JP2011010195A - Input/output device for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a capacity necessary for a recorder and decrease a hardware scale in an input/output device for communication having a plurality of output ports.SOLUTION: The input/output device includes: a multiplexer which inputs respective communication data from a plurality of input ports and multiplexes the communication data by adding output destination information to the communication data; a recorder which has a plurality of logic recording areas (queues) corresponding to the output destination information, writes the communication data input from the multiplexer into the queues related to the output destination information and reads out the communication data from a predetermined queue; and a demultiplexer which designates a queue of the recorder to read out the communication data according to the priority order of a plurality of output ports, distributes the communication data read out from the designated queue to the output port corresponding to the output destination information and outputs the data after conversion to the speed of the output port.

Description

  The present invention relates to a communication input / output device that inputs and outputs a large amount of communication data (frames).

  In a communication input / output device that inputs and outputs communication data such as an Ethernet frame used in Internet communication or the like, a recording device (memory or the like) is usually used for each output port.

  The conventional communication input / output device shown in FIG. 6 has a configuration in which independent recording devices (MEMs) 51, 52, 53 are arranged between the input ports 1, 2, 3 and the output ports 1, 2, 3, respectively. It is.

  In the conventional communication input / output device shown in FIG. 7, the communication data of the input ports 1, 2, and 3 is time-division multiplexed by a multiplexer (MUX) 61 and further time-division multiplexed by a demultiplexer (DEMUX) 62. The communication data is demultiplexed and output to the corresponding output ports 1, 2, 3 via the recording devices (MEM) 63, 64, 65. The DEMUX 62 performs output port selection and priority control for each output port when demultiplexing.

  The conventional communication input / output device (Patent Document 1) shown in FIG. 8 distributes the communication data of the input port 1 to the recording devices (MEM) 72, 73, 74 via the distribution unit 71, and the corresponding output port 1 , 2 and 3.

JP 2008-227593 A

  The recording device (MEM) in the communication input / output device requires a larger size (capacity) as the physical rate (maximum data amount per unit time) of input communication data (frame) increases. The communication input / output devices shown in FIGS. 7 and 8 use three recording devices (MEMs) corresponding to the output ports 1, 2, and 3. When the number is increased, the amount of communication data input to the communication input / output device does not change, and the total size of the necessary recording devices increases in proportion to the number.

  It is an object of the present invention to reduce the capacity required for a recording apparatus and to reduce the scale of hardware in a communication input / output device having a plurality of output ports.

  In a communication input / output device for inputting / outputting communication data between a plurality of input ports and a plurality of output ports, the first invention inputs the communication data from each of the plurality of input ports, and outputs to each communication data. Multiplexing device that multiplexes each communication data by adding information and a plurality of logical recording areas (queues) corresponding to the output destination information, and communication data input from the multiplexing device is output to the output destination information The queue of the recording device that writes to the queue corresponding to the data and further reads the communication data from the predetermined queue and the queue of the recording device that reads the communication data according to the priority order of the plurality of output ports are read out from the designated queue. A demultiplexer that distributes the communication data to the output port corresponding to the output destination information, converts the output to the output port speed, and outputs the converted data.

  A second invention is a communication input / output device for inputting / outputting communication data between one input port and a plurality of output ports, inputting communication data from the input port, and adding output destination information to the communication data Output data and a plurality of logical recording areas (hereinafter referred to as “queues”) corresponding to the output destination information, and write communication data input from the input device to a queue corresponding to the output destination information. Further, a recording device that reads the communication data from a predetermined queue and a queue of the recording device that reads the communication data according to the priority order of the plurality of output ports are specified, and the communication data read from the specified queue is output. A demultiplexer that distributes to the output port corresponding to the destination information, converts the output port to the output port, and outputs the converted output port.

  In the communication input / output device according to the first or second invention, the plurality of queues of the recording device are set corresponding to the plurality of output ports, and are added to the communication data input to the recording device. The output destination information is information for designating a queue corresponding to the output port of the output destination, and the demultiplexer is configured to output communication data read from the designated queue to one corresponding output port. is there.

