JPH0574257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission control method in an information transmission system. That is, the present invention has two transmission paths that transmit data in opposite directions, and has a function of transferring data between the two transmission paths.
The purpose of the present invention is to provide a transmission control method for detecting an abnormality in a transmission path and detecting an abnormal location in an information transmission system in which a plurality of transmission control devices that control data transmission via these two transmission paths are connected. shall be.

In the information transmission system described above, the present invention is realized by a data transfer function between transmission lines provided in a transmission control device, and transmits a loop check signal to a loop formed by at least two transmission control devices and two transmission lines. Each transmission control device independently determines whether or not to perform transfer between transmission lines, transmits a check signal, and monitors the response.

Hereinafter, in this specification, the transmission path is composed of two loop lines, and the transmission control equipment is a transmission control device (Network Control Processor, hereinafter referred to as "Network Control Processor") arranged in pairs on each of the two loop lines.
It is called NCP. ) and a bidirectional loop link line that connects a pair of NCPs. In such a loop transmission system, data transmitted through a loop link line is called a "detour", and a loop having two such detours is called a "middle loop". In addition, it is formed only by loop lines, that is, the loop that goes around the loop line is formed by two adjacent NCP pairs of the large loop and the medium loop, and the data is
A loop that goes around the NCP is called a small loop. Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

FIG. 1 shows an example of the basic configuration of the device according to the present invention, and includes loop lines L0, L1, and NCP01 to NCP01.
0n and 11 to 1n and the loop link line 21
~2n and terminal link lines 31 and 32, and a test terminal 30.

Next, Figure 2a shows an example of the frame structure of transmitted data, where FC is a function code.
A code corresponding to the content of the data (Date) that follows this is attached. Note that FIG. 5B will be described later.

FIG. 3 shows an example of the block configuration of the test terminal 30, in which 300 is a processing device, 310 and 311 are interfaces for exchanging data with each terminal link line 31, 32, 320 is an input device, 321 is an output device, 330 331 is a transmission buffer, 340 is a timer, and 341 to 343 are registers.

Also, Figure 4 shows NCP01~0n and 11~1n, for example.
An example of the block configuration of NCP01 is shown. 40 is a processing unit, 51 to 54 are interfaces for transmitting and receiving data with the line, 51 is a bidirectional interface for terminal link line, and 52 is a bidirectional interface for loop link line. Aces, 53 and 54 are unidirectional interfaces for loop lines. Further, 61 is a reception buffer, 62 is a transmission buffer, 70 and 83 are counters, 71, 72 and 81, 82 are registers,
73 is a memory, and 80 is a timer.

Next, an overview of the operation of the test terminal 30 will be explained.

(1) Test start When a test start signal is input from the input device 320, the processing device 300 creates a test start command for the NCP, stores it in the transmission buffer 331, and sets a flag specifying the transmission line in the register 342. stand on

The line interface 310 or 311 designated by the register 342 transmits the data in the transmission buffer 331 to NCP01 or 11, and at the same time, the timer 340 is reset.

(2) During the test period When the test terminal 30 receives data from the terminal link lines 31 and 32, the data is transferred to the reception buffer 33.
0, and a flag indicating the receiving line is set in the register 341. The processing device 300 outputs the received data and the receiving line number to the output device 321.

(3) End of test The processing device 300 uses the timer 340 and the register 34.
Compare the contents stored in advance in 3, and if the contents match, and if a termination command is input from the input device 320, create a test termination command and send it from the interface 310 or 311 to NCP01 or 11. Send.

Next, we will explain the transmission/reception processing operation in NCP to NCP01.
This will be explained using an example.

(1) Reception Process When data is received by any of the NCP interfaces 51 to 54, the received data is stored in the reception buffer 61, and a flag indicating the reception line is set in the register 71. Processing device 4
0 is the function code FC of the received data, and the memory 73
Check with the code table stored in advance,
The processing of the received data is determined based on the contents of the register 71 (the number of the receiving circuit) and is processed.

