JP2009147569A - Frame transmission device and frame reception device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of voice jitter in a network without increasing capacity of a reception buffer, and improve transfer efficiency in the network with a frame transmission device and a frame reception device which performs flow control for easing burst of frames. <P>SOLUTION: If the frames are transmitted from the frame transmission device 101 to the frame reception device 102, the frame data are stored in the reception buffer 121. If it is discriminated that congestion occurs based on a buffer usage amount of the reception buffer 121, a PAUSE frame establishing a transmission interval of the frames, is transmitted from the frame reception device 102 to the frame transmission device 101. The frame transmission device 101 controls to transmit the frames by the transmission interval established in the received PAUSE frame. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a frame transmission apparatus and a frame reception apparatus that perform flow control for relaxing a burst of frames in a communication network that transmits and receives signals that require real-time characteristics such as voice and images.

  Conventionally, in a configuration in which a frame transmission device and a frame reception device communicate via Ethernet (registered trademark), when the reception device cannot receive burst transmission from the transmission device, IEEE (Institute of Electrical and Electronic Engineers) ) As specified in 802.3, the receiving apparatus performs flow control on the transmitting apparatus and requests the transmitting apparatus to stop output. In the case of the full-duplex communication method, the receiving device transmits a PAUSE frame to the transmitting device and designates the stop time.

  FIG. 13 shows a configuration example of a wide area Ethernet (registered trademark) that transmits and receives audio signals and image signals. The host device 12 is, for example, a content server, and transmits frames of audio signals and image signals to the radio base station devices 13 to 15 via the IP (Internet Protocol) network 11. In the IP network 11, when a frame passes through multistage network devices 16 to 20 such as routers, switches, and hubs, a burst of frames may occur in a subsequent device due to buffer characteristics of the devices.

  For example, when a frame is transmitted from the network device 19 to the radio base station device 13 and the radio base station device 13 receives a frame exceeding the amount that can be absorbed by the reception buffer, the PAUSE frame is sent to the network device 19 by flow control. 22 is transmitted to request that frame transmission be suppressed. The network device 19 that has received the PAUSE frame interrupts transmission of the frame for the interruption time specified in the PAUSE frame 22. Meanwhile, the radio base station apparatus 13 processes the frames stored in the reception buffer.

  FIG. 14 shows a configuration example of a frame transmission device and a frame reception device in conventional flow control. The frame transmission device 31 and the frame reception device 32 correspond to, for example, the network device 19 and the radio base station device 13 in FIG. 13, respectively, and the solid line arrow and the broken line arrow represent the main signal and the control signal, respectively.

  The frame transmission device 31 includes a transmission buffer 41, a transmission control unit 42, an interruption time parameter extraction unit 43, and a PAUSE frame extraction unit 44. The frame reception device 32 includes a reception buffer 51, a reception buffer control unit 52, a buffer congestion determination. Unit 53, interruption time parameter insertion unit 54, PAUSE frame generation unit 55, and selector 56.

  Frames transmitted from the frame transmission device 31 to the frame reception device 32 are accumulated in the reception buffer 51. The amount of data stored in the reception buffer 51 is constantly monitored by the reception buffer control unit 52 and notified to the buffer congestion determination unit 53. The buffer congestion determination unit 53 determines the presence / absence of congestion from the data accumulation amount information, and notifies the interruption time parameter insertion unit 54 of an interruption time parameter instruction.

  The interruption time parameter insertion unit 54 notifies the PAUSE frame generation unit 55 of the interruption time parameter, and the PAUSE frame generation unit 55 transfers the PAUSE frame including the interruption time parameter to the selector 56. The selector 56 selects a PAUSE frame or a normal frame and transmits it to the frame transmission device 31.

  The PAUSE frame extraction unit 44 of the frame transmission device 31 extracts a PAUSE frame from all received frames and transfers it to the interruption time parameter extraction unit 43. The interruption time parameter extraction unit 43 extracts an interruption time parameter from the PAUSE frame and notifies the transmission control unit 42 of a frame suppression instruction. The transmission control unit 42 stops frame transmission from the transmission buffer 41 in accordance with the frame suppression instruction.

  FIG. 15 shows a frame format of a conventional PAUSE frame. This PAUSE frame includes fields of a preamble, an SFD (Start Frame Delimiter), a destination address, a transmission source address, a length / type, an operation code, an interruption time, padding, and an FCS (Frame Check Sequence). Of these, the padding field is an unused area.

  According to such a configuration, when the capacity of the reception buffer 51 is sufficiently large, it is possible to absorb the burst by adjusting the data accumulation amount in the reception buffer 51 according to the pause time of the PAUSE frame.

