JP2004007255A - Network band control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress missing of packets in data transmission between networks. <P>SOLUTION: The network band control apparatus 11 changes a frequency band of data 13 integrated in a packet 12 received from a LAN 1 via a transmission reception circuit 9 and transmits the resulting data to a WAN 2 via a transmission reception circuit 10. The network band control apparatus 11 includes: a number of stop data counter 14 for repetitively counting the number of data received from the transmission reception circuit 9 until the number reaches a specified number M of data; a number of stop data calculation section 18 for calculating the number of stop date C<SB>R</SB>for the specified number of data M on the basis of an externally designated operating frequency band and a data frequency band of received data; a number of stop data counter 16 for counting the number of stop data every time completing count of the specified number of data; a stop signal transmission section 17 for transmitting a stop signal f of the data to the transmission reception circuit 9 for a period when the number of stop data is counted; and a data buffer 15 for storing the received data for the stop signal output period until a stop signal release time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a network relay device for relaying between networks, and more particularly, to a network relay device that is incorporated in the network relay device and changes a frequency band corresponding to a transmission speed of data input from one network to another network. The present invention relates to a network band control device for sending to a network band.
[0002]
[Prior art]
For example, as shown in FIG. 5, a network relay device 3 that relays data transmission between a LAN 1 that performs high-speed data communication on the order of G1 bps and a WAN 2 that performs low-speed data communication on the order of 200 to 300 Mbps has been put to practical use. ing. Each data is transmitted and received on the LAN 1 and the WAN 2 in a state of being incorporated in a packet.
[0003]
The network relay device 3 incorporates a transmission / reception circuit 4 for transmitting / receiving packets to / from the LAN 1 and a transmission / reception circuit 5 for transmitting / receiving packets to / from the WAN 2. Each of the transmission / reception circuits 4 and 5 converts the received packet into a frequency band corresponding to the transmission speed of the transmission destination and converts the frequency band corresponding to the transmission speed of the received packet to the transmission / reception circuits 5 and 4 of the other party. I do.
[0004]
In such a network system, when various kinds of information are transmitted from the information providing server 6 connected to the LAN 1 to the user terminal 7 connected to the WAN 2, for example, the speed of data output from the information providing server 6 ( In the case where the frequency band is 1 Gbps and the data speed (frequency band) that can be processed by the user terminal 7 is 200 Mbps, the network relay device, which is the entrance where the speed drops if transmission continues from the information providing server 6 as it is. The data received at 3 overflows without processing. Therefore, when the number of packets transmitted to the WAN 2 within the unit time reaches a predetermined limit number of packets that can be processed by the terminal 7 in the network relay device 3, the data is transmitted to the information providing server 6 of the transmission source via the LAN 1. By transmitting a transmission stop command, data transmission from the information providing server 6 is stopped for a predetermined period of time.
[0005]
[Problems to be solved by the invention]
However, the following problems still need to be solved in the network relay device 3 shown in FIG.
[0006]
That is, as described above, the data transmitted on the LAN 1 and the WAN 2 are each incorporated into a packet and transmitted. However, the number of data to be incorporated in each packet can be arbitrarily set by a designer. Therefore, the packet length of each packet is not constant. For example, the packet length of a packet output from one information providing server 6 is set to be long, and the packet length of a packet output from another information providing server 6 is set to be short.
[0007]
As described above, even if packets having an inconsistent packet length (number of data) are collected by the above-mentioned limit number of packets, the total number of data greatly fluctuates. However, the next data transmission stop time is constant. In this case, if the total number of data becomes larger than the number of data that can be processed by the user terminal 7, unprocessed data remains in the terminal 7 even after the next data transmission suspension time elapses, and the packet including the data is transmitted. Loss occurs.
[0008]
In this case, the user terminal 7 transmits a packet retransmission request to the information providing server 6. The information providing server 6 retransmits the same packet, but if retransmission of the same packet occurs frequently, the data transmission efficiency decreases.
[0009]
Further, in the network relay device 3 shown in FIG. 5, when data is relayed from the high-speed LAN 1 to the low-speed WAN 2, the transmission speed (frequency band) is reduced to the maximum data processing capacity of each terminal 7 connected to the WAN 2. It is converted to the corresponding transmission speed (frequency band).
