JPS61154243A - System for detecting faulty section - Google Patents

Abstract

PURPOSE:To specify correctly a faulty section by providing duplicatedly an error detection code area in a packet and allowing a packet sender device to set the result operating an operation object data to the 1st area and set the result of the code itself to the error detection code operated additionally to the 2nd area. CONSTITUTION:The error detection code area in the packet is provided duplicatedly, and the packet sender device sets the result of operation of an operation object data to generate an error detection code CK1 to the 1st area and sets the result of additional operation of the code itself to the error detection code CK1 set to the 1st area to the 2nd area. Repeaters except the packet sender repeater apply the operation of an EC2 section, check the result of operation and compare/check the result of operation with the error detection code CK1 set to the 2nd area. Then the result of operation resets the 2nd area. Since all the repeaters apply resetting, no error is propagated to specify the transmission error causing section.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting an Lf fault section in a data transmission system in which a plurality of data transfer devices are connected in series.

2. Description of the Related Art Data transmission systems in which a plurality of data transfer devices are connected in series exist in various forms for various uses.

A typical example of such data transmission systems is a packet-switched data highway.

In a packet-switched data highway, the data transmitted through the system is packetized, and the packets typically contain transmission control data, text data blocks, and some or all of the transmission control data and text data. - Consists of error detection codes that operate on blocks. Address data for the packet source and destination devices is often present in the transmission control data.

The data transfer device that generated the transmission data transmits the packet data 1? to send it inside. When transmitting data that does not match the destination address, the packet manually input from the transmission path is relayed to the opposite transmission path, and transmission errors are detected on the input transmission path using an error detection code in the data in the packet. The data transfer device that matches the destination address captures the packet and simultaneously performs transmission error detection.

If a transmission error is detected as described above, i
Each data transfer device always records the number of error detections.
A control device that controls the entire transmission system periodically collects the number of error detections of each data transfer device. If the control device finds a section where errors occur frequently from the collected number of error detections, it performs control such as looping back before and after that section.

The present invention relates to a method that can correctly identify a faulty section in the situation described above.

[Conventional Technique 1] FIG. 3 shows a typical configuration of a packet-switched data highway. In the figure, N2. N3°N4. N,
is a data transfer device called a data highway system.

T2+, Tn, Th2. '＋T5
Reference numeral 3 denotes a data communication device or a terminal device, which is connected to each channel in the respective channels to which it belongs, and actually serves as a data transmission source and a data reception source. L +, L'
2.1. , 3. L4°L5 is a transmission line connecting each node, and the arrow indicates the direction in which the data frame flows.

Each note N? , N3. N4. N, L, compares the destination address of each packet of data frames flowing on the transmission path with its own note atrus, detects errors, and performs inner box transmission to the output side transmission path.

FIG. 4 is a diagram showing the structure of the data flowing on the data high.

Data frame 11 is a frame header? The iv3° packet consists of pages #1 to #n.

Each packet includes a control data part (C'rL1.CTI, 2) which is not the object of calculation of the error detection code (CK), a calculation object part (EC) for creating the error detection code (CK),
It consists of an error detection code (CM).

The calculation target part (RC) for CK creation is data transmission destination channel -7 trace (IIA), data transmission source channel address (OA), effective data length (1, NG),
It consists of #, text data part (DATA), etc.

The data destination channel address (nA) is further
It consists of a node address field (Nx) and an intra-note channel address field (Cy).

At the data transmission source node, the error detection code (GK) is
), add it, and send it.

Each node performs error detection calculations for each packet of data frames flowing on the transmission path to detect errors.

[Problems to be Solved by the Invention] For example, when a transmission path error occurs within the transmission section Li shown in FIG. and
Transmission path errors can be detected.

However, the same packet is L 2+ r, 3. - is relayed and no error occurs on the transmission path after L2, even if N3. N4. − each node is N2
A transmission path error is detected by the same calculation as . That is, there is a problem in that a transmission error that occurs at Ll is detected at all subsequent nodes, making it impossible to identify the transmission line section where the error occurred.

The present invention aims to eliminate such problems and provide a method that can correctly identify faulty sections.

V.Means to solve the problem The problem described above is that the error detection code area in the packet is duplicated, and the packet source device uses the result of calculating the data to be calculated for creating the error detection code. 1, and the result of adding the error detection code itself to the error detection code set in the first area is set in the second area.
The data transfer device other than the packet source device calculates the calculation target data in the packet and the error detection code set in the first area, and determines the calculation result. This problem is solved by the fault section detection method of the present invention, which is configured to compare and determine the error detection code set in the second area, and further set the calculation result again in the second area.

[Operation] That is, the error detection code area in the bucket is provided in a duplicate manner, and (1) the packet source device stores the result of calculating the calculation target data for creating the error detection code in the first area, and further stores the result in the first area. The error detectability code set in the first area is subjected to an additional operation on the code itself, and the result is set in the second area.

