WO2011093133A1 - Communication apparatus, communication method, communication program, and band measuring system - Google Patents

Abstract

Provided are a communication apparatus, a communication method, a communication program and a band measuring system whereby, even if there occurs a variation in the processing times of packet transmissions, data can be communicated in such a manner that the band can be precisely measured. The communication apparatus performs packet communications in such a manner that the band can be measured based on transmission intervals, at which the transmission of each of a plurality of packets to be successively transmitted is performed, and also based on reception intervals at which the plurality of packets are received via a network. The communication apparatus acquires a variation in the processing times required for the transmissions of the plurality of packets (S2). The communication apparatus decides, based on the acquired variation, transmission conditions including at least the transmission intervals of the plurality of packets (S3). The communication apparatus sequentially transmits the plurality of packets in accordance with the transmission conditions decided based on the variation (S5).

Description

Communication device, communication method, communication program, and bandwidth measurement system

The present invention relates to a communication device, a communication method, a communication program, and a bandwidth measurement system that transmit data so that bandwidth can be measured when performing data communication via a network.

When a communication apparatus transmits / receives data via a network such as the Internet, the communication apparatus needs to transmit / receive data at a transmission rate suitable for a band (bandwidth: Available Bandwidth). The bandwidth that can be used by the communication apparatus varies depending on the situation such as the region, the provider, and the time zone. Therefore, it is desirable for the communication device that transmits data to control the transmission rate in accordance with the fluctuating band.

Non-Patent Document 1 discloses a measurement method for appropriately measuring a fluctuating band. In this measurement method, the communication device on the transmission side includes time information for determining the packet transmission interval in the packet. The communication device on the transmission side continuously transmits a plurality of packets while changing the transmission interval. The communication device on the receiving side records the packet reception interval. Thereafter, a difference between the transmission interval of the packet determined by the time information in the packet and the reception interval recorded by the communication device on the receiving side is calculated. The current bandwidth is measured from the change tendency of the calculated difference values.

CaoLe Thanh Man, Go Hasegawa, Masayuki Murata, “A Study on Inline Network Measurement for Service Overlay Networks”, IEICE Technical Report, IEICE, January 17, 2003, Vol. 102, no. 565, p. 53-58

However, when the bandwidth is measured by the above-described technology, the communication device on the transmission side cannot include time information in the packet after processing such as encryption is performed and the data is packetized. Therefore, before performing packetization, the communication device on the transmission side needs to include time information in the data to be packetized. However, in the communication apparatus, a certain amount of processing time is required from the start of data packetization to the completion of packet transmission. The processing time varies depending on processing conditions such as the type of OS, the number of clocks of the communication device, and the CPU usage rate. If the processing time varies, it will be difficult to accurately measure the bandwidth due to a shift in the processing time variation between the time interval indicated by the time information in the packet and the actual packet transmission interval. .

The present invention provides a communication device, a communication method, a communication program, and a bandwidth measuring system capable of communicating data so that bandwidth can be measured accurately even when the processing time of packet transmission processing varies. The purpose is to provide.

The communication apparatus according to the first aspect of the present invention includes: a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted; and reception of the plurality of packets received via a network. A communication device that performs packet communication so that a bandwidth can be measured based on the interval, a generation unit that generates a packet including time information for determining the transmission interval, and transmission processing of the plurality of packets A variation acquisition unit that acquires a variation in required processing time, a transmission condition determination unit that determines a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquisition unit; The plurality of packets generated by the generation means are sequentially transmitted under the transmission conditions determined by the transmission condition determination means. And a transmitting means.

If the processing time required for packet transmission processing varies, the transmission interval determined by the time information included in each packet (interval for transmission processing) and the interval at the time when transmission processing for each packet is completed (actual transmission interval) , Hereinafter referred to as “transmission completion interval”). The greater the variation in processing time, the greater the error between the transmission interval and the transmission completion interval. However, even if an error occurs, if the ratio of the error to the transmission interval is small, the influence of the error on the measurement result is small. The communication apparatus according to the first aspect determines a packet transmission condition including at least a transmission interval (interval for performing transmission processing) based on variations in processing time required for transmission processing of a plurality of packets. As a result, it is possible to reduce the influence of the processing time variation on the band measurement result. Therefore, the communication device can transmit data so that the bandwidth can be measured with high accuracy.

The transmission condition determining unit obtains a transmission interval difference, which is a difference between one interval among a plurality of intervals included in the transmission interval and an interval before or after the one interval, by the variation obtaining unit. The transmission interval may be determined so as to be larger than the variation. The transmission interval and the reception interval are theoretically the same if the transmission speed when the communication device on the transmission side transmits data is equal to or less than the bandwidth and there is no variation in the processing time of the transmission process. If the transmission rate is higher than the bandwidth, the reception interval is longer than the transmission interval. In the bandwidth measurement method used in the system including the communication device according to the first aspect, the transmission-side communication device transmits a plurality of packets while gradually shortening or gradually increasing the transmission interval. As a result, the transmission rate at the time when the value of “reception interval−transmission interval” changes can be made a usable band. Here, specifically, a case where a plurality of packets are transmitted while gradually increasing the transmission interval is considered. In this case, if the variation in processing time is larger than the transmission interval difference, the length of a certain transmission completion interval may be shorter than the transmission completion interval before this transmission completion interval. As a result, it becomes extremely difficult to detect a point in time when the value of “reception interval−transmission interval” changes. The communication apparatus can transmit a plurality of packets so that the time point at which the value of “reception interval−transmission interval” changes can be accurately detected by making the transmission interval difference larger than the variation in processing time.

The transmission condition determination means includes a search range that is a measurement target range of a band by the plurality of packets, a measurement packet number that is the number of packets that constitute the plurality of packets, and a packet that includes the packets. A first calculation unit that calculates the transmission interval according to a packet size, and all the transmission interval differences in the transmission interval calculated by the first calculation unit are greater than the variation acquired by the variation acquisition unit. When the first determination means for determining whether or not the transmission interval difference determines that at least a part of the transmission interval difference is equal to or less than the variation, the search range, the number of measurement packets, And changing means for changing at least one of the packet sizes. In this case, the communication apparatus can accurately determine the transmission condition in which the transmission interval difference is larger than the variation by changing at least one of the search range, the number of measurement buckets, and the packet size.