[0010]
In general, when a user of each terminal 7 uses a network for a fee, it tends to be expensive if communication is performed at a high speed (a wide frequency band). However, some users of each terminal 7 consider that a lower price is better, even if the speed is low (the frequency band is narrow). The network relay device 3 of FIG. 5 cannot cope with such a request.
[0011]
The present invention has been made in view of such circumstances, and by stopping data input by the separately calculated stop data number each time data sequentially input from the network reaches the specified data number, even if a high speed Even when data is relayed from a network to a low-speed network, packet loss can be significantly suppressed, data transmission efficiency can be improved, and a user can select a desired transmission speed (frequency band). It is an object to provide a control device.
[0012]
[Means for Solving the Problems]
According to the present invention, a frequency band of data incorporated in a packet input from a first network via a first network transmission / reception circuit is changed and transmitted to a second network via a second network transmission / reception circuit. It is a network bandwidth control device.
[0013]
Further, in the network band control device according to the present invention, a data number counter for repeatedly counting the number of data input from the first network transmission / reception circuit until the number of data reaches a predetermined specified data number; A stop data number calculation unit for calculating a stop data number for a specified data number from a frequency band and a frequency band of data input from the first network transmitting / receiving circuit, and each time the data number counter finishes counting the specified data number A stop data number counter for counting the number of stop data calculated by the stop data number calculation unit, and sending data to the first network transmitting / receiving circuit during a period when the stop data number counter is counting the number of stop data. A stop signal sending unit for outputting a stop signal for instructing stop, and a first network during a stop signal output period. And a data buffer for holding data inputted from the click receiving circuit to the stop signal cancel time.
[0014]
In the network bandwidth control device configured as described above, for each data incorporated in a packet input from the first network via the first network transmission / reception circuit, the frame of each packet is removed by the data number counter. Counting is repeated until the specified number of data is reached in the state. Further, the number of stop data with respect to the specified number of data is calculated from the used frequency band specified from the outside and the frequency band of the data input from the first network transmitting / receiving circuit. More specifically, when the specified number of data is input via the first network transmission / reception circuit, the number of data when the data input is maintained in the stopped state is the number of stopped data.
[0015]
Therefore, for example, a user of a terminal connected to a low-speed network can specify a low-speed transmission rate (frequency band) other than the high-speed transmission rate (frequency band) corresponding to the maximum data processing capability of the own terminal. .
[0016]
When calculating the number of stop data with respect to the prescribed number of data, when the user specifies a used frequency band that is half the frequency band of the data output from the first network transmission / reception circuit, the number of stop data is equal to the prescribed number of data. If the user specifies the same frequency band as the frequency band of the data output from the first network transmitting / receiving circuit, the number of stopped data becomes zero.
[0017]
The stop data number counter starts counting the calculated stop data number each time the counting of the specified data number in the data number counter is completed. While the counting of the number of stop data is being performed, a stop signal is transmitted to the first network transmitting / receiving circuit. Therefore, no data is input to the second network transmission / reception circuit during the output period of the stop signal.
[0018]
The number of stop data is determined by the used frequency band specified by the user, the frequency band of data output from the first network transmitting / receiving circuit, and the specified number of data as described above, and the number of data to be incorporated in the packet. Does not depend at all. Therefore, in the terminal connected to the second network that has received the data, it is possible to prevent unprocessed data from remaining in the terminal even after the elapse of the data reception suspension period, and suppress packet loss.
[0019]
According to another aspect of the present invention, the stop data number counter in the network bandwidth control device according to the above invention is configured to stop data based on a clock of a data reception clock signal transmitted from the second network transmission / reception circuit to the first network transmission / reception circuit. Count the number.
[0020]
In the network bandwidth control device according to another aspect of the present invention, the transmission of the data reception clock signal is stopped while the data transmission stop request is being input from the second network to the second network transmission / reception circuit.
[0021]
In the network bandwidth control device configured as described above, for example, when a data processing load increases in a terminal connected to the second network and a data transmission stop request is output from the terminal, the data transmission stop request During the output period, the transmission of the data reception clock signal is stopped.
[0022]
As a result, since the count value of the stop data number counter does not advance during this transmission stop period, the stop signal to the first network transmission / reception circuit maintains the output state. Therefore, no data is output from the first network transmission / reception circuit during the data transmission stop request output period from the terminal.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a network system in which a network band control device according to an embodiment of the present invention is incorporated. The same parts as those of the conventional network system shown in FIG. 5 are denoted by the same reference numerals, and detailed description of the overlapping parts will be omitted.
