JPH01120149A - Traffic control system - Google Patents

Abstract

PURPOSE:To perform the data transmission of a transmitter with high priority efficiently at the time of high traffic intensity and to send a sufficient amount of data while a token is held at the time of low traffic intensity by limiting the right to send which is given to the whole network. CONSTITUTION:A signal from an upstream transmission line 1a is received 3 and then sent as a traffic signal to the signal measuring circuit 11 of a decision circuit 4 for deciding whether or not the right to send is given. The measuring circuit 11 sends information generated by averaging a signal frequency to a circuit 13 which decides whether or not the right is given. The decision circuit 13 holds the right and passes the token by making the value of a token circulation timer smaller than an initial value unless said frequency exceeds a 1st frequency and the right to send is given to its transmitter. Further, when the frequency decreases below a 2nd predetermined frequency, the decision circuit 13 is given the right by resetting the value of the token circulation timer to the initial value even when its transmitter is not given the right.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to traffic in a token ring local network in which a plurality of transmission devices are connected to a ring transmission path and tokens are used to acquire transmission rights to the ring transmission path. Regarding control method.

[Prior Art] Generally, in this type of token ring type local network, each transmission device has a token cycle timer for monitoring the time until one cycle of tokens. Conventionally, the value of this token circulation timer can be freely set at the time of initial setting, but this value is fixed when the local network is in operation after the initial setting is completed.

[Problems to be Solved by the Invention] As described above, in the conventional token ring local network, the value of the token circulation timer is fixed;
If the token cycle timer value of a transmission device that is not given transmission priority is initially set to a small value in case of high traffic, it may not be possible to send a sufficient amount of data while holding the token during low traffic. There are drawbacks.

[Means for Solving the Problems] In the traffic control system according to the present invention, a plurality of transmission devices are connected to a ring-type transmission path, a token is used to acquire a transmission right to the ring-type transmission path, and each of the transmission devices In a token ring type local network having a token circulation timer for monitoring the time until the token circulates, each of the transmission devices receives a signal flowing through its own node portion of the ring type transmission path. means for measuring the frequency of the token cycle timer; and when the measured frequency exceeds a predetermined first frequency and the own transmission device is not given transmission priority, the value of the token circulation timer is set to an initial value. means for suspending transmission by setting the value to a smaller value so that transmission is not possible even if there is a transmission request; and means for restoring the transmission right by returning the value of to the initial value.

[Effect: During times of high traffic, the value of the token cycle timer is set to a value smaller than the initial value to suppress transmission by transmission equipment with low transmission priority, and during times of low traffic, the value of the token cycle timer is set to the initial value. By returning it, the transmission right is restored.

[Examples] Examples of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, a token ring type local network to which a traffic control method according to an embodiment of the present invention is applied has a plurality of nodes connected to a ring type transmission line (upstream and downstream transmission lines 1a and lb). (Only one transmission device designated by reference numeral 2 is shown in FIG. 1). The transmission device 2 includes a reception circuit 3, a transmission right grant determination control circuit 4, a transmission circuit 5, and a transmission/reception buffer and transmission/reception control circuit 6. Since other transmission devices (not shown) have similar configurations, their descriptions will be omitted.

The signal flowing from the upstream transmission path 1a is taken into the transmission right grant determination control circuit 4 via the reception circuit 3 of the transmission device 2. The receiving circuit 3 analyzes the received packet frame, and if it is determined as a result of this analysis that this packet frame is a packet frame that should be taken into the own transmission device, the receiving circuit 3 uses the data contained in the packet frame as received data. It is sent to the transmission/reception buffer and transmission/reception control circuit 6.

The transmission right grant determination control circuit 4 is a main part for realizing the traffic method of the present invention, and measures the frequency of the signal flowing from the upstream transmission path 1a (signal flowing through its own node), Determine whether transmission priority is given to the own transmission device.