The changing unit may reduce the number of measurement packets while fixing the search range and the packet size. In this case, since the search range and the packet size are the same, the transmission interval difference is increased by reducing the number of measurement packets. Therefore, the communication device has the effect of variation in processing time on the bandwidth measurement result without causing a decrease in bandwidth measurement accuracy by expanding the search range and an increase in processing load by changing the packet size. Can be reduced.

The transmission condition determining unit determines whether or not the number of measurement packets is equal to or less than a first threshold when the first determination unit determines that at least a part of the transmission interval difference is equal to or less than the variation. You may further provide the 2nd judgment means to do. When the second determination unit determines that the number of measurement packets is equal to or less than the first threshold, the changing unit may widen the search range and reset. The changing unit may decrease the number of measurement packets while fixing the search range and the packet size when the second determination unit determines that the number of measurement packets is larger than the first threshold. . If the number of measurement packets is reduced too much, the time point at which the value of “reception interval−transmission interval” changes cannot be detected in detail, and the bandwidth measurement accuracy is greatly reduced. When the number of measurement packets is less than or equal to the first threshold, the communication device determines the appropriate transmission conditions while preventing a significant decrease in measurement accuracy due to a decrease in the number of measurement packets by expanding and resetting the search range can do. On the other hand, if the number of measurement packets is larger than the first threshold, the influence of the decrease in the number of measurement packets on the measurement accuracy is small. In this case, the communication apparatus can determine an appropriate transmission condition while reducing the number of measurement packets and preventing a significant decrease in measurement accuracy due to the expansion of the search range.

The transmission condition determination means determines whether the number of measurement packets is equal to or greater than a second threshold when the first determination means determines that all the transmission interval differences are larger than the variation. Three determination means, and when the third determination means determines that the number of measurement packets is smaller than the second threshold value, further includes an increase means for increasing the number of measurement packets with the second threshold value as a limit. Also good. If the number of measurement packets is increased too much, the processing burden required for bandwidth measurement increases. However, the communication apparatus can improve the measurement accuracy of the band by increasing the number of measurement packets within a range where the processing load does not increase excessively.

The communication apparatus may further include processing time acquisition means for acquiring a plurality of processing times required for transmission processing of each of the plurality of packets. It is desirable that the variation acquisition unit acquires a standard deviation of a plurality of processing times acquired by the processing time acquisition unit as the variation. In this case, the communication apparatus can efficiently and accurately determine the transmission condition by using the standard deviation of the processing time as the variation.

The processing time acquisition unit may acquire the processing time from the time required to transmit and receive the packet generated by the generation unit. In this case, the communication apparatus can accurately acquire the processing time at that time.

The communication device includes a table in which the processing conditions of the communication device including at least one of the OS type of the communication device, the number of clocks of the communication device, and the CPU usage rate of the communication device are associated with the variation. You may further provide the information acquisition means which acquires the information of the said table from the memory | storage means to memorize | store. The variation acquisition unit may acquire the variation associated with the current processing condition by referring to the information in the table acquired by the information acquisition unit. In this case, the communication device can easily obtain the variation only by referring to the information in the table.

The communication apparatus includes: a receiving unit that receives a plurality of packets transmitted continuously; a reception interval acquisition unit that acquires a reception interval of the plurality of packets received by the receiving unit; and the reception unit that receives the reception unit Transmission interval acquisition means for acquiring transmission intervals of the received plurality of packets from the time information included in each of a plurality of packets, the reception interval acquired by the reception interval acquisition means, and the transmission interval acquisition means And a measuring unit that measures a band based on the transmission interval obtained by the step S1. In this case, the communication device can function as both the communication device on the transmission side and the communication device on the reception side. Therefore, when communicating with another communication device, the communication device can easily measure the band even when the communication device on the other side has only one function of the transmission side and the reception side.

The communication method according to the second aspect of the present invention includes a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted, and reception of the plurality of packets received via a network. A communication method performed by a communication device that performs packet communication so that a bandwidth can be measured based on the interval, and a generation step of generating a packet including time information for determining the transmission interval; and A variation acquisition step for acquiring variation in processing time required for packet transmission processing, and a transmission condition for determining a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquisition step A plurality of packets generated by the determining step and the generating step, the transmission condition determining step; Tsu and a transmission step of sequentially transmitting at the determined the transmission condition by flop.

According to the communication method according to the second aspect, it is possible to reduce the influence of the processing time variation on the band measurement result. Therefore, data is transmitted so that the bandwidth can be measured with high accuracy.

The communication program according to the third aspect of the present invention includes a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted, and reception of the plurality of packets received via a network. A communication program for controlling the operation of a communication device that performs packet communication so that a bandwidth can be measured based on the interval, and generating a packet including time information for determining the transmission interval in a computer A variation acquisition step of acquiring a variation in processing time required for the transmission processing of the plurality of packets, and a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquisition step A transmission condition determination step for determining a plurality of parameters generated by the generation step. Tsu preparative, characterized in that to execute a transmission step of sequentially transmitting in the transmission conditions determined by the transmission condition determining step.

According to the communication program according to the third aspect, it is possible to reduce the influence of the processing time variation on the bandwidth measurement result. Therefore, the communication device can transmit data so that the bandwidth can be measured with high accuracy.

A bandwidth measuring system according to a fourth aspect of the present invention includes: a transmitting device that continuously transmits a plurality of packets; and a receiving device that receives the plurality of packets transmitted by the transmitting device via a network. Between the transmission device and the reception device based on a transmission interval that is an interval for performing transmission processing of each of the plurality of packets in the transmission device and a reception interval of the plurality of packets in the reception device. A bandwidth measuring system for measuring a bandwidth of a plurality of packets, wherein the transmission device generates a packet including time information for determining the transmission interval, and a variation in processing time required for the transmission processing of the plurality of packets. Based on the variation obtained by the variation obtaining unit and the variation obtained by the variation obtaining unit, the transmission of the plurality of packets is performed. Transmission condition determining means for determining a transmission condition including at least an interval; and transmission means for sequentially transmitting the plurality of packets generated by the generating means under the transmission condition determined by the transmission condition determining means, The receiving apparatus includes: a receiving unit that receives the plurality of packets; a reception interval acquisition unit that acquires reception intervals of the plurality of packets received by the receiving unit; and each of the plurality of packets received by the receiving unit. The transmission interval acquisition means for acquiring the transmission intervals of the plurality of packets from the time information included in the reception interval, the reception interval acquired by the reception interval acquisition means, and the transmission interval acquired by the transmission interval acquisition means And measuring means for measuring a band between the transmitter and the transmitter.

