JP2004253960A - Data transfer apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the transmission efficiency for transfer of data from a plurality of input transmission lines to one output transmission line by shortening the transfer standby time even when the number of input transmission lines increases, and when a packet having a long packet length is inputted. <P>SOLUTION: A data transfer apparatus has a plurality of input ports P1 to Pn, a plurality of buffer parts 211 to 21n which store packet data inputted to the plurality of input ports, weighting parts 231 to 23n, and 241 to 24n which set weighting values of data transfer among the plurality of input ports according to units of read processes of the buffer parts, a scheduling part 31 which determines priority order for reading processes for packet data stored in the buffer parts and multiplexes packet data according to the priority order, and an output port P20 which outputs the data sent out of the scheduling part 31 to the outside. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data transfer device, and more particularly, to a data transfer device that multiplexes and outputs packet data input to a plurality of input ports.
[0002]
[Prior art]
A typical example of a scheduling method of a data transfer device that stores packet data input from a plurality of input ports in a buffer and then multiplexes and outputs the data is a round robin method. In the data transfer by the round robin method, the order of transmitting the data stored in the buffer is determined according to the priority order determined as an initial condition (hereinafter, referred to as “basic priority order”). In particular, when it is desired to assign a priority ratio (hereinafter, referred to as "weighting") to each port, a weighted round-robin method in which weighting between each port is set in the round robin method described above is used.
[0003]
In the data transfer by the weighted round robin method, the data transmission order and the data transmission amount for each port are adjusted by determining the data transmission order based on the weighting value in addition to the basic priority order. FIG. 10 shows an example of the configuration of a data transfer device using the weighted round robin method. Hereinafter, the components and operation of the data transfer device will be described with reference to FIG.
[0004]
As an initial setting, the weight values are set in the weight storage units 741 to 74n in units of the number of packets. Further, the weighting counters 731 to 73n set the weighting values as initial values of the counter. When a packet is input from the plurality of ports P21 to P2n, the packet is temporarily stored in the buffer units 721 to 72n of the port processing units 711 to 71n via the input interface units 701 to 70n. Next, each of the buffer units 721 to 72n issues data standby signals 851 to 85n for notifying that a packet is stored to the priority scheduling unit 771 of the scheduling unit 751. Then, a scheduling process for sequentially transmitting packets input to the port processing units 711 to 71n is performed. The priority scheduling unit 771 sends the output request signals 861 to the buffers 721 to 72n in the order determined by the scheduling process, and sends the packets to the multiplexing unit 781.
[0005]
For example, when the output request signal 861 is sent to the port processing unit 711, the weighting counter unit 731 performs a countdown process every time packet data is sent from the buffer unit 721. Thereafter, when the counter value becomes “0”, a transfer prohibition signal 841 is transmitted to the priority scheduling unit 771 in order to stop data transmission from the port processing unit 711. The packet transmitted from the buffer unit 721 is multiplexed in the multiplexing unit 781 with the packets from the other port processing units 712 to 71n, and output from the output interface unit 791 to the port P30.
[0006]
In this data transfer device, data transfer is performed by repeating the above operations. The priority scheduling unit 771 performs a scheduling process in the following manner.
▲ 1 ▼. The order of packet transmission is determined according to the basic priority order determined as the initial condition. Here, it is not necessary to consider the weight between ports. For example, packets are transmitted in the order of the port processing unit 711, the port processing unit 712, the port processing unit 713,..., The port processing unit 71n, and thereafter, unless otherwise noted, the basic priority of each port processing unit is , A port processing unit 711, a port processing unit 712, a port processing unit 713,..., A port processing unit 71n.
▲ 2 ▼. When the data standby signals from the port processing units 711 to 71n are not input, the order according to (1) is skipped.
(3). When the transfer prohibition signals are input from the port processors 711 to 71n, the order is skipped.
▲ 4 ▼. When the processing is completed for all the ports according to (1) to (3), the processing returns to the top of the basic priority order, and the same processing is repeated.
[0007]
According to the above scheduling process, the priority scheduling unit 771 sends out the output request signal 861. When the transfer prohibition signal 841 is input to the priority scheduling unit 771 from all the port processing units 711 to 71n, the count clear generation unit 761 sends the count clear signal to all the port processing units 711 to 71n. Then, the counter values of the weighting counters 731 to 73n are returned to the initial values again. In this method, as described above, a port having a large weight value (a large counter initial value) transfers a large amount of data preferentially according to the value.
