JP2002135287A - Band limit circuit, communication device, communication network system, and band limiting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band limit circuit and band limiting method, capable of limiting a band at a PHY layer level in a communication network system as well as a communication device and communication network system capable of limiting a band for every communication line, by solving the problem of a band being difficult to be limited for each communication line which is provided to a user, because it is not possible to determine whether a plurality of packets have been transmitted on the same communication line. SOLUTION: A cycle counter 3 counts the number of clocks CLKA generated by frequency-dividing a transmission clock CLK. A comparator circuit 7 outputs a clear signal B1, when the count value exceeds the holding value of a cycle register 5. A limit counter 4 counts the number of clock CLKB of AND of an effective frame signal A1 and the clock CLKA. An over limit detecting circuit 8 outputs a limit exceedance detecting signal B3, when the count value B2 exceeds the holding value of a limit register 6. An effective frame signal control circuit 9 controls, when the over limit detecting signal B3 is inputted, so that the effective frame signal A1 is invalidated and outputs an effective frame signal A3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to IEEE802.
The present invention relates to a band limiting circuit, a communication device, a communication network system, and a band limiting method for forming a frame in synchronization with a transmission clock to limit a transmission amount of data to be transmitted in a communication network system conforming to a three-series standard or the like.

[0002]

2. Description of the Related Art In recent years, a LAN (local area network) has been constructed not only in a premises such as a company or a university, but also in a condominium or other apartment complex or in a general home. These LANs are usually connected to the Internet or other LANs via public networks or leased lines, thereby providing WAN access.
(Wide area network) will be established. The line connecting the LANs to construct this WAN is called a backbone (backbone) line, but its transmission speed (transmission band) is generally lower than the transmission speed in the LAN. For example, in a LAN conforming to the IEEE 802.3 series standard, 10 Mbit / sec, 100 Mbit / sec.
It is possible to communicate at a transmission speed of 1 Gbit / sec or the like, but it is 64 Kbit / sec or 1.5 Mbit / sec in an ISDN line often used as a backbone line. As a backbone line,
Although high-speed dedicated lines can be used, there is a problem that the usage fee is high. For this reason, in order to match the transmission band of the backbone line, the transmission band on the output side of the backbone line is limited in the LAN. In the following description, the transmission band may be simply referred to as a band.

FIG. 10 shows a conventional band limiting method.
It is a block diagram which shows the example of a structure of the communication network system (LAN41) which restricts the transmission band on the backbone line output side. The LAN 41 includes switching hubs 43-1 to n (n; an integer of 1 or more), which are communication devices, and a router 42.
, A router 42 and a switching hub 43
Each of −1 to n is connected by an upper communication line 102. Each of the switching hubs 43-1 to 43-n connects a plurality of lower communication lines 101, and the PC 33, the server 34, and the like are connected via the respective communication lines 101. The router 42 is connected to a backbone line 103 for connecting the LAN 41 to another communication network such as the Internet or a LAN.

[0004] The LAN 41 is a communication network system conforming to the IEEE 802.3 series standard.
The switching hubs 43-1 to 43-n are connected to a destination MAC (Media
Access Control) Forwards packets based on addresses. The router 42 is connected to a destination IP (Internet Protocol).
col) Forward the packet based on the address. As a result, in the LAN 41, a packet transmitted from the PC 33, the server 34, or the like is transferred based on the destination address (MAC address and IP address) added to the header of the packet. At this time, the router 42 sends the packet destined for the external network to the backbone line 1
03, the transmission amount of data to be output to the backbone line is limited by a conventional band limiting method.

[0005] As this conventional band limiting method, for example, in the receiving buffers of the switching hubs 43-1 to n in the router 42, received packet queue management is individually performed based on the destination IP address, and the queue management unit is used. A method is known in which a packet is read from the reception buffer and output to the backbone line, and the reception buffer reading speed for each queue management unit is determined so that the speed (band) read from the reception buffer falls within the transmission band of the backbone line. ing. Also, as another method,
TCP (Transmission Control P) added to the packet
There is a method of controlling the communication speed between nodes by rewriting the window size value of the (rotocol) header. Also, the flow rate of data to be output to the backbone line is measured in units of the queue management, and when the transmission bandwidth of the backbone line is likely to be exceeded, the PAUSE frame specified by the IEEE 802.3 series standard is used to transmit the data. There is also a method of interrupting packet transmission to the node.

[0006]

However, in the above-described conventional bandwidth limiting method, the router 42 shown in FIG.
The bandwidth is limited as the processing of the P layer, but the processing of the TCP / IP layer is generally performed by a CPU (Central Processing Unit). When the CPU performs the bandwidth limiting processing in addition to the packet transfer processing, the router There is a problem that the processing capacity required for the CPU of 42 increases.

[0007] By the way, an Internet connection provider (Internet service provider) requests the following for its own LAN for providing a communication line (Internet connection line) for connecting to a user to the Internet. There is. (1) In order to set a fee for a user according to the available transmission band of the Internet connection line, it is possible to perform a fine band limitation for each Internet connection line. (2) The transfer processing capability of the router and the transmission band of the backbone line can be gradually increased in accordance with the increase in the total required transmission band of the Internet connection line contracted with the user. (3) The transmission bandwidth of the backbone line caused by an excessive transmission load applied by a malicious user can be avoided.

In order to meet the requirements (1) to (3), it is necessary for the LAN to be able to limit the bandwidth for each Internet connection line provided to the user. However, when the router performs band limiting as processing of the TCP / IP layer as in the related art, it is difficult to perform band limiting for each communication line provided to the user. The reason for this is that when a plurality of packets with different IP addresses are multiplexed and transmitted on one communication line, the TCP /
This is because it is not possible to identify whether the plurality of packets are packets transmitted on the same communication line in the processing of the IP layer. Therefore, in order to easily limit the bandwidth for each communication line provided to the user, it is necessary to limit the bandwidth at the PHY (physical) layer level in the LAN.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a band limiting circuit and a band limiting method capable of performing band limitation at a PHY layer level in a communication network system. It is in. Another object of the present invention is to provide a communication device and a communication network system capable of performing band limitation for each communication line.

[0010]

According to a first aspect of the present invention, there is provided a band limiting circuit for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock. Wherein a value based on the transmission clock is counted within a valid period of the frame, and data is transmitted until the count value reaches a predetermined limit value. According to the present invention, it is not necessary to refer to header information of a transmitted packet when restricting transmission of transmitted data, and an effect is obtained that a band can be restricted at a PHY layer level in a communication network system. . Further, by changing the predetermined limit value, the band can be freely limited from a state where the band limit is zero at the maximum.