The bandwidth measurement system according to the fourth aspect can reduce the influence of the processing time variation on the bandwidth measurement result. Therefore, the receiving apparatus can measure the band with high accuracy.

1 is a diagram illustrating an electrical configuration of a communication device 1 and a configuration of a band measurement system 100. FIG. It is a flowchart of the transmission main process performed when the communication apparatus 1 operate | moves as a transmission apparatus. It is a flowchart of the dispersion | variation acquisition process performed during a transmission main process. It is a flowchart of the transmission condition determination process performed during a transmission main process. It is a flowchart of the transmission process performed during a transmission main process. It is a flowchart of the reception main process performed when the communication apparatus 1 operate | moves as a receiver. It is a flowchart of the reception process performed during a reception main process. It is a schematic diagram which shows the structure of the data memorize | stored in the packet information storage area of RAM12 of a receiver. It is a flowchart of the band measurement process performed during the reception main process. It is a schematic diagram which shows the structure of the dispersion | variation determination table memorize | stored in HDD13 of the transmitter which concerns on a modification.

Hereinafter, a communication device 1 that is an embodiment of a communication device according to the present invention and a band measurement system 100 including a plurality of communication devices 1 will be described with reference to the drawings. The drawings to be referred to are used for explaining technical features that can be adopted by the present invention. The configuration of the apparatus, the flowcharts of various processes, and the like described in the drawings are not intended to be limited to these, but are merely illustrative examples.

The band measurement system 100 will be described. As shown in FIG. 1, the band measurement system 100 includes at least two communication devices 1. The communication device 1 is connected to another communication device 1 via the network 8. The communication device 1 communicates various data with other communication devices 1.

The bandwidth measurement system 100 according to the present embodiment is a video conference system for users at a plurality of bases to hold a video conference. Each communication device 1 transmits and receives image data and audio data to share video and audio from a plurality of locations. The communication device 1 may be any device that can execute data communication via the network 1. Specifically, it may be a dedicated video conference terminal arranged at each base for performing a video conference, or may be a personal computer that performs various information processing.

In the bandwidth measurement system 100, each communication device 1 measures the bandwidth that can be used with the communication device 1 of the communication partner while packetizing and transmitting and receiving image data and audio data. When a packet is transmitted at a transmission rate that exceeds the usable bandwidth, packet loss, transmission delay, and the like occur. On the other hand, if the transmission rate is too low, the bandwidth cannot be fully utilized and the efficiency is poor. Accordingly, each communication device 1 controls the transmission rate according to the measured bandwidth. Here, the “usable bandwidth” refers to the maximum transmission rate at which the receiving communication device 1 can receive data at a transmission rate substantially equal to the transmission rate of data transmitted by the transmitting communication device 1. In order to compare the bandwidth and the transmission speed between the communication apparatuses 1, the bandwidth is represented by a transmission path capacity (bps).

The electrical configuration of the communication device 1 will be described. As shown in FIG. 1, the communication device 1 includes a CPU 10 that controls the communication device 1. A ROM 11, a RAM 12, a hard disk drive (hereinafter referred to as “HDD”) 13, and an input / output interface 19 are connected to the CPU 10 via a bus 18.

The ROM 11 stores a program for operating the communication device 1, an initial value, and the like. The RAM 12 temporarily stores various information used in the control program. The HDD 13 is a non-volatile storage device that stores various types of information such as a control program. A storage device such as an EEPROM or a memory card may be used instead of the HDD.

The input / output interface 19 is connected to an audio input processing unit 21, an audio output processing unit 22, a video input processing unit 23, a video output processing unit 24, an operation unit 25, and an external communication I / F 26. The voice input processing unit 21 processes input of voice data from the microphone 31 that inputs voice. The audio output processing unit 22 processes the operation of the speaker 32 that outputs audio. The video input processing unit 23 processes input of video data (moving image data) from the camera 33 that captures video. The video output processing unit 24 processes the operation of the display device 34 that displays video. The operation unit 25 is used for a user to input various instructions to the communication device 1. The operation unit 25 may be connected to the input / output interface 19 from the outside of the communication device 1. The external communication I / F 26 connects the communication device 1 to the network 8.

Next, the bandwidth measurement method used in the bandwidth measurement system 100 of the present embodiment will be schematically described. The bandwidth measurement method used in the bandwidth measurement system 100 is a known method described in the following document. “CaoLe Thanh Man, Go Hasegawa, Masayuki Murata,“ A Study on Inline Network Measurement for Service Overlay Network ”, IEICE Technical Report, IEICE, January 17, 2003, Vol. 102, no. 565, pp. 53-58 "Note that the bandwidth measurement method to which the present invention can be applied is not limited to the method described in the above document. The present invention can be applied to any system that measures the bandwidth using the packet transmission interval and the reception interval.

* Explain the measurement principle. In the bandwidth measurement system 100, the communication device 1 that transmits data (hereinafter referred to as “transmitting device”) packetizes the data into a plurality of packets. The transmission device transmits a plurality of packets continuously to another communication device 1 (hereinafter referred to as “reception device”) via the network 8. If the transmission rate (unit: bps) at the time of transmitting a packet is equal to or less than the bandwidth (unit: bps) that can be used between the transmission device and the reception device, the packet does not jam. In this case, the interval (reception interval) at which the reception device receives a plurality of packets transmitted by the transmission device is theoretically the same as the transmission interval. On the other hand, if the transmission rate is higher than the bandwidth, the packet is congested and the reception interval is longer than the transmission interval.

When measuring the bandwidth, the transmission device transmits a plurality of packets while gradually increasing or decreasing the transmission interval. The transmission rate when a packet is transmitted is given by the following equation (1)
Transmission rate (bps) = packet size (bit) / time interval between previous packet transmission and current packet transmission (s) (1)
Is required. When a plurality of packets are transmitted while gradually increasing the transmission interval, the reception interval becomes longer than the transmission interval while the transmission rate is higher than the bandwidth. However, if the transmission interval becomes longer and the transmission speed becomes equal to or less than the bandwidth, the reception interval and the transmission interval become the same. Therefore, the transmission rate at the time when the value of “reception interval−transmission interval” changes can be measured as a band.

A measurement procedure will be described. In the bandwidth measurement system 100, the bandwidth is roughly measured by the following procedure.
1. Sets the initial search range of the band.
By limiting the search range in which it is expected that the bandwidth at that time can be measured, the bandwidth can be measured efficiently.

