WO2018123710A1

WO2018123710A1 - Communication system, communication method, transfer device, and transfer method

Info

Publication number: WO2018123710A1
Application number: PCT/JP2017/045454
Authority: WO
Inventors: 優宇青木
Original assignee: 日本電気株式会社
Priority date: 2016-12-28
Filing date: 2017-12-19
Publication date: 2018-07-05

Abstract

In order that, in a system for notifying an upstream device of a communication band permitted for a communication path to a downstream device, a data transfer from the upstream device is transferred to the downstream device without being stopped and disposal of the data is prevented, a transfer device 10 has a buffer 11 for temporarily storing the data received from a first communication device 20 and transmitted to a second communication device 40, a notification band determination unit 12 for determining band information to be notified to the first communication device 20 on the basis of first information relating to a band usable in a traffic transfer path 50 to the second communication device 40 and second information relating to a band that corresponds to a free space of the buffer 11, and a band notification transmission unit 13 for transmitting the band information to the first communication device 20.

Description

COMMUNICATION SYSTEM, COMMUNICATION METHOD, TRANSFER DEVICE, AND TRANSFER METHOD

The present invention relates to a communication system, a communication method, a transfer device, and a transfer method, and more particularly, to a communication system, a communication method, a transfer device, and a transfer method for notifying an upstream device of a communication band allowed with a downstream device.

The transfer device that receives data from the upstream device and transmits the received data to the downstream device needs to be controlled so as to transmit the data in a communication band allowed in the communication path with the downstream device. If data is transmitted from the upstream device at a rate larger than the communication band allowed on the communication path with the downstream device, there is a possibility that the transfer device will discard the packet. A communication method for notifying an upstream device of a communication band allowed on a communication path with a downstream device is defined in the ITU-T standard or the like.

For example, ITU-T G. 8013 / Y. 1731 defines a band notification called ETH-BN (Ethernet Bandwidth Notification) as one function of ETH-OAM (Ethernet (registered trademark) Operation. Administration and Maintenance).

This function transmits a message notifying a band called BNM (Bandwidth Notification Message) to another L2 switch that performs network QoS (Quality of Service) control from a device with a narrow band. This aims at performing QoS control in consideration of the entire network by the L2 switch. According to the recommendation, 1s, 10s, and 1min are defined as the transmission cycle, and notification is made according to the band change in this cycle.

The transfer device with a narrow bandwidth transmits BNM or the like indicating an allowable communication bandwidth to another device that performs QoS control of the upstream network. The bandwidth control unit of the other upstream device performs rate control with the data transfer amount per time based on the communication bandwidth notified by BNM or the like, and transmits data to the transfer device that notifies the bandwidth information.

As another related technique, for example, Patent Documents 1 and 2 disclose an apparatus for controlling the amount of transmission data so as not to exceed the limit value of the communication band allowed on the wireless path.

In the ATM multiplexing apparatus of Patent Document 1, an allowable bandwidth is set for the data transmission request unit, and the transmission data from the data transmission request unit does not exceed the allowable bandwidth through the buffer means. Sent by. The buffer means holds data corresponding to the difference between the data amount input from the data transmission request unit and the data amount output. The amount of data stored in the buffer means is compared with the allowable data amount. When the allowable data amount is exceeded, transmission from the data transmission request unit is stopped, and then the data stored in the buffer means If the amount becomes smaller than the allowable bandwidth, transmission is enabled.

Patent Document 2 discloses an in-vehicle wireless communication device that transmits a transmission rate and a band to a base station when information is downloaded from the base station. The in-vehicle wireless communication device of Patent Literature 2 determines a transmission rate to be applied from estimated terminal position information and speed information at the time of receiving the next frame. The in-vehicle wireless communication device calculates the amount of data required to be received and the reception time limit from the data accumulation amount of the reception buffer, the increase / decrease state of the data accumulation amount, the allowable data delay and the transmission rate, and sets the bandwidth allocated for data communication. decide. For example, if the in-vehicle wireless communication device continues to download at a low rate, the amount of data stored in the reception buffer is small, the bandwidth of map information with a small allowable delay is expanded, and the amount of data stored in the reception buffer is large. The bandwidth of music information having a large allowable delay is set to “no allocation”.

Japanese Patent Laid-Open No. 07-123099 International Publication No. 2011/045828

In a configuration in which bandwidth information such as BNM is notified from a device with a narrow bandwidth to another device that performs network QoS control, the physical bandwidth of a traffic transfer path from another device to a device with a narrow bandwidth is, for example, 1 Gbps. The usable communication bandwidth in a device with a narrow bandwidth is, for example, 10 Mbps, and the physical bandwidth of the traffic transfer path is larger than the usable communication bandwidth in a device with a narrow bandwidth. For this reason, when looking at the rate in a short time, there is a case where transmission is performed at a rate larger than the control rate of 10 Mbps notified from a device with a narrow band. This phenomenon is called instantaneous burst. When the amount of data transmitted from another device that has notified the communication band by a device with a narrow bandwidth by BNM or the like exceeds the amount that can be received by the buffer of the device with a narrow bandwidth due to an instantaneous burst, the data is discarded.

The ATM multiplexing device disclosed in Patent Document 1 stops data transmission from the data transmission request unit in the ATM multiplexing device when the amount of data stored in the buffer means is larger than the allowable data amount. is there. In the in-vehicle wireless communication device disclosed in Patent Document 2, if downloading at a low rate continues when downloading information from a base station, the bandwidth of music information with a large amount of data stored in the reception buffer is set to “no allocation”. In any case, when there is a lot of data in the buffer, data transmission from the upstream device is stopped. Any of the techniques in the literature stops data transfer from the upstream.

It is an object of the present invention to transfer data to the downstream device without stopping the data transfer from the upstream device in a system that notifies the upstream device of the communication bandwidth allowed with the downstream device, and to suppress data discarding. A communication system, a communication method, a transfer device, and a transfer method are provided.

A transfer device according to one aspect of the present invention is used in a communication path between a buffer that temporarily stores data received from a first communication device and transmitted to a second communication device, and the second communication device. A notification bandwidth determining unit that determines bandwidth information based on first information relating to a possible bandwidth and second information relating to a bandwidth corresponding to the free capacity of the buffer; and a bandwidth for transmitting the bandwidth information to the first communication device. A notification transmission unit.