[0008]
Conventionally, when performing data transfer in the above-mentioned weighted round robin method, if the input data is variable-length data, the input data is divided into fixed lengths, and weighting is performed on each fixed-length data. There is a method for scheduling input data. Hereinafter, this method is referred to as conventional method 1.
[0009]
On the other hand, as described in Patent Literature 1, there is a method of scheduling input data by controlling a transmission guarantee data capacity by one transfer permission. Hereinafter, this method is referred to as conventional method 2.
[0010]
FIG. 11 shows an example of the conventional method 1. In this method, before inputting the packet data from the input port to the buffer units 721 to 725, the dividing units 901 to 905 divide the variable-length packet into data of a fixed length, and To 725. Here, the weight value set for each port is set in units of the number of the divided fixed length. Then, the fixed-length data is transferred according to the weighted round robin method.
[0011]
FIG. 12 shows a state where data transfer is continued from the state shown in FIG.
[0012]
Packets transmitted from the input interface units 701 to 705 are divided by division units 901 to 905 and stored in buffer units 721 to 725. Since the basic priorities are determined in the order of the port processing units 711 to 715, data transmission is performed in the order of the packet data 11, 21, 31, and 41. Here, in the order of the packet data 51, the weighting counter value is “0”, so that the transmission order is skipped and the next packet data 12 is transmitted. Data is transferred by repeating the above operations until there is no more packet data.
[0013]
The advantage of this method is that even if the input data is of variable length, regardless of the size of the packet length, weighting is performed in fixed length units, that is, data capacity units, and data transfer is possible. It is. With this, when data transfer is performed with variable-length packet data and packets with greatly different data lengths are to be transferred, the weighting value of each port is the same, and even if the same number of packets is transmitted, the weighting counter of the weighting counter is used. Since the count unit is a packet unit, it is possible to prevent a state in which the transfer capacity of each port is several times larger. That is, as shown in FIG. 13, it is possible to prevent the port processing units 711 and 712 from performing weighted data transfer without dividing the variable-length packets, thereby preventing the transfer speed from becoming an open state. it can.
[0014]
Next, an example of the conventional method 2 is shown in FIG. In this system, weighting is not controlled on a fixed length or packet basis, but a transmission guarantee data capacity (for example, 10 bytes / one time) is provided by permitting one transfer, thereby controlling the transfer data capacity. In this method, when the scheduling unit 751 sends data from the buffer units 721 to 725, it keeps sending packets until it exceeds the transmission guaranteed data capacity. Then, when it is confirmed that the transmission of the halfway-transmitted packet is completed when the transmission guarantee data capacity is exceeded, the control shifts to the control of the next port. This method has a feature that even if input data has a variable length, scheduling can be performed according to weighting in units of data capacity without dividing the input data.
[0015]
FIG. 15 shows a state where data transfer is continued from the state shown in FIG.
[0016]
When the length of the data waiting for transmission is longer than the transmission guarantee data capacity or the same packet 11 is transmitted as in the port processing unit 711, the process proceeds to the processing of the next port after transmitting all the packets 11. . When the data length during transmission standby is smaller than the transmission guarantee data capacity as in the port processing unit 712, after transmitting the packet 22 following the packet 21, the processing shifts to the processing of the next port. The port processing units 713 and 714 perform the same processing as the port processing unit 712, and the port processing unit 715 performs the same processing as the port processing unit 711.
[0017]
[Patent Document 1]
JP-A-2002-217961
[0018]
[Problems to be solved by the invention]
FIG. 16 shows an example of a state before data transfer and FIG. 17 shows an example of a state after data transfer in the data transfer of the conventional method 1.
[0019]
In the conventional method 1, the scheduling process is performed by dividing into a fixed length. However, as shown in the weighting counter of the port processing unit 712 in FIG. 17, the counter value of the weighting counter becomes “0” during the transfer of one packet. ". At this time, the transmission of data from the buffer unit 722 is stopped until the counters of all the port processing units 711 to 715 become “0”. Therefore, as shown in FIG. The data transmission standby time from the previously transmitted data to the transmission of the remaining second half data is greatly increased.
[0020]
Since a circuit for monitoring the state after the transfer of the packet data is often installed at the subsequent stage of the data transfer circuit, if the transfer standby time becomes longer, a packet length error or a stop bit is lost in the monitor circuit. There is a possibility that an erroneous determination such as an error is made and an unnecessary alarm is generated. Further, in this method, it is necessary to construct a circuit for performing the dividing process and a circuit for performing the assembling process, so that there is a problem that the entire circuit scale becomes large.