2. A plurality of packets (measurement streams) corresponding to the search range are transmitted and received.
First, transmission conditions for a plurality of packets for measuring a bandwidth within the search range are determined. The transmission conditions include the number of packets constituting a plurality of packets (hereinafter referred to as “measured packet number”), the packet size of each packet, and the time from the previous packet transmission to the transmission of the next packet. A transmission interval is included. In the present embodiment, since the transmission interval is determined so as to gradually increase, the band is searched in order from the upper limit value to the lower limit value of the search range. Next, a plurality of packets are transmitted from the transmission device according to the determined transmission condition. Each packet includes time information for the receiving device to determine the transmission interval. Although the search range is divided into a plurality of small sections and a measurement stream is transmitted for each of the small sections, a measurement result having high resistance against temporary abnormalities can be obtained, but details thereof are omitted.

3. The bandwidth that can be used between the transmission device and the reception device is measured from the difference between the reception interval and the transmission interval. The reception interval is determined from the time when the receiving apparatus actually receives the packet. The transmission interval is determined from the time information included in the received packet. Next, the relationship between the transmission rate when the packet is transmitted and the reception rate (bps) when the packet is received is approximated by two straight lines by the linear regression method. As a result, the time when the value of “reception interval−transmission interval” changes is determined, and the bandwidth is measured. If the change of “reception interval−transmission interval” is not determined within the search range, the lower limit or the upper limit of the search range is provisionally set as a band.

4). The search range is reset, and 2. Return to.
Bandwidth can be measured efficiently by statistically resetting the next search range from past measurement results. Since the calculation formula for resetting the search range is described in the above document, the description thereof is omitted.

As described above, in the method of measuring the bandwidth using the packet transmission interval and the reception interval, the transmission interval of a plurality of packets is important. In order for the receiving apparatus to accurately determine the transmission interval, it is desirable for the transmitting apparatus to include information on the time at which the packet is transmitted in the packet. However, the transmission apparatus cannot include time information in the packet after performing processing such as encryption to packetize the data. Therefore, the transmission interval calculated from the time information included in the packet is an interval at which the transmission apparatus performs transmission processing of each packet. In the transmission apparatus, a certain amount of processing time is required until data is packetized and transmission is completed. The processing time varies (fluctuates) depending on processing conditions such as the type of OS, the number of clocks of the communication device, and the usage rate of the CPU 10. When the processing time varies, a difference in processing time varies between the transmission interval determined by the time information in the packet and the transmission completion interval, which is the actual packet transmission interval. As a result, a deviation occurs between the measured band and the actual band, and the measurement accuracy of the band decreases.

In the above method, the transmission apparatus transmits a plurality of packets while changing the transmission interval. However, as the degree of change of the transmission interval is smaller, the influence of the processing time variation on the measurement result becomes larger. Specifically, the transmission device needs to gradually increase or decrease the transmission completion interval. However, if the transmission interval difference, which is the difference between one of the transmission intervals in the series of measurement streams and the other interval, is the same as the variation in processing time, the packet is transmitted at the same transmission completion interval. Cases arise. If the transmission interval difference is smaller than the variation in processing time, even if the transmission completion interval should be gradually increased, a part of the transmission completion interval can be shorter than the transmission completion interval before the transmission completion interval. The same problem occurs when the transmission completion interval is gradually shortened. As a result, it becomes extremely difficult to determine the time point at which the value of “reception interval−transmission interval” changes.

In the bandwidth measurement system 100 according to the present embodiment, the transmission device determines at least the transmission intervals of the plurality of packets among the transmission conditions of the plurality of packets based on the variation in processing time. As a result, the transmission apparatus can reduce the influence of the variation in processing time on the band measurement result, and improve the band measurement accuracy. Hereinafter, processing performed by the communication device 1 will be described in detail.

A transmission main process executed when the communication apparatus 1 operates as a transmission apparatus that transmits a measurement packet will be described with reference to FIGS. The transmission main process is executed by the CPU 10 of the transmission apparatus according to a program stored in the HDD 13 when an instruction to transmit / receive data to / from the reception apparatus is input.

As shown in FIG. 2, when the transmission main process is started, it is determined whether or not there is an instruction to end transmission of a packet for measuring the bandwidth (S1). If there is no end instruction (S1: NO), a variation acquisition process is performed (S2). In the variation acquisition process, a variation in processing time required for the transmission process of the measurement packet is acquired. Next, transmission condition determination processing is performed (S3). In the transmission condition determination process, based on the obtained variation, a transmission interval of a plurality of measurement packets, a bandwidth search range, the number N of measurement packets, and a packet size Ps of each measurement packet are determined as transmission conditions. Next, data indicating the determined number N of measurement packets is notified by being transmitted to the receiving device (S4), and transmission processing is performed (S5). In the transmission process, a plurality of measurement packets are generated and sequentially transmitted to the receiving device according to the determined transmission conditions. Data indicating the measurement result of the band is received from the receiving device (S6), and the process returns to the determination of S1. Until an instruction to end packet transmission is given (S1: NO), the processes of S2 to S6 are repeated. When an end instruction is given (S1: YES), the transmission main process ends.

With reference to FIG. 3, the variation acquisition process executed in step S2 during the transmission main process will be described in detail. In the present embodiment, the processing time required for the transmission processing of one packet is acquired a plurality of times. The standard deviations of the acquired processing times are acquired as variations. First, in the variation acquisition process, the current time is acquired as the transmission time (S11). A packet including time information of the acquired transmission time is generated as a processing time measurement packet (S12). The processing time measurement packet has no particularly meaningful data, but has the same packet size as the measurement packet transmitted to the reception device last time. As a result, a processing time similar to the processing time of the measurement packet that is actually transmitted to the receiving device can be acquired.

Next, the generated processing time measurement packet is transmitted to the transmission device itself, that is, to itself without passing through the network 8 (S13). The transmitted processing time measurement packet is received by the transmitting device itself that transmitted the packet (S14). The current time at the time of reception is acquired as the reception time (S15). By calculating the difference between the acquired reception time and the transmission time included in the received processing time measurement packet, the processing time for one packet is acquired (S16). Next, it is determined whether or not acquisition of a predetermined number (for example, 10) of processing times has been completed (S17). If the predetermined number of processing times have not yet been acquired (S17: NO), the processing of S11 to S16 is performed again. When the predetermined number of processing times is acquired (S17: YES), the standard deviation of the acquired predetermined number of processing times is calculated. The calculated standard deviation is acquired as a variation in processing time (S18), and the process returns to the transmission main process. Next, a transmission condition determination process is performed (S3, see FIG. 2).