[0024]
For example, a network relay device that relays data transmission between a LAN 1 as a first network that performs high-speed data communication on the order of Gbps and a WAN 2 as a second network that performs low-speed data communication on the order of 200 to 300 Mbps 8 are connected. An information providing server 6 for providing various information is connected to the LAN 1, and a user terminal 7 is connected to the WAN 2. As shown in FIG. 3, each data is transmitted and received on the LANL1 and the WAN2 while being incorporated in a packet. That is, in each successive packet 12, a plurality of data 13 is incorporated between the start flag at the head and the end flag at the end. Each of the start flag, the end flag and each data is formed by 8 bits. The packet length of the packet 12 is a value obtained by adding the start flag and the end flag at both ends to the number of data. In this embodiment, both the start flag and the end flag are regarded as one data 13.
[0025]
In the network relay device 8, a transmission / reception circuit 9 as a first network transmission / reception circuit for transmitting / receiving each data 13 incorporated in the packet 12 to / from the LAN 1 and each of the transmission / reception circuits 9 incorporated in the packet 12 to the WAN 2 A transmission / reception circuit 10 as a second network transmission / reception circuit for transmitting / receiving data 13 and a network band control device 11 are incorporated.
[0026]
The transmission / reception circuit 9 for the LAN 1 converts a transmission speed (frequency band) of, for example, 1 Gbps (Hz) of the packet 12 in which each received data 13 is incorporated into a transmission speed (frequency band) of 622 Mbps (Hz), and performs network band control. Send it to the device 11.
[0027]
The transmission / reception circuit 10 for the WAN 2 transmits, via the WAN 2, each packet 12 in which each data 13 in which the transmission speed (frequency band) received from the network band control device 11 is converted to the specified transmission speed (frequency band) is incorporated. It is transmitted to the user terminal 7.
[0028]
A data signal “a”, which is continuous from the data 13 and constitutes the packet 12 shown in FIG.
[0029]
The transmission / reception circuit 10 connected to the WAN 2 is, as shown in FIGS. 2 and 3, a data reception clock signal for receiving each data 13 of the data signal a output from the transmission / reception circuit 9 connected to the LAN 1. c is transmitted to the transmission / reception circuit 9. Therefore, the clock cycle of the data reception clock signal c is equal to the transmission cycle of each data 13 of the data signal a output from the transmission / reception circuit 9. The data reception clock signal c is sent to the stop data number counter 16 in addition to the transmission / reception circuit 9.
[0030]
Further, the user terminal 7 connected to the WAN 2 disconnects the WAN 2 when data processing for each data 13 incorporated in each packet 12 of the data signal g supplied from the transmission / reception circuit 10 via the WAN 2 is delayed. A data transmission stop request signal b is transmitted to the transmission / reception circuit 10 via the transmission / reception circuit 10. The transmission / reception circuit 10 interrupts the transmission of the data reception clock signal c to the transmission / reception circuit 9 during the period T _S during which the data transmission stop request signal b is input.
[0031]
The data number counter 14 counts each data 13 of the packet 12 included in the input data signal a in a state where the framework of each packet 12 is removed. When the data number M (= 128) is reached, a count-up signal d is sent to the stop data number counter 16 and the stop signal output unit 17, as shown in FIG. Thereafter, the count value (the number of data) is reset, and the counting of the number of data is restarted.
[0032]
The set value α of the use frequency band (use transmission speed) desired by the user of the terminal 7 is input from the use band setting unit 19 to the stop data number calculation unit 18. The set value α of the used frequency band is shown as a ratio to the transmission speed B (= 622 Mbps) of the data signal a input from the transmission / reception circuit 9 to the network band control device 11, as shown in FIG. . For example, when the operating frequency band is equal to the transmission speed B of the data signal a, the set value α is 1, and when the operating frequency band is half the transmission speed B of the data signal a, the set value α is 0.5. It is.
[0033]
The stop data number calculation unit 18 calculates the stop data number C for the specified data number M (= 128) using the set value α of the used frequency frequency band and the specified data number M (= 128) by the following equation. _R is calculated.
[0034]
C _R = M (1−α) / α
According to this equation, as shown in FIG. 4, when the used frequency frequency band (used transmission speed) is equal to the transmission speed B of the data signal a, the set value α is 1 and the number of stop data _CR is 0. . Further, when the use frequency frequency band (used transmission rate) is half of the transmission rate B of the data signals a, setpoint α is 0.5, stop data number C _R is equal to the prescribed number of data M. Furthermore, when the use frequency frequency band (used transmission rate) is 1/3 of the transmission rate B of the data signals a, setpoint α is 0.33, stop data number C _R is twice the prescribed number of data M Become.