According to another aspect of the present invention, there is provided a transfer method in which data received from a first communication device and transmitted to a second communication device is temporarily stored in a buffer, and a communication path between the second communication device and the second communication device. Obtaining first information on available bandwidth, calculating second information on bandwidth corresponding to the free capacity of the buffer, determining bandwidth information based on the first and second information, and determining the determined Band information is transmitted to the first communication device.

A communication system according to another aspect of the present invention includes a first communication device that transmits data at a rate based on notified bandwidth information, and the transfer device.

A communication method according to another aspect of the present invention transmits data from a first communication device to a transfer device at a rate based on notified bandwidth information, temporarily stores the data in a buffer of the transfer device, First information relating to a bandwidth that can be used in a communication path between two communication devices is acquired, and data stored in the buffer is transmitted to the second communication device at a rate according to the first information. The second information related to the bandwidth corresponding to the free space of the buffer is acquired, the bandwidth information is determined based on the first and second information, and the determined bandwidth information is transmitted to the first communication device. To do.

According to the present invention, the transfer device that notifies the upstream device of the bandwidth information based on the bandwidth available on the communication path with the downstream device can transfer the data from the upstream device to the downstream device without stopping the data transfer. It is possible to provide a communication system, a communication method, a transfer device, and a transfer method that can prevent discarding.

FIG. 1 is a block diagram showing a schematic configuration of the first embodiment. FIG. 2 is a diagram illustrating a change in the amount of transmission data from the first communication apparatus in FIG. FIG. 3 is a flowchart showing the band information determination operation of FIG. FIG. 4 is a block diagram showing the configuration of the second exemplary embodiment of the present invention. FIG. 5 is a flowchart showing a buffer free space notification operation. FIG. 6 is a diagram illustrating a first change in the free space of the buffer when the buffer notifies the free space. FIG. 7 is a diagram illustrating a second change in the free space of the buffer when the buffer notifies the free space. FIG. 8 is a diagram illustrating a third change in the free space of the buffer when the buffer notifies the free space. FIG. 9 is a diagram illustrating a setting example of bandwidth information corresponding to the free space of the buffer. FIG. 10 is a flowchart showing an example of an operation for setting bandwidth information corresponding to the free space of the buffer. FIG. 11 is a flowchart showing another example of the operation for setting the bandwidth information corresponding to the free space of the buffer. FIG. 12 is a diagram showing another setting example of the shaper rate corresponding to the free space of the buffer by the operation of FIG. FIG. 13 is a diagram showing still another setting example of the shaper rate corresponding to the free space of the buffer. FIG. 14 is a diagram illustrating still another setting example of the shaper rate corresponding to the free space of the buffer. FIG. 15 is a flowchart showing the band information determination operation of FIG. FIG. 16 is a block diagram showing a configuration of the third exemplary embodiment of the present invention.

Hereinafter, the configuration of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first exemplary embodiment of the present invention. As shown in FIG. 1, the transfer device 10 receives data from the upstream first communication device 20 via the traffic transfer path (communication path) 30, and sends the received data to the downstream second communication device 40. On the other hand, the data is transmitted via a traffic transfer path (communication path) 50. Here, the traffic transfer path 50 may be a wireless communication path. The transfer device 10 acquires first information regarding a bandwidth that can be used on a traffic transfer path (communication path) 50 between the transfer apparatus 10 and the second communication apparatus 40. The first communication device 20 is notified of the band information from the transfer device 10 and restricts the data transmission band with the notified band information when transmitting data to the transfer device 10. The transfer device 10 is not limited to the transfer device, and may be a communication device similar to the first communication device 20 and the second communication device 40.

The transfer device 10 of the present invention includes a buffer 11, a notification band determination unit 12, and a band notification transmission unit 13 as shown in FIG.

The buffer 11 temporarily stores data to be transmitted to the second communication device 40.

The notification bandwidth determination unit 12 monitors the dynamically usable bandwidth of the traffic transfer path 50 and the free capacity of the buffer 11, and performs the first communication based on the available bandwidth of the traffic transfer path 50 or the free capacity of the buffer 11. Band information to be notified to the device 20 is determined. The notification bandwidth determination unit 12 includes first information related to a bandwidth that can be used on a traffic transfer path (communication path) 50 between the second communication device 40 and a second bandwidth related to the free space of the buffer 11. Based on the information, band information to be notified to the first communication device 20 is determined.

An example of the second information regarding the bandwidth corresponding to the free capacity of the buffer 11 will be described. FIG. 2 is a diagram illustrating a change in the amount of transmission data from the first communication apparatus in FIG. As shown in FIG. 2, it is assumed that the first communication device 20 controls the data transmission band with the control band R. The control band R may be, for example, a shaper rate or a policer rate. Hereinafter, it is described as a shaper rate in this specification. Assume that an instantaneous burst occurs at this time, and the data is transmitted from the first communication device 20 at the burst transmission rate Rb exceeding the shaper rate R when viewed in a short time Δt. In this case, the first communication device 20 transmits data larger than the data capacity assumed at the shaper rate R during Δt by the capacity (Rb−R) × Δt to the transfer apparatus 10. Therefore, if the free capacity Q of the buffer 11 of the transfer apparatus 10 is smaller than (Rb−R) × Δt, the buffer 11 cannot receive the transmission data and data is discarded. As the shaper rate R increases, transmission data due to instantaneous bursts increases, and the required free space Q increases.

The notification bandwidth determination unit 12 includes a buffer free space Q that allows the transfer device 10 to receive transmission data even when an instantaneous burst occurs while the first communication device 20 is transmitting data at the shaper rate R, and its shaper. Correspondence with rate R is set. Specifically, the free capacity Q equal to or greater than the increment of the transmission data capacity when an instantaneous burst occurs while the first communication apparatus 20 is controlling at the shaper rate R is made to correspond to the shaper rate R. From the relationship between the free capacity Q and the shaper rate R set in this way, the notification bandwidth determination unit 12 obtains the shaper rate R for the free capacity Q of the buffer 11 at which data discard due to an instantaneous burst does not occur. The shaper rate obtained from the free capacity of the buffer 11 is the second information regarding the bandwidth corresponding to the free capacity of the buffer.