  However, when the capacity of the reception buffer 51 is relatively small, it is necessary to frequently send out PAUSE frames. Furthermore, bursts cannot be absorbed in the reception buffer 51, which causes voice jitter (fluctuation) in the IP network 11 and a decrease in transfer efficiency. Even when the capacity of the reception buffer 51 is sufficiently large, a transfer delay occurs due to data retention due to bursts.

  As a countermeasure against this problem, a method is known in which an unused area of a PAUSE frame is used to notify a port ID where congestion has occurred, and a device that has received the PAUSE frame suppresses only frames addressed to the notified port. (For example, see Patent Document 1).

In addition, when a PAUSE frame is received, a method is also known in which a transmission interval is set so as to obtain a predetermined transmission ratio instead of stopping transmission for a specified time (see, for example, Patent Document 2). ). In this method, an inter-frame gap (IFG: Inter Frame Gap) is inserted.
JP 2006-31191 A JP 2004-104427 A

However, the conventional flow control described above has the following problems.
In the method of Patent Document 1, when the frame transmitting apparatus receives the PAUSE frame, the frame transmission to only the designated port where congestion occurs is stopped. It is impossible to solve the occurrence and the decrease in transfer efficiency.

  In the method of Patent Document 2, when the frame transmission apparatus receives a PAUSE frame, transmission is performed with a transmission interval at a ratio determined in advance from the network configuration, so that burst can be relaxed and transfer efficiency can be increased. However, the reception interval corresponding to the amount of data stored in the reception buffer of the frame reception device is not guaranteed, and it is not always possible to prevent audio jitter and maximize transfer efficiency.

A first object of the present invention is to prevent the occurrence of voice jitter in a network without increasing the capacity of a reception buffer in a network having a frame transmission device and a frame reception device that perform flow control for relaxing a burst of frames. And improving the transfer efficiency.

  A second problem of the present invention is to reduce transfer delay due to data retention in the reception buffer.

The frame reception device includes a reception buffer unit, a determination unit, a transmission unit, and a setting unit, and receives a frame from the frame transmission device via a communication network.
The reception buffer means accumulates the received frame data, and the determination means determines whether congestion has occurred based on the buffer usage of the reception buffer means. The transmission means transmits a frame suppression request to the frame transmission device when congestion occurs. The setting means sets a parameter for designating a transmission interval of frames transmitted by the frame transmitting apparatus in the frame suppression request.

The frame transmission device includes a transmission unit, a reception unit, an extraction unit, and a control unit, and transmits a frame to the frame reception device via a communication network.
The transmission means transmits the frame to the frame reception device. The receiving unit receives a frame suppression request from the frame receiving device when congestion occurs in the frame receiving device. The extraction unit extracts a parameter that specifies a transmission interval of frames transmitted by the transmission unit from the frame suppression request. The control unit controls the transmission unit to transmit the frame at a transmission interval specified by the extracted parameter.

  When a frame is transmitted from the frame transmission device to the frame reception device, the frame data is stored in the reception buffer means. When it is determined that congestion has occurred based on the buffer usage of the reception buffer means, a frame suppression request in which a frame transmission interval is set is transmitted from the frame reception apparatus to the frame transmission apparatus. The frame transmission device performs control to transmit frames at the transmission interval set in the received frame suppression request.

  A frame suppression request transmitted from the frame receiving apparatus to the frame transmitting apparatus corresponds to, for example, a PAUSE frame in FIG. 2 to be described later, and a parameter for specifying a frame transmission interval corresponds to, for example, the number of IFG insertions in FIG. .

  Depending on the load status of the frame receiving device, the burstiness of the transmission path can be lowered by the receiving device. As a result, occurrence of burst transmission is suppressed, and fluctuations in the network can be prevented. In addition, it is possible to reduce the reception buffer for absorbing burst transmission in the reception apparatus, and it is possible to reduce the transfer delay due to passage through the reception buffer.

  Conventionally, it is possible to reduce the load on the network by providing a function such as a line shaper to the frame transmission device, but it is possible to grasp whether the reception device has a margin or a high load in the transmission device. Is impossible, and transfer efficiency is not maximized. On the other hand, if the transmission apparatus is notified of the frame transmission interval that can be processed by the reception apparatus, the transfer efficiency can be adjusted to be maximized.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
In a configuration in which a frame transmission device and a frame reception device communicate via Ethernet (registered trademark), the reception device adds an IFG value to the PAUSE frame as information when congestion is detected, and notifies the transmission device. When a PAUSE frame is received, the frame transmission interval is controlled according to the IFG information instead of stopping the frame transmission.