Stop data number calculation unit 18 sets the stop data number C _R for the calculated specified number of data M (= 128) to stop the data counter 16.
[0035]
As shown in FIG. 2, when the count-up signal d for the specified data number M (= 128) is input from the data number counter 14, the stop signal output unit 17 outputs a high (H) level stop signal f to the transmission / reception circuit. 9 and transmission to the data buffer 15 is started.
[0036]
At the same time, as shown in FIG. 2, when the count-up signal d for the specified data number M (= 128) is input from the data number counter 14, the stop data number counter 16 counts the number of clocks of the data reception clock signal c, that is, Start counting the number of stop data. Then, the stop data number counter 16 sends the signal e to the stop signal output unit 17 during the counting period of the high (H) level. Further, stopping the data counter 16, the count value of the clock reaches the stop data number C _R, to release the counting period in the signal e to the low (L) level, clears the count value of the clock to zero.
[0037]
As shown in FIG. 2, when the signal e is released to the low (L) level during the counting period, the stop signal output unit 17 sends the high (H) level stop signal to the transmission / reception circuit 9 and the data buffer 15. f is released to the low (L) level. That is, the stop data number counter 16, is output only stop signal f period that counts the stop data number C _R.
[0038]
Reception circuit 9, high (H) level period stop signal f is input, i.e., a period corresponding to the stop data number C _R stops sending the data 13. Then, when the stop signal f is released to the low (L) level, the transmission of the data 13 is restarted. The transmission / reception circuit 9 sends a transmission stop request of the packet 12 to the information providing server 6 which is the transmission source of the packet 12 via the LAN 1 while the transmission of the data 13 is stopped.
[0039]
Since the stop signal f is output once each time the data 13 of the specified data number M (= 128) is input, the data signal a output from the transmission / reception circuit 9 is the data signal a of the specified data number M (= 128). 13 is output continuously, then the output for a period corresponding to the stop data number C _R is stopped, then the M (= 128) signal form the pieces of data 13 is continuously output.
[0040]
Each data 13 of the data signal a output from the transmission / reception circuit 9 is delayed by one data time in a data buffer 15 composed of, for example, a FIFO memory, and then, as shown in FIG. Input to the circuit 10.
[0041]
Considering the details, after detecting the specified data number M (= 128) th data 13, the stop signal f rises to the high (H) level, so that only the next data (next leading data) 13 to be stopped is The data is output and input to the data buffer 15. The next head data 13 input to the data buffer 15 should be sent to the other transmitting / receiving circuit 10 after being delayed by one data time, but at the point of time when the data buffer 15 is delayed by one data time. Is applied with a stop signal f of a high (H) level, the next head data 13 is stored and held in the data buffer 15, and when the stop signal f is set to a low (L) level, the subsequent data 13 is input to the other transmitting / receiving circuit 10 as a new data signal g.
[0042]
The transmission / reception circuit 10 transmits a data signal g having a specified use frequency band (use transmission speed) input from the other transmission / reception circuit 9 via the data buffer 15 to the user terminal 7 via the WAN 2. . The user terminal 7 receives and processes each data 13 of each packet 12 included in the data signal a having the use frequency band (use transmission rate) designated by the user.
[0043]
Further, as shown in FIG. 2, in a period T _S of the terminal 7 of the user is outputting data transmission stop signal b, as described above, the data reception clock signal c is not transmitted to the receiving circuit 9. As a result, in the transmission suspension period T _S , the count value of the suspension data number counter 16 does not advance, and the suspension signal f to the transmission / reception circuit 9 maintains the high (H) level output state. Therefore, data 13 is not output from transmission / reception circuit 9 during the period of data transmission stop request output signal b from terminal 7. Therefore, the data 13 is not input from the transmission / reception circuit 10 to the terminal 7 via the WAN 2.
[0044]
Further, in the network bandwidth control device 11 configured as described above, the stop data number calculation unit 18 determines the use frequency band setting value α specified by the user of the terminal 7 connected to the WAN 2 and the transmission / reception circuit 9. stop data number C _R and a frequency band of the input data for the prescribed number of data M (= 128) is calculated.