For example, the notification band determination unit 12 determines the relationship between the shaper rate of the first communication device 20 and the increase in transmission data capacity when an instantaneous burst occurs while the first communication device 20 is controlling at the shaper rate. keeping. The notification band determination unit 12 calculates the shaper rate R corresponding to the free capacity Q of the buffer 11 from the relationship between the shaper rate and the increase in transmission data capacity when an instantaneous burst occurs. When the shaper rate R corresponding to the free capacity Q of the buffer 11 is equal to or higher than the bandwidth that can be used in the traffic transfer path 50, the notification bandwidth determination unit 12 determines the available bandwidth of the traffic transfer path 50 as the first communication device. 20 is determined as bandwidth information to be notified to the network 20. In addition, when the shaper rate R corresponding to the free capacity Q of the buffer 11 is smaller than the available bandwidth of the traffic transfer path 50, the notification bandwidth determination unit 12 determines the shaper rate R corresponding to the free capacity Q of the buffer 11. 1 is determined as bandwidth information to be notified to the first communication device 20.

The bandwidth notification transmission unit 13 transmits the bandwidth information determined as the bandwidth information to be notified to the first communication device 20.

Next, the operation of the first embodiment will be described. FIG. 3 is a flowchart showing the band information determination operation of FIG. The operation of FIG. 3 may be started when at least one of the available bandwidth of the traffic transfer path 50 and the free capacity of the buffer 11 changes, but is not limited thereto.

First, the transfer device 10 temporarily stores the data received from the first communication device 20 and transmitted to the second communication device 40 in the buffer 11 (step S1). Next, the transfer device 10 acquires first information related to a bandwidth that can be used on the traffic transfer path 50 between the transfer device 10 and the second communication device 40 (step S2).

The transfer apparatus 10 calculates second information related to the bandwidth corresponding to the free capacity of the buffer 11 (step S3). As described above, the transfer device 10 receives the shaper rate R of the first communication device 20 and the buffer 11 when an instantaneous burst occurs while the first communication device 20 is controlling at the shaper rate R. The relationship with the necessary free space Q is maintained. From the relationship between the shaper rate R and the free capacity Q required to be received by the buffer 11 when an instantaneous burst occurs during transmission at that shaper rate, the notification bandwidth determination unit 12 uses the shaper rate R corresponding to the free capacity Q. (Second information) is calculated.

The notification bandwidth determination unit 12 of the transfer device 10 determines bandwidth information based on the first and second information (step S4). Specifically, when the calculated shaper rate R is equal to or higher than the bandwidth that can be used in the traffic transfer path 50, the notification band determination unit 12 of the transfer device 10 determines the available bandwidth of the traffic transfer path 50 as the first communication. The bandwidth information to be notified to the device 20 is determined. On the other hand, when the calculated shaper rate R is smaller than the available bandwidth of the traffic transfer path 50, the notification bandwidth determination unit 12 of the transfer device 10 notifies the first communication device 20 of the calculated shaper rate R. Determine as information.

The transfer device 10 transmits the determined bandwidth information to the first communication device 20 (step S5). The first communication device 20 controls the transmission rate of data to be transmitted to the transfer device 10 at the notified shaper rate.

As described above, according to the first embodiment, when the shaper rate R corresponding to the free capacity Q of the buffer 11 is smaller than the available bandwidth of the downstream traffic transfer path 50, the notification bandwidth determination unit of the transfer device 10 12 determines the shaper rate R corresponding to the free capacity Q of the buffer 11 as band information to be notified to the first communication device 20. With this configuration, in the transfer device 10 that notifies the upstream communication device 20 of the bandwidth information based on the bandwidth available on the downstream traffic transfer route 50, the downstream traffic transfer route without stopping the data transfer from the upstream communication device. 50, and discarding of data in the buffer 11 can be prevented.

Next, a second embodiment will be described. FIG. 4 is a block diagram showing the configuration of the second exemplary embodiment of the present invention. The packet transfer device 60 receives packet data via the traffic transfer path 30 from the upstream packet transfer device 70 which is the first communication device in the first embodiment. Further, the packet transfer device 60 transmits the received packet data to the second communication device 40 via the traffic transfer path 50.

The packet transfer device 60 according to the present embodiment includes a buffer 11, a notification bandwidth determination unit 12, a bandwidth notification transmission unit 13, a buffer free space notification unit 61, a radio bandwidth determination unit 62, and a bandwidth control unit 63. ing. The upstream packet transfer apparatus 70 includes a band notification receiving unit 71 and a band control unit 72.

The buffer free space notification unit 61 notifies the notification bandwidth determination unit 12 of the free space. Note that the buffer free space notifying unit 61 does not always have to continuously notify the notification bandwidth determining unit 12 of the buffer free space change. The buffer free space notification unit 61 sets a plurality of thresholds, and notifies the free space when the detected free space exceeds or falls below any of the plurality of thresholds.

FIG. 5 is a flowchart showing the free space notification operation of the buffer free space notification unit 61. As shown in FIG. 5, first, the buffer free space notification unit 61 detects free space (step S11). Initially, i = 1 is set (step S12), and it is determined whether the detected free space is equal to or smaller than the i-th threshold i of a plurality of thresholds (step S13). If it is equal to or less than the threshold value i, it is determined whether or not the free space is larger than the i-th threshold i when the previous free space is detected (step S14), and if the free space is larger than the i-th threshold i when the previous free space is detected, The buffer free space notification unit 61 notifies the notification bandwidth determination unit 12 of the free space corresponding to the threshold value i (step S15). If the free space is not less than or equal to the i-th threshold i in step S13, it is determined whether or not the free space is smaller than the i-th threshold i when the previous free space was detected (step S16). If the free space is smaller than the i-th threshold i at the previous detection of the free space, the buffer free space notification unit 61 notifies the notification bandwidth determination unit 12 of the free space corresponding to the threshold i (step S15). Then, it is determined whether i is equal to the number of thresholds, that is, whether the determination for the last threshold is completed (step S17). If i is not equal to the number of thresholds, 1 is added to i (step S18), and step S13 is performed. Return to. That is, the buffer free space notifying unit 61 proceeds to a determination on the next threshold value i + 1. If the free space is not greater than the i-th threshold value i at the previous detection of free space in step S14, the buffer free space notification unit 61 does not notify the free space and proceeds to step S17. If the free space is not smaller than the i-th threshold i at the time of the previous free space detection in step S16, the buffer free space notification unit 61 does not notify the free space and proceeds to step S17. When i is equal to the number of thresholds in step S17, that is, when the determination about the last threshold is completed, the buffer free space notification unit 61 ends the free space notification operation.

The operation of FIG. 5 in a specific change state will be described. In the following example, it is assumed that five levels of threshold values from threshold value A to threshold value E are set. For example, it is assumed that the threshold A is the first threshold and the threshold E is the fifth threshold in ascending order of free space.