(2) In the relay device other than the bucket source, perform calculations up to the first area, and check the calculation results. Next, the result of the calculation is compared and inspected with the error detection code stored in the second area. Next, the second area is set according to the calculation result.

Furthermore, since the 100 sets of ■ in (2) are performed in all relay devices, errors do not propagate, and the two (α) and becomes possible.

[Example] The gist of the present invention will be comprehensively explained below with reference to an example shown in FIGS. 1 and 2.

FIG. 1 is a diagram showing the pake-node configuration of an embodiment of the present invention. In FIG. 6, the same symbol Σ- as in FIG. 4 indicates the same object.

F
, c2 indicates an operation target part for creating an error detection code CK2 that is input to the second error detection code area.

ECKI has a new T! The results of calculations using cI and CKI as calculation targets are shown.

Next, the sequence of operations of each data transfer device in this embodiment will be explained.

(1) The packet source data transfer device (node) is the I
The calculation result CKl of the l, C1 part is set in the first error detection code area, and the calculation result CK2 of the l1C2 part is set in the second error detection code area.

(2) Each relay node other than the packet transmission source performs 1. C2
1. Perform the calculations for the first part and check the calculation result RCI to determine whether a transmission error has occurred on the transmission path from the source node to the self-relay node. Error detection codes used in data transmission are often cyclic redundancy codes (CRC), and the CKI is usually set to a specific value in the normal case. This point remains the same as before.

(3) Furthermore, the same relay node sets the calculation result ECKI in the second error detection code area and compares it with CK2 to determine whether a transmission error has occurred on the transmission path from the previous node to the own node. Determine whether

(4) Furthermore, the relay node resets the calculation result ECKI in the second error detection code area as a new CK2.

In the operation sequence explained above, the 20th
Since the re-separation of the detection code area is performed at all relay nodes, the calculation result 1 in (2) is
'iCK] and the calculation result ECKI in (3)
Inspection by comparing with CK2 set at the previous node,
A faulty section can be identified by performing two types of tests:

FIG. 2 is a diagram showing the fault section detection method according to this embodiment in a table format.

In the figure, 1. Previously, the transmission line section immediately before the own note was
Ln-2 indicates the transmission line section immediately before the previous node.

The three vertical columns are ■R (Jl value judgment result and ■l1C
This shows the process of occurrence of a transmission path error determined based on the results of comparing the values of K1 and (J2) and the results of (1) and (2) above.

(A) The ECKI value judgment result is normal (○), and the ECKI value is normal (○).
When KI = CM2, it is clear that there is no transmission path error before the own node.

CII) The judgment result of the FCKI value is normal (○), and the I
', CK 1≠CK2, and (C) The judgment result of the FCKl value is abnormal (×) and the EC
In the case of K1=CK2, as shown in the figure, it is possible to uniquely identify the transmission path error occurrence section.

(D) The ECKIO value judgment result is abnormal (×) and the PC
If old≠CK2, a double error has occurred, and it is determined that this is one of three cases.

In either case, it is possible to reliably determine at least whether the transmission path immediately before the own node is normal or abnormal.

Although a packet-switched data highway has been described above as an embodiment of the present invention, the present invention is not limited to this. Data highways are connected in series, and error detection codes are added. This can be applied to any data transmission system that transmits data.

[Effects of the Invention] As explained above, the present invention makes it possible to correctly determine the section in which a transmission path error occurs, and by taking appropriate measures accordingly, the reliability of the data transmission system can be significantly improved. It has the effect of -1-.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram of a Pakeso 1 according to an embodiment of the present invention, Fig. 2 is a diagram illustrating a transmission path error detection method according to an embodiment of the present invention, and Fig. 3 is a data・The system configuration diagram of Hikeei. Figure 4 is a data frame configuration diagram. In the drawing, N2. N3. N4. N is a data transfer device (node), T21, T1+, T]2. -,
T53 is a data communication device or a terminal device, L1. I-2, L 3. T-4, I, 5 are transmission lines, C
K, CKI, CK2 are error detection codes, FCI is C
EC2 is the calculation target part for creating K1, EC2 is the calculation target part for creating CK2, 1'4cK1 is PCI and CKI
The error detection calculation results are shown respectively. -9Q Q-

Claims (1)

[Claims] In a data transmission system that connects multiple data transfer devices in series and transmits data in packets,
The error detection code area in the packet is duplicated, and the packet source device sets the result of calculating the calculation target data for creating the error detection code in the first area, and further sets the result in the first area. The data transfer device other than the packet source device reads the data to be computed in the packet and the first region. The calculation result is determined by calculating up to the error detection code set in the second area, and the calculation result is compared with the error detection code set in the second area, and the calculation result is transferred to the second area. A failure section detection method characterized in that it is configured to be reset.