According to a second aspect of the present invention, there is provided a band limiting circuit for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock using a reference clock based on the transmission clock. Cycle measuring means for measuring a cycle, limit measuring means for measuring the cumulative count value of the reference clock number during the valid period of the frame in the predetermined cycle, and comparing the cumulative count value with a predetermined limit value, And an excess limit detection unit for detecting an excess of the transmission amount, wherein the transmission of the data is limited based on a detection result of the excess limit detection unit. According to the present invention, it is not necessary to refer to header information of a transmitted packet when restricting transmission of transmitted data, and an effect is obtained that a band can be restricted at a PHY layer level in a communication network system. . Further, by changing the predetermined limit value, the band can be freely limited from a state where the band limit is zero at the maximum.

According to a third aspect of the present invention, in the first or second aspect of the present invention, there is provided a frame control means for invalidating the frame based on a result of the detection of the excess transmission amount limit. It is characterized by. According to the present invention, it is possible to easily limit the amount of data transmission, and it is possible to reduce the size of the band limiting circuit.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the frame control means continues the frame until the end of the frame when the transmission amount limit excess is detected. I do. ADVANTAGE OF THE INVENTION According to this invention, the effect that the occurrence of communication failures due to frame discard due to band limitation can be reduced is obtained.

According to a fifth aspect of the present invention, there is provided a communication apparatus connected to one or more communication lines, wherein at least one of the communication lines has a communication line side. It is characterized by comprising the band limiting circuit described in the paragraph. According to the present invention, it is possible to provide a communication device that limits the bandwidth of a predetermined communication line.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the band limiting circuit is provided on either the input side or the output side of the communication line, or on both the input side and the output side. It is characterized by doing. With this invention,
The effect of being able to provide a communication device that more efficiently limits the bandwidth of a predetermined communication line can be obtained.

According to a seventh aspect of the present invention, in a communication device connected to a communication network, the PHY layer processing unit and the M
An interface portion with the AC layer processing section is provided with a band limiting circuit for limiting a data transmission amount within a predetermined period. With this invention, a standard PHY
It is possible to realize a communication device that limits the bandwidth only by adding a band limiting circuit without changing the circuit configurations of the layer processing unit and the MAC layer processing unit. Therefore, the circuit configuration of the communication device can be simplified, and the cost can be reduced. The advantage of being excellent in merit is obtained.

According to an eighth aspect of the present invention, in the fifth or sixth aspect of the present invention, the band limiting circuit comprises:
It is characterized in that it is provided at the interface between the PHY layer processing unit and the MAC layer processing unit. According to the present invention, in addition to the effects described in the first to fourth aspects, the band limitation is performed only by adding the band limitation circuit without changing the circuit configuration of the standard PHY layer processing unit and the MAC layer processing unit. Since the communication device that performs the communication can be realized, the circuit configuration of the communication device can be simplified, and an advantage that cost merit is excellent can be obtained.

According to a ninth aspect of the present invention, there is provided a communication network system comprising a router and a switching hub and connected to at least one communication line on each of an upper side and a lower side. A band limiting circuit according to any one of the above items 4 is provided. According to the present invention, the transmission amount of data output to a communication line connected to a communication network can be limited, and the communication line can be used efficiently. According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the band limiting circuit is provided in at least one or more lower communication lines. According to the present invention, the transmission amount of data input from the lower communication line can be limited, and as a result, the transmission amount of data output to the upper communication line can also be limited. It is possible to construct a communication network system capable of freely setting the maximum transmission amount of the lower input communication line irrespective of the setting of the communication device connected to the lower communication line. The effect that it can be obtained is obtained.

The invention according to claim 11 is a band limiting method for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock, wherein the band limiting method comprises the steps of: A step of obtaining an accumulated count value of a reference clock number based on the transmission clock during a frame valid period; a step of detecting an excess of the transmission amount based on the accumulated count value; and Limiting the data transmission. According to the present invention, it is not necessary to refer to header information of a transmitted packet when restricting transmission of transmitted data, and an effect is obtained that a band can be restricted at a PHY layer level in a communication network system. .

According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, the band limiting method comprises the step of invalidating the frame within the predetermined period after detecting that the transmission amount has been exceeded. Is further included. According to the present invention, an effect is obtained that the amount of data transmission can be easily limited.

According to a thirteenth aspect, in the twelfth aspect, the bandwidth limiting method further includes a step of continuing the frame until the end of the frame when the excess of the transmission amount is detected. It is characterized by the following. ADVANTAGE OF THE INVENTION According to this invention, the effect that the occurrence of a communication failure due to frame discard due to band limitation can be reduced can be obtained.

According to a fourteenth aspect of the present invention, there is provided a bandwidth limiting method for limiting a transmission amount of data transmitted by forming a frame, wherein the bandwidth limiting method measures real time within a predetermined cycle. A step of determining a transmission amount of data within the period, a step of detecting an excess of a transmission amount of data based on the measurement result of the real time and the transmission amount of the data, and Limiting the data transmission. According to the present invention, it is not necessary to refer to header information of a transmitted packet when restricting transmission of transmitted data, and an effect is obtained that a band can be restricted at a PHY layer level in a communication network system. . Further, by causing a computer to execute a program for performing the above-described processes, an effect of increasing the degree of freedom of the configuration for performing the band limiting process can be obtained. Furthermore, even if there is a change in the required specification of the band limitation, it is only necessary to modify the program, and it is possible to flexibly respond without changing the hardware configuration.

According to a fifteenth aspect of the present invention, in the invention of the fourteenth aspect, the band limiting method further includes a step of obtaining a time difference between a start time of the cycle and a current time as a real time in the cycle. It is characterized by including. According to the present invention, when a general-purpose computer or the like having a clock function is used as a communication device, an effect that a band limiting function can be easily realized by software without providing a dedicated timer for real time measurement. can get.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the band limiting circuit 12 according to one embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the communication device 11 according to the first embodiment of the present invention. The communication device 11 includes the band limiting circuit 12 shown in FIG. Is realized. First, FIG.
The communication device 11 to which the band limiting circuit 12 of FIG. 1 is applied will be described with reference to FIG. In this FIG.
Reference numerals -1 and 2 denote band limiting circuits having the same configuration as the reference numeral 12 in FIG. 1. The band limiting circuit 12-1 limits the amount of data transmitted from the input line 100-1. -2 limits the amount of data transmitted to the output line 100-2. Symbol 13 is IEEE80
M that performs processing of the MAC layer specified by the 2.3 series standard
The AC layer processing unit. Reference numeral 14 indicates IEEE802.3.
A PHY layer processing unit that performs PHY layer processing specified by the stream standard; a receiver 15 that receives data input from the input line 100-1; and a descrambling and decoding process on the output of the receiver 15 , A coding / scrambler 17 for coding and scrambling the data to be output to the output line 100-1, and an output of the coding / scrambler 17 To the output line 100-1. These band limiting circuits 12-1,
2. The PHY layer processing unit 14 and the MAC layer processing unit are connected to a CPU (Central Processing Unit) (not shown) via a control signal A2, and are controlled by the CPU.

