JP2501977B2 - Communication control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device for detecting destruction of control data circulating on a ring-shaped communication network, and more particularly to shortening the waiting time for notification of control data destruction and recovering control data. The present invention relates to a communication control device capable of performing quickly.

[0002]

2. Description of the Related Art A token ring network, which is one type of communication network such as a LAN (Local Area Network), is an IEEE Std. As specified in 802.5, a plurality of communication control devices are connected in a ring shape, and normally, a frame including communication data and a token for controlling the communication of the frame are sequentially arranged as a bit string. It circulates on the network via each communication control device.

As shown in FIG. 11, each communication control device 101 receives a data bit string from another communication control device and detects a token of the data bit string.
03, and a transmission unit 104 for receiving the communication data from the reception unit 103 and transmitting the communication data to another communication control device,
Furthermore, the counting of time is restarted by the token detection signal from the receiving unit 103, and if the next token detection signal is not sent even after a predetermined time, a token destruction notification signal (time-out notification) is output. It has a timer unit 105 and a protocol control unit 107 which supplies a token transmission signal to the transmission unit 104 when there is no token destruction notification signal from the timer unit 105. Then, the transmitting unit 10
4 receives a token transmission signal from the protocol control unit 107, generates a token (generatio).
n) It is designed to be sent. As described above, with the above configuration, it is detected that the token is destroyed by noise or the like between the communication control devices, and the token is reproduced (recover).
y). The token is shown in Figure 1.
It has a format such as 2.

FIG. 13 is a block diagram showing the configuration of a timer unit in a conventional communication control device.

The timer section has a good token (GT) timer 121, and when the enable signal is given from the protocol control section 107 (GT), the timer 121 operates as follows. The fixed waiting time 122 is loaded by using the token detection signal from the receiving unit 103 as a restart signal (restart signal), and the counting is restarted. G. The T timer 121 counts, and the next token detection signal is received by the receiving unit 10 even after the fixed waiting time.
If it is not sent from 3, the time-out notification signal is output as a token destruction notification signal and counting is stopped. Also,
If the next token detection signal is sent from the receiving unit 103 before the fixed waiting time, G. T timer 121
Restarts as described above.

[0006] In the token ring, up to 260 stations can be connected, and the token holding time per station is 10 msec. Therefore, if the token ring has 260 stations, it takes one round of tokens. The maximum time is about 10 ms × 260 stations = 2.6 seconds. Therefore, the waiting time 122 is fixedly set to this maximum value = 2.6 seconds.

That is, 2.6 after the token is detected.
If the token is not detected again after the elapse of seconds, the good token timer 121 expires and a token destruction notification signal is generated. With this token destruction notification signal,
It is considered that the token was destroyed by noise or the like, and recovery processing such as retransmitting the token is performed.

Here, as shown in FIG. 14, a token ring network 125 composed of four stations of communication control devices (stations A to D) equipped with a normal good token timer 123 designed as described above. Above, consider the case where the token is orbiting counterclockwise.

The good token timer 121 provided in all stations restarts counting every time a certain token is received, and when the next token is received within a predetermined time (2.6 seconds), Normal communication is performed.

If a certain circulating token is destroyed by noise or the like during transmission from station A to station B, it means that the good token timer 121 of station B has been restarted in the oldest time. Therefore, station B times out first and outputs the token destruction notification.

[0011]

However, since the token holding time in which one station receives and holds a token and then transmits communication data is 10 msec at the maximum, the token ring of four stations shown in FIG. In the case of the network 125, the time required for the token to make one round is 10 ms × 4 stations = 40 ms. Therefore, 40 ms is sufficient for the waiting time of the good token timer 121.

However, as described above, the waiting time of the good token timer 121 is fixed at 2.6 seconds at the designing stage, corresponding to the connection of up to 260 stations.
40m for a small token ring consisting of 4 stations
2.6 seconds-where you can judge that the token is destroyed in seconds-
40 msec = 2.56 sec. As a result, the token destruction notification is delayed, and the transmission becomes impossible during that time. For example, in the case of a token ring having a transfer rate of 4 Mbps, there is a drawback that about 10 Mbps of information cannot be transmitted within 2.56 seconds, resulting in a significant decrease in communication performance.

[0013] In particular, if it is assumed that none of the four stations is transmitting communication data, the token is not kept waiting at each station, so that the token circulates on the talk ring network 125 at a very high speed. Also in this case, the token destruction notification is not output until approximately 2.6 seconds have passed since the token destruction, and no communication can be performed during this period.
In this case, the above-mentioned drawbacks are particularly promoted.