FIG. 6 is a diagram illustrating a first change in the free space when the buffer free space notification unit 61 notifies the free space. FIG. 6 shows a change in which the free space is larger than the threshold A at the previous detection, but the free space is smaller than the threshold A at the current detection. In this case, Yes in step S13 when i = 1, and YES in step S14, so that the buffer free space notification unit 61 notifies the notification bandwidth determination unit 12 of the free space corresponding to the threshold value A in step S15.

FIG. 7 is a diagram showing a second change in the free space of the buffer when the buffer free space notification unit 61 notifies the free space. FIG. 7 shows a change in which the free space is larger than the threshold C at the previous detection, but the free space is smaller than the threshold C at the current detection. In this case, YES is obtained in step S13 when i = 3, and YES is obtained in step S14. Accordingly, in step S15, the buffer free capacity notifying unit 61 notifies the notification bandwidth determining unit 12 of the free capacity corresponding to the threshold C.

FIG. 8 is a diagram showing a third change in the free space of the buffer when the buffer free space notification unit 61 notifies the free space. FIG. 8 shows a change in which the free space is smaller than the threshold E during the previous detection, but the free space is smaller than the threshold E during the current detection. In this case, NO is obtained in step S13 when i = 5, and YES is obtained in step S16. Therefore, in step S15, the buffer free space notification unit 61 notifies the notification bandwidth determination unit 12 of the free space corresponding to the threshold value E.

Returning to FIG. 4, the configuration of the second embodiment will be described.

The radio bandwidth determination unit 62 determines the ETH bandwidth (the maximum bandwidth of the traffic transfer path 50).

The bandwidth control unit 63 sets the shaper rate of the traffic transfer path 50 based on the ETH bandwidth determined and notified by the wireless bandwidth determination unit 62. The bandwidth control unit 63 sets the transfer rate according to the shaper rate when transmitting the data temporarily stored in the buffer 11 from the packet transfer device 60 to the second communication device 40 via the traffic transfer path 50. Control.

The notification bandwidth determination unit 12 acquires the ETH bandwidth determined by the wireless bandwidth determination unit 62, acquires information on the free space from the buffer free space notification unit 61, and based on the acquired ETH bandwidth and the free space of the buffer 11, Band information to be notified to the packet transfer apparatus 70 on the opposite side is determined. Similar to the first embodiment, the notification bandwidth determination unit 12 uses the buffer 11 when an instantaneous burst occurs while the packet transfer device 70 is controlling at the shaper rate R and the shaper rate R of the upstream packet transfer device 70. The relationship with the free space Q necessary to receive the data is held. The notification bandwidth determination unit 12 may set a free capacity corresponding to each threshold and a shaper rate corresponding to the free capacity in association with a plurality of thresholds.

FIG. 9 is a diagram showing an example of setting the shaper rate corresponding to the free space of the buffer. As shown in FIG. 9, the notification bandwidth determination unit 12 corresponds to the threshold value notified from the buffer free space notification unit 61 and the actual free space of the buffer 11 and the packet transfer device 70 at a constant shaper rate. A shaper rate is set to suppress data discard even if an instantaneous burst occurs during transmission.

For example, when the free space is notified from the buffer free space notification unit 61 as “threshold A”, the free space of the buffer 11 is 10 kbytes, and the shaper rate is set to 100 Mbps for this free space. This means that when the free space is notified from the buffer free space notification unit 61 as “threshold A”, even if an instantaneous burst occurs when the packet transfer device 70 transmits a packet at 100 Mbps, data discard occurs. Indicates that no. The threshold A is a threshold indicating that the buffer usage is Full, but in this case as well, the free space of the buffer is not 0 bytes, and the shaper rate is not 0 but 100 MBbps. With such a configuration, there is an effect that it is possible to prevent the free capacity of the transmission buffer in the upstream packet transfer apparatus 70 from rapidly decreasing.
The bandwidth may be set larger than 0 when the buffer free space is 0 bytes. In this way, there is an effect that communication can be continued within a possible range even if there is no free space in the buffer. It is also possible to set the data transfer to be stopped (the shaper rate is 0 Mbps) with respect to a threshold with a small buffer free space.

Similarly, for example, when the free space is notified from the buffer free space notification unit 61 as “threshold C”, the free space of the buffer 11 is 100 kbytes, and 300 Mbps is set for this free space. This means that when the free space is notified from the buffer free space notification unit 61 as “threshold C”, even if an instantaneous burst occurs when the packet transfer device 70 transmits a packet at 300 Mbps, data discard occurs. Indicates that no.

FIG. 10 is a flowchart showing an example of an operation for setting the shaper rate corresponding to the free space of the buffer.

First, i = 1 is set (step S21), and the notification bandwidth determination unit 12 sets the shaper rate within a range where the data transfer from the packet transfer device 70 is not stopped for the i-th threshold i (step S22). The notification bandwidth determination unit 12 acquires information on the capacity transferred when an instantaneous burst occurs during packet transmission from the packet transfer device 70 at the set shaper rate (step S23). Then, the notification bandwidth determination unit 12 sets the free capacity of the buffer with the threshold value i based on the capacity transferred by the instantaneous burst (step S24). The notification bandwidth determination unit 12 determines whether i is equal to the number of thresholds set, that is, whether the setting for the last threshold has been completed (step S25). Is added (step S26), and the process returns to step S22. That is, the notification bandwidth determination unit 12 moves to setting for the next threshold value i + 1. When i is equal to the number of threshold values in step S25, that is, when the setting for the last threshold value is completed, the notification bandwidth determination unit 12 ends the shaper rate setting operation corresponding to the free space.