FIG. 1 shows a configuration example of a frame transmission device and a frame reception device in the flow control of the embodiment. The solid line arrow and the broken line arrow represent the main signal and the control signal, respectively.
The frame transmission apparatus 101 includes a transmission buffer 111, a transmission control unit 112, a frame transmission interval control unit 113, an IFG parameter extraction unit 114, an interruption time parameter extraction unit 115, a PAUSE frame extraction unit 116, and a physical layer control unit 117. The frame receiving apparatus 102 includes a reception buffer 121, a reception buffer control unit 122, a buffer congestion determination unit 123, an IFG adjustment unit 124, an interruption time parameter insertion unit 125, an IFG parameter insertion unit 126, a PAUSE frame generation unit 127, a selector 128, and A physical layer control unit 129 is provided.

  A frame transmitted from the frame transmission apparatus 101 to the frame reception apparatus 102 is accumulated in the reception buffer 121 via the physical layer control unit 129. The amount of data stored in the reception buffer 121 is constantly monitored by the reception buffer control unit 122 and notified to the buffer congestion determination unit 123 and the IFG adjustment unit 124.

  The buffer congestion determination unit 123 determines the presence / absence of congestion from the data accumulation amount information, and notifies the IFG adjustment unit 124 of the congestion presence / absence information. The IFG adjustment unit 124 determines the IFG and the interruption time from the data accumulation amount information and the congestion presence / absence information, notifies the IFG parameter insertion unit 126 of a specific frame interval instruction, and transmits the interruption time parameter instruction to the interruption time parameter insertion unit. 125 is notified.

  In the embodiment, the time during which frame transmission is restricted by the instructed IFG and the time during which frame transmission is stopped are collectively referred to as “interruption time”. This interruption time corresponds to a time during which frame suppression control is continued in the frame transmission apparatus 101.

  The IFG parameter insertion unit 126 notifies the PAUSE frame generation unit 127 of the IFG parameter, and the interruption time parameter insertion unit 125 notifies the PAUSE frame generation unit 127 of the interruption time parameter. The PAUSE frame generation unit 127 transfers the PAUSE frame including the IFG parameter and the interruption time parameter to the selector 128. The selector 128 selects a PAUSE frame or a normal frame and transmits it to the frame transmitting apparatus 101 via the physical layer control unit 129.

  The frame transmitted to the frame transmission apparatus 101 is transferred to the PAUSE frame extraction unit 116 via the physical layer control unit 117. The PAUSE frame extraction unit 116 extracts a PAUSE frame from all received frames, and transfers it to the IFG parameter extraction unit 114 and the interruption time parameter extraction unit 115. The IFG parameter extraction unit 114 extracts the IFG parameter from the PAUSE frame and notifies the frame transmission interval control unit 113, and the interruption time parameter extraction unit 115 extracts the interruption time parameter from the PAUSE frame and extracts the frame transmission interval control unit 113. Notify

  The frame transmission interval control unit 113 notifies the transmission control unit 112 of frame transmission interval information and a frame suppression instruction. The transmission control unit 112 performs IFG insertion for a frame from the transmission buffer 111 or stops frame transmission according to the notified information and instruction. The transmitted frame is transmitted to the frame receiving apparatus 102 via the physical layer control unit 117.

FIG. 2 shows a frame format of the PAUSE frame of the embodiment. This P
The format of the AUSE frame is the same as the conventional format shown in FIG. However, conventionally, one octet of the unused padding fields 42 octets is used as a type field for designating whether IFG designation is valid or invalid, and two octets are used as a field for designating the number of IFG insertions.

  When the type field is set to invalid IFG designation, this indicates that frame transmission is stopped, and the IFG insertion number field is invalid. In this case, the frame transmission interval control unit 113 stops frame transmission for the time set in the interruption time field. On the other hand, when the type field is set to enable IFG designation, the IFG insertion number field is valid, and 12 octets × IFG insertion number is the IFG value. In this case, the frame transmission interval control unit 113 continues the IFG insertion for the time set in the interruption time field.

  The frame reception apparatus 102 determines the effect of the IFG value notified to the frame transmission apparatus 101 when congestion occurs by monitoring the transition of the usage amount of the reception buffer 121 so that the load on the frame reception apparatus 102 is optimized. Change the IFG value. As a result, the IFG value is adjusted so that the transfer efficiency is maximized.