Therefore, the present invention has been made in view of the above-mentioned conventional circumstances, and the purpose thereof is G. By making the waiting time of the T timer variable according to the state of the network, the G.T. Another object of the present invention is to provide a communication control device capable of shortening the waiting time of the token destruction notification output from the T timer and performing the token recovery process quickly.

[0015]

In order to achieve the above object, a feature of the present invention is to provide a communication control device for receiving or transmitting control data and / or communication data on a ring-shaped communication network. A means for detecting the number of terminals actually existing and operating on the communication network during the operation of the communication network, and a waiting time until the loss of control data circulating on the communication network is detected, Waiting time updating means for updating the waiting time updated according to the number of terminals which are actually operating in the communication network detected by the detecting means, and waiting time holding means for holding the waiting time updated by the waiting time updating means Means for counting the time by receiving the control data and controlling even after the waiting time held in the waiting time holding means has elapsed. If you can not re-receiving the data, is that which is provided a time counting means for outputting the control data destruction notification signal.

Further, the waiting time determining means receives a presence notification signal transmitted from each communication control device arranged on the communication network, and from this presence notification signal, the communication control device operating on the communication network. Calculate the number of
It is configured to calculate the minimum latency required for this communication network from the calculated number of communication controllers.

Alternatively, the waiting time determining means determines whether the number of communication control devices is input to the communication network by using the existing station number input means and the number of communication control devices input by the existing station number input means. A waiting time calculating means for calculating the minimum waiting time required.

Alternatively, the waiting time determining means receives the presence notification signal transmitted from each communication control device arranged on the communication network, and from the presence notification signal, the presence control signal of the communication control device arranged on the communication network is received. First waiting time calculation means for calculating the number and waiting time from the calculated number of communication control devices, existing station number input means for arbitrarily inputting the number of communication control devices, and this existing station number input Second waiting time calculating means for calculating a waiting time from the number of communication control devices inputted by the means, and the waiting time calculated by the first waiting time calculating means and the second waiting time calculating means. Latency comparison means for comparing the calculated latency with the longer latency as the minimum latency required for this communication network.

[0019]

With the above arrangement, the present invention calculates the number of existing stations from the number of presence notification signals transmitted from each station existing on the communication network. The minimum required waiting time is calculated from the calculated number of existing stations, and written in the waiting time holding means.
The time counting means, when receiving the control data transmitted on the communication network, reads the waiting time held in the waiting time holding means and counts the time. Then, if the control data cannot be re-received even after the waiting time elapses, a destruction notice notifying that the control data is abnormal is output.

Alternatively, according to the above configuration, an arbitrary number of existing stations is input from the existing station number input means to the waiting time calculation means. Furthermore, the waiting time calculation means calculates the necessary minimum waiting time from the input number of existing stations and writes it in the waiting time holding means. When receiving the control data, the time counting means reads the waiting time and counts the time. If the control data cannot be received again even after the waiting time elapses, the destruction notification is output.

Further, according to the above configuration, the waiting time calculated from the number of existing stations calculated from the number of presence notification signals, and the waiting time calculated from the number of existing stations input from the existing station number input means. To compare. As a result of the comparison, the longer waiting time is written in the waiting time holding means as the necessary minimum waiting time. When receiving the token, the time counting means reads the waiting time and counts the time. Then, if the token cannot be received again even after the waiting time elapses, a destruction notification is output.

[0022]

1 is a block diagram showing an outline of a timer section of a communication control apparatus according to a first embodiment of the present invention. The other configuration of the communication control device is the same as that of the conventional one shown in FIG.

Here, the schematic configuration of the communication control apparatus according to the present invention will be described with reference to FIG.

The communication control apparatus shown in the figure comprises a Good token (GT) timer 1, a waiting time register 3, and a waiting time determining unit 5.

G. The T timer 1 uses the restart signal (rest
(art) is input, the waiting time written in the waiting time register 3 is read and counting by the timer is restarted. In addition, G. The T-timer 1 outputs a time-out notification signal and stops counting when the loaded waiting time elapses during counting.

The waiting time register 3 is used by the waiting time calculation unit 5
Holds the latency calculated by T timer 1
To give to.

The waiting time determining unit 5 calculates the waiting time according to the number of stations actually existing on the network and writes the calculation result in the waiting time register 3.

As described above, the communication control device according to the present invention is provided with the waiting time determining unit 5 in order to make the waiting time of the timer variable, and the waiting time determining unit 5 provides the waiting time according to the state of the network. Calculated. The calculated waiting time is written in the waiting time register 3.
G. When the activation signal is input to the T timer 1, the waiting time written in the waiting time register 3 is G.T. It is read by the T timer 1 and counted. If the waiting time elapses while counting, G. A time-out notification signal is output from the T timer 1.