[0021]
On the other hand, in the data transfer of the conventional method 2, an example of a state before the transfer is shown in FIG. 18, and an example of a state after the transfer (during the transfer) is shown in FIG.
[0022]
In the conventional method 2, the transfer data capacity is controlled by setting the transmission guarantee data capacity. The unit of data transfer is one packet data. Therefore, the time allocated to one port becomes relatively long. Therefore, as shown in the port processing units 714 and 715 in FIG. 19, when a packet having a long data length is input, the data transmission waiting time until the packet stored in each of the buffer units 721 to 725 is transmitted becomes long. . If the transmission waiting time is long, the transmission processing from the buffer units 721 to 725 is not performed, but new data is successively input from the input interface units 701 to 705, so that the transmission processing time as shown in FIG. It becomes the relation of the internal capacity of the buffer unit. Therefore, there is a possibility that the buffer section will eventually overflow.
[0023]
Similarly, even when the number of input ports increases, the transmission standby time before transmitting the packets stored in each buffer unit increases in proportion to the number of input ports. If the transmission waiting time of the packet becomes longer, the transmission process from the buffer unit is not performed, but since new data is input one after another from the input interface unit, there is a possibility that the buffer unit will eventually overflow.
[0024]
When the buffer overflow as described above occurs, the data transfer apparatus performs processing such as discard processing and retransmission request processing, so that the transmission efficiency of the entire transmission path is reduced.
[0025]
Therefore, the present invention has been made in view of the above-mentioned problems in the conventional data transfer device, and when transferring data from a plurality of input transmission lines to one output transmission line, the number of input transmission lines is large. In the event that a packet with a long packet length is input, or when a packet is divided, by reducing the transfer standby time, unnecessary alarms are prevented and buffer overflows are suppressed. It is an object of the present invention to provide a data transfer device which can increase transmission efficiency, cope with high-speed processing, and has a simple configuration.
[0026]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a data transfer device, comprising: a plurality of input ports; a plurality of buffer units for storing packet data input to each of the plurality of input ports; A weighting unit that sets a weight value in data transfer between ports based on a unit of read processing of the buffer unit, and determines a priority order for performing read processing on packet data stored in the buffer unit. And a scheduling unit for multiplexing the packet data according to the priority order, and an output port for outputting data transmitted from the scheduling unit to the outside.
[0027]
The present invention is characterized in that a weight value between input ports is set in a unit of a read process of a buffer unit (a unit of a buffer read). For example, n times of read processing to the buffer unit and the like are set as weighting values. Here, the data capacity that can be read in one read process varies depending on the type of the buffer unit and the like and is small, so that the minimum capacity at the time of data transfer is weighted.
[0028]
That is, according to the present invention, the data capacity that can be transmitted by the buffer unit of each port with one transmission right is one buffer read unit. Therefore, data transfer is performed by repeating the process of reading out to the buffer unit once for each port in the determined priority order. Thereby, the data transmission standby time of each port is averaged. Therefore, even when the number of input ports increases or when a lot of packet data having a long data length is input, the transmission standby time of each port becomes a constant standby time in proportion to the number of ports.
[0029]
FIG. 9 shows the relationship between the transfer time and the capacity in the buffer unit at this time. As can be seen from comparison with FIG. 20 in the case of the conventional method, a state in which buffer overflow is unlikely to occur is realized. However, when data is not stored in each buffer unit, the standby time becomes equal to or shorter than the average, and when the weight counter indicates “0”, that is, when the transfer is stopped by weighting, as will be described later. Time is the exception.
[0030]
As described above, in the present invention, by using the buffer read unit as the data transfer unit, the data capacity in one read process is small, and the read order is determined in that unit. The data transmission standby time is a fixed time. Also, the setting of the weighting is simplified.
[0031]
As a result, even when packet data having a long data length is input, the data transmission standby time is not affected, so that a buffer overflow due to an increase in the data transmission standby time can be suppressed. Even when the number of ports increases, the data transmission standby time is average and is not occupied by a single port, so that buffer overflow due to an increase in the data transmission standby time can be suppressed. it can.
[0032]
As described above, the transmission efficiency of the entire data transfer device can be improved to cope with high-speed processing, and a data transfer device having a simple configuration can be provided.