  In the communication input / output device according to the first or second invention, the plurality of queues of the recording device are set corresponding to the plurality of output ports and the plurality of output ports, respectively. The output destination information added to the communication data input to the recording device is information for specifying a queue corresponding to the output port of the output destination. The read communication data is output to one corresponding output port or a plurality of output ports.

  In the communication input / output device of the first invention or the second invention, the plurality of queues of the recording device correspond to the plurality of output ports and are set corresponding to the plurality of priorities. The output destination information added to the communication data input to the recording device is information for designating a queue corresponding to the output port of the output destination and priority, and the demultiplexing device is read from the designated queue. The communication data is output to one corresponding output port.

  In the communication input / output device of the first invention or the second invention, the plurality of queues of the recording device respectively correspond to a plurality of output ports and are set corresponding to a plurality of priorities, The output destination information added to the communication data input to the recording device is configured to have a queue that corresponds to a plurality of output ports and is set corresponding to each of a plurality of priorities. This is information for designating a queue corresponding to the priority, and the demultiplexing device is configured to output communication data read from the designated queue to a corresponding one or more output ports.

  In the communication input / output device according to the first or second invention, the priority order of the plurality of output ports is equal to the effective output rate indicating the data amount per unit time of the communication data output to the plurality of output ports. Or a standard for fairing so that the effective output rate of each output port is proportional to the physical rate of each output port. Further, an output port having a physical rate smaller than a predetermined value may be set with complete priority.

  The communication input / output device of the present invention receives communication data that is input from one or a plurality of input ports and is output to any one of a plurality of output ports or broadcast data that is broadcast to a plurality of output ports. By enabling writing to and reading from one recording device, the hardware scale can be reduced.

  The communication input / output device of the present invention sets a plurality of logical recording areas (queues) in the recording device, associates the plurality of output ports with the queue, and provides a queue corresponding to the plurality of output ports. In addition, by providing multiple queues according to the priority of output ports, priority control according to the physical rate and effective output rate of multiple output ports becomes possible, and between output ports with a simple and low-scale hardware configuration Can be ensured.

It is a figure which shows Example 1 of the input / output device for communication of this invention. 1 is a diagram illustrating a configuration example of a multiplexing device (MUX) 10. FIG. 2 is a diagram illustrating a configuration example of a recording device (MEM) 20 and a demultiplexing device (DEMUX) 30. FIG. It is a figure explaining Example 2 of the input / output device for communication of this invention. It is a figure explaining Example 3 of the input / output device for communication of this invention. It is a figure which shows the structural example 1 of the conventional input / output device for communication. It is a figure which shows the structural example 2 of the conventional input / output apparatus for communication. It is a figure which shows the structural example 3 of the conventional input / output device for communication.

FIG. 1 shows a first embodiment of a communication input / output device according to the present invention.
In FIG. 1 (1), the communication input / output device of this embodiment includes a multiplexer (MUX) 10 connected to a plurality of input ports 1, 2, 3 and a plurality of output ports 1, 2, 3. A demultiplexer (DEMUX) 30 to be connected and one recording device (MEM) 20 connected between the MUX 10 and the DEMUX 30 are configured. The MEM 20 has logical recording areas (queues) corresponding to the output ports 1, 2, and 3, respectively. The queue and the output port have a one-to-one correspondence as shown in FIG. Note that the number of input ports and the number of output ports may be different.

FIG. 2 shows a configuration example of the multiplexer (MUX) 10.
In FIG. 2, the MUX 10 includes queue designation information adding units 11, 12, and 13 connected to input ports 1, 2, and 3, and a multiplexing unit 14. The queue designation information adding units 11, 12, and 13 determine queue designation information indicating in which of the queues of the MEM 20 the communication data input from the input ports 1, 2, and 3 are recorded, and communicate the queue designation information. The data is added to the data and output to the multiplexing unit 14. The multiplexing unit 14 time-division multiplexes the communication data to which the queue designation information is added and outputs the communication data to the MEM 20.

