 210A executes the processes after step SA130. As a result, the data packet is transferred while reflecting the result of the previous bandwidth measurement.
On the other hand, when the determination result in step SA150 is “Yes”, control unit 210A sets the data size of the measurement packet to the average value calculated in step SA150, and the data size and operation manager. The number of transmissions corresponding to the measurement accuracy set in advance is read from the management table, the value is reset to the measurement parameter (step SA160), and the processing after step SA120 described above is executed.

  As described above, according to the relay device 200 according to the present embodiment, the average value of the data size of the data packet transferred by the relay device 200 and the measurement used when the bandwidth measurement was performed last time. When the difference from the data size of the packet for use exceeds a predetermined threshold, the bandwidth is measured again with the measurement packet having a data size equal to the average value, and the measurement result is reflected in the packet transfer process. become. As a result, it is possible to perform bandwidth measurement according to the actual usage status of the communication network 100 and to perform packet transfer processing according to the usage status of the communication network 100 at that time. Play. Also, according to the relay device 200 according to the present embodiment, the operation manager sets a desired measurement accuracy in advance, thereby transmitting a number of measurement packets corresponding to the measurement accuracy and performing bandwidth measurement. Is possible.

(C. deformation)
Although one embodiment of the present invention has been described above, it is needless to say that the above embodiment may be modified as described below.
(1) In the above-described embodiment, the case where the present invention is applied to a relay device that mediates communication between a public network and a LAN has been described. However, the present invention is applied to a transmission device and a reception device located at both ends of a communication path. Of course, it may be applied. In short, any communication device that transmits and receives data blocks to and from a partner device via a communication network may be used.

(2) In the above-described embodiment, the case has been described in which the bandwidth is measured by comparing the transmission interval and the reception interval of packets that are data blocks in the network layer. However, the bandwidth may be measured by comparing the transmission interval and the reception interval of frames that are data blocks in the lower layer (for example, the data link layer) than the network layer, and conversely, the upper layer ( For example, it is of course possible to measure the bandwidth by comparing the transmission interval and the reception interval of the segments that are data blocks in the transport layer). In short, as long as the bandwidth is measured by comparing the transmission interval and the reception interval of data blocks transmitted and received according to a predetermined communication protocol, the protocol hierarchy to which the communication protocol belongs is not limited.

(3) In the above-described embodiment, the difference between the average value of the data sizes of all the data packets transferred by the above-described packet transfer operation and the data size of the measurement packet used for the bandwidth measurement is A case has been described in which when a predetermined threshold value is exceeded, bandwidth measurement is performed again using a measurement packet having a data size that matches the average value. However, instead of the average value, the most frequent value (or median value) is calculated, and the value is compared with the data size of the measurement packet used in the previous bandwidth measurement. If it exceeds, the bandwidth measurement may be performed again using a measurement packet having a data size that matches the most frequently occurring value (or median). In short, the value obtained by applying some statistical processing to the history of the data size of the data packet transferred by the packet transfer operation described above (that is, the average value, the most frequent value, the median value, etc.) Any mode may be used as long as it is necessary to compare the data size of the measurement packet used in the bandwidth measurement to determine whether or not the bandwidth measurement needs to be performed again.

(4) In the above-described embodiment, when the average value of the data size of the data packet transferred by the packet transfer process described above is compared with the data size of the measurement packet used in the previous bandwidth measurement Explained. However, for each data packet type (for example, for each application program that is a packet transmission source), whether the average value is calculated and compared with a threshold value, and whether or not it is necessary to repeat the bandwidth measurement for each data packet type. You may make it determine. In addition, a management table having different storage contents for each type of data packet may be written in the nonvolatile storage unit 252 in advance, and the measurement parameters may be determined for each type of data packet.

(5) In the above-described embodiment, the case where the characteristic function of the communication apparatus according to the present invention is realized by a software module has been described. However, it goes without saying that the function may be realized by a hardware module. In the above-described embodiment, a case has been described in which a program for causing the control unit 210 to perform a bandwidth measurement operation characteristic of the communication apparatus according to the present invention is stored in the storage unit 250 in advance. It may be distributed by writing on a computer-readable recording medium such as a CD-ROM (Compact Disk-Read Only Memory), or may be distributed via an electric communication line such as the Internet. In this case, the program written in the recording medium or the program distributed through the telecommunication line is installed in a general computer device, so that the computer device is the same as the communication device according to the present invention. It becomes possible to give the function of.

1 is a block diagram illustrating an example of an overall configuration of a communication system 10 including a relay device 200 that is an embodiment of a communication device according to the present invention. 3 is a block diagram illustrating a configuration example of the relay device 200. FIG. 3 is a block diagram showing an example of a table format of a management table stored in a storage unit 250 of the relay device 200. FIG. 4 is a flowchart showing a flow of a band measurement operation executed by a control unit 210 of the relay apparatus 200. It is a flowchart which shows the flow of the packet transfer operation | movement which the control part 210 performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Communication system, 100 ... Communication network, 200, 200A, 200B ... Relay apparatus, 300, 300A, 300B ... LAN, 210 ... Control part, 220 ... UI part, 230 ... 1st communication IF part, 240 ... 2nd communication IF unit, 250 ... storage unit, 251 ... volatile storage unit, 252 ... nonvolatile storage unit, 260 ... bus.

Claims (2)

Storage means;
A communication means for performing transmission / reception of a data block according to a predetermined communication protocol with a counterpart device via a communication network;
Writing means for writing a history of the data size of the data block transmitted or received by the communication means to the storage means;
Transmitting a predetermined number of measurement data blocks having a data size as a data size obtained by performing predetermined statistical processing on the history stored in the storage means, and the communication network a measuring means for the available bandwidth to communicate with the partner apparatus, measured as compared to the reception interval in those the counterpart device of the measurement data blocks and said transmission interval through,
When measuring the bandwidth by the measurement means, while writing the data size of the measurement data block used for the measurement to the storage means as the data size at the time of the previous measurement,
When the difference between the value obtained by performing predetermined statistical processing on the history stored in the storage unit and the data size at the time of the previous measurement exceeds a predetermined threshold, the bandwidth is measured again And a measurement control means for controlling the measurement means . In the storage means,
A plurality of different data sizes are written in advance for the measurement data block, and the bandwidth of the measurement data block having the data size is determined in association with each data size with a predetermined measurement accuracy. When making the measurement means perform the measurement, the number of measurement data blocks to be transmitted to the measurement means is written for each measurement accuracy,
The measurement control means includes
A value obtained by performing predetermined statistical processing on the history stored in the storage unit is a data size, and the number of measurement data blocks corresponding to the data size and a predetermined measurement accuracy is stored in the storage unit. The measurement means is controlled to re-measure the bandwidth by using the number of measurement data blocks having the data size corresponding to the specified data size with reference to the stored contents. The communication apparatus as described in.

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