  FIG. 3 shows a threshold for the usage amount of the reception buffer 121 in the IFG adjustment processing. The buffer congestion determination unit 123 determines the congestion state of the reception buffer 121 using the congestion continuation determination threshold A1, the congestion determination threshold A2, and the congestion elimination determination threshold A3. Here, A1> A2> A3. When the buffer usage exceeds the threshold A2, it is determined that congestion has occurred. When the buffer usage exceeds the threshold A1, it is determined that congestion is continuing. When the buffer usage is below the threshold A3, it is determined that congestion has been eliminated. The

  FIG. 4 is a flowchart of the IFG adjustment process using these threshold values. The in-adjustment flag used in this process and the timer for measuring the internal monitoring time T1 are held in the IFG adjustment unit 124.

  First, the buffer congestion determination unit 123 determines whether or not the buffer usage amount exceeds the threshold value A1 (step 401). If the buffer usage amount does not exceed the threshold value A1, then the buffer usage amount is equal to the threshold value. It is determined whether or not A2 has been exceeded (step 402). If the buffer usage does not exceed the threshold A2, the processing in step 401 is repeated, and if the buffer usage exceeds the threshold A2, the occurrence of congestion is notified to the IFG adjustment unit 124.

  The IFG adjustment unit 124 checks the adjustment-in-progress flag (step 403). If the adjustment-in-progress flag is on, the IFG adjustment unit 124 notifies the IFG parameter insertion unit 126 of the adjustment-in-progress IFG value, and starts the internal monitoring time T1 timer. (Step 404). On the other hand, if the in-adjustment flag is off, the IFG initial value is notified to the IFG parameter insertion unit 126, and the timer for the internal monitoring time T1 is started (step 405). As a result, a PAUSE frame in which the IFG value is set is transmitted. As the IFG initial value, a value that does not cause sufficient congestion is selected in consideration of the network configuration and the reception frame length.

  Next, the buffer congestion determination unit 123 determines whether or not the buffer usage exceeds the threshold A1 (step 406). When the buffer usage exceeds the threshold A1, the IFG adjustment unit 124 stops frame transmission. The IFG parameter insertion unit 126 is instructed (step 407). As a result, a PAUSE frame in which frame transmission stop is set is transmitted. The IFG adjustment unit 124 turns off the adjustment-in-progress flag (step 408), and repeats the processing after step 401. When the buffer usage exceeds the threshold value A1 in step 401, the processing after step 407 is performed.

  If the buffer usage does not exceed the threshold A1 in step 406, the buffer congestion determination unit 123 next determines whether or not the buffer usage has fallen below the threshold A3 (step 409). When the buffer usage falls below the threshold A3 within the internal monitoring time T1, the IFG adjustment unit 124 instructs the IFG parameter insertion unit 126 to decrease the IFG value being adjusted by one rank (step 410).

  Then, the IFG adjustment unit 124 turns on the adjustment flag (step 411), and notifies the interruption time parameter insertion unit 125 of the value “0000” of the interruption time T2 in order to forcibly stop the frame suppression control (step 412). . As a result, “0000” is set in the interruption time field, and a PAUSE frame with the IFG insertion number reduced by 1 is transmitted. The frame transmission control unit 113 of the frame transmission apparatus 101 that has received this PAUSE frame stops the frame suppression instruction to the transmission control unit 112. The IFG adjustment unit 124 repeats the processing after step 401.

  If the buffer usage is not less than the threshold value A3 in step 409, the IFG adjustment unit 124 determines whether or not the internal monitoring time T1 has elapsed (step 413). If the internal monitoring time T1 has not elapsed, the processing after step 406 is repeated. When the internal monitoring time T1 has elapsed, the buffer congestion determination unit 123 next determines whether or not the buffer usage exceeds the threshold A2 (step 414).

  If the buffer usage does not exceed the threshold A2, the IFG adjusting unit 124 adopts the current IFG value as the adjusting IFG value (step 415), turns on the adjusting flag (step 416), and executes step 401. The subsequent processing is repeated. In this case, since the current IFG value is an optimum value, the frame inhibition control is not forcibly stopped.

  When the buffer usage exceeds the threshold A2 in step 414, the IFG adjustment unit 124 instructs the IFG parameter insertion unit 126 to increase the IFG value being adjusted by one rank (step 417). As a result, a PAUSE frame with the IFG insertion number increased by 1 is transmitted (step 418). Then, the IFG adjustment unit 124 turns on the adjustment-in-progress flag (step 419), and repeats the processing after step 406.

  FIG. 5 shows an example of transition of the buffer usage in such IFG adjustment processing. The solid line arrow represents the duration of the timer of the internal monitoring time T1 in the IFG adjustment unit 124 or the timer of the interruption time T2 in the frame transmitting apparatus 101. A black circle represents the time when the timer was interrupted, and a broken arrow represents the remaining time of the interrupted timer.