  The queue designation information adding units 11, 12, and 13 can be realized by a bridge function such as IEEE802.1D. Specifically, output port search by MAC address learning, output port designation by VLAN ID, and the like are possible.

  The MUX 10 may be configured to add queue designation information after time-division multiplexing of communication data input from the input ports 1, 2, and 3. Further, when there is one input port, the MUX 10 may be configured as an input device having only a queue designation information adding unit.

FIG. 3 shows a configuration example of the recording device (MEM) 20 and the demultiplexing device (DEMUX) 30.
In FIG. 3, the MEM 20 includes a memory unit 21, a writing unit 22, a reading unit 23, and a queue map 24. The DEMUX 30 is composed of a speed conversion unit 33, 34, and 35 connected to the reading unit 31, the distribution unit 32, and the output ports 1, 2, and 3, respectively.

  The memory unit 21 of the MEM 20 has a plurality of queues individually corresponding to a plurality of output ports. This is realized by dividing the address of the memory unit 21 and determining the address range of each queue. The queue map 24 stores the corresponding head address and end address of each queue as mapping information. The address range of each queue may be determined in advance, or may be set by a control signal from, for example, an external control device.

  When there are a plurality of input ports of the communication input / output device, the output (write) to the MEM 20 requires a physical rate corresponding to the sum of the physical rates of all the input ports, and the output (read) from the MEM 20 Requires a physical rate corresponding to a value obtained by adding the physical rates of all output ports, but the MEM 20 can be configured by one memory unit 21.

  The writing unit 22 of the MEM 20 receives communication data to which queue designation information is added from the MUX 10, and the queue designation information, mapping information of the queue map 24, and read end address information (for example, output from the reading unit 23). The final address of the read communication data) is determined, the address to be written in the memory unit 21 is determined, and the input communication data is written in the address of the memory unit 21. After the communication data has been written, the written address information (for example, the start address and the final address of the frame) is output to the reading unit 23.

  The reading unit 23 of the MEM 20 refers to the queue information instructed from the DEMUX 30 as a reading instruction signal, the mapping information of the queue map 24, and the written address information output from the writing unit 22, and reads from the memory unit 21. The address is determined, the communication data written in the address of the memory unit 21 is read and output to the DEMUX 30. Further, referring to mapping information of the queue map 24 and information such as a written address output from the writing unit 22, whether or not there is communication data to be output to each queue is present Outputs the total accumulated data amount to the DEMUX 30 as queue information. Further, the read end address information is output to the writing unit 22.

  The reading unit 31 of the DEMUX 30 refers to the queue information output from the MEM 20 and the reading stop instruction signal output from the speed conversion units 33, 34, and 35, and indicates which queue communication data is read to the MEM 20. A read instruction signal is output, and communication data read from the MEM 20 is output to the distribution unit 32 in response to the read instruction signal.

  The distribution unit 32 determines an output port to be output according to the queue designation information added to the input communication data, and outputs the communication data to the speed conversion units 33, 34, and 35 connected to the output port. . The speed converters 33, 34, and 35 output the speed of the input communication data in accordance with the speed of the output port. Further, when the input speed is higher than the output speed, the speed conversion units 33, 34, and 35 output a read stop instruction signal for preventing buffer overflow to the read unit 31. Note that the queue designation information added to the communication data is deleted by the distribution unit 32 or the speed conversion units 33, 34, and 35.

  Further, the reading unit 23 of the MEM 20 calculates the frame size from information such as a written address output from the writing unit 22, and subtracts the already read value from the accumulated value for each queue of the frame size and the value. Thus, the amount of communication data stored in each queue can be calculated. The reading unit 23 may output the amount of communication data stored in each queue to the reading unit 31 of the DEMUX 30, and the reading unit 31 may instruct a queue having the largest storage amount to perform reading.

