JP4302014B2 - Ethernet frame transfer apparatus and method - Google Patents

Description

  The present invention is used for information transmission by Ethernet (registered trademark). In particular, it relates to priority control technology.

(Priority Queue Overview)
The Ethernet described in Non-Patent Document 1 basically provides a best-effort service, but is required to cope with various communication qualities due to diversification of applications. In order to satisfy this requirement, Diffserve of Non-Patent Document 2 has been proposed as a conventional technique.

In communication quality control by Diffserv, transfer packets are classified into classes based on audio, video, file, or profile of sender / recipient, etc., priorities are defined for each class, and independent input queues are arranged. This enables control for each profile. Such control is done with Priority.
It is called Queueing.

  Priority queuing, which performs transfer control only by packet priority, is relative to packets of different priorities by assigning the packet to a high priority class when it is difficult to lose the packet or when it is desired to reduce the transfer delay. Communication quality control can be performed.

(Problems with priority queuing)
The conventional Ethernet system described in Non-Patent Document 1 uses a Store-and-Forward (hereinafter referred to as S & F) type transfer control in which the entire frame is temporarily stored and then output. The above Priority
S & F transfer control is also used in queuing. For example, even when a lower priority packet is being output from the input queue and a higher priority packet is input, until the transfer of the packet being output is completed High priority packets will remain in the input queue. This is a kind of priority inversion phenomenon.
It is called Inversion.

Priority Inversion is more likely to occur as the amount of low-priority traffic increases and the length of low-priority packets increases. IEEE 802.3 / 802.1Q has a maximum packet length (MTU) of 1.5 Kbytes, but when using Jumbo-frame (9 Kbytes, 14 Kbytes,...) Over IPv6, the priority is four times or more.
Inversion can occur.

(Premium service)
In order to realize a higher quality service on the Ethernet by the conventional technology from the above phenomenon, a bandwidth guarantee network such as ATM, MPLS, SONET using IntServ / RSVP as described in Non-Patent Document 3 By bypassing the network and providing only UNI as an Ether-IF, or operating in a sufficiently low load state in an Ether network preferentially controlled by Diffserv etc., the characteristics equivalent to the best effort at no load (Controlled) -Load) service is used.

Rich Seifert, “LAN switching thorough explanation”, Nikkei BP, pp. 24-34 (2001/08) Constances Dvorolis, et. al. "A case for relevant differentiated services and the proportional differentiated model", IEEE Network Sep. / Oct. 1999, pp. 26-34. “ADSL: Business Service> Network Technology”, [online], [Search June 9, 2004], Internet <URL: http: // www. acca. ne. jp / businesses / network. html>

When performing communication quality control with Ethernet in the prior art, Priority
Due to the inversion, a high-priority frame is a low-priority frame, which causes a large delay, and a desired delay target cannot be achieved.

  Priority Inversion is more likely to occur as there is more low-priority traffic and longer low-priority packets, and is more noticeable in an environment using Jumbo-frame.

  If Priority Inversion occurs frequently, the delay amount of high-priority packets fluctuates due to low-priority traffic despite priority control, and the effect of priority control is reduced.

  As described above, the Ethernet itself does not have a mechanism for guaranteeing strict communication quality, and the desired delay characteristics cannot be achieved even with a high priority frame. Therefore, when a high quality service is realized on the Ethernet using the conventional technology For example, it is necessary to use a network capable of bandwidth management such as ATM, MPLS, SONET, etc., or to operate the Ethernet network with extremely low traffic. Either way, excessive hardware resources are required, and the operation and control are complicated. Both capital investment and operation costs are very high.

The present invention has been made in view of such circumstances,
(1) Priority in the input queue in priority control in the Ethernet system
An object of the present invention is to provide means for eliminating inversion and performing more precise priority control.
(2) An object of the present invention is to reduce buffer processing at the video receiving end by minimizing transfer delay / delay dispersion and to improve network time synchronization accuracy.
(3) An object of the present invention is to add a means for surely achieving a desired delay characteristic to the Ethernet technology, and to realize a higher quality service economically than the conventional technology.