  First, at time t1, when the buffer usage exceeds the threshold value A2 and the adjustment-in-progress flag is OFF, an IFG initial value PAUSE frame is transmitted, and timers T1 and T2 are started simultaneously (step 405). Thereafter, when the buffer usage falls below the threshold A3 at time t2, the timer is interrupted. Then, the IFG value during adjustment is lowered by one rank (step 410), the adjustment flag is turned on (step 411), and the frame suppression control is forcibly stopped (step 412).

  Next, when the buffer usage exceeds the threshold A2 at time t3, a PAUSE frame is transmitted with the adjusting IFG value, and timers for T1 and T2 are started simultaneously (step 404). Thereafter, when the buffer usage falls below the threshold A3 at time t4, the timer is interrupted. Then, the IFG value during adjustment is lowered by one rank (step 410), the adjustment flag is turned on (step 411), and the frame suppression control is forcibly stopped (step 412).

  Next, when the buffer usage exceeds the threshold value A2 at time t5, a PAUSE frame with an adjusting IFG value is transmitted, and timers for T1 and T2 are started simultaneously (step 404). If the buffer usage does not fall below the threshold A3 and T1 times out at time t6, the current IFG value is the optimum value, so that value is adopted as the adjusting IFG value (step 415), and frame suppression control is performed. Will continue.

  Next, at time t7, T2 times out, and even if the buffer usage exceeds the threshold A2 at time t8, the current IFG value is the optimum value. Therefore, as long as there is no change in the frame flow rate, time t8 The same processing is repeated at t10.

  As indicated by the broken line 501, if the buffer usage exceeds the threshold value A1 within time T1 from time t5, a PAUSE frame for stopping frame transmission is transmitted (step 407), and the adjustment-in-progress flag is turned off (step 407). 408).

  As indicated by the broken line 502, when the buffer usage does not exceed the threshold A1 and exceeds the threshold A2 within the time T1 from the time t5, the adjusting IFG value is increased by one rank at the time t6 ( Step 417). Then, the PAUSE frame having the increased IFG value is transmitted (step 418), and the adjustment in progress flag is turned on (step 419). The buffer usage is constantly monitored, and when it exceeds the threshold value A1, a PAUSE frame for stopping frame transmission is transmitted (step 407) and the adjustment in progress flag is turned off (step 408), as in the case of the broken line 501. .

  Next, an IFG adjustment method different from the above method will be described. In this method, the frame receiving apparatus 102 constantly monitors the average value of the received frame length from the frame transmitting apparatus 101, and selects an appropriate input bit rate in the frame receiving apparatus 102 from the previous frame length average value when congestion occurs. . Then, by setting an IFG value corresponding to the bit rate in the PAUSE frame, the frame transmission interval is notified to the frame transmission apparatus 101 so that the load on the frame reception apparatus 102 is optimal.

  FIG. 6 shows a configuration example of the IFG adjustment unit 124 that performs such IFG adjustment processing. The IFG adjustment unit 124 includes a control unit 601, an input frame counter 602, a timer 603, an IFG value calculation unit 604, and a bit rate storage unit 605.

  The input frame counter 602, based on the information of the unit time Δt output from the timer 603, the input frame length information and the input frame number information from the reception buffer control unit 122, and the input frame length total L per Δt, The number of frames F is constantly counted.

  Information on the appropriate input bit rate in the frame receiving apparatus 102 is set in the bit rate storage unit 605 by upper software or the like. As this appropriate input bit rate, a value somewhat smaller than the allowable value is set. Since the processing capability of the frame receiving apparatus 102 is affected by the input frame length, an appropriate input bit rate corresponding to each of a plurality of frame lengths is prepared in advance.

  When notified of the occurrence of congestion from the buffer congestion determination unit 123, the control unit 601 notifies the IFG value calculation unit 604 to that effect. The IFG value calculation unit 604 reads the input frame length total L and the input frame number F per Δt immediately before from the input frame counter 602, and calculates the average frame length L / F using these values. Next, a value r corresponding to the average frame length L / F is selected from a plurality of appropriate input bit rates stored in the bit rate storage unit 605. Then, assuming that the maximum bit rate of the input line is r0, the IFG value is calculated by the following equation.

IFG value = (r0−r) / (F / Δt) −C [bit]

The constant C corresponds to the number of bits including the preamble and SFD, and is 8 × 8 bits in the format of FIG.

The IFG value calculation unit 604 notifies the calculated IFG value to the control unit 601, and the control unit 601 instructs the IFG parameter insertion unit 126 about the IFG value.
FIG. 7 shows a threshold value for the usage amount of the reception buffer 121 in this IFG adjustment processing. The buffer congestion determination unit 123 determines the congestion state of the reception buffer 121 using the congestion continuation determination threshold A1 and the congestion determination threshold A2. Here, A1> A2. When the buffer usage exceeds the threshold A2, it is determined that congestion has occurred, and when the buffer usage exceeds the threshold A1, it is determined that congestion is continuing.

