JPS6156540A - Transmission controller - Google Patents

Abstract

PURPOSE:To obtain an equal load between two transmission lines by measuring or estimating the amount of data received on both transmission lines of a duplicated transmission line and deciding a using transmission line according to the result of comparison between measured values of both lines. CONSTITUTION:The receiver 101 of a transmission controller produces pulses for each start of reception of data, and these pulses are counted by a counter 109. The counter 109 is reset every fixed time by a timer 111, and the contents (data receiving frequency) of the counter 109 are stored to a register 110 immediately before the counter is reset. A processor 100 reads the value of said receiving frequency out of the register 110 and transmits it to a transmission/reception terminal. At this terminal a processor 200 sets the received value to a register 208. In the same way, the value showing the receiving frequency at the other loop side is set to a register 209. Then the processor 200 compares the contents of both registers 208 and 209 with each other and selects the contents of smaller value for operation of a switch SW2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a transmission-side m-device, and in particular to a transmission control device capable of equalizing the load of each loop of the double loop in a double loop transmission system. Regarding.

[Background of the invention]

An example of a double loop transmission system to which the transmission control device of the present invention is applied is shown in FIG.

Duplicated loop transmission IIN (loop Lot loop L
l), and a plurality of pairs of transmission control devices provided on each of the transmission paths.
z eC12+...Cin and a plurality of transmitting/receiving terminals TL, T2... connected to these transmission control devices. ...T
It is composed of n.

In the double loop transmission system configured as described above, conventionally, when transmitting data from each transmitting/receiving terminal Ti (i""1 to n), a pair of connected transmission control *ICom e C11 Data may be transmitted in either direction; in other words, it is generally possible for each transmitting and receiving terminal to select a transmission control device as a destination. In some cases, all transmitting/receiving terminals may be divided into two groups, and one group of transmitting/receiving terminals may be connected to a transmission control device connected to the same loop, and the other transmitting/receiving terminal group may be connected to a transmission control device connected to a different loop. Fukagawa has also proposed a method in which data is mechanically specified to be sent to each device, and a method in which the transmitted data is divided into two groups depending on the type and data length and the loops are used differently.

However, in the above-mentioned method, if the data generation distribution is known in advance, it is possible to equalize the data transmission density (hereinafter referred to as "load") of each loop, but in general, .

Data is generated randomly, and even if each transmission/reception terminal uses a transmission control device, that is, a loop, it is not always possible to equalize the load on each loop.

This includes the problem that depending on the # condition, a long waiting time may occur at the #M end. The cause of this problem is that the conventional transmission control system or the transmission control device used therefor does not have a means for equalizing the loads on the respective loops.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of conventional transmission control systems or transmission control devices, and to provide a transmission control device capable of equalizing the loads of the respective loops.

[Summary of the invention]

The above object of the present invention is to provide a double loop transmission system comprising a duplicated loop transmission path, a plurality of pairs of transmission control devices provided on each of the transmission paths, and a plurality of transmitting/receiving terminals connected to the transmission control device. , means for measuring the amount of data received up to the present time corresponding to each of the loop transmission paths, means for estimating the amount of data received after the present time based on the output of the measuring means, and the estimation corresponding to each of the loops. This is achieved by a transmission control device that is provided with means for comparing the outputs of the means, and determines the loop transmission path to be used based on the output of the comparison means.

In the present invention, the phrase "estimate the amount of data received after the present time based on the amount of data received up to the present time" includes each of the following cases.

(1) When estimating the number or amount of data received in a certain period up to the present time as the load on the transmission control device for the same period after the present time.

(2) The number or amount of data that has been backed up in the transmission control device at a certain point up to the present time,
When estimating the load of the transmission control device at a certain point after the current time.

(3) A certain period up to the present time: When estimating the change in the loop load in a certain period up to the present time as the change in the loop load in a certain period after the present time.

[Embodiments of the invention]

EMBODIMENT OF THE INVENTION Below, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a transmission control device, and FIG. 2 is a block diagram showing an example of the configuration of a transmitting/receiving terminal. The transmission control device shown in FIG.
02. A receiver 105 which has a transmission buffer 104 and also controls transmission and reception with the transmission and reception terminals shown in FIG. Transmitter 10
7 and their corresponding reception buffers I06
, and a transmission buffer 108. In addition, the reception 481
01, a register 110 for holding the contents of the counter, and a timer 111.

The transmitting/receiving terminal shown in FIG. 2 is centered around a processing device 200, a receiver 201 connected to a transmission control device on the loop Lo (see FIG. 3), a transmitter 205, and a corresponding receiving buffer 202. A receiver 203, a transmitter 206 and a corresponding reception buffer 204 connected to the transmission control device of the loop transmission path, loop LO+loop LL
Shared transmit buffer 207. It has registers 208 and 209 that indicate the load status of each of the switch SW2 and loop LC1+loop L, which switch the transmission destination to either loop LO+loop L1.

The operation when transmitting data from the transmitting/receiving terminal having the above configuration will be described below.

The processing device 1200 compares the contents of the registers 208 and 209 indicating the load status of the loop, selects the smaller value, and operates the switch SW2 (register 20
8,209 will be described later).

Consider a case where the contents of register 208 are smaller than the contents of register 209. In this case, the processing device! 200 operates changeover switch SW to connect transmission buffer 207 and transmission 9205 to loops t and o, and at the same time stores transmission data in transmission buffer 207. The data stored in the transmission buffer 207 is transmitted from the transmitter 205, received by the receiver 105 of the corresponding transmission control device, and stored in the reception buffer 106.