  A first aspect of the present invention is an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from two or more input queues.

Here, the feature of the present invention is that S & F type transfer control is performed in which, for the frames that have arrived outside the specific input queue among the two or more input queues, the entire frame is temporarily stored and then output. And for a frame that has arrived at the specific input queue, immediately when the frame is being output from another input queue other than the specific input queue when the storing of the frame is started The frame output from the other input queue is stopped, a control code indicating a frame interrupt is added before and after the frame that has arrived at the specific input queue, and the frame is output. Resumes transfer of frames from the other input queue whose output was interrupted, and outputs frames from the other input queues other than the specific input queue. If in no, Ru near where the data in the frame arriving at the particular input queue is Cut-Through outputs immediately on arrival and means for performing (in the following and referred CT) control.

  As described above, in the present invention, a frame arriving at a specific input queue can be transferred by being interrupted by a frame arriving at another input queue.

  Originally, in the Ethernet standard, there is no means for interrupting another frame in the frame. Therefore, in the present invention, the interrupt is realized by clearly indicating the start and end of the interrupt with a control code not used in the standard frame.

Alternatively, the Ethernet frame transfer apparatus according to the present invention performs normal S & F transfer control that temporarily stores the entire frame and outputs it for frames that have arrived outside the specific input queue among the two or more input queues. And when a frame arrived at the specific input queue is stored, and when the frame storage in the specific input queue is completed, a frame is being output from another input queue other than the specific input queue. Immediately stop outputting the frame from the other input queue, add a control code indicating a frame interrupt before and after the frame stored in the specific input queue, and output the frame. When the transmission is completed, the transfer of the frame of the other input queue whose output is interrupted is resumed, and the specific input is resumed. A specific S & F transfer control for performing the same control as the means for performing the normal S & F transfer control for a frame that has arrived at the specific input queue when a frame is not being output from the other input queue other than the queue comprising the means.

  That is, while the CT control has a short transfer time, an erroneous frame is transmitted to the subsequent stage as it is, whereas the S & F control transfers the frame to the subsequent stage after completion of frame input and error checking. In the case where accuracy is required rather than performance, S & F control can be performed even for frames with high priority.

Further, Ru can be provided with means for performing an addition of the control code is limited to a pre-specified time period.

  According to this, since it becomes possible to control the output timing of frames with high priority, it is possible to transfer in synchronization with the frame rate of moving images etc. using a predetermined time zone, and to set the sampling rate of audio etc. By performing synchronized transfer, it is possible to eliminate phenomena such as jitter accumulation and overrun / underrun during multistage connection. In addition, it is possible to prevent steady band occupation of high priority frames.

Further, when frame storage in the specific input queue is started in the case of CT control or completed in the case of S & F control, from the end of frame output from the previous specific input queue, The frame is accumulated in the specific queue until the previous frame length × α (a real number where α> 0) has elapsed, and when the previous frame length × α time or more has elapsed, the frame is being output from the other input queue Ru can be provided with means for performing an addition of the control code.

  According to this, priority control of frames with high priority can be performed with a certain interval. Therefore, it is possible to avoid a situation in which a frame with a low priority is not transferred at all, so that it is possible to secure a certain level of service quality for a user who wants to transfer a frame with a low priority.

Further, on the receiving side, a means for detecting the control code indicating the frame interrupt and separating the interrupt frame, and a means for combining a plurality of frames divided by the interrupt of the interrupt frame to reproduce the original one frame We then desirable to include and.

  That is, on the receiving side, in order to restore the interrupt frame and the frame fragmented by the interrupt, the interrupt frame can be handled as a normal frame except for the added control code. As the means for reproducing, for example, the S & F queue waits for the end of the frame to start output transfer, so the fragmented frame is reproduced as the original frame by passing the S & F queue once except for the interrupt part. Is done.