(2) Transmission processing When data to be transmitted occurs, the processing device 40
sets a flag specifying the transmission line in the register 72 and stores the transmission data in the transmission buffer 62. Next, one of the interfaces 51 to 54 corresponding to the contents of the register 72, that is, the designated line, transmits the data in the transmission buffer 62 to the line.

The operation of each part in the system of the present invention will be explained below.

The NCP that received the data checks the contents of the memory 73 and the function code FC of the received data.
If it determines that this is a test start command, it creates loop check data in the configuration shown in FIG. 2b and transmits it to the loop line L0 or L1 to which it belongs. In Fig. 2b, FC is a function code, that is, in this case, a function code indicating that the data is medium loop check data, N is a parameter indicating the size of the medium loop to be checked, and CN
is a count value that integrates the number of NCPs that this data has passed through, and has an initial value of 1. In addition, the flag is connected to the test terminal and NCP
= Set when received on CN.

FIG. 5 shows an example of the configuration of the middle loop starting from NCP01. The form of the check data used to test the middle loops 0-i and 1-i is FciCN0, and CN is incremented by 1 each time it passes through one NCP, as described above. In addition, the ● mark inside the ○ mark indicates NCP.
Indicates the starting point where check data is created and sent.

Regarding this middle loop check method, the following 2
The method of two embodiments is shown.

Method 1: This method transfers all middle loop and check data to the NCP that receives the test start command from the test terminal.
(hereinafter referred to as the test starting NCP) is created and sent to the loop line to which it belongs.

FIG. 6a shows middle loop check paths 0-1 and 0-2 in which NCP01 is the test start NCP, as an example of the middle loop check according to this method. Note that the path indicated by the broken line is the flow of check data.
Also, the numbers (1, 1) and (1, 2) attached to the broken line
... is the N (loop size) and CN (number of NCPs passed through) of the check data transmitted in that part
shows. The middle loop check data transmission control according to method 1 will be described below.

When the test start NCP receives the test start command, it puts the value of N (=1) into the counter 70, creates middle loop check data Fc110, sends it to the neighboring NCP through the loop line to which it belongs, and resets the timer. , clears the counter 83. The value in the counter 70 is the size of the middle loop being tested, that is, the value of N of the middle loop check data waiting to be received, and the timer 80 is used to measure the time since the check data was sent. When the check data does not return within a predetermined time, the counter 83 counts up and records the number of retransmissions when the same check data is sent again (retransmission).

The processing device 40 of the NCP that has received the middle loop check data performs arithmetic judgment based on N and CN of the received data, and performs the following processing.

(1) When CN=N: Check the contents of the counter 70 and the value of N in the check data. (a) If they match, set a flag in the flag section of the check data and set the value of CN to 1. The check data increased by the amount is sent to the paired NCP via the loop ring line.

(b) If they do not match, send medium loop check data with the CN value incremented by 1 to the paired NCP via the loop ring line.

(2) When CN=2N+1: The medium loop check data with the CN of the received data increased by 1 is sent to the paired NCP through the loop ring line.
Send to.

(3) When CN=2N+2: Check the contents of the counter 70 and the value of N in the check data. (a) If they do not match, it is determined that a transmission error has occurred in this check data and it is deleted. .

(b) If they match, send the data indicating that loop N is normal in this check data.
The check data is sent to the test terminal via the terminal link line, and it is checked whether a flag is set in the flag section of this check data.

If it is not set, the counter 70
is increased by 1, this value is set as the value of N, medium loop check data FcN10 is created, and transmitted to the loop line to which it belongs. At the same time, the timer 80 is reset and the counter 83 is cleared.

If the flag is set, new medium loop check data is not created, but data indicating that the test has completed normally is created and sent to the test terminal via the terminal link line, and the data is sent to the counter 7.
Clear 0 and 83.

(4) If the above does not apply: The middle loop check data with the CN of the received data incremented by 1 is sent to the adjacent through the loop line.
Send to NCP.