Here, the hardware scale of the communication input / output device of the present embodiment and the conventional communication input / output device shown in FIGS.
When comparing the communication input / output device of this embodiment with the conventional communication input / output device shown in FIG. 6, the hardware scale of this embodiment appears to be larger by the amount of MUX10 and DEMUX30. However, in an apparatus that handles a large amount of communication data, the hardware scale of the MUX 10 and the DEMUX 30 becomes relatively small with respect to the MEM 20 due to the integration of an integrated circuit (LSI). Since the capacity required for the MEM 20 is determined by the total value of the input physical rates of the respective queues, there is no difference between the configuration of this embodiment and the conventional configuration. However, since the statistical multiplexing effect is obtained by multiplexing with the MUX 10 in the configuration of this embodiment, the total capacity may be reduced as compared with the conventional configuration.

  Further, when the MEM in the communication input / output device is not built in the LSI but connected to another memory chip, it is desirable that the number of wirings used for connection between the LSI and the memory chip is as small as possible. . When the comparison is made under the condition that the clock rates of the signals used for connection to the memory chip are the same, the total number of data signals used for inputting / outputting data to / from the memory chip is the same between the configuration of this embodiment and the conventional configuration. . However, in the configuration of the present embodiment, only one system of address signals, write instruction signals, etc. is required, whereas in the conventional configuration shown in FIG. 6, as many address signals as the number of ports must be prepared. This also applies to the conventional communication input / output device shown in FIGS.

  By the way, in order to determine which communication data of a plurality of queues of the MEM 20 is to be output first, it is necessary to perform priority control. In a communication input / output device having a plurality of output ports, it is usually desired that the effective output rate (average data amount per unit time) for each output port is equal or fair according to the physical rate. However, since the output destination of input communication data may be biased to a specific output port, priority control must be performed in consideration of such a case.

  Here, since the physical rate of output (reading) of communication data from the queue is larger than the physical rate of each output port, the communication data cannot be continuously read from the same queue. For example, if the capacity of each queue is the same, priority control can be performed by outputting (reading) from the queue having the largest amount of communication data stored in the queue among the readable queues. it can.

  In addition, when there are ports with different physical rates among multiple output ports, priority control is performed by performing priority control so that the output of the output port with a physical rate smaller than the predetermined value is output with full priority. The hardware scale of the circuit is smaller than the conventional configuration. The reason is as follows. When the output rate differs depending on the output port, priority control is normally performed so that the effective output rate for each queue is proportional to the physical rate of the output port, and the effective output rate for each output port is made fair. In order to realize such a function, a function for counting the amount of communication data actually output for each queue is required. On the other hand, when the output of the output port whose physical rate is smaller than the predetermined value is output with complete priority, the count function as described above is unnecessary, and priority control can be realized with a simple circuit.

  Further, by incorporating means for displaying the physical rate for each output port in the reading unit 31 of the DEMUX 30, priority control can be performed as follows. The correspondence between the queue and the physical rate of the output port is determined by referring to the physical rate of the output port since the output port is determined by the queue. The output port with the smallest physical rate is confirmed among the queues in which the accumulation amount per queue is not 0, and a read stop instruction signal is sent from the speed conversion unit (33, 34, 35) of the DEMUX 30 connected to the output port. If not output (output enabled state), the queue corresponding to the output port is instructed to read. On the other hand, when the read stop instruction signal is output, the output port with the second lowest physical rate is confirmed in the queue whose accumulated amount for each queue is not 0, and the speed connected to the output port When the reading stop instruction signal is not output from the conversion unit (output permission state), reading is performed by instructing a queue corresponding to the output port. When a read stop instruction signal is output from the speed conversion unit connected to the output port corresponding to all the queues for which the accumulation amount for each queue is not 0, all the queues for which the accumulation amount for each queue is not 0 Wait until the output of any of the read stop instruction signals from the speed converter connected to the output port corresponding to the output port is stopped (output enabled state), and then instruct the queue corresponding to the corresponding output port to read. Do.