[0033]
In the data transfer device, a packet length recognition unit that recognizes packet length data of a packet stored in the buffer unit from output data output from the plurality of buffer units, and a packet length recognized by the packet length recognition unit. A packet counter unit that counts the capacity of the packet output from the buffer unit based on data; and a weight counter unit that counts output data from the buffer unit based on a weight value set by the weighting unit. Only when the counter values of the packet counter unit and the weighting counter unit both become "0", data can be prevented from being output from the buffer unit.
[0034]
As a result, even when the weight counter value becomes "0", if the packet length counter value does not become "0", the transfer prohibition signal is not transmitted, that is, the weight count becomes "0". When the transmission of all variable-length packet data transmitted to the CPU has been completed, a transfer prohibition signal is transmitted to stop the data transmission processing. Therefore, in the present invention, when performing weighted transfer in units of packet division, the state in which the packet is divided as in the conventional method 1 does not continue, and the data transmission standby in the divided state is not performed. Can be prevented from continuing for a long time.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0036]
FIG. 1 shows the overall configuration of a data transfer device according to the present invention. The data transfer device includes input interface units 11 to 1n for controlling input interfaces of packet data input from input ports P1 to Pn, A plurality of port processors 21 to 2n for performing control for storing and outputting the packet data input from the interface units 11 to 1n, and read out the packet data stored in each of the port processors 21 to 2n. Scheduling unit 31 that determines a priority order for performing processing, reads out packet data from each of port processing units 21 to 2n according to the determined priority order, multiplexes the packet data, and sends out the multiplexed packet data to output interface unit 41. And the data transmitted from the scheduling unit 31 to the output port P20. Composed of the output interface section 41 for outputting.
[0037]
When a packet is input from each of the input ports P1 to Pn, the input interface units 11 to 1n writes the packet data to the buffer units 211 to 21n of the corresponding port control units 21 to 2n.
[0038]
The plurality of port processors 21 to 2n have the same function and the same configuration. Thus, as an example, the configuration of the port processing unit 21 will be described with reference to FIG.
[0039]
Upon receiving the write control signal 521 from each input interface unit 11, the buffer unit 211 performs a write process and stores the input packet data 511. Further, the buffer unit 211 performs a read process according to a read control signal input from the scheduling unit 31, and the stored data is sent to the scheduling unit 31.
[0040]
The buffer monitoring unit 221 monitors the write control signal 521 from the input interface unit 11 to the buffer unit 211, and monitors the capacity of the buffer unit 211. When data is stored in the buffer unit 211, a read request signal 551 for requesting a data transmission instruction is issued to the scheduling unit 31. Further, the buffer monitoring unit 221 monitors the read control signal 611 to the buffer unit 211 and monitors the internal capacity of the buffer unit 211 based on the relationship with the write control signal 521. Further, when there is no more area for writing in the buffer unit 211, the buffer monitoring unit 221 sends a buffer full signal 631 to the scheduling unit 31 to inform that the writing to the buffer unit 211 is disabled. .
[0041]
The weight storage unit 231 stores the weight values in buffer read units (units of the reading process of the buffer unit 211), and the weight counter unit 241 obtains the weight values 571 from the weight storage unit 231 and sets the initial value of the counter. And Then, the weighting counter unit 241 performs a countdown process using the read control signal 611 sent to the buffer unit 211 as an input signal of the counter. At the same time, the weight counter 241 sends the weight count flag 561 to the transfer prohibition signal generator 271 as the logic of counting (for example, “High”). When the counter value becomes “0”, the weighting counter unit 241 informs the transfer prohibition signal generating unit 271 of the weight count flag 561 with the logic of counting end (for example, “Low”) to notify that the counting of the weighting value has ended. Send out. When the counter value becomes “0”, the weighting counter unit 241 holds the state of “0”, and upon receiving the count clear signal 531 from the scheduling unit 31, returns the counter to the initial value again and repeats the countdown process. .
[0042]
The packet length recognition unit 261 reads information about a packet from the output data 601 output from the buffer unit 211. As shown in FIG. 3, the packet data includes information on the packet length at the beginning of the packet. Therefore, the packet length recognition unit 261 shown in FIG. 2 monitors the start bit of the packet, Is stored. When recognizing the start bit, the packet length recognizing unit 261 gives a count start trigger 621 for notifying the packet counter unit 251 of the start of counting.