Thus, the assignment a specific input queue priority class, by the less classes can be allocated to the other input queues, in Ethernet networks, Ru can be performed precise priority control than the prior art.

  The second aspect of the present invention is an Ethernet frame transfer method for sequentially outputting frames from two or more input queues.

Here, a feature of the present invention is that S & F type transfer control is performed in which the entire frame is temporarily stored and output for a frame that has arrived outside the specific input queue among the two or more input queues. For a frame that has arrived at the specific input queue, if the frame is being output from another input queue other than the specific input queue when the frame is stored, the frame is immediately output. Stop frame output from other input queues, add a frame interrupt control code before and after the frame that arrived at the specific input queue, and output the frame. The transfer of the frame of the other input queue that has been interrupted is resumed, and no frame is being output from the other input queue other than the specific input queue. If, Ru near the place of performing CT control data in the frame arriving at the particular input queue is outputted immediately on arrival.

Alternatively, the Ethernet frame transfer method of the present invention performs normal S & F type transfer control in which the entire frame is temporarily stored and then output for frames that have arrived outside the specific input queue among the two or more input queues. When a frame that has arrived at the specific input queue is stored, and when storing of the frame in the specific input queue is completed, a frame is being output from another input queue other than the specific input queue. Immediately stop outputting the frame from the other input queue, add a control code indicating a frame interrupt before and after the frame stored in the specific input queue, output the frame, and send the frame. When complete, the frame transfer of the other input queue whose output has been suspended is resumed, and the specific input queue is resumed. When a frame is not being output from the other input queue outside, the specific S & F type transfer control for performing the same control as the normal S & F type transfer control is performed on the frame arriving at the specific input queue. It shall be the feature.

In this case, Ru can be restricted to pre-specified time period performing the addition of the control code.

Alternatively, when frame storage in the specific input queue is started in the case of CT control or completed in the case of S & F control, from the end of frame output from the previous specific input queue, The frame is accumulated in the specific queue until the previous frame length × α (a real number where α> 0) has elapsed, and when the previous frame length × α time or more has elapsed, the frame is being output from the other input queue Ru can be performed the addition of the control code.

On the receiving side, the control code indicating the frame interrupt is detected and the interrupt frame is separated, and a plurality of frames divided by the interrupt of the interrupt frame are combined to be reproduced as one original frame. not desirable.

The allocation of specific input queue priority class, less classes you can assign to the other input queues.

As described above, when the present invention is used, priority control in the input queue is performed in priority control in the Ethernet system.
Inversion can be eliminated and more precise priority control can be performed. In addition, since transfer delay and delay dispersion can be minimized, for example, buffer processing at the video receiving end can be reduced, and network time synchronization accuracy can be improved. Furthermore, the present invention can achieve a desired delay characteristic for high-priority traffic even under a high load, so that high-quality service can be achieved using only the Ethernet technology, and the cost is lower than when using the conventional technology. It has the effect of providing high quality services.

(First Embodiment: Implementation how the Gigabit Ethernet)
A first embodiment of the present invention is shown in FIGS. FIG. 1 is a block diagram of the main part of an Ethernet frame transfer apparatus according to the first embodiment. FIG. 2 is a diagram for explaining an Ethernet frame transfer method according to the first embodiment.

  As shown in FIG. 1, the first embodiment is an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from input queues a1 to aN, and a specific input queue among the input queues a1 to aN. For frames arriving at other than aN, the means for performing S & F transfer control that stores and outputs the entire frame once, and for frames arriving at a specific input queue aN, storage of the frame is started. If a frame is being output from the other input queues a1 to aN-1 other than the specific input queue aN, the frame output from the other input queues a1 to aN-1 is immediately stopped. Then, the control code indicating the frame interrupt before and after the frame arriving at the specific input queue aN is sent by the control code adding means b. In addition, the frame is output, and when the transmission of the frame is completed, the transfer of the frames of the other input queues a1 to aN-1 whose output is interrupted is resumed, and the other input queues a1 to aN other than the specific input queue aN When a frame is not being output from aN-1, it is provided with means for performing CT control for outputting data immediately after arrival in a frame that has arrived at a specific input queue aN.