In the communication device 11 shown in FIG.
The interface connecting the HY layer processing unit 14 and the MAC layer processing unit is defined by the IEEE 802.3 series standard and is called MII (Media Independent Interface) or GMII (Giga Media Independent Interface). is there. These MII and GMII define specifications such as a transmission clock, data to be transmitted, and an effective frame signal. Differences between the MII and the GMII are mainly the speed of the transmission clock and the bit width of the transmission data. . Although the case where the MII is used is shown in the communication device 11 of FIG. 2, the GMII can be used similarly. FIG. 3 is a waveform diagram showing an example of the timing relationship between the transmission clock, the transmission data, and the effective frame signal in the MII, and shows the signals (RX_CLK, A1-1, RX_D0 to RX_CLK) received from the input line 100-1.
3 shows the timing relationship, the signals (TX_CLK, A1-2,
TX_D0-3). Note that the valid frame signals A1-1 and A1-2 referred to here are IEEE
It refers to the RX_DV signal and the TX_EN signal defined in the E802.3 series standard. Also, MII has
Error signals RX_ER, TX_ER, collision detection signal CO
L, carrier detection signal CRS, etc. are also defined,
Here, the description thereof is omitted.

FIG. 3A shows the transmission clock RX_CLK.
FIG. 6 is a waveform chart showing the waveform of FIG. FIG. 3B is a waveform diagram showing the waveform of the effective frame signal A1-1. FIG. 3 (3)
FIG. 7 is a waveform diagram showing waveforms of 4-bit width data RX_D0 to RX_D3 to be transmitted. Note that the data RX_D0 to RX_D3
Is formed and transmitted in a frame having a structure defined by the IEEE 802.3 series standard, and FIG. 3 (3) shows a part of the frame structure. In addition, FIG.
With respect to the effective frame signal A1-1 shown in FIG.
As shown in these figures, the effective frame signal A1-1 and the data RX_D0 to RX_D0 are transmitted clock RX_CLK
And the effective frame signal A1-1 is
X_D0 to X_3 indicate frame validity periods. In a conventional communication device that does not include the band limiting circuits 12-1 and 12-1, the effective frame signals A1-1 and A1-2 are M
Since the data is input to the AC layer processing unit 13 and the PHY layer processing unit 14, the data TX_D0 to TX_D3 within the frame valid period determined by the valid frame signal A1-2 is output to the output line 100-2.

The communication device 11 shown in FIG. 2 includes band limiting circuits 12-1 and 12-1 at the connection portion between the PHY layer processing unit 14 and the MAC layer processing unit 13, and provides the valid frame signals A1-1 and A1- 2 to control the effective frame signal A3
-1 and A3-2 are input to the MAC layer processing unit 13 and the PHY layer processing unit 14 so as to limit the band at the PHY layer level. The communication device 11
Is configured to include the band limiting circuits 12-1 and 12-2 on both the input line side and the output line side. Depending on the necessity of the band limiting function, either the input line side or the output line side may be used. You may make it prepare for only one side.

Next, the configuration of the band limiting circuit 12 for realizing band limiting at the PHY layer level will be described with reference to FIG. 1, the transmission clock CLK input to the band limiting circuit 12 is the transmission clock RX_C of FIG.
LK or TX_CLK, and the valid frame signal A
1 corresponds to the valid frame signal A1-1 or A1-2, and the valid frame signal A3 corresponds to the valid frame signal A3-
1 or A3-2. The band limiting circuit 12
2 corresponds to the control signal A2 in FIG.

In FIG. 1, reference numeral 1 denotes a transmission clock C
This is a frequency dividing circuit that divides LK by a predetermined number of times to generate a clock CLKA. Reference numeral 2 denotes an AND circuit that generates a clock CLKB based on a logical product of the clock CLKA and the valid frame signal A1. Reference numeral 3 denotes a clock CLK.
A cycle counter for counting the number of clocks of A. Reference numeral 4 denotes a limit counter that counts the number of clocks CLKB and outputs a count value B2. Code 5
Is a cycle register for holding a cycle count number corresponding to the band limitation period. Here, the band limitation cycle refers to a cycle indicating a time unit for limiting a transmission amount of data to be transmitted. Reference numeral 6 denotes a limit register that holds a limit value corresponding to an allowable transmission amount of data transmitted within the band limitation period. Reference numeral 7 compares the count value of the cycle counter 3 with the cycle count number held in the cycle register 5, and when the count value of the cycle counter 3 exceeds the value held in the cycle register 5,
This is a comparison circuit that outputs a clear signal B1.

Reference numeral 8 denotes an over-limit detection that outputs an over-limit detection signal B3 when the count value B2 exceeds the limit value held in the limit register 6 and the transmission amount of data to be transmitted exceeds the limit. Circuit. Symbol 9 is
When the excess limit detection signal B3 is input, the valid frame signal control circuit controls the newly input valid frame signal A1 to indicate that the frame is invalid and outputs the invalid frame signal A3. A control interface unit 10 performs various settings for each block in the band limiting circuit 12 based on the input control signal A2. The control interface unit 10 sets the number of divisions of the frequency dividing circuit 1, sets the values held in the cycle register 5 and the limit register 6, and resets each block.

The clear signal B1 output from the comparison circuit 7 resets the cycle counter 3, limit counter 4, and excess limit detection circuit 8. The interval between the pulses of the clear signal B1 indicates the band limitation period. The count value B2 of the limit counter 4 is the cumulative count value of the number of “reference clocks (CLKA) based on the transmission clock (CLK)” during the valid period of the frame within the band limitation period, that is, the amount of data to be transmitted. Since the output of the excess limit detection signal B3 is determined by the value, the limit value set in the limit register 6 corresponds to the allowable transmission amount of data transmitted within the band limitation period.

In the band limiting circuit 12, the cycle counter 3, the cycle register 5, and the comparison circuit 7 correspond to cycle measuring means. The AND circuit 2 and the limit counter 4 correspond to a limit measuring unit.
The excess limit detection circuit 8 and the limit register 6 correspond to excess limit detection means, and the valid frame signal control circuit 9 corresponds to frame control means.