  When the output of an output port whose physical rate is smaller than a predetermined value is output with complete priority, whether or not there is fairness between output ports with different physical rates becomes a problem. For example, if one of the two output ports is 10 Gbit / s and the other is 1 Gbit / s, the communication data delay to the 10 Gbit / s output port is delayed even if the 1 Gbit / s side is given full priority. Since it does not become extremely large or the communication data is frequently discarded to the output port of 10 Gbit / s, it does not cause a problem effectively. In other words, assuming that all the communication data frame sizes are the same, a frame for a 1 Gbit / s output port can be read only once every 11 times due to the speed limitation of the output port. There is no problem because the frame for 10 Gbit / s output port is read out 10 times. Even if the frame size is random, reading of frames for an output port of 1 Gbit / s does not continue, and so on.

  The priority control rules as described above are determined at the time of designing the communication input / output device. For example, the priority control rules are set in advance in the reading unit 31 of the DEMUX 30, and the reading unit 31 of the DEMUX 30 sets the priority control rules. It shall be controlled based on the rules of control.

  The memory unit 21 of the MEM 20 of the communication input / output device according to the first embodiment has a plurality of queues individually corresponding to a plurality of output ports, as shown in FIG. Under the control of 23, communication data to be output to a predetermined output port is written to and read from the corresponding queue.

  As shown in FIG. 4, the memory unit 21 of the MEM 20 of the communication input / output device according to the second embodiment includes the queues 4 to 4 corresponding to a plurality of output ports in addition to the queues 1 to 3 individually corresponding to the output ports. 7 is installed. For example, the queue 4 corresponds to the output ports 1 and 2, and the queue 7 corresponds to the output ports 1, 2, and 3. This is used as a function for broadcasting the same communication data to a plurality of output ports.

  In the configuration of FIGS. 1 to 3, when the MUX 10 receives communication data (frame) with a multicast address, the MUX 10 displays queue designation information for designating the queues 4 to 7 corresponding to the output ports to be multicast. Append to The writing unit 22 and the reading unit 23 of the MEM 20 and the reading unit 31 of the DEMUX 30 control to write to the corresponding queues 4 to 7 and to read from the corresponding queues 4 to 7 according to the queue designation information.

  Furthermore, in the DEMUX 30, it is necessary to change the operation depending on the type of queue. If the queue to be read is a queue prepared for each output port, the read communication data is output from the corresponding output port. If the queues to be read are queues 4 to 7 corresponding to a plurality of output ports, the read communication data is output from a plurality of output ports predetermined for each queue. When outputting from a plurality of output ports, they may be output simultaneously from a plurality of output ports or may be output sequentially. When outputting from a plurality of output ports, the next reading is not performed until the output from all the ports to be output is completed. Alternatively, the next reading is not performed until the output from the reading unit 31 to the speed conversion unit connected to all the ports to be output of the DEMUX 30 is completed. Output destinations when outputting from a plurality of output ports may be determined in advance, or may be set by a control signal from an external control device, for example.

  In addition, priority control is complicated in this embodiment. In other words, it is difficult to control the fairness for each output port. For example, in order to reduce the probability of frame discard as much as possible, the amount of communication data stored in the queue is the largest among the readable queues. What is necessary is just to output (read) from the queue.

  As shown in FIG. 5, the memory unit 21 of the MEM 20 of the communication input / output device according to the third embodiment installs the queues individually corresponding to the output ports, for example, by dividing them into two read priorities (priority and non-priority). To do. For example, the queue 1-1 records communication data output with priority to the output port 1, and the queue 1-2 records communication data output with priority to the output port 1.

  In the configuration of FIGS. 1 to 3, when the MUX 10 receives communication data (frame) with a priority for each output port, the MUX 10 sets queue designation information for designating a queue corresponding to the output port and the priority. Append to communication data. The writing unit 22 and the reading unit 23 of the MEM 20 and the reading unit 31 of the DEMUX 30 control to write to the corresponding queue according to the queue designation information and to read from the corresponding queue. This enables priority control within the same output port. The distribution unit 32 of the DEMUX 30 outputs communication data to the output port specified by the queue specification information regardless of the priority.