Timeout judgment: The NCP that sent the middle loop check data
If the transmitted check data is not returned within a predetermined time, it is determined that it has timed out and retransmission is performed. A timeout is determined by comparing the contents of a register 81, in which a predetermined time value is stored, with the contents of a timer 80, and if the latter is greater than the former, a timeout is determined.

Retransmission processing: When a timeout is determined, the following retransmission processing is performed.

A counter 83 that records the number of retransmissions performed for medium loops of the same size is compared with the contents of a register 82 in which the maximum number of retransmissions is previously stored.

(1) If both match, it is determined that there is an abnormality in the middle loop whose size is the value (N) in the counter 70, and the counter 70
, and data indicating abnormal termination are created and transmitted to the test terminal via the terminal link line, and the counters 70 and 83 are cleared.

(2) They do not match (the former is smaller than the latter)
In this case, medium loop check data FcN10 is created with the value in the counter 70 as N, and is retransmitted to the adjacent NCP via the loop line, the timer 80 is reset, and the counter 83 is incremented by one. This retransmission process is repeated until the retransmitted check data goes through a loop of size N and returns to normal, or until the abnormal termination as described in (1) above occurs.

Hereinafter, the case where there are a plurality of test terminals in method 1 will be explained with reference to FIG. 6b.

In FIG. 6b, consider the case where NCPa and b perform a middle loop check. Here, middle loop check data a(n,
Suppose that m) and b(n, m) flow. Note that a and b indicate the NCP of the transmission source. Further, as described above, n and m are the N and CN of the check data, that is, the parameter indicating the size of the middle loop to be checked, and the accumulated value of the number of NCPs through which the data has passed.

In the worst case, immediately after NCPb sends loop check data of size n, the loop check data of size n sent by NCPa becomes N.
When the check data is received by NCPb in the state of =CN (=n), a flag is set in this check data. As a result, when this check data goes around the path indicated by the broken line and returns to the NCPa, the flag is set on the returned check data, so the NCPa does not create any larger medium loop check data.

In this way, when tests are performed simultaneously by multiple test terminals, in the worst case, each test terminal may be able to test only part of the transmission system, that is, the middle loop up to the adjacent test terminals. When the parts tested by each test terminal are combined, the entire transmission system is covered and the entire test is performed.

Method 2: In method 1 above, all middle loop check data is created by the test starting NCP, but in method 2,
When the test start NCP receives a test start command from the test terminal, it creates only the middle loop check data of the Fc110. Medium loop check data where N is 2 or more is created by the NCP on the loop line to which the test starting NCP belongs. For this purpose, the following processing is performed.

The NCP that received the test start command from the test terminal (test start NCP) uses the counter 7 as in method 1 above.
The contents of 0 are set to 1, the timer 80 is reset, the counter 83 is cleared, medium loop check data is created in the Fc 110, and the data is sent to the adjacent NCP via the loop line.

The NCP that received the middle loop check data
The values of N and CN of the received check data are compared and the following processing is performed.

(1) When CN=N: Compare the contents of the counter 70 with the value of N in the received check data.

(b) If both match, set a flag in the flag section of the received check data, increment the value of CN by 1, and send it to the paired NCP via the loop link line.

(b) If the two do not match, increase the CN value of the received check data by 1 and connect the pair using the loop link line.
At the same time as transmitting it to the NCP, medium loop check data is created by increasing the values of N and CN of the received check data by 1, and is transmitted from the loop line to the neighboring NCP.

(2) When CN=2N+1: Increase the CN value of the received check data by 1 and send it to the paired NCP via the loop link line.

(3) When CN=2N+2: Compare the contents of the counter 70 with the value of N in the received check data.

(b) If the two do not match, it is assumed that there is a transmission error and the received check data is deleted.

(b) If the two match, check the flag section of the received check data.

If the flag is not set, the value of N in the received check data is transmitted as data to the test terminal via the terminal link line, the counter 70 is incremented by 1, the timer 80 is reset, and the counter 83 is cleared. If the flag is set, the N value of the received check data and data indicating that the test has completed normally are created and transmitted to the test terminal via the terminal link line, and the counters 70 and 83 are cleared.