In the above-described band limiting circuit 12, the frequency dividing circuit 1 is provided to divide the frequency of the transmission clock CLK.
The frequency-divided clock CLKA is used as a reference clock for band limitation. For example, in the communication device 11, the transmission clock RX_CLK input to the band limiting circuit 12 as the transmission clock CLK is a reference clock in units of 4-bit data. Is set to 1/8), the clock CLKA becomes a reference clock of 32 bits (4 bytes) data unit. The transmission clock CLK itself may be used as the “reference clock based on the transmission clock” without providing the frequency dividing circuit 1. However, the frequency dividing circuit 1 is provided and the transmission clock CLK is used according to the accuracy required for the band limitation. By generating the clock CLKA having the frequency division ratio and using it as the reference clock, the bit width of each of the counters 3 and 4 and each of the registers 5 and 6 can be reduced, and the scale of the band limiting circuit 12 can be reduced. it can.

Next, the operation of the band limiting circuit 12 will be described with reference to FIGS. FIG. 4 shows the band limiting circuit 12.
FIG. 4 is a waveform chart showing waveforms of respective parts of FIG. First, the frequency dividing circuit 1 outputs a clock CLKA obtained by dividing the input transmission clock CLK by a predetermined number of times. The cycle counter 3 counts the number of clocks of the clock CLKA.
Compares the count value of the cycle counter 3 with the value held in the cycle register 5. On the other hand, the limit counter 4 counts the number of clocks of the clock CLKB based on a logical product of the clock CLKA and the input valid frame signal A1, and outputs a count value B2.

Next, it is assumed that the count value of the cycle counter 3 exceeds the value held in the cycle register 5, and the comparison circuit 7 outputs the pulse P1 of the clear signal B1 shown in FIG. This pulse P1 causes the cycle counter 3,
The limit counter 4 and the limit excess detection circuit 8 are reset, and the respective operations are restarted. Then, FIG.
When the pulse F1 of the valid frame signal A1 shown in (2) is input, the AND circuit 2 inputs the clock CLKB shown in FIG. 4 (3) corresponding to the input section of the pulse F1 to the limit counter, and Counts the number of clocks of the input clock CLKB. At this time, the valid frame signal control circuit 9 outputs the pulse F1 of the input valid frame signal A1 as it is as the valid frame signal A3 because the excess limit detection signal B3 is not input.

Next, similarly, the limit counter 4
Counts the number of clocks of the clock CLKB corresponding to the input section of the pulse F2 of the effective frame signal A1, and counts the pulse number P2 of the clock CLKB.
It is assumed that 2 exceeds the limit value held in the limit register 6. The over-limit detection circuit 8 that detects this over-limit,
The over-limit detection signal B3 shown in FIG. The valid frame signal control circuit 9 receiving the excess limit detection signal B3 outputs the pulse F of the valid frame signal A1 being input.
Only the frame corresponding to 2 outputs the pulse F2 as it is as the effective frame signal A3 in order to continue the effective period until the end of the effective period.

Next, the pulse F of the effective frame signal A1
When 3 is input, the valid frame signal control circuit 9 invalidates the frame by not outputting the pulse F3 as the valid frame signal A3. As a result, data corresponding to the pulse F3 is not transmitted. Next, when the count value of the cycle counter 3 exceeds the value held in the cycle register 5, that is, the band limit period ends, and the comparison circuit 7 outputs the pulse P3 of the clear signal B1 shown in FIG. 3. The limit counter 4 and the over-limit detection circuit 8 are reset, and the over-limit detection circuit 8 does not output the over-limit detection signal B3.

By the way, the cycle count set in the cycle register 5 is a value indicating the band limitation period, but is also a value indicating the total transmission amount of data transmitted within the band limitation period. For example, if cycle register 5 is 1
If the register has a 6-bit width, the maximum cycle count that can be set is 0xffff (= 2 ¹⁶ −1 = 6).
5535), and assuming that the clock CLKA is a reference clock in units of 4-byte data as in the example of the above paragraph number 0026, the maximum bandwidth limitation period is 262144 (=
This corresponds to a data transmission amount of 65536 × 4) bytes. Further, the limit value set in the limit register 6 indicates the allowable transmission amount of data transmitted within the band limit period, so that the set value of the cycle register 5 is “B” and the set value of the limit register 6 is “C”. , And the bandwidth limit set value is defined as the bandwidth usage rate Y, the bandwidth usage rate Y becomes “C
/ B ”. Therefore, if C and B are set to the same value, the band usage rate Y becomes “1” (= 100%), and there is no band limitation. If C is set to a value that is half of B, the band usage rate Y becomes “0.5” (= 50).
%), And the band limitation ratio is set to 50%.

For example, the frequency division set value of the frequency division circuit 1 is set to “7”.
, The frequency of the frequency division is eight (that is, the frequency division ratio is 1 /
8), the clock CLKA has 32 bits (4
Byte) It becomes a reference clock in data unit. In this case, the cycle count number of the cycle register 5 is set to 0x1.
When fff (= 8191) is set, the band limiting period becomes 3
This corresponds to a data transmission amount of 2768 (= 8192 × 4) bytes. Then, 0x0 is set to the limit value of the limit register 6.
When fff (= 4095) is set, the transmission allowance of data transmitted within the band limitation period is 16384 (= 4099).
6 × 4) bytes, and a band limitation of 50% is performed. Usually, the band limiting period is 8192 to 6553
The frequency dividing circuit 1 corresponds to a data transmission amount of 6 bytes.
And the cycle count number of the cycle register 5 are determined.

The transmission speed of the input line 100-1 and the output line 100-2 in FIG. 2 may be either 10 Mbits / sec or 100 Mbits / sec. , The setting values of the band limiting circuit 12 (the frequency division setting value of the frequency dividing circuit 1, the cycle count number of the cycle register 5, and the limit value of the limit register 6) may be the same. However, when the band limitation is performed based on the maximum transmission speed, it is necessary to set a setting value according to the transmission speed of 10 Mbits / sec or 100 Mbits / sec. This is because, even if the maximum transmission rate is the same, the transmission rate is different, so that the band usage rate has a different value. For example, when the maximum transmission rate is 1 Mbit / s, the bandwidth usage rate is 10% when the transmission rate is 10 Mbits / second, whereas the bandwidth usage rate is 1% when the transmission rate is 100 Mbits / second.