  In the second embodiment, as shown in FIG. 4, in addition to the queues 1 to 3 individually corresponding to the output ports, queues 4 to 7 corresponding to a plurality of output ports (broadcast) are installed. As shown in the third embodiment, these queues may be divided into two read priorities (priority and non-priority), for example. Thereby, priority control can be performed within the same output port for communication data output to each output port and communication data broadcast to a plurality of output ports.

10 Multiplexer (MUX)
11, 12, 13 Queue designation information adding unit 14 Multiplexing unit 20 Recording device (MEM)
21 Memory Unit 22 Writing Unit 23 Reading Unit 24 Queue Map 30 Demultiplexer (DEMUX)
31 Reading unit 32 Distribution unit 33, 34, 35 Speed conversion unit

Claims (8)

In a communication input / output device that inputs and outputs communication data between a plurality of input ports and a plurality of output ports,
A multiplexing device that inputs communication data from each of the plurality of input ports, adds output destination information to each communication data, and multiplexes each communication data;
A plurality of logical recording areas (hereinafter referred to as “queues”) corresponding to the output destination information; the communication data input from the multiplexing device is written into a queue corresponding to the output destination information; A recording device for reading the communication data from the queue;
Specify the queue of the recording device that reads the communication data according to the priority of the plurality of output ports, distribute the communication data read from the specified queue to the output port corresponding to the output destination information, and A communication input / output device comprising: a demultiplexer that converts the output port speed into an output. In a communication input / output device for inputting / outputting communication data between one input port and a plurality of output ports,
An input device that inputs communication data from the input port, adds output destination information to the communication data, and outputs the communication data;
A plurality of logical recording areas (hereinafter referred to as “queues”) corresponding to the output destination information; the communication data input from the input device is written into a queue corresponding to the output destination information; and a predetermined queue A recording device for reading the communication data from
Specify the queue of the recording device that reads the communication data according to the priority of the plurality of output ports, distribute the communication data read from the specified queue to the output port corresponding to the output destination information, and A communication input / output device comprising: a demultiplexer that converts the output port speed into an output. The communication input / output device according to claim 1 or 2,
The plurality of queues of the recording device are configured to correspond to the plurality of output ports,
The output destination information added to the communication data input to the recording device is information specifying a queue corresponding to the output port of the output destination,
The communication demultiplexer is configured to output communication data read from the designated queue to a corresponding output port. The communication input / output device according to claim 1 or 2,
The plurality of queues of the recording device are configured to have a queue set corresponding to each of the plurality of output ports and a queue set corresponding to the plurality of output ports,
The output destination information added to the communication data input to the recording device is information specifying a queue corresponding to the output port of the output destination,
The communication demultiplexer is configured to output communication data read from the designated queue to a corresponding output port or a plurality of output ports. The communication input / output device according to claim 1 or 2,
The plurality of queues of the recording device correspond to the plurality of output ports, respectively, and are configured to be set for each of a plurality of priorities.
The output destination information added to the communication data input to the recording device is information specifying a queue corresponding to the output port of the output destination and priority,
The communication demultiplexing device is configured to output communication data read from the designated queue to a corresponding output port. The communication input / output device according to claim 1 or 2,
The plurality of queues of the recording apparatus correspond to the plurality of output ports, respectively, and are set corresponding to the plurality of priorities, and correspond to the plurality of output ports, and each of the plurality of priorities. A configuration with correspondingly configured queues,
The output destination information added to the communication data input to the recording device is information specifying a queue corresponding to the output port of the output destination and priority,
The communication demultiplexer is configured to output communication data read from the designated queue to a corresponding output port or a plurality of output ports. The communication input / output device according to claim 1 or 2,
The priority order of the plurality of output ports is a standard that equalizes the effective output rate indicating the data amount per unit time of communication data output to the plurality of output ports, or the effective output rate of each output port is each output. An input / output device for communication, characterized in that it is set on the basis of fairness so that it is proportional to the physical rate of the port. The communication input / output device according to claim 7,
An input / output device for communication, characterized in that an output port having a physical rate smaller than a predetermined value is set with full priority.

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