The transmission condition determination process will be described in detail with reference to FIG. First, it is determined whether or not it is the first measurement process in the repeated band measurement process (S21). In other words, it is determined whether the bandwidth with the current receiving apparatus has not yet been measured. If it is the first measurement process (S21: YES), the initial search range, the number N of measurement packets, and the packet size Ps of each measurement packet are set to predetermined values (S22). In the present embodiment, a default value is used as the predetermined value. As an example, the initial search range is set to 0.5 Mbps to 1.5 Mbps, the number of measurement packets N is set to 25, and the packet size Ps is set to 1500 bytes. However, the method of setting these values can be changed. For example, each value may be set with reference to a band measured by another band measuring method. On the other hand, if it is not the first measurement process in the process of step S21 (S21: NO), the band search range is reset using a statistical method from the band between the reception terminal measured in the past. The Since this method is described in the above-mentioned document, detailed description is omitted. By using a statistical method, it is possible to reset the search range for measuring the bandwidth efficiently and accurately.

Next, the set search range is equally divided by (N-1) (S25). As a result, a search band value Ki (i = 1,..., N−1), which is a band value searched for by each measurement packet, is uniquely determined. Next, the transmission interval of each measurement packet for searching for each search band value Ki is calculated (S26). The transmission interval for searching for one search band value Ki (bps) is obtained by the following equation (2) with the packet size (bit) as Ps.
Ps / Ki (2)

A transmission interval difference is calculated from the calculated transmission interval, and it is determined whether or not the minimum value of the calculated transmission interval differences is larger than the variation (S27). As described above, the transmission interval difference is a difference between one interval and another interval in a series of measurement streams. If the minimum value of the plurality of transmission interval differences is larger than the variation, all the transmission interval differences are larger than the variation. The CPU 10 can easily compare a plurality of transmission interval differences with variations by comparing only the minimum transmission interval difference with variations.

If the minimum transmission interval difference is larger than the variation (S27: YES), it is determined whether or not the number N of measurement packets is equal to or greater than a predetermined upper limit value (S28). In the bandwidth measurement method employed in the present embodiment, as the number of measurement packets N increases, the time point at which “reception interval−transmission interval” changes can be detected more finely, so that the bandwidth can be measured with high accuracy. On the other hand, if the number N of measurement packets is too large, measurement processing may be delayed. The transmission apparatus stores in advance an upper limit value of the number N of measurement packets that is unlikely to cause a problem such as a delay in measurement processing in the HDD 13. When it is determined that the number N of measured packets is smaller than the upper limit value (S28: NO), the transmission condition set at that time is stored (S29). In order to increase the measurement accuracy of the bandwidth, the number N of measurement packets is increased to the upper limit with the search range and packet size Ps fixed (S30), and the process returns to S25. In the present embodiment, the number N of measurement packets is incremented by “1”, so that the upper limit value is not exceeded. However, the value of the number N of measurement packets to be increased can be changed. If the value of the number N of measurement packets does not exceed the upper limit value, a value of “2” or more may be increased at a time.

Note that if the number of measurement packets N is increased without changing the search range, the change point of “reception interval-transmission interval” can be detected in detail, but the difference in transmission interval is shortened. Therefore, if the number N of measurement packets is increased too much, the minimum transmission interval difference may be less than the variation (S27: NO). In this case, it is determined whether or not a transmission condition (hereinafter referred to as “transmission condition that satisfies the processing time condition”) in which the minimum transmission interval difference is larger than the variation has already been set and stored (S32). If the transmission condition that satisfies the processing time condition is stored in S29 (S32: YES), the latest transmission condition stored last is determined as the transmission condition to be actually used (S33), and the process Return to processing. If the number N of measured packets reaches the upper limit (S28: YES), the process returns to the main transmission process without changing the transmission condition set at that time. When the process returns to the main process, all the transmission conditions stored in S28 are deleted.

If the set transmission condition does not satisfy the processing time condition (S27: NO), and no transmission condition that satisfies the processing time condition is set before that (S32: NO), the number N of measurement packets is equal to or lower than the lower limit value. It is determined whether or not there is (S35). If the number N of measurement packets is reduced too much, the transmission interval difference becomes long, but the change point of “reception interval−transmission interval” cannot be detected in detail, and the measurement accuracy is greatly reduced. The transmission apparatus stores in advance in HDD 13 a lower limit value of the number N of measurement packets that is unlikely to decrease the bandwidth measurement accuracy. When the number N of measured packets is larger than the lower limit (S35: NO), the number N of measured packets is decreased while the search range and the packet size Ps are fixed (S36), and the process returns to S25. In the present embodiment, the number N of measurement packets is decreased by “1”. However, if the value of the number N of measurement packets does not exceed the lower limit value, the value “2” or more may be decreased at a time.

In the second and subsequent transmission condition determination processing, the search range is set by a statistical method based on the past band measurement results. By setting the search range by a statistical method, the bandwidth can be measured efficiently and accurately. Therefore, it is desirable to increase the transmission interval difference by decreasing the number N of measurement packets or increasing the packet size Ps while fixing the search range that has already been set. Also, changing the packet size Ps increases the processing load on the communication device 1. Therefore, it is more desirable to change the number N of measurement packets while fixing the packet size Ps.

If the number N of measurement packets is less than or equal to the lower limit value, the search range is forcibly reset so that the transmission interval difference satisfies the processing time condition (S37). Hereinafter, a process for forcibly resetting the search range will be described. First, a minimum transmission interval difference T that is slightly larger than the obtained variation is determined. The median value B of the search range set in S22 or S23 is determined. When the maximum search band value in the new search range to be reset is Km, and the width between the upper limit value and the lower limit value of the new search range is R, the following equation (3) is established.
Km = B + R / 2 (3)
In the present embodiment, each search band value Ki is determined by equally dividing the search range by (N−1). Accordingly, the difference L between the second largest search band value Ks and the maximum search band value Km is obtained as follows.
L = R / (N-1) (4)
Therefore, the second largest search band value Ks is expressed by the following formula (5).
Ks = Km−L = B + R / 2−R / (N−1) (5)
In the bandwidth measurement method employed in the present embodiment, the difference between the transmission interval for searching for the maximum search bandwidth value Km and the transmission interval for searching for the second largest search bandwidth value Ks is the smallest. This is the transmission interval difference. If the minimum transmission interval difference is T, the processing time condition is satisfied. Since the transmission interval is obtained by the above-described equation (2), if the following equation (6) is satisfied, the processing time condition is satisfied.
T = Ps / Ks−Ps / Km (6)
A new search range can be reset by solving the equations (3), (5), and (6) to obtain the value of R. In the present embodiment, when a new search range is reset, the latest measurement packet number N and packet size Ps that are already set are used as they are.