The processing device ff1loo of the transmission processing device is a changeover switch SW.
1 to connect the transmission buffer 104 and the transmitter 103, and at the same time, the data to be transmitted in the reception buffer 106 is transferred to the transmission buffer 104. The data to be transmitted stored in the transmission buffer 104 is transmitted on a loop by the transmitter 103.The reception operation is the opposite of the transmission operation described above, and the data received from the receiver 101 is sent to the reception buffer 102. ii
! too, is sent to the sending/receiving terminal via the sending buffer 108 and the transmitter 107 (inside the transmission control device),
Processing device 20 via receiver 201 and reception buffer 202
reaches 0.

Here, the register 208.20 indicates the respective load status of loop LO + loop L in the above-mentioned transmitting and receiving terminal.
9 will be explained in detail.

The receiver 101 of the transmission control device generates a pulse every time it starts receiving data, and a counter 109 counts the FA pulses. This counter 109 is reset by a timer 111 at regular intervals.

Further, the register 110 stores the contents of the counter 109 immediately before the reset. That is, the contents of register 110 indicate the data reception frequency of the transmission control device. The processing unit 100 reads the value indicating the reception frequency from the register 110 and transmits it to the transmitting/receiving terminal.

In the transmitting/receiving terminal, the processing device 200 stores a value indicating the reception frequency of the transmitted data in the register 208.

Similarly, a value indicating the reception frequency transmitted from the transmission control device on the other loop side is set in the register 209. Therefore, by selecting the smaller value set in both registers, a loop with a light load (low data transmission density) can be selected.

In the above embodiment, the case where only the number of data is measured is shown, but if there is a large difference in data length, the following mode is desirable.
A pulse of 1 is generated for each data unit length (for example, 1 byte). This makes it possible to select a transmission loop based on the actual data transmission amount on the loop.

Furthermore, if we pay attention to the load on the transmission control device itself rather than the amount of data transmitted on the loop, for example, the number of buffered data in the transmission buffer 104 of the transmission control device in FIG. Since this indirectly represents the load situation, it is also possible to transmit this data number to the transmitting/receiving terminal to select a transmission control device with a light load. In order to do this more precisely, the data length of the buffering data i is set to Xl, and the buffering data is measured by the processing device 100.

D=　,Σ　X.

z=1 It is also possible to calculate and use this value.

It is also possible to use the processing unit @20o of the transmitting/receiving terminal to select a loop that is expected to have a lighter load by estimating changes in the load.

That is, when the value indicating the loop load received from the transmission control device at the current time t is yt1 and the loop load at the time τ before is yt-, the load 't+r after the time τ is calculated by the following formula. .

Yl, 10τ = 2 '1t = 'yt+ with 'It-τ
Find the value of 7 for each loop and store it in register 2.
By setting the values to 08 and 209, it is possible to quickly follow changes in load.

In the above description, the present invention is applied to a double lube transmission system in which each pair of transmission control devices can transmit and receive data to and from each other, as shown in FIG. 3. However, the present invention is not limited to this. It is also applicable to a system configuration in which transmission and reception are not possible between each pair of transmission control devices, as shown in Figure 4. (In Figure 4, the same symbols as used in Figure 3 indicate the same components ), furthermore, as shown in FIG. 5, the two double loop transmission systems shown in FIG.
Even in a multi-loop transmission system coupled by LJ, it is possible to equalize the loads of each loop by applying the present invention to the loop coupling device.
In FIG. 5, symbols other than the loop coupling device LJ are assigned according to FIG. 1).

[Effect of the invention 3 As described above, according to the present invention, a duplex loop transmission path, nine pairs of transmission control devices provided on each of the transmission paths, and a plurality of transmitting/receiving devices connected to the transmission control device are provided. In a double loop transmission system consisting of terminals, a means for measuring the amount of data received up to the present time corresponds to each loop transmission path, and a data receiver is estimated from the present time based on the output of the tX measuring means. A means for comparing the outputs of the estimating means corresponding to each loop is provided, and the loop transmission path to be used is determined based on the output of the comparing means, so that the load on the pig to be transmitted is reduced. It is now possible to always select the smaller loop,
As a result, it has the remarkable effect of making it possible to transmit all the data to be transmitted with a relatively short response.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing a transmission control device and a transmitting/receiving terminal according to an embodiment of the present invention, FIGS. 3 and 4,
FIG. 5 is a diagram showing an example of a double loop transmission system to which the present invention is applied. -LOeLl: Loop transmission line/COl ""'C011pC1l~Cxn: Transmission control device, T, ~'r: Transmitting/receiving terminal, 100,200
: Processing device, 101゜105.201, 203: Receiver, 103, 107.205, 206: Transmission @, 1゛02
,106°202.204: Receive buffer, 104,1
08°207: Transmission buffer, 109: Counter, 11
O: Register, 111: Timer% 208, 209: Register. Figure 1 Figure 2

Claims (1)

[Claims] In a double loop transmission system comprising a duplicated loop transmission path, a plurality of pairs of transmission control devices provided on each of the transmission paths, and a plurality of transmitting/receiving terminals connected to the transmission control devices, each of the loop transmission paths correspondingly, means for measuring the amount of data received up to the present time, means for estimating the amount of data received after the present time based on the output of the measuring means, and means for comparing the outputs of the estimating means corresponding to each of the loops. 1. A transmission control device characterized in that a loop transmission path to be used is determined based on the output of the comparing means.