[0043]
Upon receiving the count start trigger 621 from the packet length recognizing unit 261, the packet counter unit 251 sets the packet length data 591 stored in the packet length recognizing unit 261 as an initial value and sends the read control signal The countdown process is started using 611 as the input signal of the counter. At the same time, the packet counter unit 251 sends the packet transmission flag 581 to the transfer prohibition signal generation unit 271 as logic during counting (for example, “High”). When the counter value becomes “0”, the packet counter 251 informs the transfer prohibition signal generator 271 of the completion of counting the packet transmission flag 581 (eg, “Low”) in order to notify that transmission of one packet has been completed. To send. When the counter value becomes “0”, the packet counter unit 251 holds the state of “0”, and when receiving the count start trigger from the packet length recognition unit 261 again, the packet counter unit 251 newly stores the count start trigger in the packet length recognition unit 261. The packet length data 591 is used as an initial value, and the countdown process is repeated.
[0044]
If the weight count flag 561 from the weight counter 241 has the logic of counting end and the packet transmission flag 581 from the packet counter 251 has the logic of counting end, the transfer prohibition signal generator 271 The transfer prohibition signal 541 is transmitted to the unit 31.
[0045]
Next, the scheduling unit 31 will be described with reference to FIG.
[0046]
When the read control unit 313 receives a read instruction signal 641 to one port processing unit (for example, the port processing unit 21) among the plurality of port processing units 21 to 2n from the priority order scheduling unit 312, By sending the read control signal 611 to the buffer unit 211 of the port processing unit 21 instructed, the data stored in the buffer unit 211 is read. The read control unit 313 repeats this process, performs multiplexing processing on the read output data 601 to 60n from the buffer units 211 to 21n, and transfers the multiplexed data to the output interface unit 41 as one multiplexed output data 651.
[0047]
If at least one of the read request signals 551 to 55n from each of the port processing units 21 to 2n is received, the priority scheduling unit 312 performs a scheduling process for determining a priority order for transferring data. The method of determining the priority order in the priority order scheduling unit 312 is as follows.
▲ 1 ▼. Follow the basic priority order determined as the initial condition. Here, it is not necessary to consider the weight between ports. For example, the packets are transmitted in the order of port processing unit 21, port processing unit 22, port processing unit 23,... Port processing unit 2n.
▲ 2 ▼. If no read request signal has been input from the port processors 21 to 2n, the order is skipped.
(3). When a transfer prohibition signal is input from the port processors 21 to 2n, the order is skipped.
▲ 4 ▼. When the processing is completed for all the ports according to (1) to (3), the processing returns to the top of the basic priority order, and the same processing is repeated.
[0048]
According to the above-described method, the priority order scheduling unit 312 sends a read instruction signal 641 for causing the read control unit 313 to execute a read process according to the determined order.
[0049]
When receiving the transfer prohibition signals 541 to 54n from all the port processors 21 to 2n, the count clear signal generator 311 returns the count counters of the port processors 21 to 2n to the initial values. Send 53n. When receiving at least one of the buffer full signals 631 to 63n from each of the port processors 21 to 2n, the count clear signal generator 311 sends out the count clear signals 531 to 53n to suppress buffer overflow.
[0050]
As shown in FIG. 1, the output interface unit 41 performs an output control process of outputting the packet data transmitted from the scheduling unit 31 to the output port P20.
[0051]
Next, the operation of the data transfer apparatus according to the present invention having the above configuration will be described with reference to FIGS.
[0052]
FIG. 5 shows an initial state of the data transfer device. As an initial setting, the weighting values are read into the weighting counter units 241 to 245 of the respective port processing units 21 to 25 in buffer read units, and are set as initial values of the counters. In order to simplify the description of the operation, the weighting value is set to a low value. The initial values of the values of the packet counters 251 to 255 are “0”. In the state illustrated in FIG. 5, packet data is input to the input interface units 11 to 15, the data is written into the respective port processing units 21 to 25, and the process of reading from the scheduling unit 31 is awaited. State.
[0053]
At this time, since a read request signal is issued from each of the port processors 21 to 2n (excluding the port processor 24) to the scheduling unit 31, the scheduling unit 31 performs the scheduling process. FIG. 6 shows a state after data transfer (not all transfer ends) when data transfer is started from the port processing units 21 to 2n (excluding the port processing unit 24) from the state of FIG.