  The means for performing the S & F type transfer control and the means for performing the CT control are provided in a control device provided outside the figure, and include the input queues a1 to aN, the control code adding means b, and the Queue selection control means c shown in FIG. The input queues a1 to aN, the control code adding means b, and the Queue selection control means c each have means for controlling itself, and control these. The means may cooperate to constitute means for performing the S & F transfer control and means for performing the CT control.

  This embodiment shows a method of applying the invention to the operation on the sending side that outputs a frame to Ethernet. In the configuration of FIG. 1, a frame is input to each of the input queues a1, a2,. The interrupt start code is defined as “T / R / R / R” and the end code is defined as “/ R / R / S / D”, and the control code adding means b applies these to the frame output of the input queue aN. Add a control code. Here, unused control codes are selected in Ethernet for the control codes “/ T / R / R / R” and “/ R / R / S / D” indicating the start and end of the interrupt. The queue selection control means c performs S & F control on the input queues a1 to aN-1, but performs CT control on the input queue aN and the control code addition means b simultaneously with the input of the frame.

  FIG. 2 shows an example of the operation. The low priority frame A (1) arrives at the input 1 first, and then the high priority frame B (2) arrives at the input N. The queue selection control means c waits for the frame arrival of the low priority frame A (1) to be completed and starts the transfer of the low priority frame (4), but the high priority frame is transferred during the transfer of the low priority frame (4). When the priority frame B (2) arrives, the transfer of the low priority frame (4) is immediately stopped and the frame transfer of the high priority frame (2) to which the control code is added by the control code adding means b is started ( 6).

  The queue selection control means c restarts the transfer of the low priority frame (4) at the same time as the transfer of the high priority frame (6) is completed. Here, the output frame (7) has a configuration in which the low priority frame (4) and the high priority frame (6) are connected. Hereinafter, this process is called an interrupt, and a high priority frame is called an interrupt frame.

As described above, according to the present invention, the high priority frame is transferred immediately after arrival at the input queue aN even when the low priority frame is being transferred.
Inversion can be avoided.

(Second Example: Implementing how the Gigabit Ethernet)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram of the main part of the Ethernet frame transfer apparatus of the second embodiment. FIG. 4 is a diagram for explaining an Ethernet frame transfer method according to the second embodiment.

  In the second embodiment, as shown in FIG. 3, the reception queue selection means d for detecting the control code indicating the frame interrupt and separating the interrupt frame is combined with a plurality of frames divided by the interrupt of the interrupt frame. And an input cue e to be reproduced in one original frame.

  This embodiment shows a method of applying the invention to the operation of the receiving side that receives a frame from Ethernet. The configuration of FIG. 3 has a function of converting the interrupted low priority frame into the original frame. The reception queue selection means d separates the high priority interrupt frame from the other frames. The input queue e is an S & F queue, and a frame other than the interrupt frame is input. The S & F queue waits for the end of the frame to start output transfer. Therefore, the fragmented frame passes through the S & F queue once except for the interrupt portion. To play back to the original frame.

  FIG. 4 shows an example of the operation. When a frame arrives at the input (1), the reception queue selection means d transfers a frame other than the interrupt frame to the input (2) of the input queue e that performs S & F control. When the reception queue selection means d detects the interrupt start code, the frame transfer destination is switched to output 2 (5). When the interrupt end code is detected, the transfer destination is switched again to (2), and the input queue e waits for the end of frame reception and starts transfer to the output 1 (4).