Further, the transmission right grant determination control circuit 4 performs well-known token passing control. Furthermore, the transmission right grant determination control circuit 4
When the transmission priority is given, regardless of the amount of traffic, upon receiving the token, the transmission circuit 5 is given the transmission right. On the other hand, when transmission priority is not granted, the transmission right grant determination control circuit 4 grants the transmission right to the transmission circuit 5 by setting the value of a token circulation timer (not shown) to a value smaller than the initial value. control so that it does not occur. The detailed configuration and operation of this transmission right grant determination control circuit 4 will be explained later with reference to FIG. 2.

Further, as shown in the drawing, portions that are not important in the detailed description of the present invention are collectively shown as one block as a transmission/reception buffer and a transmission/reception control circuit 6, and the description thereof will be omitted.

Referring to FIG. 2, the transmission right grant determination control circuit 4 shown in FIG. 1 includes a signal frequency measurement circuit 11, a token determination circuit 12, and a transmission right grant determination circuit 13.

The signal from the upstream transmission path 1a is received at the receiving port #! After the signal is received by the receiver No. 3, it is sent as a traffic signal to the signal frequency measuring circuit 11 of the transmission right grant determination control circuit 4. The signal frequency measurement circuit 11 sends information obtained by averaging signal frequencies after filtering transient traffic signals to the transmission right granting determination circuit 13 .

Based on the information sent from the signal frequency measuring circuit 11, the transmission right grant determination circuit 13 determines whether the frequency exceeds a predetermined first frequency and the own transmission device is given transmission priority. If not, by setting the value of the token circulation timer to the transmitting circuit 5 to a value smaller than the initial value, the transmission right is reserved and the token is passed.

By each transmission device performing the above-mentioned transmission right reservation operation, the number of transmission devices attempting to transmit data is reduced, making it possible to maintain an efficient amount of traffic in the token ring local network. . Furthermore, by changing the above-described first frequency in accordance with the transmission priority given to each transmission device, it is possible to set the transmission right reservation state for the entire network in stages.

When the transmission right is reserved in this way, even if the token is not received, the token cannot be bused and the ring transmission path cannot be accessed.

Further, when the frequency of information sent from the signal frequency measuring circuit 11 becomes lower than a predetermined second frequency, the transmission right granting determination circuit 13 determines whether the transmission priority is not given to the own transmission device. The transmission right is granted (reactivated) by returning the value of the token circulation timer to its initial value.

Similarly to the first frequency, this predetermined second frequency is also changed in accordance with the transmission priority given to each transmission device, so that the transmission right reservation state of the entire network can be gradually changed. Can be set. Furthermore, the first
The frequency and the second frequency may be equal.

In this way, high traffic conditions are avoided and efficient transmission occurs.

[Effects of the Invention] As explained above, the present invention has the effect that data transmission by a transmission device with a high transmission priority can be performed efficiently during high traffic by restricting the granting of transmission rights for the entire network. . Furthermore, during low traffic, even a transmission device with a low transmission priority can send a sufficient amount of data while holding a token.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a partial configuration of a token ring type local network to which a traffic control method according to an embodiment of the present invention is applied, and FIG. 2 is a block diagram showing the transmission right determination control shown in FIG. 1. FIG. 2 is a block diagram showing a detailed configuration of a circuit. 1a...Upstream transmission line, 1b...Downstream transmission line, 2
. . . Transmission device, 3. Receiving circuit, 4. Transmission right granting determination control circuit, 5. Transmission circuit, 6. Transmission/reception buffer and transmission/reception control circuit, 11. Signal frequency measuring circuit. , 12... Token judgment circuit, 13... Transmission right grant judgment circuit.

Claims (1)

[Claims] 1. A plurality of transmission devices are connected to a ring-type transmission path, and a token is used to acquire transmission rights to the ring-type transmission path,
In a token ring local network, each of the transmission devices has a token circulation timer for monitoring the time it takes for the token to come around, and each of the transmission devices connects to its own node portion of the ring transmission path. means for measuring the frequency of a signal flowing through the transmission device; and when the measured frequency exceeds a predetermined first frequency, when the own transmission device is not given transmission priority, the token circulation timer means for suspending transmission by setting a value smaller than an initial value so that transmission is not possible even if there is a transmission request; , means for restoring the transmission right by returning the value of the token circulation timer to an initial value.