For this setting, for example, a setting value may be determined by actually performing the following measurement in advance and the above setting may be performed. First, the packet transfer apparatus 70 actually transmits a packet at a plurality of shaper rates, for example, 100 Mbps, 200 Mbps, 300 Mbps, 400 Mbps, and 500 Mbps in the example of FIG. 9 within a range where data transfer from the packet transfer apparatus 70 is not stopped. When an instantaneous burst occurs, the transfer capacity at time Δt is measured for each shaper rate, and the maximum value of the transfer capacity at time Δt is measured. The maximum value is recorded as the difference capacity from the transfer capacity at the shaper rate. In step S22, the notification band determination unit 12 sets each shaper rate. In step S24, the notification band determination unit 12 is transferred when an instantaneous burst is generated from recorded information on a plurality of shaper rates measured in advance. Based on the maximum transfer capacity, the buffer free capacity of the threshold value i is set. For example, it is assumed that measurement is performed at a shaper rate of 100 Mbps, 200 Mbps, 300 Mbps, 400 Mbps, and 500 Mbps. In this case, in step S22, as shown in FIG. 9, 100 Mbps, 200 Mbps, 300 Mbps, 400 Mbps, and 500 Mbps are set as the shaper rates corresponding to the threshold values A, B, C, D, and E. If the difference between the maximum transfer capacity at time Δt and the normal transfer capacity is 10 Kbytes, 50 Kbytes, 100 Kbytes, 200 Kbytes, and 400 Kbytes as the measurement results at these shaper rates, respectively, in step S24 As shown in FIG. 9, 10 Kbytes, 50 Kbytes, 100 Kbytes, 200 Kbytes, and 400 Kbytes are set as the free capacities corresponding to the threshold values A, B, C, D, and E.

Note that the operation for setting the shaper rate corresponding to the free space of the buffer is not limited to the above. FIG. 11 is a flowchart showing another example of the operation for setting the shaper rate corresponding to the free space of the buffer. FIG. 12 is a diagram showing another setting example of the shaper rate corresponding to the free space of the buffer by the operation of FIG. In this example, the notification bandwidth determination unit 12 first sets a ratio between the transfer capacity at the time Δt when an instantaneous burst occurs and the transfer capacity at which the data is transferred at the shaper rate during the time Δt (step S31). ). For example, the notification bandwidth determination unit 12 sets 70% when the transfer capacity at the shaper rate is 70% of the maximum transfer capacity when an instantaneous burst occurs. First, i = 1 is set (step S21), and the shaper rate is set for the i-th threshold i within a range where data transfer from the packet transfer apparatus 70 is not stopped (step S22). Next, based on the above ratio for the set shaper rate, the notification band determination unit 12 sets the free space of the buffer with the threshold value i (step S32). That is, the notification bandwidth determination unit 12 sets a capacity (ratio of 70% as a ratio) corresponding to (100− (set ratio))% of the transfer capacity in which data is transferred at a shaper rate for a short time Δt as the buffer free capacity. If set, 30%) is set. Thereafter, as in the example of FIG. 10, the notification bandwidth determination unit 12 determines whether i is equal to the number of thresholds set, that is, whether the setting for the last threshold has been completed (step S25). If it is not equal to the number, 1 is added to i (step S26), and the process returns to step S22. That is, the notification bandwidth determination unit 12 moves to setting for the next threshold value i + 1. When i is equal to the number of thresholds in step S25, that is, when the setting for the last threshold is completed, the setting operation of the shaper rate corresponding to the free space is terminated.

For this setting, for example, the following measurement may be actually performed in advance to determine the set value, and the above setting may be performed. First, the packet transfer apparatus 70 actually transmits a packet for a plurality of shaper rates set within a range where data transfer from the packet transfer apparatus 70 is not stopped. Then, the transfer capacity in a short time when an instantaneous burst occurs is measured, and the maximum value of the transfer capacity in a short time is obtained. The ratio between the maximum value and the transfer capacity at the shaper rate is recorded. In step S31, the notification band determination unit 12 sets the minimum ratio among the ratios at all the shaper rates from the recording information measured for the plurality of shaper rates.
For example, as a result of measuring the transfer capacity in a short time when an instantaneous burst occurs at a shaper rate of 100 Mbps, 200 Mbps, 300 Mbps, 400 Mbps, or 500 Mbps, the ratio between the maximum transfer capacity in the short time and the transfer capacity at the shaper rate Is 70 or more, in step S31, 70% is set. In step S22, the notification band determination unit 12 sets each shaper rate. For example, as shown in FIG. 12, shaper rates of 100 Mbps, 200 Mbps, 300 Mbps, 400 Mbps, and 500 Mbps are set.
In step S32, the notification bandwidth determination unit 12 has a capacity (30% when 70% is set as the ratio) corresponding to (100− (the set ratio))% of the transfer capacity in a short time Δt at each shaper rate. Is set as the buffer free space. For example, as shown in FIG. 12, assuming that the transfer capacity of each shaper rate in a short time Δt is 200 Kbytes, 400 Kbytes, 600 Kbytes, 800 Kbytes, and 1000 Kbytes, when the ratio setting is 70%, the transfer capacity is 30%. 60 Mbytes, 120 Mbytes, 180 Mbytes, 240 Mbytes, and 300 Mbytes are set. By operating in this way, it is possible to collectively set a plurality of shaper rates by inputting one ratio from the user.
FIG. 13 is a diagram showing still another setting example of the shaper rate corresponding to the free space of the buffer. As shown in FIG. 13, the actual free space of the buffer 11 and the margin for the available bandwidth may be held in correspondence with the threshold value notified from the buffer free space notification unit 61. For example, when the bandwidth available on the transfer path 50 is 500 Mbps, the shaper rate corresponding to the buffer free capacity thresholds A to E is set to 300 Mbps, 350 Mbps, 400 Mbps, 450 Mbps, and 500 Mbps for the buffer free capacity thresholds A to E. Furthermore, as shown in FIG. 13, the margin for the available bandwidth may be set to 200 Mbps, 150 Mbps, 100 Mbps, 50 Mbps, and 0 Mbps with respect to the thresholds A to E of the free space of the buffer.
In this case, when the free space of the buffer is large, the margin for the available bandwidth may be a negative value. In this case, a shaper rate larger than the available bandwidth is notified. For example, the thresholds A to E may be set to 100 Mbps, 50 Mbps, 0 Mbps, −50 Mbps, −100 Mbps, and the like. In this case, when the bandwidth available on the transfer path 50 is 500 Mbps, the shaper rates corresponding to the free capacity of the buffer with respect to the thresholds A to E are 400 Mbps, 450 Mbps, 500 Mbps, 550 Mbps, and 600 Mbps.
FIG. 14 is a diagram illustrating still another setting example of the shaper rate corresponding to the free space of the buffer. As shown in FIG. 14, the actual free space of the buffer 11 and the ratio to the available bandwidth may be held in correspondence with the threshold value notified from the buffer free space notification unit 61. For example, when the bandwidth available on the transfer path 50 is 500 Mbps, instead of setting the shaper rate to 250 Mbps, 350 Mbps, 400 Mbps, 450 Mbps, and 500 Mbps for the buffer free space thresholds A to E, as shown in FIG. The ratio to the available bandwidth may be set to 50%, 70%, 80%, 90%, and 100%.
In this case, when the buffer free space is large, the ratio to the available bandwidth may exceed 100%. For example, the thresholds A to E may be set to 50%, 80%, 100%, 110%, and 120%. In this case, when the bandwidth that can be used on the transfer path 50 is 500 Mbps, the shaper rates corresponding to the buffer free capacity with respect to the thresholds A to E are 250 Mbps, 400 Mbps, 500 Mbps, 550 Mbps, and 600 Mbps.