When the new search range is reset, the new search range is equally divided by (N-1) (S38) as in the process of S25. Similar to the processing of S26, the transmission interval is calculated by equation (2) (S39). The minimum transmission interval difference in the transmission interval calculated here is T, which satisfies the processing time condition. The calculated transmission interval is determined as one of the transmission conditions, and the process returns to the transmission main process. As shown in FIG. 2, when the transmission condition determination process ends, the number N of measurement packets is notified to the receiving terminal (S4), and the transmission process is performed (S5).

The transmission process will be described in detail with reference to FIG. In the transmission process, first, a measurement packet having the determined packet size Ps is generated (S41). The measurement packet includes image data, packet number information, and time information indicating a transmission interval between the previously transmitted measurement packet. The packet number is a number indicating the order of each measurement packet in the measurement stream, and a serial number or the like is used. Next, it waits for the determined transmission interval (S42).

When the standby time has elapsed, the generated measurement packet is transmitted to the receiving terminal (S43). It is determined whether or not all N measurement packets in the measurement stream have been transmitted (S44). If they have not been transmitted (S44: NO), the processes of S41 to S43 are repeated. When N measurement packets are transmitted (S44: YES), the process returns to the transmission main process. Thus, one measurement stream transmission process is completed.

Next, the reception main process will be described with reference to FIGS. The reception main process is executed when the communication device 1 operates as a receiving device that receives a measurement packet and measures a bandwidth. The reception main process is executed by the CPU 10 of the receiving device according to a program stored in the HDD 13 when an instruction to transmit / receive data to / from the transmitting device is input.

As shown in FIG. 6, when the reception main process is started, it is determined whether or not there is an instruction to end reception of a packet for measuring a bandwidth (S51). If there is no end instruction (S51: NO), data indicating the measurement packet number N is received from the transmission device, and the measurement packet number N is recognized (S52). In the reception process, the measurement packet transmitted from the transmission terminal is received (S53). In the bandwidth measurement process, a bandwidth that can be used with the transmission terminal is measured (S54). The bandwidth measurement result is transmitted to the transmission terminal (S55), and the process returns to the determination of S51. Until an instruction to end packet reception is given (S51: NO), the processing of S52 to S55 is repeated. When an end instruction is given (S51: YES), the reception main process ends.

The reception process will be described in detail with reference to FIG. 7 and FIG. In the reception process, first, one of the measurement packets transmitted from the transmission terminal is received (S61). When the measurement packet is received, the time at that time is acquired as the reception time (S62). A reception interval that is a time interval from the reception time of the previous measurement packet is calculated (S63). A packet number and a transmission interval are extracted from the data included in the received measurement packet (S64). The extracted transmission interval and the calculated reception interval are stored in order in the packet information storage area (see FIG. 8) of the RAM 12 of the receiving device in association with the packet number (S65). It is determined whether all N measurement packets in the measurement stream have been received (S66). If reception has not been completed (S66: NO), the processing of S61 to S65 is repeated. When reception of N measurement packets is completed (S66: YES), the process returns to the reception main process (see FIG. 6), and a band measurement process (S54) is performed.

The band measurement process will be described in detail with reference to FIG. When the bandwidth measurement process is started, the difference between the reception interval and the transmission interval stored in the packet information storage area (see FIG. 8) is calculated for each packet number (S71). By the linear regression method, a time point at which the difference value of “reception interval−transmission interval” starts to change is detected (S72). When the change time point is detected (S73: YES), the search band value Ki at the change time point is determined as a band that can be used with the transmission device (S74), and the process returns to the reception main process. When the change time point of the difference “reception interval−transmission interval” is not detected (S73: NO), it is determined whether or not the difference is substantially “0” in the entire search range (S75). If the difference is approximately “0” (S75: YES), it is determined that the available bandwidth exceeds the search range (S76), the upper limit value of the search range is set as a provisional measurement result, and the process is a reception main process. Return to. If the difference between “reception interval−transmission interval” is a positive value in the entire search range (S75: NO), it is determined that the available bandwidth is below the search range (S77). In this case, the lower limit value of the search range is set as a provisional measurement result, and the process returns to the reception main process. In the reception main process (see FIG. 6), the measured bandwidth is notified to the transmission device (S55), and the process of receiving one measurement stream is completed.

As described above, the communication device 1 according to the present embodiment determines the measurement packet transmission condition based on the variation in processing time required for the measurement packet transmission process. Specifically, the communication device 1 determines a transmission interval, which is an interval for performing at least measurement packet transmission processing, among a plurality of transmission conditions based on the variation. As a result, the communication device 1 can reduce the influence of the variation in processing time on the band measurement result. Therefore, the communication device 1 can transmit the measurement packet so that the bandwidth can be measured with high accuracy. Specifically, the communication device 1 determines the transmission interval so that the transmission interval difference becomes larger than the processing time variation. Therefore, the communication apparatus 1 can transmit a plurality of measurement packets so that the change time of the difference of “reception interval−transmission interval” can be accurately detected.

The communication device 1 changes at least one of the search range, the number N of measurement packets, and the packet size Ps if at least a part of the transmission interval difference is less than or equal to the variation. As a result, the communication device 1 can accurately determine a transmission condition in which the transmission interval difference is larger than the variation. In particular, if a part of the transmission interval difference is less than or equal to the variation, the communication device 1 according to the present embodiment decreases the number N of measurement packets while keeping the search range and the packet size Ps fixed, and lengthens the transmission interval difference. . The search range is set by a statistical method so that the bandwidth can be measured efficiently. Furthermore, if the search range is expanded, the bandwidth measurement accuracy decreases. Therefore, it is not desirable to change the search range. Also, changing the packet size Ps increases the processing load on the communication device 1. The communication device 1 can increase the transmission interval difference efficiently by reducing only the number N of measurement packets.

However, if the number N of measurement packets is reduced too much, the detection accuracy at the time of change of “reception interval−transmission interval” is greatly reduced. Therefore, if the number N of measurement packets is equal to or less than the lower limit value, the communication device 1 resets the search range so that the minimum transmission interval difference is slightly larger than the variation. As a result, the communication apparatus 1 can determine an appropriate transmission condition while preventing a significant decrease in measurement accuracy due to a decrease in the number N of measurement packets. On the other hand, if the number N of measurement packets is larger than the lower limit value, the communication device 1 reduces the number N of measurement packets, thereby preventing a significant decrease in measurement accuracy due to changing the search range and performing appropriate transmission. Conditions can be determined.