(4) If (1), (2), or (3) above does not apply, increase the CN value of the received check data by 1 and send it to the adjacent NCP via the loop line.

The test start NCP sets CN=2N+2 and N=the contents of the counter 70 (the value of N of the check data waiting to be received) until the value of the timer 80 matches the contents of the register 81 specified in the timer out time. If check data is not received, it is determined that a timeout has occurred, and the same retransmission process as in method 1 is performed.

An example of the middle loop check using method 2 is shown in Figure 7a.
Shown below. In this case, NCP01 is the test starting NCP.

In method 2, the case where a plurality of test terminals are provided will be explained with reference to FIG. 7b.

In the worst case, when NCPb is waiting for middle loop check data of N=n (the contents of the counter 70 is n), when the check data of the middle loop check starting from NCPa becomes N=CN=n and reaches NCPb, NCPb does not create new check data by receiving this check data. Therefore, NCPa can only receive medium loop check data up to NCPb. However, NCPb checks the middle loop after NCPb. Therefore, if the parts checked by each test terminal are combined, the entire area of the transmission system is covered and the entire area has been checked.

In this way, using either method 1 or method 2, if the transmission path is normal, all middle loop checks are performed, and all of the data is stored at the start of the test.
Sent from NCP to test terminal.

If there is a disconnection of the line or a failure of the NCP,
The middle loop check data that must pass through the abnormal location is not received by the test initiation NCP.

Also, in some NCP, calculation judgment processing of N and CN
Even if a CN's count-up processing is not performed normally, the middle loop check data that must pass through that NCP will not be received by the test starting NCP.

The middle loop check is performed using one connected to the test terminal.
Both of the paired NCPs are used as the starting NCPs. Therefore, by knowing the reception line output from the test terminal, that is, the test start NCP and the value of N of the medium loop check that was performed normally or the value of N of the medium loop check that was found to be abnormal, the tester can check the transmission path. It is possible to detect the presence or absence of an abnormality and the location of the abnormality.

Next, the end of the test is determined by the timeout described in the test end operation (3) of the test terminal and the input device 32.
By inputting the end command from 0. At this time, the test terminal creates test termination command data using the processing device 300, transmits this data to the NCP connected to the test terminal, and then stops. The NCP that receives the test end command data clears counters 70 and 83.

As described above, the transmission control method of the present invention has the advantage that it is possible to estimate not only the presence or absence of an abnormality in the transmission path, but also the location of the abnormality, and its effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Figs. 2 a and b are explanatory diagrams showing an example of the structure of general data and check data to be transmitted, and Figs. 3 and 4 are diagrams of a test terminal and a transmission control device. The configuration diagrams illustrating each embodiment and FIGS. 5 to 7 are explanatory diagrams each showing an example of the configuration of an intermediate loop formed in a transmission path. 21~2n...Loop link line, 31, 32
...Terminal link line, 30...Test terminal, 01~
0n, 11-1n...Transmission control device, L0, L1
...Loop line.

Claims (1)

[Claims] 1. Two transmission paths that transmit data in opposite directions, and a plurality of transmission paths that control the transmission of data on the two transmission paths and the detour of data from one of the transmission paths to the other. In an information transmission system having a transmission control device, the size of an intermediate loop formed by at least two transmission control devices including the transmission control device and the two transmission paths is calculated from any of the transmission control devices. Each of the transmission control devices on the middle loop that has received the check signal transmits the check signal based on the information in the check signal. In addition to determining whether or not to cause the transmission to take a detour, the information regarding the transmission control equipment that has passed through the route is updated and transmitted, and the above-mentioned information is transmitted based on the response to the check signal received by at least one of the transmission control equipment on the middle loop. A transmission control method characterized by performing a test within the middle loop. 2. The transmission control device is configured to include a pair of transmission control devices provided on each of the two transmission lines, and a link line that connects the pair of transmission controls, and the detour is made by connecting the link line to the pair of transmission control devices. 2. The transmission control method according to claim 1, wherein the transmission control method is carried out by transferring data between the pair of transmission control devices via the transmission control device.