[0054]
The scheduling unit 31 performs data transfer by performing data reading processing in the order of the port processing units 21, 22, 23, 24, 25, 21,... In accordance with the basic priority order. Therefore, as shown in FIG. 6, the actual reading order is the packet data 11, 21, 31. Here, in the buffer unit 214 of the port processing unit 24, since no packet data is stored, the port processing unit 224 does not send a read request signal to the scheduling unit 31. Therefore, the reading order is skipped, and the next packet data 51 is transferred.
[0055]
Further, as in the port processing unit 22, when the read processing of all the packet data 21, 22, and 23 stored in the buffer unit 212 is completed, the transmission of the read request signal to the scheduling unit 31 is stopped. Thereafter, the data is read out in the order of the packet data 33, 53, and 14, and when the order is next turned to the port processing unit 22, the reading order is skipped. As described above, the port processing unit in which no packet data is stored is skipped, and data transfer is performed.
[0056]
Further, the weighting counter units 241 to 245 perform a countdown process of the counter when the packet data is read out from the scheduling unit 31 and controlled. Taking the port processing unit 21 of FIG. 5 as an example, the countdown process is performed every time read control is performed from the initial value “10” (that is, data transfer is performed). After the ports 11, 12, 13, and 14 have been transmitted from the port processing unit 21, the counter value becomes "6".
[0057]
When the packet data is sent from the buffer units 211 to 215, the packet counter units 251 to 255 read the packet length information and use it as the initial value of the counter in buffer read units. Is the remaining packet capacity for one packet.
[0058]
Taking the port processing unit 21 of FIG. 5 as an example, when the packet data 11 is transmitted, “4” is fetched as the initial value of the counter of the packet counter unit 251, and “3” is set to start the countdown process at the same time. Value. Thereafter, each time the packet data is transmitted in buffer read units, the countdown processing is performed, so that after the packet data 11, 12, and 13 are transmitted from the port processing unit 21, the value becomes "1".
[0059]
Next, the operation performed when the counters of the weighting counters 241 to 245 become “0” and the counters of the packet counters 251 to 255 become “0” are illustrated before the data transfer. 7, and a state after data transfer will be described with reference to FIG.
[0060]
In FIG. 7, the port processing unit 21 is in a state where the counter value of the weight counting unit 241 is “1” or more, the counter value of the packet counting unit 251 is “0”, and the packet data is not stored in the buffer unit 211. It is. As described above, when no packet data is stored, the order of data transfer is skipped from the scheduling unit 31 regardless of the values of both counters.
[0061]
In the port processing unit 22, the counter value of the weight counting unit 242 is "1" or more, and the counter value of the packet counting unit 252 is also "1" or more. In this case, since the counter of the weighting counting unit 242 is not “0”, data transfer is performed from the scheduling unit 31 in the basic priority order, and the data transfer order is not skipped.
[0062]
In the port processing unit 24, the counter value of the weight counting unit 244 is “1” or more, and the counter value of the packet counting unit 254 is “0”. In this case, as in the case of the port processing unit 22, the counter of the weighting counting unit 244 is not "0", so that the data transfer is performed from the scheduling unit 31 in the basic priority order. No skip is performed.
[0063]
In the port processing unit 25, the counter value of the weight counting unit 245 is “0”, and the counter value of the packet counting unit 255 is also “0”. In this case, the data transfer order from the scheduling unit 31 is skipped, and no data transfer is performed.
[0064]
In the port processing unit 23, the counter value of the weight counting unit 243 is “0”, and the counter value of the packet counting unit 253 is “1” or more. As shown in FIG. 7, the counter value of the packet counting unit 253 indicates “3”, that is, since one packet is still being transferred, the counter value of the weighting counting unit 243 is “0”. ", The scheduling unit 31 does not skip the basic priority of data transfer for the packet data 31, 32, and 33. However, after the transmission of the packet data 33, the counter value of the packet counting unit 253 becomes “0” and the counter value of the weighting counting unit 243 is “0”. The order of data transfer is skipped, data transfer is not performed, and the state of the port processing unit 23 in FIG. 8 is set.
[0065]
As described above, the data transfer is stopped because the counter values of the weighting counters 243 and 245 are “0” and the counters of the packet counters 253 and 255 as shown in the port processors 23 and 25 in FIG. Only when the value is "0". That is, as in the port processing unit 23 of FIG. 7, even if the counter value of the weight counting unit 243 is “0”, if the counter value of the packet counting unit 253 is “1” or more, one packet Until the transfer is completed, the data transfer is not stopped. As a result, a state in which the state in which the packet data is divided continues does not occur.