As described above, the notification bandwidth determination unit 12 obtains a shaper rate corresponding to the free space from the free space notified from the buffer free space notification unit 61, that is, a shaper rate at which data discard due to an instantaneous burst does not occur.

The notification bandwidth determination unit 12 compares the shaper rate corresponding to the free space with the shaper rate determined by the wireless bandwidth determination unit 62, and if the shaper rate exceeds the shaper rate corresponding to the free space, it corresponds to the free space. The shaper rate to be determined is determined as bandwidth information to be notified to the packet transfer apparatus 70.

The bandwidth notification transmission unit 13 transmits the bandwidth information determined by the notification bandwidth determination unit 12 to the packet transfer device 70 in a prescribed frame format.

The bandwidth notification receiving unit 71 that has received the notification of the bandwidth information sets the shaper rate in the bandwidth control unit 72 of the packet transfer device 70 based on the bandwidth information.

The bandwidth control unit 72 controls the bandwidth based on the set shaper rate when the packet is transferred from the packet transfer device 70 to the packet transfer device 60.

Next, the operation of the second embodiment will be described. FIG. 15 is a flowchart showing the band information determination operation of FIG.

First, the notification bandwidth determination unit 12 of the packet transfer device 60 acquires first information regarding a bandwidth that can be used on the traffic transfer path 50 with the second communication device 40 (step S41), and a buffer free space notification unit The free capacity of the buffer 11 is acquired from 61 (step S42).

The notification bandwidth determination unit 12 obtains a shaper rate corresponding to the free space of the buffer 11, that is, a shaper rate at which data discard due to an instantaneous burst does not occur with respect to the current free space, and the available bandwidth of the traffic transfer path 50 Are compared (step S43). The notification bandwidth determination unit 12 determines whether the buffer is insufficient, that is, whether the bandwidth corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth of the traffic transfer path 50 (step S44).

When the buffer is not insufficient, the notification bandwidth determination unit 12 sets the bandwidth information notified to the packet transfer device 70 as the available bandwidth of the traffic transfer path 50 (step S45), and the bandwidth notification transmission unit 13 of the packet transfer device 60 The determined bandwidth information is transmitted to the upstream packet transfer device 70.

If it is determined in step S44 that the buffer is insufficient, the notification bandwidth determination unit 12 sets the bandwidth information notified to the packet transfer device 70 as the shaper rate corresponding to the free capacity of the buffer 11 (step S46), and the packet transfer device 60 The bandwidth notification transmission unit 13 transmits the determined bandwidth information to the upstream packet transfer device 70.

The first communication device 20 transmits data by controlling the transmission rate in the notified band.

The operation of FIG. 12 in a specific change state will be described. Similar to FIGS. 6 to 8, in the following example, five levels of thresholds are set from “threshold A” to “threshold E”. For example, it is assumed that “threshold A” is the first threshold and “threshold E” is the fifth threshold in ascending order of free space. It is assumed that the shaper rate corresponding to the threshold is set as shown in FIG.

First, an example in which the available bandwidth of the traffic transfer path 50 increases and the free capacity of the buffer does not change will be described. For example, as an initial state, the free capacity of the buffer 11 is in the “threshold A” state shown in FIG. 6, and the available bandwidth of the traffic transfer path 50 is 100 Mbps. It is assumed that a bandwidth of 100 Mbps corresponding to “threshold A” is obtained from the free capacity, compared with the available bandwidth of 100 Mbps of the traffic transfer path 50, and bandwidth information of 100 Mbps is transmitted to the packet transfer apparatus 70.

When the available bandwidth of the traffic transfer path 50 is changed to 500 Mbps from this state, the bandwidth 100 Mbps corresponding to the “threshold A” obtained from the correspondence relationship shown in FIG. 9 in step S43 and the traffic transfer path 50 can be used. Compared with a new bandwidth of 500 Mbps. In step S44, since the bandwidth 100 Mbps corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that the buffer is insufficient. In step S46, the bandwidth information notified to the packet transfer device 70 is set to a bandwidth of 100 Mbps corresponding to the “threshold A”, and the packet transfer device 60 transmits the bandwidth information 100 Mbps to the upstream packet transfer device 70.

Next, for example, as an initial state, it is assumed that the free capacity of the buffer 11 is the free capacity corresponding to the state of “threshold C” shown in FIG. 7, and the available bandwidth of the traffic transfer path 50 is 100 Mbps. Assume that a bandwidth of 300 Mbps corresponding to “threshold C” is obtained, compared with the available bandwidth of 100 Mbps on the traffic transfer path 50, and bandwidth information of 100 Mbps is transmitted to the packet transfer apparatus 70.

When the available bandwidth of the traffic transfer path 50 changes from this state to 500 Mbps, the bandwidth 300 Mbps corresponding to the “threshold C” obtained from the correspondence relationship as shown in FIG. The possible bandwidth is compared with 500 Mbps. In step S44, since the bandwidth 300 Mbps corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that the buffer is insufficient. In step S46, the notified bandwidth information is a bandwidth of 300 Mbps corresponding to the free capacity of the buffer 11, and the packet transfer device 60 transmits the bandwidth information of 300 Mbps to the upstream packet transfer device.

Further, for example, as an initial state, the free capacity of the buffer 11 is the free capacity corresponding to the “threshold E” shown in FIG. 8, and the available bandwidth of the traffic transfer path 50 is 100 Mbps. It is assumed that a bandwidth of 500 Mbps corresponding to “threshold E” is obtained, compared with the available bandwidth of 100 Mbps of the traffic transfer path 50, and bandwidth information of 100 Mbps is transmitted to the packet transfer apparatus.

If the available bandwidth of the traffic transfer path 50 changes from this state to 500 Mbps, the bandwidth information 500 Mbps corresponding to the “threshold value E” obtained from the correspondence relationship as shown in FIG. The available bandwidth is compared with 500 Mbps, and it is determined in step S44 that there is no buffer shortage. In step S45, the notified bandwidth information is set to a usable bandwidth 500 Mbps of the traffic transfer path 50, and the packet transfer device 60 transmits the bandwidth information 500 Mbps to the upstream packet transfer device 70.