(Third embodiment: Comparison with a commercially available switch)
A third embodiment will be described with reference to FIGS. To confirm the effect of priority control of the present invention, Gigabit Ethernet device corresponding to the Ethernet frame transfer apparatus of the present onset bright, and using commercially available Gigabit Ethernet switch for comparison. FIG. 5 shows the measurement environment. A low-priority traffic QP1 and a high-priority traffic QP4 are respectively generated from the gigabit Ethernet tester and are collected by the device under test DUT1.

  The aggregated traffic was separated for each priority by the device under test DUT2, and the delay amount of the high priority traffic QP4 was measured. In measurement with a commercially available Gigabit Ethernet device, IEEE802.1p is used for definition of priority, and the priority control algorithm is PriorityQueueing. The apparatus in which the present invention is implemented uses the interrupt start / end code of the first embodiment as a class capable of interrupting high priority traffic.

The measurement results are shown in FIG. In FIG. 6, the abscissa indicates priority traffic and the ordinate indicates delay time. It was found that the delay amount of the high priority traffic increases by about 30 μs when the high priority traffic amount + the low priority traffic amount exceeds the physical rate (1 Gbit / s) in the commercially available Gigabit Ethernet device. This is the aforementioned Priority
Presumed to be the effect of Inversion.

  On the other hand, the effect of the priority control of the present invention was confirmed in the apparatus in which the present invention was implemented, without the influence of the low priority traffic on the high priority traffic.

(Fourth embodiment: constant frame rate for synchronous transfer / priority traffic )
A fourth embodiment will be described with reference to FIG. FIG. 7 is a diagram for explaining the operation when the present invention (Claims 3 and 9) is applied. Periods Tk and Tk + 1 are predetermined periods as transmission priority periods for high-priority frames. The apparatus configuration is the same as in the first embodiment (FIG. 1), but the operation of the queue selection control means c is different.

  The low priority frame A (1) arrives at the input 1 first, and then the high priority frame B (2) arrives at the input N. The queue selection control means c waits for the frame arrival of the low priority frame A (1) to be completed, and starts the transfer of the low priority frame (4), but the high priority frame B in the predetermined period Tk. Since the input of (2) is started in the input queue, the transfer of the low priority frame (4) is immediately stopped, and the frame transfer of the high priority frame (2) to which the control code is added by the control code adding means b is performed. Start (6).

  The queue selection control means c restarts the transfer of the low priority frame (4) at the same time as the transfer of the high priority frame (6) is completed. In the period Tk + 1, the high priority frame C (2) is input to the input queue aN. However, since the low priority frame is not being transferred, the frame transfer is started without adding the control code (6). . As a result, the high priority frame is transmitted without fluctuation in time during a predetermined period.

Thus, the present onset bright Accordingly, it becomes possible to control the output timing of the high-priority frame, transfer and synchronized with the frame rate and video using a predetermined time period, such as voice By performing transfer in synchronization with the sampling rate, it is possible to eliminate such phenomena as jitter accumulation and overrun / underrun during multi-stage connection. In addition, it is possible to prevent steady band occupation of high priority frames.

(Fifth embodiment: constant priority traffic data rate )
The fifth embodiment corresponding to the onset bright shown in FIG. 8. The apparatus configuration is the same as in the first embodiment (FIG. 1), but the operation of the queue selection control means c is different. The low priority frame A (1) arrives at the input 1 first, and then the high priority frame B (2) arrives at the input N. Let TB be the transfer time of frame B.

The operation relating to the transfer of the frame B (2) is not different from that in the first embodiment. The frame C (2) is different from the first embodiment in that, after the transfer of the frame B is completed, transfer of TB × α period (showing the case of α = 2 in FIG. 8) is not started. As a result, by carrying out the present onset bright, it is possible to limit the maximum transfer rate of the high priority frame. The maximum transfer rate of the high priority frame can be expressed by G / (α + 1); (G: transmission rate).

Thus, it can be applied to the strict band control when provision of prevention and bandwidth limit the band occupancy is required high priority frame by applying the present onset bright.