The setting error of the band limitation depends on the band limitation period. The longer the band limitation period, the smaller the setting error. The generation of the setting error is caused by the process of activating the last frame when the band limitation occurs. In the case of Ethernet (registered trademark), the maximum frame length is 151.
The maximum error is 8 bytes. For example, when the bandwidth limitation period is set to 32768 bytes, the maximum error is 4.6.
%, And 0.6% when the band limitation period is set to 262144 bytes, so that highly accurate band limitation can be realized.

The above-mentioned band limiting circuit 12 outputs the effective frame signal A1 as it is as the effective frame signal A3 from the start of the band limitation period to the time when the limitation is detected. The transmission amount of the data transmitted without outputting the effective frame signal A1 is limited. This makes it possible to maintain the burstiness of data to be transmitted by forming a frame, as compared to the case where the amount of data transmission is limited by being dispersed within the band limitation period. Therefore, if the set value of the cycle register 5 is determined according to the burst length required for the communication apparatus to which the present embodiment is applied, the bandwidth can be limited while satisfying the required burst length. This is more useful for transmitting packets with higher transmission efficiency when transmitting with a longer packet length.

In the above-described embodiment of the band limiting circuit, the data transmission amount is determined based on the accumulated count value (count value B2) of the number of “reference clocks based on the transmission clock” during the frame validity period within the band limiting period. Is detected, and the amount of data transmitted is limited based on the detection result. This eliminates the need to refer to the header information of the transmitted packet when restricting the amount of data to be transmitted, and allows band limitation at the PHY layer level in the communication network system. Here, the PHY layer level is defined as I
In addition to the PHY layer specified by the EEE802.3 series standards, OSI (Open System
ms Interconnection) A layer corresponding to the PHY layer of the reference model.

Further, based on the result of the detection of the data transmission amount exceeding the limit, after the detection of the excess of the limit, the valid frame input within the band limitation period is invalidated, thereby limiting the transmission amount of the data to be transmitted. . This makes it possible to easily limit the amount of data transmission and reduce the scale of the band limiting circuit.

Further, by making only the newly input valid frames the frames to be invalidated after the detection of the excess of the data transmission limit, it is possible to reduce the occurrence of communication failures due to frame discard due to band limitation.

It should be noted that the above-mentioned band limiting circuit 12 is provided with an effective frame signal control circuit 9 (frame control means) for invalidating a frame within the band limiting period after detecting that the transmission amount has been exceeded. However, instead, the PA specified in the IEEE 802.3 series standard
The transmission node may be configured to interrupt the transmission of the packet using the USE frame.

The band limiting circuit according to the above-described embodiment is also characterized in that the upper limit of the line speed is not limited.
That is, even when the present band limiting circuit is added,
If the band limitation is released, the line can be used up to the upper limit of the inherent speed. For example, in the band limiting circuit 12 shown in FIG. 1, by setting the set value of the limit register 6 larger than the set value of the cycle register 5, it is possible to use the line speed up to the upper limit. The reason is,
This is because the case where the bandwidth limit is exceeded does not exist, and as a result, the bandwidth limitation is released, and the line can be used up to the upper limit of the speed originally possessed. Alternatively, it is possible by controlling the excess limit detection circuit 8 from the control interface unit 10 shown in FIG. 1 so that the excess limit detection signal B3 is invalidated.

Next, an embodiment of the communication apparatus 11 shown in FIG. 2 to which the above-mentioned band limiting circuit 12 is applied will be described. FIG.
FIG. 3 is a block diagram showing a configuration of a switching hub 21 with a band limiting function which is an embodiment of the communication device 11. This switching hub 21 with a band limiting function is an IEEE80
It conforms to 2.3 series standards. In FIG. 5, reference numeral 22 denotes a switching hub 21 with a band limiting function.
Is a CPU that controls each block. Reference numeral 23 denotes a first PHY unit including a plurality of PHY layer processing units 14 shown in FIG.
Connected to 1. Reference numeral 24 denotes a band limiting unit including a plurality of band limiting circuits 12-1 and 12-2 connected to the PHY layer processing unit 14 of the first PHY unit, similarly to the configuration shown in FIG.

Reference numeral 25 denotes a switching circuit connected to the plurality of band limiting circuits 12-1 and 12-2 of the band limiting unit 24 and the second PHY unit 26. The switching circuit 25 has a destination MAC address added to the header of the input packet. The packet is transferred based on the packet. This switching circuit 25 corresponds to M
Corresponds to the AC layer processing unit. Reference numeral 26 denotes a second PHY unit including the PHY layer processing unit 14, and the PHY layer processing unit 14 of the second PHY unit is connected to the communication line 102. The communication line 102 may have the same transmission band as the communication line 101, or may have a transmission band larger than the communication line 101. Further, the second PHY unit includes a plurality of PHY layer processing units 14, and a plurality of communication lines 1
02 may be connected.

The CPU 22 is connected to another device (not shown), and receives various settings (such as settings related to band limitation) for the switching hub 21 with a band limiting function from the connected device. As a connection method, a device that performs various settings on the switching hub 21 with the band limiting function transmits a packet addressed to the CPU 22 via the communication line 101 or 102, and the switching circuit 25 transfers the packet to the CPU 22. There is a method of connecting by communication. Alternatively, the CPU 22 and its device are connected to the RS-2
There is also a method of directly connecting with a 32C interface or the like.
If connection is made by packet communication, various settings can be made to the switching hub 21 with a band limiting function by a remote CPU via a communication network.

Switching hub 21 with band limiting function
, A packet input from each communication line 101 is transmitted to a communication line 102 based on its destination MAC address.
The packet output from the communication line 102 is output to one of the communication lines 101 based on the destination MAC address. Here, in the band limiting unit 24, the band limiting circuit 12-1 limits the band of the input line of the communication line 101 as described above. This allows the band limiting unit 24 to limit the band of the input line for each communication line 101, and can arbitrarily limit the transmission amount of data output to the communication line 102. In the band limiting unit 24, the band limiting circuit 12-
2 limits the bandwidth of the output line of the communication line 101. For example, the switching hub 21 with the band limiting function is
The front end of the communication line 101 has a transmission rate of 100 per second
If the backbone of the communication line 102 has an M bit × 8 port and the transmission speed of 1000 Mbit / s × 1 port, the amount of data flowing into the backbone will be 800 Mbit / s as it is. If the band limit rate is set to 50% on the side, the amount of data flowing into the backbone can be limited to 400 Mbits / sec.