Next, an example in which the available bandwidth of the traffic transfer path 50 decreases and the buffer free space does not change will be described. For example, as an initial state, the free capacity of the buffer 11 is the free capacity corresponding to the “threshold A” shown in FIG. 6 and the available bandwidth of the traffic transfer path 50 is 500 Mbps. Assume that bandwidth information 100 Mbps corresponding to the free capacity of the buffer is obtained, the available bandwidth of the traffic transfer path 50 is compared with 500 Mbps, and 100 Mbps is transmitted to the packet transfer apparatus 70.

When the available bandwidth of the traffic transfer path 50 changes from this state to 100 Mbps, the bandwidth information 100 Mbps corresponding to the free capacity of the buffer obtained from the correspondence relationship as shown in FIG. 9 in step S43 and the use of the traffic transfer path 50 The possible bandwidth is compared with 100 Mbps. In step S44, since the bandwidth information 100 Mbps corresponding to the free capacity of the buffer 11 is equal to or larger than the available bandwidth 100 Mbps of the traffic transfer path 50, it is determined that there is no buffer shortage. In step S45, the notified bandwidth information is set to 100 Mbps usable in the traffic transfer path 50, and the packet transfer device 60 transmits 100 Mbps to the upstream packet transfer device 70.

Further, for example, as an initial state, the free capacity of the buffer 11 is the free capacity corresponding to the “threshold C” shown in FIG. 7, and the available bandwidth of the traffic transfer path 50 is 500 Mbps. Assume that bandwidth information 300 Mbps corresponding to the free capacity of the buffer is obtained, the available bandwidth of the traffic transfer path 50 is compared with 500 Mbps, and 300 Mbps is transmitted to the packet transfer apparatus 70.

If the available bandwidth of the traffic transfer path 50 changes from this state to 100 Mbps, the bandwidth information 300 Mbps corresponding to the free capacity of the buffer obtained from the correspondence relationship as shown in FIG. 9 and the use of the traffic transfer path 50 in step S43. The possible bandwidth is compared with 100 Mbps. In step S44, since the bandwidth information 300 Mbps corresponding to the free capacity of the buffer 11 is the available bandwidth 100 Mbps or more of the traffic transfer path 50, it is determined that there is no buffer shortage. In step S45, the notified bandwidth information is set to 100 Mbps usable in the traffic transfer path 50, and the packet transfer device 60 transmits 100 Mbps to the upstream packet transfer device 70.

Further, for example, as an initial state, the free capacity of the buffer 11 is the free capacity corresponding to the “threshold E” shown in FIG. 8, and the available bandwidth of the traffic transfer path 50 is 500 Mbps. Assume that bandwidth information 500 Mbps corresponding to the free capacity of the buffer is obtained, the available bandwidth of the traffic transfer path 50 is compared with 500 Mbps, and 500 Mbps is transmitted to the packet transfer device 70.

If the available bandwidth of the traffic transfer path 50 is changed to 100 Mbps from this state, the bandwidth information 500 Mbps corresponding to the free capacity of the buffer obtained from the correspondence relationship as shown in FIG. 9 in step S43 and the use of the traffic transfer path 50 The possible bandwidth is compared with 100 Mbps. In step S44, since the bandwidth information 500 Mbps corresponding to the free capacity of the buffer 11 is equal to or greater than the available bandwidth 100 Mbps of the traffic transfer path 50, it is determined that there is no buffer shortage. In step S45, the notified bandwidth information is set to 100 Mbps usable in the traffic transfer path 50, and the packet transfer device 60 transmits 100 Mbps to the upstream packet transfer device 70.

Further, an example in which the available bandwidth of the traffic transfer path 50 is not changed and the free capacity of the buffer is increased will be described. For example, as an initial state, the free capacity of the buffer 11 is the free capacity corresponding to the “threshold A” shown in FIG. 6 and the available bandwidth of the traffic transfer path 50 is 500 Mbps. It is assumed that a bandwidth of 100 Mbps corresponding to the free capacity of the buffer is obtained, the available bandwidth of the traffic transfer path 50 is compared with 500 Mbps, and bandwidth information 100 Mbps is transmitted to the packet transfer device 70.

When the free capacity of the buffer changes from this state to the state of “threshold C” shown in FIG. 7, the bandwidth 300 Mbps corresponding to “threshold C” obtained from the correspondence as shown in FIG. 50 available bandwidths, 500 Mbps, are compared. In step S44, since the bandwidth 300 Mbps corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that the buffer is insufficient. In step S46, the notified bandwidth information is the bandwidth information 300 Mbps corresponding to the free capacity of the buffer 11, and the packet transfer device 60 transmits the bandwidth information 300 Mbps to the upstream packet transfer device 70.

If the buffer free capacity changes from the same initial state to the “threshold E” state shown in FIG. 8, the bandwidth corresponding to “threshold E” obtained from the correspondence as shown in FIG. The available bandwidth of the traffic transfer path 50 is compared with 500 Mbps. In step S44, since the bandwidth 500 Mbps corresponding to the free capacity of the buffer 11 is equal to the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that there is no buffer shortage. In step S46, the bandwidth information to be notified is set to a usable bandwidth 500 Mbps of the traffic transfer path 50, and the packet transfer device 60 transmits the bandwidth information 500 Mbps to the upstream packet transfer device 70.

Further, an example in which the available bandwidth of the traffic transfer path 50 is not changed and the buffer free space is reduced will be described. For example, as an initial state, the free capacity of the buffer 11 is in the “threshold E” state shown in FIG. 8 and the available bandwidth of the traffic transfer path 50 is 500 Mbps. It is assumed that a bandwidth of 500 Mbps corresponding to the free capacity of the buffer 11 is obtained, the available bandwidth of the traffic transfer path 50 is compared with 500 Mbps, and 500 Mbps is transmitted to the packet transfer apparatus 70.

When the free space of the buffer changes from this state to the “threshold A” state shown in FIG. 6, the bandwidth information 100 Mbps and traffic corresponding to “threshold A” obtained from the correspondence as shown in FIG. The available bandwidth of the transfer path 50 is compared with 500 Mbps. In step S44, since the bandwidth information 100 Mbps corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that the buffer is insufficient. In step S46, the notified bandwidth information is the bandwidth information 100 Mbps corresponding to the free capacity of the buffer 11, and the packet transfer device 60 transmits the bandwidth information 100 Mbps to the upstream packet transfer device 70.