  FIG. 8 is a flowchart of the IFG adjustment process using these threshold values. First, the buffer congestion determination unit 123 determines whether or not the buffer usage amount exceeds the threshold value A1 (step 801). If the buffer usage amount does not exceed the threshold value A1, the buffer usage amount is then set to the threshold value. It is determined whether or not A2 has been exceeded (step 802). If the buffer usage does not exceed the threshold A2, the processing in step 801 is repeated, and if the buffer usage exceeds the threshold A2, the occurrence of congestion is notified to the IFG adjustment unit 124.

  The IFG adjustment unit 124 calculates a necessary IFG value by the above-described method (step 803), and notifies the IFG parameter insertion unit 126 of the IFG value (step 804). As a result, a PAUSE frame in which the calculated IFG value is set is transmitted. Then, the IFG adjustment unit 124 repeats the processing from step 801 onward.

  When the buffer usage exceeds the threshold A1 in step 801, the IFG adjustment unit 124 instructs the IFG parameter insertion unit 126 to stop sending frames (step 805). As a result, a PAUSE frame in which frame transmission stop is set is transmitted. Then, the IFG adjustment unit 124 repeats the processing from step 801 onward.

  FIG. 9 shows an example of transition of the buffer usage in such IFG adjustment processing. First, when the buffer usage exceeds the threshold A2 at time t1, a PAUSE frame having the calculated IFG value is transmitted (step 804), and the frame transmission apparatus 101 starts a timer for the interruption time T2. Thereafter, at time t2, when T2 times out, the frame transmitting apparatus 101 releases the frame suppression control.

  Next, when the buffer usage exceeds the threshold A2 again at time t3, the same processing is repeated at times t3 to t4. If the buffer usage exceeds the threshold value A1 at time t3, a PAUSE frame for stopping frame transmission is transmitted (step 805).

  FIG. 10 shows a frame transmission interval when frame suppression is not performed. In this case, the frame transmitting apparatus 101 inserts an IFG having a minimum value (96 bits) between the frames 1001 to 1004, and continuously transmits the frames 1001 to 1004.

  FIG. 11 shows a frame transmission interval when frame suppression is performed by specifying an IFG value. In this case, the frame transmitting apparatus 101 inserts the IFG designated by the IFG parameter between the frames 1101 to 1104, and transmits the frames 1101 to 1104 intermittently.

  Next, an information exchange method using the extended function of auto negotiation will be described. By using this function, it is possible to exchange information on whether or not to use the IFG value of the PAUSE frame between link partners before the start of communication. If this information is not exchanged, the IFG instruction of the PAUSE frame is ignored by the existing device, so that the IFG value of the PAUSE frame can be prevented from being erroneously used due to the connection between the device of the embodiment and the existing device. it can.

FIG. 12 is a flowchart illustrating auto-negotiation between the frame transmitting apparatus 101 and the frame receiving apparatus 102 that are in a link partner relationship with each other.
First, the physical layer control unit 117 of the frame transmitting apparatus 101 transmits a Base Page Word in which full-duplex PAUSE operation is set to be valid or invalid to the frame receiving apparatus 102 (step 1201).

  Next, the Next Page Word in which the IFG designation of the PAUSE frame is set to be valid or invalid by the Message Code is transmitted to the frame receiving apparatus 102 (Step 1202). For example, when the IFG designation of the PAUSE frame is validated, the Message Code code number is set to 26 and the Next Page Word is transmitted.

  The physical layer control unit 129 of the frame receiving apparatus 102 refers to the Base Page of the link partner (Step 1203) and checks whether the PAUSE operation is valid (Step 1204). If the PAUSE operation is valid, the link partner's Next Page is then referenced (step 1205), and the code number of the Message Code is checked (step 1206).

  If the code number is 26, it is determined that the IFG designation of the PAUSE frame is valid with the link partner, and the IFG adjustment unit 124 is notified that the IFG designation of the PAUSE frame is usable (step 1207). . If the code number is other than 26, it is determined that the IFG designation of the PAUSE frame is invalid, and the IFG adjustment unit 124 is notified that the IFG designation of the PAUSE frame cannot be used (step 1208).

  If the PAUSE operation is invalid in step 1204, the IFG adjustment unit 124 is notified that the PAUSE frame cannot be used (step 1209).