¡The higher the number of measurement packets N, the higher the bandwidth measurement accuracy. However, if the number N of measurement packets is increased too much, the processing burden required for bandwidth measurement increases. The communication apparatus 1 can improve the measurement accuracy by increasing the number N of measurement packets within a range where the processing load does not increase excessively.

The communication apparatus 1 can efficiently and accurately determine the transmission condition by using the standard deviation of the processing time required for the packet transmission process as a variation. The communication device 1 obtains the processing time from the time required to transmit and receive the generated packet and calculates the standard deviation. As a result, it is possible to accurately acquire the processing time and the standard deviation.

The communication device 1 can function as both a transmission device and a reception device. Therefore, when communicating with another device, the communication device 1 can easily measure the band even if the counterpart device has only one function of the transmission device and the reception device. When the communication device 1 functions as a reception device, the communication device 1 can measure the bandwidth by itself using the information included in the measurement packet and the reception interval. Since the reception device only needs to notify the transmission device of the measurement result, the measurement result can be shared with the transmission device without excessively increasing the amount of data transmitted to and received from the transmission device. it can.

It goes without saying that the present invention is not limited to the above embodiment, and various modifications are possible. For example, variation in processing time required for packet transmission processing can be acquired by a method different from the method described in the above embodiment. With reference to FIG. 10, a modified example in which the processing conditions of the transmission apparatus are applied to a table to obtain variation will be described. The transmission apparatus according to the modification stores the variation determination table shown in FIG. In the variation determination table, a plurality of OS types, CPU clocks, CPU usage rates, and variation values are associated with each other. The variation value in this case may be determined by actually operating the communication device under the corresponding processing conditions. In the variation acquisition process (S2, see FIG. 2), the transmission apparatus first acquires its own OS type, CPU clock, and CPU usage rate at that time as its processing conditions. By referring to the variation determination table, the variation associated with the acquired processing condition is acquired as the variation of the current transmission apparatus. In this case, the transmission device can easily acquire the variation only by referring to the information of the variation determination table.

Note that the HDD 13 in the communication device 1 according to the modification corresponds to a “storage unit”. The CPU 10 that acquires information of the variation determination table in S2 of FIG. 2 functions as an “information acquisition unit”. In the above modification, information used as a processing condition of the transmission device can be changed. For example, one or two of the above three conditions (OS type or the like) may be used as a processing condition, or other conditions may be used as a processing condition.

The present invention can be modified in other ways. For example, the communication apparatus 1 according to the above embodiment lengthens the transmission interval difference mainly by reducing the number N of measurement packets. However, it is possible to increase the transmission interval difference by increasing the packet size Ps. Specifically, in the transmission condition determination process shown in FIG. 4, if the transmission condition that satisfies the processing time condition is not set (S27: NO, S32: NO), the packet with the search range and the number of measured packets N fixed. The size Ps may be increased. In this case, it is possible to lengthen the transmission interval difference without considering the decrease in measurement accuracy caused by changing the number N of measurement packets. Needless to say, two or more of the search range, the number N of measured packets, and the packet size Ps may be changed.

In the above embodiment, the usable bandwidth between the receiving device and the transmitting device is measured. However, the present invention can be applied even when the transmission device itself receives the measurement packet transmitted to the network 8. The present invention can also be applied to a method of measuring a band used by another communication device by transmitting a dummy packet. In addition, when the value of the bandwidth to be measured is large, the measurement packet may be transmitted in bursts, but the present invention can also be applied to this case. When burst transmission is performed, the transmission interval of measurement packets other than during burst may be determined according to the present invention. Furthermore, “bandwidth measurement” in the present invention includes determining whether or not a bandwidth suitable for communication is secured. The “bandwidth suitable for communication” is a bandwidth value within which the packet transmission time delay falls within an allowable range. The “band suitable for communication” is preferably a value equal to or less than an available band that does not cause a delay in transmission time. However, even if the value is larger than the usable bandwidth, a certain value that can tolerate transmission time delay may be set as a “band suitable for communication”.

In the above embodiment, the receiving device measures the band and notifies only the measurement result to the transmitting device. However, it is also possible for the transmission device and other servers to measure the bandwidth. For example, when the transmission device measures a band, the reception device calculates a reception interval and a transmission interval, and transmits information on the calculated reception interval and transmission interval to the transmission device for notification. The transmitting device may detect the change time of the difference of “reception interval−transmission interval” using the information of the reception interval and the transmission interval transmitted from the receiving device, calculate the band, and measure it. However, the amount of data transmitted and received between the receiving device and the transmitting device is larger than when only the measurement result is notified from the receiving device to the transmitting device.

In the above embodiment, a plurality of search band values Ki are calculated by equally dividing the band search range, and the transmission interval is calculated. However, the method for calculating the transmission interval is not limited to this. For example, it is possible to divide the search range so that the transmission interval difference is constant and calculate the transmission interval. In other words, the bandwidth measurement method to which the present invention can be applied may be any method that measures the bandwidth based on the reception interval and the transmission interval. In addition, when the number N of measurement packets is equal to or lower than the lower limit value, the present invention can be realized without performing the process of forcibly resetting the search range (S37 to S39).

In the above embodiment, standard deviations of a plurality of processing times are used as variations in processing time required for the transmission processing of measurement packets. However, what can be used as variation is not limited to the standard deviation. For example, the difference between the maximum value and the minimum value of the processing time can be used as the variation. Variations may be calculated from a plurality of processing times using other statistical methods. An average value of the processing times may be calculated, and the difference between the average value and the maximum value and the difference between the average value and the minimum value may be used as variations. A value obtained by multiplying the difference between the maximum value and the minimum value by an arbitrary n (0 <n <1, for example, n = 0.5) may be used as the variation. In the above-described embodiment, the “communication program” in the present invention is stored in the HDD 13 of the communication apparatus 1, but it goes without saying that it may be stored in another storage medium such as a CDROM.