The bandwidth limiting section 24 limits the bandwidth of both the input and output lines of the communication line 101. However, in response to a bandwidth limiting request of the communication network in which the switching hub 21 with the bandwidth limiting function is used. Thus, only one of the band limiting circuits 12-1 and 12 may be provided. In the switching hub 21 with the band limiting function described above, the first PHY unit and the switching circuit 2
5, a band limiting circuit 12-1,
2, the interface between the second PHY unit and the switching circuit 25 is provided with a band limiting circuit 12-.
It is also possible to provide both or one of the two.
As a result, the amount of data output to the higher-level communication line 102 can be limited, so that the load on a communication device such as a router that bundles the higher-level communication line 102 can be reduced. By selecting the router or the like, the cost of the network equipment can be reduced.

FIG. 6 is a block diagram showing the configuration of a communication network system according to an embodiment of the present invention.
This is a communication network system that conforms to three series of standards. 6, the LAN 31 is connected to the switching hubs 21-1 to 21-n (n; 1) having the band limiting function of FIG.
Router 32).
2 and the switching hubs 21-1 to 21-n with a band limiting function are connected by a communication line 102, respectively. The switching hubs 21-1 to 21 -n with a band limiting function connect a plurality of communication lines 101, respectively, and connect the PC 33 via each communication line 101.
And the server 34 are connected. Also, the router 32
It is connected to a backbone line 103 for connecting the LAN 31 to another communication network such as the Internet or a LAN. As described above, the LAN 31 is connected to the router 32
And a switching network 21-1 to n with a band limiting function, wherein one or more communication lines 103 and 101 are connected on the backbone side (upper side) and the terminal side (lower side) respectively. Is done. This L
In the AN 31, switching hubs 21-1 to 21 -n with a band limiting function are provided on the terminal side and connected to the communication line 101. The band limiting circuit may be provided on either side of the terminal side communication line 101 or the upper side communication line 102 of the switching hubs 21-1 to 21 -n with the band limiting function.
2 can be limited, but in the example shown in FIG. 6, the band limiting circuit of FIG. 1 is provided at least on the input side of one or more communication lines 101 on the terminal side.

In the LAN 31, the above-described FIG.
The switching hubs 21-1 to 21-n with the band limiting function perform band limiting on the input side of the predetermined communication line 101. As a result, the bandwidth of a specific terminal can be limited, and at the same time, the switching hubs 21-1 to 21-1 having the bandwidth limiting function can be used.
It is possible to limit the bandwidth of the communication line 102 on the output side from n and the bandwidth of the output from the router 32 to the communication line 103. In the router 32, it is necessary to limit the bandwidth of the backbone line 103. Disappears. Therefore, the CPU of the router 32 only needs to perform the packet transfer process, and performs the band limiting process in addition to the packet transfer process as in the router 42 in FIG.
The problem that the processing capacity required for the CPU is increased is also solved.

Further, a switching hub 2 with a band limiting function
By 1-1 to n, the transmission amount of data output to each communication line 102 can be arbitrarily limited. Therefore, if the bandwidth of each communication line 102 is limited in the LAN 31 so as to limit the transmission load on the backbone line 103, it is possible to select the router 32 having a transfer capacity corresponding to the required transmission band to the backbone line 103. become able to. As a result, when configuring the LAN 31, particularly at the initial stage of the operation of the LAN 31, it is possible to obtain the effect that the capital investment for the backbone lines such as the backbone line 103 and the router 32 can be minimized. In the LAN 31 of FIG. 6, the switching hub with the band limiting function is used for all the switching hubs, but may be used for only some of the switching hubs as needed.

An example of the selection process when selecting the router 32 will be described below. First, as the router 32, the communication capability of the communication line 102 at the end (front end) is 1 per second.
Select a high-speed one such as 00M bits. Here, the communication line 101 of all users (communication terminals) is set to, for example, 100 per second.
If the transmission speed of M bits is allowed, the router 32 needs a processing capacity of 100 M bits per second × the number of users. On the other hand, the user does not always request a transmission rate of 100 Mbits / sec from the beginning, and often wants to use a lower-speed communication line 101 at the beginning of use in consideration of the usage fee of the communication line 101. Therefore, according to the present embodiment, if a user request (low-speed communication line 101) is realized by restricting the bandwidth for each user's communication line 101, an inexpensive router 32 having a low processing capability is used as the router 32 at first. You only need to prepare it. Next, when the user requests the use of the high-speed communication line 101 and the need to relax the band limitation arises, the processing capacity of the router 32 is increased according to the degree.

In the case of an Internet connection company, FIG.
By configuring a communication network system such as the LAN 31 as an Internet connection line that provides the communication line 101 to the user, the bandwidth can be limited for each Internet connection line provided to the user. Therefore, if configured like the LAN 31, it is possible to realize a communication network system that meets the above requirements (1) to (3).

As another embodiment of the communication apparatus 11 shown in FIG. 2, there is an application to network equipment such as a router, a repeater hub, and an optical converter used for configuring a LAN. Further, in order to connect to a LAN conforming to the IEEE 802.3 series standard, the present invention can be applied to a LAN card or transceiver provided in a personal computer or the like. That is, the PHY layer processing unit of these network devices, LAN cards and transceivers and the MAC
By adding the band limiting circuit 12 to the connection unit of the layer processing unit as described above, the band of the communication line to be connected can be limited.

The location where the communication device 11 is implemented and the location where the band limiting circuit 12 is added vary depending on the application. In consideration of the band limitation effect of the entire system, the most effective point is generally the last branch point, and it is generally effective to perform band limitation in the upstream direction. Therefore, in the case of the network as shown in FIG. 10, it is most efficient to equip the transmission side of the PC at the end with the PC. It may be more effective to add it to the switching hub as shown in FIG. 6 than to the switching hub. In such a case, it is most efficient in terms of management to provide a band limiting unit on the receiving side of each downstream port of the switching hub as shown in FIG.

Note that the embodiment of the present invention is the same as that shown in FIG.
However, the present invention is not limited to a configuration in which the band-limiting function is realized by dedicated hardware, as in the band-limiting circuit 12 shown in FIG. 1, but by executing a program for realizing the band-limiting function on the CPU, That is, the band limiting function may be realized by software. For example, instead of controlling the transmission amount of data by counting the reference clock by a physical circuit, the real time can be measured by a control CPU or the like in the communication device and controlled by software.

FIG. 7 is a block diagram showing the configuration of a communication device 50 according to the second embodiment of the present invention. The communication device 50 implements a band limiting function by software. In FIG. 7, reference numeral 51 denotes a communication device 50.
A program for realizing a band limiting function (a band limiting program) is stored, and the program is executed to perform a band limiting process. Reference numeral 52 denotes a LAN card provided in the input port, and performs a process of receiving input data. Symbol 53 is LA
This is a buffer memory for temporarily holding input data received by the N card 52, and data is written from the LAN card 52. Reference numeral 54 denotes a processing unit that reads data from the memory 53 and processes the data. Reference numeral 55 denotes a buffer memory for temporarily holding data output from the processing unit 54,
4 is written. Reference numeral 56 denotes a LAN card provided in the output port, which reads out data from the memory 55 and sets it as output data, and performs transmission processing of the output data.