  In this way, by performing auto-negotiation before the start of communication between the frame transmitting apparatus 101 and the frame receiving apparatus 102, it is confirmed whether or not the IFG value of the PAUSE frame is used, and erroneous recognition of the IFG instruction is prevented. Can do. Therefore, the apparatus of the embodiment can be connected to the existing apparatus.

With respect to the embodiment described with reference to FIGS. 1 to 12, the following additional notes are disclosed.
(Supplementary note 1) A frame receiving device for receiving a frame from a frame transmitting device via a communication network,
Receiving buffer means for storing received frame data;
Determining means for determining whether congestion has occurred based on the buffer usage of the receiving buffer means;
A transmission means for transmitting a frame suppression request to the frame transmission device when congestion occurs;
A frame receiving apparatus comprising: setting means for setting, in the frame suppression request, a parameter that specifies a transmission interval of frames transmitted by the frame transmitting apparatus.
(Additional remark 2) It further has an adjustment means which adjusts the sending interval of the frame, and the determination means determines that congestion has occurred when the buffer usage exceeds a congestion determination threshold, and the adjustment means When the buffer usage exceeds the congestion determination threshold after a lapse of a certain time after transmitting a frame suppression request, the frame transmission interval is increased, and the setting means designates the increased transmission interval. The frame receiver according to appendix 1, wherein a parameter is set in the frame suppression request.
(Additional remark 3) It further has the adjustment means which adjusts the transmission interval of the said frame, The said determination means determines that congestion generate | occur | produced when the said buffer usage exceeds the congestion determination threshold value, and this buffer usage is congestion When the threshold is less than the cancellation determination threshold, it is determined that congestion has been resolved, and when the congestion is resolved, the adjustment unit decreases the transmission interval of the frame, and the setting unit specifies a parameter for specifying the decreased transmission interval. Is set in the frame suppression request. 2. The frame receiving apparatus according to appendix 1, wherein:
(Additional remark 4) It further has a calculation means which calculates the average frame length of the received frame when congestion occurs, and calculates the frame transmission interval using the appropriate input bit rate corresponding to the obtained average frame length. The frame receiving apparatus according to claim 1, wherein the setting means sets a parameter for specifying the obtained transmission interval in the frame suppression request.
(Supplementary Note 5) When the buffer usage exceeds the congestion determination threshold, the determination unit determines that congestion has occurred, and when the buffer usage exceeds the congestion continuation determination threshold, congestion continues. The frame according to appendix 1, 2, 3, or 4, wherein the setting means sets a parameter for designating frame transmission stop in the frame suppression request when congestion continues. Receiver device.
(Supplementary Note 6) Receiving means for receiving, from the frame transmitting apparatus, control information indicating whether or not to use a transmission interval specified by a parameter set in the frame suppression request before starting frame reception The frame receiver according to appendix 1, 2, 3, or 4, characterized by comprising:
(Supplementary note 7) A frame transmission device for transmitting a frame to a frame reception device via a communication network,
Transmitting means for transmitting a frame to the frame receiving device;
Receiving means for receiving a frame suppression request from the frame receiving device when congestion occurs in the frame receiving device;
An extraction means for extracting a parameter for specifying a transmission interval of frames transmitted by the transmission means from the frame suppression request;
A frame transmission apparatus comprising: a control unit that controls the transmission unit so as to transmit a frame at a transmission interval specified by the extracted parameter.
(Supplementary note 8) A frame receiving method for receiving a frame from a frame transmitting device via a communication network,
The received frame data is stored in the reception buffer means,
Determine whether congestion has occurred based on the buffer usage of the receiving buffer means,
When congestion occurs, set a parameter for specifying a transmission interval of frames transmitted by the frame transmission device in a frame suppression request,
A frame receiving method, wherein the frame suppression request is transmitted to the frame transmitting apparatus.
(Supplementary note 9) A frame transmission method for transmitting a frame to a frame reception device via a communication network,
When congestion occurs in the frame receiving device, a frame suppression request is received from the frame receiving device,
Extract a parameter that specifies the frame transmission interval from the frame suppression request,
A frame transmission method comprising: transmitting a frame to the frame receiving device at a transmission interval specified by an extracted parameter.

It is a block diagram of the frame transmission apparatus and frame reception apparatus of embodiment. It is a figure which shows the PAUSE frame of embodiment. It is a figure which shows the threshold value of the 1st buffer usage-amount. It is a flowchart of a 1st IFG adjustment process. It is a figure which shows transition of the 1st buffer usage-amount. It is a block diagram of an IFG adjustment part. It is a figure which shows the threshold value of the 2nd buffer usage-amount. It is a flowchart of a 2nd IFG adjustment process. It is a figure which shows transition of the 2nd buffer usage. It is a figure which shows the 1st frame transmission interval. It is a figure which shows the 2nd frame transmission interval. It is a flowchart of an auto negotiation. It is a figure which shows a network structure. It is a block diagram of the conventional frame transmitter and frame receiver. It is a figure which shows the conventional PAUSE frame.