It is also possible to correct the influence of the processing time variation required for generating the measurement packet in the processing time by changing the processing when transmitting the measurement packet. Specifically, in the transmission process shown in FIG. 5, the CPU 10 calculates a generation process time from the start of S41 to the end. In S43, the CPU 10 waits for a time obtained by subtracting the generation processing time from the transmission interval to be waited, and then transmits the measurement packet. In this case, in the variation acquisition process shown in FIG. 3, it is only necessary to replace S11 and S12 and acquire only the variation in processing time necessary for transmitting the generated packet. As described above, by correcting the processing time required for generating the measurement packet, it is possible to reduce the influence of the variation in the processing time on the measurement result.

1 Communication device 8 Network 10 CPU
13 HDD
100 band measurement system

Claims (13)

A packet is measured so that the bandwidth can be measured based on a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted and a reception interval of the plurality of packets received via a network. A communication device for performing communication of
Generating means for generating a packet including time information for determining the transmission interval;
Variation obtaining means for obtaining variations in processing time required for transmission processing of the plurality of packets;
Transmission condition determining means for determining a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquiring means;
A communication apparatus comprising: a transmission unit that sequentially transmits the plurality of packets generated by the generation unit according to the transmission condition determined by the transmission condition determination unit. The transmission condition determining unit obtains a transmission interval difference, which is a difference between one interval among a plurality of intervals included in the transmission interval and an interval before or after the one interval, by the variation obtaining unit. The communication apparatus according to claim 1, wherein the transmission interval is determined so as to be larger than the determined variation. The transmission condition determining means includes
The transmission range is determined by a search range that is a measurement target range of a band of the plurality of packets, a measurement packet number that is the number of packets that constitute the plurality of packets, and a packet size of each packet that constitutes the plurality of packets. First calculating means for calculating the interval;
First determination means for determining whether or not all the transmission interval differences in the transmission interval calculated by the first calculation means are larger than the variation acquired by the variation acquisition unit;
Changing means for changing at least one of the search range, the number of measurement packets, and the packet size when the first determining means determines that at least a part of the transmission interval difference is equal to or less than the variation. The communication apparatus according to claim 2, further comprising: 4. The communication apparatus according to claim 3, wherein the changing unit reduces the number of measurement packets while fixing the search range and the packet size. The transmission condition determining means includes
Second determination means for determining whether or not the number of measurement packets is equal to or less than a first threshold when the first determination means determines that at least a part of the transmission interval difference is equal to or less than the variation; Prepared,
The changing means is
When the second determination means determines that the number of measurement packets is equal to or less than the first threshold, the search range is expanded and reset,
4. The measurement packet number is decreased while the search range and the packet size are fixed when the second determination unit determines that the number of measurement packets is larger than the first threshold value. The communication apparatus as described in. The transmission condition determining means includes
Third determination means for determining whether or not the number of measurement packets is equal to or greater than a second threshold when it is determined by the first determination means that all the transmission interval differences are larger than the variation;
And an increase means for increasing the number of measurement packets with the second threshold as a limit when the third determination means determines that the number of measurement packets is smaller than the second threshold. The communication device according to any one of claims 3 to 5. Processing time acquisition means for acquiring a plurality of processing times required for transmission processing of each of the plurality of packets;
The communication apparatus according to claim 1, wherein the variation acquisition unit acquires a standard deviation of a plurality of processing times acquired by the processing time acquisition unit as the variation. The communication apparatus according to claim 7, wherein the processing time acquisition unit acquires a processing time from a time required to transmit and receive the packet generated by the generation unit. From a storage unit that stores a table in which the processing conditions of the communication device including at least one of the OS type of the communication device, the number of clocks of the communication device, and the CPU usage rate of the communication device are associated with the variation , Further comprising information acquisition means for acquiring information of the table,
The communication apparatus according to claim 1, wherein the variation acquisition unit acquires the variation associated with the current processing condition by referring to the information of the table acquired by the information acquisition unit. . Receiving means for receiving a plurality of packets transmitted in succession;
A reception interval acquisition unit that acquires reception intervals of the plurality of packets received by the reception unit;
From the time information included in each of the plurality of packets received by the reception means, transmission interval acquisition means for acquiring transmission intervals of the received packets.
2. The measurement apparatus according to claim 1, further comprising a measuring unit that measures a band based on the reception interval acquired by the reception interval acquisition unit and the transmission interval acquired by the transmission interval acquisition unit. The communication device described. A packet is measured so that the bandwidth can be measured based on a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted and a reception interval of the plurality of packets received via a network. A communication method performed by a communication device that performs communication of
Generating a packet including time information for determining the transmission interval;
A variation acquisition step for acquiring variations in processing time required for the transmission processing of the plurality of packets;
A transmission condition determination step for determining a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquisition step;
And a transmission step of sequentially transmitting the plurality of packets generated by the generation step under the transmission conditions determined by the transmission condition determination step. A packet is measured so that the bandwidth can be measured based on a transmission interval that is an interval for performing transmission processing of each of a plurality of packets that are continuously transmitted and a reception interval of the plurality of packets received via a network. A communication program for controlling the operation of a communication device that performs communication of
On the computer,
Generating a packet including time information for determining the transmission interval;
A variation acquisition step for acquiring variations in processing time required for the transmission processing of the plurality of packets;
A transmission condition determination step for determining a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquisition step;
And a transmission step of sequentially transmitting the plurality of packets generated in the generation step under the transmission conditions determined in the transmission condition determination step. A transmission device that continuously transmits a plurality of packets; and a reception device that receives the plurality of packets transmitted by the transmission device via a network, wherein each of the plurality of packets is transmitted by the transmission device. A bandwidth measurement system that measures a bandwidth between the transmission device and the reception device based on a transmission interval that is an interval for performing processing and a reception interval of the plurality of packets in the reception device,
The transmitter is
Generating means for generating a packet including time information for determining the transmission interval;
Variation obtaining means for obtaining variations in processing time required for transmission processing of the plurality of packets;
Transmission condition determining means for determining a transmission condition including at least the transmission interval of the plurality of packets based on the variation acquired by the variation acquiring means;
A transmission unit that sequentially transmits the plurality of packets generated by the generation unit under the transmission condition determined by the transmission condition determination unit;
The receiving device is:
Receiving means for receiving the plurality of packets;
A reception interval acquisition unit that acquires reception intervals of the plurality of packets received by the reception unit;
Transmission interval acquisition means for acquiring transmission intervals of the plurality of packets from the time information included in each of the plurality of packets received by the reception means;
Measuring means for measuring a band between the transmission apparatus based on the reception interval acquired by the reception interval acquisition unit and the transmission interval acquired by the transmission interval acquisition unit. A featured bandwidth measurement system.

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