The control CPU 51 is a LAN card 5
2 and 56, which control the input operation of the LAN card 52 to receive the input data, thereby limiting the bandwidth of the buffer input, and controlling the LAN card 56 to control the output operation of the output data. Performs output band limiting. The control CPU 51 is also connected to the memories 53 and 55 and initializes the memories 53 and 55. Further, the control CPU 51 has a clock function to obtain the current time. However, the clock function may be realized by software, or may be realized by a hardware timer.

FIGS. 8 and 9 show the control CPU 51 described above.
8 are first and second flowcharts showing the flow of the band limiting process performed by the first embodiment. FIG. 8 shows the flow of the band limiting process of the buffer input, and FIG. 9 shows the flow of the band limiting process of the buffer output. Note that the buffer input band limiting process shown in FIG. 8 is the same as the buffer output band limiting process shown in FIG. 9, and steps S1 to S8 in FIG. 8 correspond to steps 11 to 18 in FIG. It has become. Therefore, in the following description, with reference to FIG. 7 and FIG. 8, only the buffer input band limiting process performed by the control CPU 51 will be described, and the description of the buffer output band limiting process will be omitted.

It is assumed that the band limiting cycle time is set in advance in the control CPU 51 in real time, and the number of transferable bytes within the band limiting cycle time is set as the band limiting value within the band limiting cycle. In the following description, the control CPU 51 executes a band limiting program. Unless otherwise specified, it is assumed that each process is performed based on the execution of the band limiting program. First, control C
When starting the buffer input band limiting process, the PU 51 sets the reception enable / disable flag to reception enabled. Further, the current time is set as the band limitation cycle start time, and the byte count value is initialized to “0” (steps S1 and S2 in FIG. 8). Next, the reception possibility flag is checked, and if the reception is possible, the process proceeds to step S4, while if the reception is not possible, the process proceeds to step S6 (step S3). Here, since reception is possible, the process proceeds to step S4, where the control CPU 51 permits the LAN card 52 to receive one frame of input data, and sets the number of received bytes of the received frame to the LAN card 52. 52 and added to the byte count value. This byte count value indicates the amount of data transmission within the band limitation period.

Next, the control CPU 51 checks whether or not the byte count value is less than the number of transferable bytes. If the value is less than the number of transferable bytes, the process proceeds to step S6. On the other hand, if the number of transferable bytes is equal to or more than the number of bytes that can be transferred, the reception permission flag is set to non-reception, input data after this within the current band restriction period is not received, and the bandwidth of the buffer input is limited by this. The process proceeds to step S3 (steps S5 and S8). In the process of step S6, the control CPU 51 obtains a time difference t between the current time and the band limiting cycle start time. This time difference t indicates the real time within the band limitation period. Next, the control CPU 51 shifts the processing to step S3 when the obtained time difference t is less than the band limitation cycle time, and proceeds to step S1 when it is less than the band limitation cycle time. The processing is shifted to start the processing of the next band limitation period (step S7).

In the communication device 50 described above,
Although the time difference t between the current time and the band limitation period start time is used as the real time in the band limitation period, the real time in the band limitation period may be measured by a timer. In this case, in step S2, the timer is initialized and started instead of setting the current time as the band limitation cycle start time, and the timer value is less than the band limitation cycle time in step S7. It is determined whether or not. The timer for measuring the real time within the band limitation period may be realized by software, or may be realized by a hardware timer.

In the communication device 50 according to the above-described second embodiment of the present invention, the band limiting function is realized by software. There is no need to refer to header information, and in addition to the effect that band limitation can be performed at the PHY layer level in the communication network system, the effect that the degree of freedom of the configuration for performing the band limitation processing shown in FIG. 8 or 9 is increased. Is also obtained.
For example, in the communication device 50 of FIG. 7 described above, the band limiting program is configured to be executed by the control CPU 51, but may be executed by another CPU (for example, one provided in the processing unit 54). You may. Further, even if there is a change in the required specification of the band limitation, it is only necessary to modify the band limitation program, and it is possible to flexibly cope without changing the hardware configuration.

Further, as real time within the band limitation period,
By using the time difference t between the current time and the band limiting cycle start time, when a general-purpose computer or the like having a clock function is used as the communication device, a simple timer for real-time measurement can be provided without using a dedicated timer. In addition, the effect that the band limiting function can be realized by software can be obtained.

The band limiting process shown in FIG. 8 or FIG. 9 may be configured to be performed by dedicated hardware.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. included.

[0071]

As described above, according to the present invention,
In a band limiting circuit that limits a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock, a value based on the transmission clock is counted within a valid period of the frame, and this count value is set to a predetermined limit value. , The transmission of data to be transmitted does not need to be referred to the header information of the transmitted packet when restricting the transmission of the transmitted data, and the band is restricted at the PHY layer level in the communication network system. The effect that it can be obtained is obtained. Further, by changing the predetermined limit value, the band can be freely limited from a state where the band limit is zero at the maximum.

Further, in a band limiting circuit for limiting the amount of data transmitted by forming a frame in synchronization with the transmission clock, the number of “reference clocks based on the transmission clock” during the valid period of the frame within a predetermined period is determined. Based on the accumulated count value, it is detected that the transmission amount has been exceeded, and even if the transmission of the data is restricted based on the detection result, the transmission of the transmitted data is restricted. It is no longer necessary to refer to the header information of the packet, and the band can be limited at the PHY layer level in the communication network system. Furthermore, if the excess of the transmission amount limit is detected by comparing the accumulated count value with the predetermined limit value, the band is freely limited from the maximum band limit of zero by changing the predetermined limit value. The effect that it can be obtained is also obtained.

Further, if the frame is invalidated based on the detection result of the transmission amount exceeding the limit, the data transmission amount can be easily limited, and the scale of the band limiting circuit can be reduced. it can.

Furthermore, if the frame at the time of detection of the transmission amount exceeding the limit is continued until the end of the frame, the occurrence of communication failure due to frame discard due to band limitation can be reduced.

Further, according to the present invention, it is possible to realize a communication device that limits a band only by adding a band limiting circuit without changing a circuit configuration of a standard PHY layer processing unit and a MAC layer processing unit. Therefore, the circuit configuration of the communication device can be simplified, and an advantage that cost merit is excellent can be obtained.