[0066]
In this apparatus, the above operation is repeated, and when the counter values of all the weighting counters 241 to 245 become “0”, the counter values of all the weighting counters 241 to 245 are returned to the initial values, and the data transfer is continued.
[0067]
【The invention's effect】
As described above, according to the present invention, when data is transferred from a plurality of input transmission paths to one output transmission path, the transfer standby time is reduced even if the number of input transmission paths increases. It is possible to provide a data transfer device which can be shortened to prevent generation of unnecessary alarms, suppress occurrence of buffer overflow, increase transmission efficiency, support high-speed processing, and have a simple configuration. .
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a data transfer device according to the present invention.
FIG. 2 is a configuration diagram illustrating a port processing unit of the data transfer device of FIG. 1;
FIG. 3 is a diagram illustrating an example of a packet transferred by the data transfer device of FIG. 1;
FIG. 4 is a configuration diagram illustrating a scheduling unit of the data transfer device of FIG. 1;
FIG. 5 is an operation explanatory diagram of the data transfer device of FIG. 1;
FIG. 6 is an operation explanatory diagram of the data transfer device of FIG. 1;
FIG. 7 is an operation explanatory diagram of the data transfer device of FIG. 1;
FIG. 8 is an operation explanatory diagram of the data transfer device of FIG. 1;
FIG. 9 is a graph showing the relationship between the transfer processing time and the capacity of the buffer unit in the data transfer device according to the present invention.
FIG. 10 is an overall configuration diagram showing an example (conventional method 1) of a conventional data transfer device.
FIG. 11 is a diagram illustrating the operation of the data transfer device of FIG. 10;
FIG. 12 is an operation explanatory diagram of the data transfer device of FIG. 10;
FIG. 13 is a diagram for explaining a problem when data transfer is performed without dividing a packet.
FIG. 14 is an operation explanatory diagram showing another example (conventional method 2) of the conventional data transfer device.
FIG. 15 is an operation explanatory diagram of the conventional method 2.
FIG. 16 is an operation explanatory diagram for explaining a problem of the conventional method 1.
FIG. 17 is an operation explanatory diagram for describing a problem of the conventional method 1.
FIG. 18 is an operation explanatory diagram for explaining a problem of the conventional method 2.
FIG. 19 is an operation explanatory diagram for explaining a problem of the conventional method 2.
FIG. 20 is a graph showing a relationship between a transfer processing time and a capacity of a buffer unit in a data transfer device according to Conventional Method 2.
[Explanation of symbols]
11-1n input interface
21 to 2n port processing unit
211-21n buffer unit
221-22n buffer monitoring unit
231 to 23n weighting storage unit
241 to 24n weighting counter section
251 to 25n packet counter
261 to 26n Packet length recognition unit
271 to 27n transfer prohibition signal generator
31 Scheduling unit
311 Count clear signal generator
312 Priority scheduling unit
313 Read control unit
41 Output interface
511-51n Input packet data
521 to 52n Write control signal
531 to 53n count clear signal
542-54n transfer inhibit signal
551-55n read request signal
561 to 56n Weight count flag
571-57n Weight value
581-58n Packet transmission flag
601-60n output data
611-61n read control signal
621-62n count start trigger
631-63n buffer full signal
641 to 64n read instruction signal
P1 to Pn input port
P20 output port

Claims (2)

Multiple input ports,
A plurality of buffer units for storing packet data input to each of the plurality of input ports;
A weighting unit that sets a weight value in data transfer between the plurality of input ports based on a unit of read processing of the buffer unit;
A scheduling unit that determines a priority order for performing read processing on the packet data stored in the buffer unit, and multiplexes the packet data according to the priority order;
An output port for outputting data transmitted from the scheduling unit to the outside. A packet length recognition unit that recognizes packet length data of a packet stored in the buffer unit from output data output from the plurality of buffer units;
A packet counter unit that counts the capacity of the packet output from the buffer unit based on the packet length data recognized by the packet length recognition unit;
A weight counter unit that counts output data from the buffer unit based on a weight value set by the weight unit.
2. The data transfer according to claim 1, wherein data output from the buffer unit is not performed only when the counter values of the packet counter unit and the weighting counter unit both become "0". apparatus.

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