[0045]
In this way, the user of the terminal 7 can arbitrarily specify the used frequency band (transmission speed). Therefore, for example, a user of the terminal 7 connected to the low-speed WAN 2 specifies a low-speed transmission speed (frequency band) other than the high-speed transmission speed (frequency band) corresponding to the maximum data processing capacity of the terminal 7 itself. it can. As a result, it is possible to select a network usage fee according to the transmission speed (frequency band).
[0046]
The calculated stopping data number C _R is sent to the stop data counter 16. The stop data number counter 16 starts counting a new specified data number M (= 128) every time the counting of the specified data number M (= 128) ends. During this counting, the stop signal f is transmitted to the transmission / reception circuit 9. Therefore, no data 13 is input to the transmission / reception circuit 10 during the output period of the stop signal f.
[0047]
Here, the stop data number _CR is determined by the use frequency band specified by the user, the frequency band of the data output from the transmission / reception circuit 9, and the specified data number M, and is equal to the data number of the data 13 incorporated in the packet 12. Does not depend at all.
[0048]
Therefore, once the frequency band to be used is specified based on the instruction of the user of the terminal 7 connected to the WAN ₂ , the ratio (M / C _R ) between the specified data number M and the stopped data number CR does not change. in terminal 7 data 13 is connected to the WAN2 which receives each packet 12 built, that unprocessed data remains in the terminal 7 even after the data reception stop period corresponding to the stop data number C _R Thus, the disappearance of the packet 12 is suppressed. As a result, the frequency of retransmission of the packet 12 is reduced, and the data transmission efficiency is improved.
[0049]
Note that the present invention is not limited to the embodiment described above. The stop data number counter 16 for counting the stop data number CR in the embodiment counts the stop data number CR by counting the clock of the data reception clock signal c. The clock of the generated clock signal may be counted.
[0050]
【The invention's effect】
As described above, in the network bandwidth control device of the present invention, data input is stopped by the separately calculated stop data number each time data sequentially input from the network reaches the prescribed data number.
[0051]
Therefore, even when data is relayed from a high-speed network to a low-speed network, packet loss can be greatly suppressed, data transmission efficiency is improved, and a transmission rate (frequency band) desired by a user is desired. Can be selected.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a network system in which a network band control device according to an embodiment of the present invention is incorporated; FIG. 2 is a time chart showing an operation of the network band control device of the embodiment; FIG. 4 is a diagram illustrating a frame configuration of a packet input / output to / from the network bandwidth control device according to the embodiment. FIG. 4 is a diagram illustrating a method of calculating the number of stop data in the network bandwidth control device according to the embodiment. Block diagram showing a schematic configuration of a conventional network system.
1 ... LAN
2… WAN
6 Information providing server 7 Terminal 8 Network relay device 9 10 Transmission / reception circuit 11 Network bandwidth control device 12 Packet 13 Data 14 Data number counter 15 Data buffer 16 Stop data number counter 17 Stop signal Sending unit 18: Stop data number calculating unit 19: Used band setting unit

Claims (3)

The frequency band of the data (13) incorporated in the packet (12) input from the first network (1) via the first network transmitting / receiving circuit (9) is changed to change the frequency band of the second network transmitting / receiving circuit (10). ) To the second network (2) via the network bandwidth control device (11),
A data number counter (14) for repeatedly counting the number of data input from the first network transmitting / receiving circuit until the number of data reaches a specified data number specified in advance;
A stop data number calculation unit (18) for calculating a stop data number with respect to the specified data number from a use frequency band specified from the outside and a frequency band of data input from the first network transmission / reception circuit;
A stop data number counter (16) that counts the stop data number calculated by the stop data number calculation unit each time the data number counter ends counting the specified data number;
A stop signal sending unit (17) for outputting a stop signal for instructing the first network transmitting / receiving circuit to stop sending data while the stop data number counter is counting the stop data number;
A network bandwidth control device comprising: a data buffer (15) for holding data input from the first network receiving circuit during an output period of the stop signal until a stop signal release time. 2. The stop data number counter counts the stop data number based on a clock of a data reception clock signal transmitted from the second network transmission / reception circuit to the first network transmission / reception circuit. The network bandwidth control device according to any one of the preceding claims. 3. The network band control device according to claim 2, wherein the transmission of the data reception clock signal is stopped while the data transmission stop request is being input from the second network to the second network transmission / reception circuit.

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