Next, a specific structure of the timer section will be described with reference to FIG.

When the enable signal is given, the good token timer 7 loads the waiting time value given from the waiting time register 3 into the timer by the token detection signal and restarts. When the token is not detected, the count value is decremented by the clock pulse, and when it reaches zero, the token destruction notification is output. This operation is shown in FIG. In this example, the count value is 40ms
The clock pulse is input every 1 ms. First, the timer value is 40 ms when the token is detected at time T _1.
It decreases gradually, but at time T ₂ before reaching zero.
Then the next token is detected and the timer value has returned to 40 ms. However, since the next token is not detected, the timer value reaches zero at time T ₃ , and the token destruction notification is output. Note that the timer value does not fall below zero.

The waiting time determination unit 5 is an AMP (Active Mon
Itor Present MAC Frame) reception and SMP (Standby Moni)
The waiting time is determined in the following manner from two events (presence notification signal) of reception of tor Present MAC Frame).

For example, consider the case of a token ring network 9 composed of communication control devices of four stations as shown in FIG. In this token ring network 9, there is one AM (active monitor) station (station A) as a monitoring station.
Then, there are three SM (standby monitor) stations (stations B to D) having the good token timer 7. The token ring 9 executes a neighbor notification between the AM station and the SM station every 7 seconds.

The neighbor notification is shown in FIG.
This will be described with reference to the timing chart of FIG.

Never Notification is AM
Starting with the transmission of the AMP frame by the station, the transmission from the AM station is repeated every 7 seconds. The SM station, which is a downstream station adjacent to the AM station, receives the AMP frame transmitted from the AM station, and the other SM stations receive the SMP frame 20 m seconds after receiving the SMP frame transmitted from the adjacent upstream SM station. Send. As is clear from the timing shown in FIG. 5, the next AM from the AMP frame reception event.
The number of SMP frame reception events between P frame reception events + 1 is the number of stations operating on the token ring 9.

As shown in FIG. 2, the waiting time determining unit 5 includes
Events of AMP frame reception and SMP frame reception are input. Active node counter 21 is A
"1" is loaded by the MP reception event and is incremented by +1 by the SMP reception event. This count value is input to the waiting time calculation unit 23 as an operating station value, multiplied by the token holding time, and the waiting time is calculated. As the initial value of the active node counter 21, the maximum number of stations defined by the protocol is set, and the waiting time determination unit sets a value that outputs the maximum waiting time of 2.6 seconds to the waiting time register 3. It is desirable that

When an AMP frame reception event is input, the waiting time register 3 loads and holds the waiting time output from the waiting time determining unit 5. The held value is given to the good token timer 7.

The AMP frame and the S
FIG. 6 shows the operation of the timer unit when the MP frame is received. Count the AMP frame reception time T ₁ in the example is "1" is loaded, the count up "4" by three SMP frame reception. This value is equal to the number of stations operating in the network. The waiting time calculation unit 23 multiplies this value by the token holding time (ex. 10 msec) to obtain 40 msec. This waiting time register 3 holds 40 msec when the AMP frame at time T ₂ is received.

When 40 msec has passed after the good token timer 7 was restarted, the good token timer 7 outputs a token destruction notification.

Thus, the AMP frame and the SMP
Since the number of existing stations is obtained by frame reception and the waiting time corresponding to the number of existing stations is calculated, the optimum waiting time is automatically obtained according to the number of existing stations. Therefore, even when the number of existing stations is reduced, there is no unnecessary waiting time as in the conventional case, and recovery processing after token destruction can be performed quickly. Further, even when the number of stations has increased or decreased, the waiting time register 3 is updated every 7 seconds, so that the optimum waiting time can always be held.

For example, in the case where the number of existing stations is 4, it takes 2.6 seconds from the token destruction to the detection in the conventional communication control apparatus, but according to the communication control apparatus according to the present invention, it is 0.04 before the detection. It only takes seconds. Therefore, the time difference is 2.56
It is possible to eliminate useless waiting time of seconds. This wasteful waiting time of 2.56 seconds corresponds to a transmission capacity of about 10 Mbit in the case of a 4 Mbps token ring, and the present invention can prevent a huge waste of data transmission capacity.

Second Embodiment In the first embodiment, the number of existing stations is obtained by the calculation by the waiting time determining unit 5 which inputs the AMP frame and SMP frame reception events. As another method, instead of obtaining the number of existing stations by the waiting time determining unit 5, a method of directly inputting the number of existing stations to the waiting time determining unit 5 from a user terminal, a control processor or the like can be considered. That is, the number of stations connected to the network or expected to be connected is directly input to the waiting time determination unit 5 from the user terminal, the control processor, or the like as the number of existing stations regardless of whether the stations are operating. There are possible ways to do this.