(Sixth Example: S & F control of the priority queue)
A sixth embodiment corresponding to the onset Ming 9, 10, shown in FIG. 11. The apparatus configuration is the same as in the first embodiment. Control of the priority queue that definitive in this onset Ming described above was CT control. In general, CT control immediately starts transfer to the next stage, so that the transfer time is short, but there is a problem that an erroneous frame is transmitted to the subsequent stage.

  On the other hand, in the S & F control, the frame input completion / error check is performed and then the transfer to the next stage is started, so there is no problem like the former. In applications where accuracy is more important than immediacy, it is desirable to apply the sixth embodiment. FIGS. 9, 10, and 11 show operations when priority queues by S & F control corresponding to FIGS. 2, 7, and 8, respectively, are used.

  For example, comparing FIG. 2 with FIG. 9, when frame B arrives in FIG. 2 (2), a control code is immediately added as shown in FIG. 2 (6), and as shown in FIG. 2 (7). 9B, when the frame B arrives in FIG. 9 (2), the frame B is temporarily stored. After the storage is completed, a control code is added as shown in FIG. 9 (6). As shown in (7), an interrupt is performed.

  Similarly, FIG. 7 (2), (6), (7) and FIG. 10 (2), (6), (7) or FIG. 8 (2), (6), (7) and FIG. 11 (2). , (6), and (7), in FIGS. 7 and 8, when frame B arrives, a control code is immediately added and an interruption is performed, whereas in FIGS. 10 and 11, frame B is Once it arrives, it is stored, after which a control code is added and an interrupt is made.

  As described above, when the present invention is used, accurate priority control can be performed in the Ethernet system. In addition, since transfer delay and delay dispersion can be minimized, for example, buffer processing at the video receiving end can be reduced, and network time synchronization accuracy can be improved. Furthermore, a high quality service is possible using only the Ethernet technology, and a high quality service can be provided at a lower cost than in the case of using the conventional technology.

The principal part block diagram of the Ethernet frame transfer apparatus of a 1st Example. The figure for demonstrating the Ethernet frame transfer method of a 1st Example. The principal part block diagram of the Ethernet frame transfer apparatus of 2nd Example. The figure for demonstrating the Ethernet frame transfer method of 2nd Example. The figure which shows the measurement environment for confirming the effect of the priority control of this invention. The figure which shows the measurement result for confirming the effect of the priority control of this invention. The figure for demonstrating operation | movement when a 4th Example is applied. The figure for demonstrating operation | movement when a 5th Example is applied. The figure for demonstrating operation | movement when a 6th Example is applied. The figure for demonstrating operation | movement when a 6th Example is applied. The figure for demonstrating operation | movement when a 6th Example is applied.

Explanation of symbols

a1 to aN, e Input queue b Control code adding means c Queue selection control means d Reception Queue selection means DUT1, DUT2 Device under test QP1 Low priority traffic QP4 High priority traffic

Claims (12)