If the buffer free capacity changes from the same initial state to the “threshold C” state shown in FIG. 7, the bandwidth information 300 Mbps corresponding to “threshold C” obtained from the correspondence as shown in FIG. 9 in step S43. And the available bandwidth 500 Mbps of the traffic transfer path 50 are compared. In step S44, since the bandwidth information 300 Mbps corresponding to the free capacity of the buffer 11 is smaller than the available bandwidth 500 Mbps of the traffic transfer path 50, it is determined that the buffer is insufficient. In step S46, the bandwidth information to be notified is the bandwidth information 300 Mbps corresponding to the free capacity of the buffer 11, and the packet transfer device 60 transmits the bandwidth information 300 Mbps to the upstream packet transfer device 70.

As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained. That is, the packet transfer device 60 compares the bandwidth in which data discard due to the instantaneous burst does not occur with the available capacity of the buffer 11 with the available bandwidth of the downstream traffic transfer path 50. When the bandwidth corresponding to the free capacity of the buffer 11 is small, the packet transfer apparatus 60 sets the bandwidth information notified to the packet transfer apparatus 70 as the bandwidth for the free capacity of the buffer 11. With this configuration, in the packet transfer device 60 that notifies the upstream packet transfer device 70 of the bandwidth information based on the bandwidth available on the downstream traffic transfer path 50, the data transfer from the upstream packet transfer device 70 is stopped without stopping. Can be transferred to the traffic transfer path 50, and discarding of data in the buffer 11 can be prevented.

Next, a third embodiment will be described. FIG. 16 is a block diagram showing a configuration of the third exemplary embodiment of the present invention. In this embodiment, the traffic transfer path between the packet transfer apparatus and the downstream second communication apparatus is a radio traffic transfer path, and adaptive modulation is performed. For example, the second communication device 100 transmits an SNR (Signal to Noise Ratio) in the received radio wave and a BER (Bit Error Rate) in the data based on the received radio wave to the wireless traffic transfer. The packet transfer device 90 is notified via the path 80. The transmission / reception unit 91 of the packet transfer device 90 changes the modulation method of the radio wave to be transmitted according to the notified SNR, BER, etc., and transmits the packet to the second communication device 100 via the wireless traffic transfer path 80. When the transmission / reception unit 91 changes the modulation method of the radio wave to be transmitted according to the SNR, BER, etc., the transmission / reception unit 91 notifies the radio band determination unit 62 of the changed modulation method. Next, based on the notified modulation method, the radio band determining unit 62 determines the ETH band. The band control unit 63 sets the shaper rate for the second communication apparatus 100 based on the ETH band determined by the radio band determination unit 62. The notification bandwidth determination unit 12 determines the notification bandwidth by looking at the free space of the buffer and related information as in the first and second embodiments described above.
If the communication apparatus that performs adaptive modulation in this way is configured as the transfer apparatus 10 of the first embodiment or the packet transfer apparatus 60 of the second embodiment, the bandwidth of the traffic transfer path 50 is greatly varied and frequent. Therefore, it is possible to suitably control the amount of communication from the upstream device according to the fluctuation of the downstream bandwidth.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

This application claims priority based on Japanese Patent Application No. 2016-255369 filed on Dec. 28, 2016, the entire disclosure of which is incorporated herein.

DESCRIPTION OF SYMBOLS 10 Transfer apparatus 11 Buffer 12 Notification band determination part 13 Band notification transmission part 20 1st communication apparatus 30, 50 Traffic transfer path 40

2nd communication apparatus

60, 70 Packet transfer apparatus 61 Buffer free capacity notification part 62 Wireless

band determination part

63, 72 Band control unit 71 Band notification receiving unit

Claims

A buffer for temporarily storing data received from the first communication device and transmitted to the second communication device;
Band information to be notified to the first communication device based on the first information on the bandwidth available on the communication path with the second communication device and the second information on the bandwidth corresponding to the free capacity of the buffer. Notification bandwidth determining means for determining
Bandwidth notification transmission means for transmitting the bandwidth information to the first communication device;
A transfer device.
2. The transfer device according to claim 1, wherein the notification band determining unit determines the second information as the band information when the band of the second information is smaller than the band of the first information.
The notification band determining means associates the control band with a free capacity equal to or larger than an increase in transmission data capacity when an instantaneous burst occurs during transmission control in the control band based on the band information by the first communication device. The transfer device according to claim 1, wherein the transfer device retains the corresponding relationship.
4. The buffer according to any one of claims 1 to 3, wherein the buffer sets a plurality of threshold values, and notifies the free space when the detected free space exceeds or falls below any of the plurality of thresholds. The transfer device described.
The notification bandwidth determination means is a space corresponding to the plurality of thresholds, and a free space equal to or greater than an increase in transmission data capacity when an instantaneous burst occurs during transmission control of the first communication device in a control bandwidth based on the bandwidth information. The transfer device according to claim 4, wherein a correspondence relationship in which a capacity is associated with the control band is maintained.
A wireless bandwidth determining means for determining a bandwidth that can be used in a communication path with the second communication device;
Bandwidth control means for setting a control bandwidth of a communication path with the second communication device based on the bandwidth determined by the wireless bandwidth determination means;
The transfer device according to claim 1, comprising:
Temporarily storing data received from the first communication device and transmitted to the second communication device in a buffer;
Obtaining first information relating to a bandwidth available on a communication path with the second communication device;
Calculating second information relating to the bandwidth corresponding to the free capacity of the buffer;
Determining bandwidth information to be notified to the first communication device based on the first and second information;
A transfer method of transmitting the determined band information to the first communication device.
The transfer device according to any one of claims 1 to 6,
And a first communication device that transmits data at a rate based on the notified band information.
In a communication method of a communication system, wherein data transmitted from a first communication device to a transfer device is transmitted to the second communication device in a band that can be used in a communication path with the second communication device.
Temporarily storing the data in a buffer of the transfer device;
Obtaining first information relating to a bandwidth available on a communication path with the second communication device;
Calculating second information relating to the bandwidth corresponding to the free capacity of the buffer;
Determining bandwidth information to be notified to the first communication device based on the first and second information;
A communication method for notifying the determined bandwidth information from the transfer device to the first communication device.
A buffer for storing received data;
A communication apparatus comprising: processing means for acquiring band information related to a band for communication with another apparatus and determining a band for receiving data based on the state of the buffer and the band information