FIG. 7 is a block diagram showing the configuration of the timer section of the communication control apparatus according to this method.

As shown in the figure, a user terminal 11 is added to the timer section of this communication control device.

The user terminal 11 inputs the number of existing stations to the waiting time determining unit 5.

When the number of existing stations is input from the user terminal 11, the wait time determining unit 5 causes the good token timer 7 to enter.
Waiting time is determined.

For example, the number of stations used by the user is always 100.
If the number of stations is less than or equal to the number of stations, the number of stations is 100 as the upper limit of the number of stations.
The station is input from the user terminal 11. As a result, the wait time determination unit 5 waits time = number of user-specified stations × 1
It is calculated that 0 msec = 100 stations × 10 msec = 1 sec.

The calculated waiting time is written in the waiting time register 3, and the written waiting time is read in the good token timer 7 by the token detection. If one second elapses while counting by the good token timer 7, a token destruction notification is output.

In this way, by inputting the upper limit value of the number of existing stations from the user terminal 11 in advance, it is not necessary to set a waiting time longer than necessary.

Embodiment 3 Furthermore, a method in which Embodiment 1 and Embodiment 2 are combined can be considered.

FIG. 8 is a block diagram showing the configuration of the timer unit used in the communication control apparatus according to this method.

The timer section is provided with two waiting time determining sections 5a and 5b and a time comparing section 13.

The waiting time determining unit 5a is similar to the waiting time determining unit 5 used in the first embodiment in that the AMP frame and the SM
The number of existing stations is calculated by receiving P frames, and the waiting time corresponding to the number of existing stations is calculated.

The waiting time determining unit 5b is, like the waiting time calculating unit 5 used in the second embodiment, for calculating the waiting time from the number of existing stations input from the user terminal 11.

The time comparing unit 13 includes a waiting time determining unit 5a,
Comparing each latency calculated by 5b,
The longer waiting time is written in the waiting time register 3.

AMP frame and SMP every 7 seconds
The waiting time obtained by the frame reception and the waiting time obtained by the input from the user terminal 11 are input to the time comparison unit 13. These two waiting times are compared by the time comparing unit 13, and the longer waiting time is set as the minimum waiting time in the network.

According to the third embodiment, even when the number of existing stations is larger than the number of existing stations input from the user terminal 11,
Optimal latency can be calculated by receiving AMP and SMP frames.

Fourth Embodiment In the above embodiments, the number of stations existing in the network is individually counted by each communication control device, but the values counted by each device may not match in a transient state. Conceivable. If the value counted at a certain station is extremely small, the waiting time set at that station will also be extremely small, and the Good Token timer will falsely notify the expiration of the time even if the network is operating normally. There is a possibility that it will end up. In order to eliminate such inconvenience, a specific station that counts the number of existing stations on the network is defined as a network management node as shown in FIG. 9, and the number of existing stations is notified from each station to each communication control device. good. Each communication control device may immediately calculate the waiting time based on the notified value. At this time, the network management node sets the enable signal to the high level, and the other stations set the enable signal to the low level. That is, no counting is performed except in the network management node. FIG. 10 shows a specific configuration of the timer unit of each communication control device in this case. Example 3
As described in (1), the waiting time set by the user terminal may be compared to determine the longer waiting time.

Fifth Embodiment In the second and third embodiments, the number of stations is set from the user terminal and the waiting time is calculated, but of course the waiting time may be set directly from the user terminal. good. Similarly, in the fourth embodiment, the existing station counting station notifies each communication control device of the number of stations. However, the waiting station may be calculated and the waiting time may be directly notified. Good.

[0059]

As described above, according to the communication control device of the present invention, G. The waiting time of the T timer is made variable according to the state of the network, and the optimum timer waiting time according to the network is set. This allows G.I. The waiting time for the token destruction notification output from the T timer can be shortened, and the control data recovery time can be greatly shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a timer unit of a communication control device according to the present invention.

FIG. 2 is a configuration diagram of a first embodiment of a timer unit of the communication control device according to the present invention.

FIG. 3 is an operation time chart of the good token timer in the embodiment shown in FIG.

FIG. 4 is a diagram showing a token ring using the embodiment shown in FIG.

5 is an explanatory diagram of a neighbor notification operation in the token ring shown in FIG.

FIG. 6 is an explanatory diagram of an operation of a timer unit when receiving an AMP frame and an SMP frame.