In an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from two or more input queues,
Means for performing Store-and-Forward (hereinafter referred to as S & F) type transfer control for temporarily storing and outputting the entire frame for a frame that has arrived outside the specific input queue among the two or more input queues;
For a frame that has arrived at the specific input queue, if the frame is being output from another input queue other than the specific input queue when the store of the frame is started, the other immediately Output of the frame from the input queue is stopped, and a frame is output by adding a control code indicating a frame interrupt before and after the frame arriving at the specific input queue. When the transmission of the frame is completed, the output is interrupted. When the transfer of the frame of the other input queue is resumed and no frame is being output from the other input queue other than the specific input queue, the data in the frame arriving at the specific input queue is Means for performing Cut-Through (hereinafter referred to as CT) control to output immediately upon arrival ;
An Ethernet frame transfer apparatus comprising: means for adding the control code limited to a time zone specified in advance . In an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from two or more input queues,
Means for performing normal S & F type transfer control for temporarily storing and outputting the entire frame for frames arriving at a position other than a specific input queue among the two or more input queues;
When a frame that has arrived at the specific input queue is stored, and a frame is being output from another input queue other than the specific input queue when the frame has been stored in the specific input queue, the frame is immediately output. Stops outputting frames from the other input queue, outputs a frame by adding a control code indicating a frame interrupt before and after the frame stored in the specific input queue, and completes sending the frame. Then, transfer of the frame of the other input queue whose output has been interrupted is resumed, and if the frame is not being output from the other input queue other than the specific input queue, the frame that has arrived at the specific input queue Specific S & F type transfer control means for performing the same control as the means for performing the normal S & F type transfer control ,
An Ethernet frame transfer apparatus comprising: means for adding the control code limited to a time zone specified in advance . In an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from two or more input queues,
Means for performing Store-and-Forward (hereinafter referred to as S & F) type transfer control for temporarily storing and outputting the entire frame for a frame that has arrived outside the specific input queue among the two or more input queues;
For a frame that has arrived at the specific input queue, if the frame is being output from another input queue other than the specific input queue when the store of the frame is started, the other immediately Output of the frame from the input queue is stopped, and a frame is output by adding a control code indicating a frame interrupt before and after the frame arriving at the specific input queue. When the transmission of the frame is completed, the output is interrupted. When the transfer of the frame of the other input queue is resumed and no frame is being output from the other input queue other than the specific input queue, the data in the frame arriving at the specific input queue is Means for performing Cut-Through (hereinafter referred to as CT) control to output immediately upon arrival;
When frame storage in the specific input queue is started in the case of CT control, or completed in the case of S & F control, the previous frame output from the specific input queue has been completed. Frame length × α (a real number where α> 0) time elapses, frames are accumulated in the specific queue, and when the previous frame length × α time or more elapses, the frame is output from the other input queue. An Ethernet frame transfer apparatus comprising means for adding a control code . In an Ethernet frame transfer apparatus including an Ethernet packet buffer that sequentially outputs frames from two or more input queues,
Means for performing normal S & F type transfer control for temporarily storing and outputting the entire frame for frames arriving at a position other than a specific input queue among the two or more input queues;
When a frame that has arrived at the specific input queue is stored, and a frame is being output from another input queue other than the specific input queue when the frame has been stored in the specific input queue, the frame is immediately output. Stops outputting frames from the other input queue, outputs a frame by adding a control code indicating a frame interrupt before and after the frame stored in the specific input queue, and completes sending the frame. Then, transfer of the frame of the other input queue whose output has been interrupted is resumed, and if the frame is not being output from the other input queue other than the specific input queue, the frame that has arrived at the specific input queue Specific S & F type transfer control means for performing the same control as the means for performing the normal S & F type transfer control,
When frame storage in the specific input queue is started in the case of CT control, or completed in the case of S & F control, the previous frame output from the specific input queue has been completed. Frame length × α (a real number where α> 0) time elapses, frames are accumulated in the specific queue, and when the previous frame length × α time or more elapses, the frame is output from the other input queue. An Ethernet frame transfer apparatus comprising: means for adding a control code. Means for detecting a control code indicating the frame interrupt and separating the interrupt frame;