Explanation of symbols

11 IP network 12 Host device 13, 14, 15 Wireless base station device 16, 17, 18, 19, 20, 21 Network device 31, 101 Frame transmission device 32, 102 Frame reception device 41, 111 Transmission buffer 42, 112 Transmission control Unit 43, 115 interruption time parameter extraction unit 44, 116 PAUSE frame extraction unit 51, 121 reception buffer 52, 122 reception buffer control unit 53, 123 buffer congestion judgment unit 54, 125 interruption time parameter insertion unit 55, 127 PAUSE frame generation unit 56, 128 Selectors 42, 112 Transmission control unit 113 Frame transmission interval control unit 114 IFG parameter extraction unit 117, 129 Physical layer control unit 124 IFG adjustment unit 126 IFG parameter insertion unit 501, 502 Plot 60 DESCRIPTION OF SYMBOLS 1 Control part 602 Input frame counter 603 Timer 604 IFG value calculation part 605 Bit rate storage part 1001, 1002, 1003, 1004, 1101, 1102, 1103, 1104
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Claims (8)

A frame receiving device for receiving a frame from a frame transmitting device via a communication network,
Receiving buffer means for storing received frame data;
Determining means for determining whether congestion has occurred based on the buffer usage of the receiving buffer means;
A transmission means for transmitting a frame suppression request to the frame transmission device when congestion occurs;
A frame receiving apparatus comprising: setting means for setting, in the frame suppression request, a parameter that specifies a transmission interval of frames transmitted by the frame transmitting apparatus.   The adjustment unit further adjusts the transmission interval of the frame, and the determination unit determines that congestion has occurred when the buffer usage exceeds a congestion determination threshold, and the adjustment unit outputs the frame suppression request. The transmission interval of the frame is increased when the buffer usage exceeds the congestion determination threshold after a predetermined time has elapsed after transmission, and the setting means sets a parameter for specifying the increased transmission interval to the frame The frame receiving apparatus according to claim 1, wherein the frame receiving apparatus is set to a suppression request.   The apparatus further comprises adjusting means for adjusting the transmission interval of the frame, and the determining means determines that congestion has occurred when the buffer usage exceeds a congestion determination threshold, and the buffer usage determines the congestion elimination determination threshold. When it falls below, it is determined that the congestion has been resolved, and when the congestion is resolved, the adjustment means decreases the frame transmission interval, and the setting means sets a parameter for specifying the decreased transmission interval to the frame suppression. The frame receiving apparatus according to claim 1, wherein the frame receiving apparatus is set to a request.   A calculation unit that calculates an average frame length of a received frame when congestion occurs and calculates a frame transmission interval using an appropriate input bit rate corresponding to the obtained average frame length; 2. The frame receiving device according to claim 1, wherein a parameter for specifying the obtained transmission interval is set in the frame suppression request.   The determination means determines that congestion has occurred when the buffer usage exceeds a congestion determination threshold, and determines that congestion continues when the buffer usage exceeds a congestion continuation determination threshold; 5. The frame receiving apparatus according to claim 1, wherein the setting means sets a parameter for designating frame transmission stop in the frame suppression request when congestion continues. A frame transmission device that transmits a frame to a frame reception device via a communication network,
Transmitting means for transmitting a frame to the frame receiving device;
Receiving means for receiving a frame suppression request from the frame receiving device when congestion occurs in the frame receiving device;
An extraction means for extracting a parameter for specifying a transmission interval of frames transmitted by the transmission means from the frame suppression request;
A frame transmission apparatus comprising: a control unit that controls the transmission unit so as to transmit a frame at a transmission interval specified by the extracted parameter. A frame reception method for receiving a frame from a frame transmission device via a communication network,
The received frame data is stored in the reception buffer means,
Determine whether congestion has occurred based on the buffer usage of the receiving buffer means,
When congestion occurs, set a parameter for specifying a transmission interval of frames transmitted by the frame transmission device in a frame suppression request,
A frame receiving method, wherein the frame suppression request is transmitted to the frame transmitting apparatus. A frame transmission method for transmitting a frame to a frame reception device via a communication network,
When congestion occurs in the frame receiving device, a frame suppression request is received from the frame receiving device,
Extract a parameter that specifies the frame transmission interval from the frame suppression request,
A frame transmission method comprising: transmitting a frame to the frame receiving device at a transmission interval specified by an extracted parameter.