FIG. 7 is a configuration diagram of a second embodiment of the timer unit of the communication control device according to the present invention.

FIG. 8 is a configuration diagram of a third embodiment of the timer unit of the communication control device according to the present invention.

9 is a diagram showing a token ring using the fourth embodiment shown in FIG.

FIG. 10 is a fourth timer unit of the communication control device according to the present invention.
It is a block diagram of an Example.

FIG. 11 is a block diagram showing a schematic configuration of a general communication control device.

FIG. 12 is a diagram showing a format of control data (token).

FIG. 13 is a block diagram showing a timer unit in a conventional communication control device.

FIG. 14 is a diagram showing a token ring network for explaining a conventional technique.

[Explanation of symbols]

 1 C. T timer 3 wait time register 5 wait time calculation unit 9 token ring network

Front page continued (72) Inventor Katsuhito Fujimoto 580-1, Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Corporation Semiconductor System Technology Center (56) References JP-A-61-82548 (JP, A) Kai 61-84939 (JP, A) JP 63-119341 (JP, A) JP 1-120149 (JP, A)

Claims (8)

(57) [Claims] 1. A communication control device for receiving or transmitting control data and / or communication data on a ring-shaped communication network, wherein the number of terminals existing on the communication network and actually operating is: A means for detecting during the operation of the communication network, and a waiting time until the loss of the control data circulating on the communication network is detected, are present in the communication network detected by the detecting means and are actually operating. Waiting time updating means for updating according to the number of terminals, waiting time holding means for holding the waiting time updated by the waiting time updating means, counting the time by receiving the control data, and holding the waiting time If the control data cannot be received again even after the waiting time held by the means, the control data destruction notification signal is sent. A communication control device being characterized in that includes a time counting means for force. 2. The communication control according to claim 1, wherein the detecting unit detects the number of terminals that are present in the communication network and are actually operating, periodically at regular time intervals. apparatus. 3. The communication control device further receives a control data and / or communication data on the communication network and detects the control data, and a control data and / or communication data from the reception unit. And a protocol control unit for supplying a control data transmission signal to the transmission unit when there is a control data destruction notification signal from the time counting means. The communication control device according to claim 1, wherein the transmission unit is configured to transmit control data when receiving a control data transmission signal from the protocol control unit. 4. The detection means receives a presence notification signal transmitted from each communication control device arranged on the communication network, and detects the presence notification signal from the communication control device operating on the communication network. The communication control device according to claim 1, wherein the number is calculated. 5. The number of second frames including communication data received between the time when the first frame including the communication data is received and the next first frame is received by the detecting means. The communication control device according to claim 1, wherein the communication control device is configured to count the number of existing stations on the ring by counting up. 6. The detecting means receives presence notification signals transmitted from the respective communication control devices arranged on the communication network, and detects the number of communication control devices arranged on the communication network from the presence notification signals. First waiting time calculation means for calculating the waiting time from the calculated number of communication control devices, existing station number input means for arbitrarily inputting the number of communication control devices, and existing station number input means Second waiting time calculating means for calculating a waiting time from the input number of communication control devices, the waiting time calculated by the first waiting time calculating means and the second waiting time calculating means And waiting time comparing means for comparing the long waiting time with the minimum waiting time required for this communication network. Communication control device. 7. A ring-shaped transmission means for circulating a token and communication data, and a plurality of communication stations connected to the transmission means for receiving or transmitting the token and communication data, the plurality of communication stations Is the first indicating the start of detection of the number of communication stations.
Of the plurality of communications, including a first communication station for transmitting the notification frame of No. 1 and a second communication station for responding to the first notification frame and transmitting a second notification frame indicating the presence of the own station. Each of the stations counts by the counting means and means for counting the number of second notification frames received from the time the first notification frame is received to the time the next first notification frame is received. And a means for detecting and recovering the disappearance of the token based on the number of tokens. 8. The communication station includes a reception unit that receives the token and communication data on the ring and detects the token, and a transmission unit that receives the token from the reception unit and transmits the token to the ring. A waiting time until the reception unit detects the disappearance of the token circulating on the ring in accordance with the number counted by the counting unit, and the waiting time determination unit. Waiting time holding means for holding the waiting time, and counting the time by receiving the token, and if the token cannot be re-received even after the waiting time held in the waiting time holding means, a token destruction notification signal is sent. The time counting means for outputting, and the token sending signal to the sending part only when there is a token destruction notification signal from the time counting means. 8. The protocol control unit for supplying, wherein the sending unit is configured to send a token when a token sending signal is received from the protocol control unit. Token ring network system.