5. The Ethernet frame transfer apparatus according to claim 1, further comprising: a unit that combines a plurality of frames divided by the interrupt of the interrupt frame to reproduce the original frame. 6.   6. The Ethernet frame transfer apparatus according to claim 1, wherein the specific input queue is assigned to the highest priority class, and classes lower than the specific input queue are assigned to the other input queue. In the Ethernet frame transfer method for sequentially outputting frames from two or more input queues,
For frames that have arrived outside the specified input queue of the two or more input queues, S & F type transfer control is performed in which the entire frame is temporarily stored and then output.
For a frame that has arrived at the specific input queue, if the frame is being output from another input queue other than the specific input queue when the store of the frame is started, the other immediately Output of the frame from the input queue is stopped, and a frame is output by adding a control code indicating a frame interrupt before and after the frame arriving at the specific input queue. When the transmission of the frame is completed, the output is interrupted. When the transfer of the frame of the other input queue is resumed and no frame is being output from the other input queue other than the specific input queue, the data in the frame arriving at the specific input queue is arriving soon have a row the CT control immediately output,
An Ethernet frame transfer method characterized in that the control code is added only in a predetermined time zone . In the Ethernet frame transfer method for sequentially outputting frames from two or more input queues,
A normal S & F type transfer control is performed for a frame that has arrived at a location other than a specific input queue among the two or more input queues.
When a frame that has arrived at the specific input queue is stored, and a frame is being output from another input queue other than the specific input queue when the frame has been stored in the specific input queue, the frame is immediately output. Stops outputting frames from the other input queue, outputs a frame by adding a control code indicating a frame interrupt before and after the frame stored in the specific input queue, and completes sending the frame. Then, transfer of the frame of the other input queue whose output has been interrupted is resumed, and if the frame is not being output from the other input queue other than the specific input queue, the frame that has arrived at the specific input queue There line specific S & F transfer control to perform the normal S & F transfer control similar control over,
An Ethernet frame transfer method characterized in that the control code is added only in a predetermined time zone . In the Ethernet frame transfer method for sequentially outputting frames from two or more input queues,
For frames that have arrived outside the specified input queue of the two or more input queues, S & F type transfer control is performed in which the entire frame is temporarily stored and then output.
For a frame that has arrived at the specific input queue, if the frame is being output from another input queue other than the specific input queue when the store of the frame is started, the other immediately Output of the frame from the input queue is stopped, and a frame is output by adding a control code indicating a frame interrupt before and after the frame arriving at the specific input queue. When the transmission of the frame is completed, the output is interrupted. When the transfer of the frame of the other input queue is resumed and no frame is being output from the other input queue other than the specific input queue, the data in the frame arriving at the specific input queue is Perform CT control to output immediately upon arrival,
When frame storage in the specific input queue is started in the case of CT control, or completed in the case of S & F control, the previous frame output from the specific input queue has been completed. Frame length × α (a real number where α> 0) time elapses, frames are accumulated in the specific queue, and when the previous frame length × α time or more elapses, the frame is output from the other input queue. Add control code
An Ethernet frame transfer method characterized by the above . In the Ethernet frame transfer method for sequentially outputting frames from two or more input queues,
A normal S & F type transfer control is performed for a frame that has arrived at a location other than a specific input queue among the two or more input queues.
When a frame that has arrived at the specific input queue is stored, and a frame is being output from another input queue other than the specific input queue when the frame has been stored in the specific input queue, the frame is immediately output. Stops outputting frames from the other input queue, outputs a frame by adding a control code indicating a frame interrupt before and after the frame stored in the specific input queue, and completes sending the frame. Then, transfer of the frame of the other input queue whose output has been interrupted is resumed, and if the frame is not being output from the other input queue other than the specific input queue, the frame that has arrived at the specific input queue Specific S & F type transfer control for performing the same control as the normal S & F type transfer control,
When frame storage in the specific input queue is started in the case of CT control, or completed in the case of S & F control, the previous frame output from the specific input queue has been completed. Frame length × α (a real number where α> 0) time elapses, frames are accumulated in the specific queue, and when the previous frame length × α time or more elapses, the frame is output from the other input queue. A method of transferring an Ethernet frame, comprising adding a control code.   11. The control code indicating the frame interrupt is detected, the interrupt frame is separated, and a plurality of frames divided by the interrupt of the interrupt frame are combined to be reproduced as one original frame. The Ethernet frame transfer method according to claim 1.   12. The method of transferring an Ethernet frame according to claim 7, wherein the specific input queue is assigned to the highest priority class, and classes lower than the specific input queue are assigned to the other input queue.

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