According to the present invention, in a communication network system including a router and a switching hub and connected to one or more communication lines on each of an upper side and a lower side, at least one or more lower side lines are provided. A communication line is provided with a band limiting circuit. As a result, the transmission amount of data input from the lower communication line can be limited, and as a result, the transmission amount of data output to the upper communication line can also be limited. And a communication network system capable of freely setting the maximum transmission amount of the lower input communication line regardless of the setting of the communication device connected to the lower communication line. The effect is obtained.

Further, according to the present invention, in a band limiting method for limiting a transmission amount of data transmitted by forming a frame, a step of measuring an actual time within a predetermined period, and a step of measuring data within the period. The method may include a step of determining a transmission amount, a step of detecting an excess of the data transmission amount based on a measurement result in real time and the data transmission amount, and a step of restricting the data transmission based on the detection result. Therefore, there is no need to refer to the header information of the transmitted packet when restricting the transmission of the transmitted data, and the effect that the band can be restricted at the PHY layer level in the communication network system can be obtained. Can be Further, by causing a computer to execute a program for performing the processes of the respective processes, the effect of increasing the degree of freedom of the configuration for performing the band limiting process can be obtained. Furthermore, even if there is a change in the required specification of the band limitation, it is only necessary to modify the program, and it is possible to flexibly respond without changing the hardware configuration.

Further, if a step of calculating the time difference between the start time of the cycle and the current time as the real time within the predetermined cycle is included, the general-purpose computer having a clock function can be used as a communication device. In addition, an effect is obtained that the band limiting function can be easily realized by software without providing a dedicated timer for real time measurement.

[Brief description of the drawings]

FIG. 1 shows a band limiting circuit 12 according to an embodiment of the present invention.
FIG. 3 is a block diagram showing the configuration of FIG.

FIG. 2 shows a communication device 11 according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing the configuration of FIG.

3 is a PHY layer processing unit 1 of the communication device 11 shown in FIG.
FIG. 4 is a waveform diagram showing an example of a timing relationship in an interface connecting the MAC layer 4 and a MAC layer processing unit.

FIG. 4 is a waveform chart showing waveforms at various parts of the band limiting circuit 12 shown in FIG.

FIG. 5 is a block diagram showing a configuration of a switching hub 21 with a band limiting function which is an embodiment of the communication device 11 shown in FIG.

FIG. 6 is a block diagram showing a configuration of a communication network system (LAN 31) according to an embodiment of the present invention.

FIG. 7 shows a communication device 50 according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing the configuration of FIG.

8 is a first flowchart illustrating a flow of a band limiting process performed by a control CPU 51 illustrated in FIG. 7;

9 is a second flowchart showing the flow of the band limiting process performed by the control CPU 51 shown in FIG.

FIG. 10 shows a conventional communication network system (LAN)
FIG. 41 is a block diagram illustrating a configuration example of 41).

[Explanation of symbols]

 1 frequency dividing circuit 2 AND circuit 3 cycle counter 4 limit counter 5 cycle register 6 limit register 7 comparing circuit 8 excess limit detecting circuit 9 valid frame signal control circuit 10 control interface unit 11, 50 communication device 12 band limiting circuit 13 MAC layer processing Unit 14 PHY layer processing unit 15 Receiver 16 Descrambler / decoder 17 Encoder / scrambler 18 Driver 31 LAN (communication network system)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K033 AA05 CA11 CB06 CC01 DA01 DA15 DB02 DB16 5K047 AA12 BB15 CC06 GG11 GG44 HH01 LL11 MM05

Claims (15)

[Claims] 1. A band limiting circuit for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock, wherein a value based on the transmission clock is counted within a valid period of the frame. A band limiting circuit for transmitting data until the count value reaches a predetermined limit value. 2. A band limiting circuit for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock, wherein a cycle measuring means for measuring a predetermined period using a reference clock based on the transmission clock. Limit measuring means for measuring an accumulated count value of the reference clock number during the valid period of the frame in the predetermined period; and comparing the accumulated count value with a predetermined limit value to detect an excess of the transmission amount. A band limiting circuit that limits transmission of the data based on a detection result of the excess limit detecting unit. 3. The band limiting circuit according to claim 1, further comprising a frame control unit that invalidates the frame based on a detection result of the transmission amount exceeding the limit. 4. The band limiting circuit according to claim 3, wherein the frame control means continues the frame until the end of the frame upon detection of the transmission amount exceeding the limit. 5. A communication device connected to one or more communication lines, wherein the band limiting circuit according to claim 1 is provided on at least one of the communication lines. A communication device comprising: 6. The communication apparatus according to claim 5, wherein the band limiting circuit is provided on either the input side or the output side of the communication line, or on both the input side and the output side. 7. A communication device connected to a communication network, wherein an interface portion between the PHY layer processing unit and the MAC layer processing unit is provided with a band limiting circuit for limiting a data transmission amount within a predetermined period. Communication device. 8. The communication device according to claim 5, wherein the band limiting circuit is provided in an interface between a PHY layer processing unit and a MAC layer processing unit. 9. A communication network system comprising a router and a switching hub and connected to at least one communication line on each of an upper side and a lower side, wherein the communication network system includes a router and a switching hub. A communication network system comprising the band-limiting circuit according to item 1. 10. The communication network system according to claim 9, wherein said band limiting circuit is provided in at least one or more communication lines on the lower side. 11. A bandwidth limiting method for limiting a transmission amount of data transmitted by forming a frame in synchronization with a transmission clock, wherein the bandwidth limitation method comprises the steps of: A step of obtaining an accumulated count value of a reference clock number based on a clock; a step of detecting an excess of the transmission amount limit based on the accumulated count value; and a step of restricting transmission of the data based on the detection result. And a bandwidth limiting method comprising: 12. The band limiting method according to claim 11, wherein the band limiting method further comprises a step of invalidating the frame within the predetermined period after detecting the transmission amount limit excess. Method. 13. The band limiting method according to claim 12, further comprising the step of: continuing the frame until the end of the frame when the transmission amount exceeds the limit. 14. A bandwidth limiting method for limiting a transmission amount of data transmitted by forming a frame, the bandwidth limiting method comprising: measuring a real time within a predetermined cycle; Obtaining a data transmission amount; detecting an excess of the data transmission amount limit based on the measurement result of the real time and the data transmission amount; and restricting the data transmission based on the detection result. A bandwidth limiting method, comprising: 15. The bandwidth limiting method according to claim 14, further comprising: determining a time difference between a start time of the cycle and a current time as a real time in the cycle.