JPH0630467B2 - Optical loop monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A monitoring device for monitoring an optical loop having a plurality of nodes, comprising a supervisory control unit duplicated in an active system and a standby system, and a monitoring control unit for the active system and the standby system. It consists of a network supervisory processor that further monitors the supervisory control unit, and the pair of supervisory control units and the network supervisory processor are all configured as a single device in the same node, so that the standby system can be protected from the active system when a failure occurs. It is possible to speed up the switching to the system and reduce the cost of the device.

[Industrial application field]

 The present invention relates to an optical loop monitoring device.

In recent years, optical communication using an optical fiber has become widespread, and a loop type optical LAN (Local Area Network) having an optical loop has been put into practical use. This optical loop generally has a plurality of nodes, and each node has a plurality of terminals under its control, and remote terminals exchange data with each other via the node and the optical transmission path. Even in such an optical loop network, improvement of reliability is the most important issue, and a duplex system is usually adopted. At the same time, a monitoring device is connected to the optical loop to monitor the occurrence of a failure in the network. This monitoring device is also usually composed of an active system and a standby system in accordance with the duplex system. This is because the failure of the monitoring device causes the system down.

[Conventional technology]

FIG. 5 is a system diagram showing a conventional optical loop monitoring device and its peripheral equipment. In the figure, a monitoring device 14 is particularly related to the present invention, and includes a monitoring control unit (SV0) 10 of an active system (0 system), a monitoring control unit (SV1) 11 of a standby system (1 system), A network monitoring processor (NSP: Network Service Processor) 12 that further monitors the units 10 and 11, and modem cables 13-0 and 13-1 connecting the units 10 and 11 and the processor 12 to each other. 15
Monitor the whole.

The optical loop 15 has a plurality of nodes 16, and the supervisory control units 10 and 11 also make up each node. The other nodes 16 are multiplexer nodes (MX), to which at least one terminal 17 is connected. 18
Is an optical transmission line.

FIG. 6 is a diagram specifically showing a conventional monitoring device, in which the active monitoring control unit 10 and the standby monitoring control unit 11 are also shown.
Both have the same configuration. The unit 10 (20) is an electric / optical converter (E / O) connected to the duplicated optical transmission line 18.
21-0, 22-0 (21-1, 22-1), optical / electrical converter (O / E) 23-0, 24-0 (23-1, 24-1), and demultiplexing unit ( CC) 25-0 (25-1) and control unit (PC) 26
-0 (26-1) and the above-mentioned modem cable 13-
0 (13-1) to connect to the common network monitoring processor 12. The demultiplexer 25-0 (25-1)
Extracts the monitoring bit in the time-division multiplexed transmission frame, or puts the monitoring data on the monitoring bit. The control unit 26-0 (26-1) has a built-in microcomputer and controls the entire unit 10 (11).

Normal data transmission is performed via the optical transmission line 18-0 of the active system (0 system), and the optical transmission line 18-1 of the standby system (1 system) is a standby. In this case, the supervisory control unit 1 of the standby system
In 1, the transmission data is simply passed (bypass). If unit 10 fails,
The standby system unit 11 is switched to, and in the unit 10 which has been the active system until now, the transmission data simply passes.

The network monitoring processor 12 determines by polling whether or not the above-mentioned failure has occurred. FIG. 7 is a sequence diagram showing a conventional system switching procedure, and a system switching command is finally issued to the supervisory control unit (SV1) 11 of the standby system by polling from the processor (NSP) 12. The sequence in this figure is based on an example in which a failure occurs in the supervisory control unit (SV0) 10 of the active system at the time of the mark x in the figure. In response to the polling from the NSP, SV0 returns a response indicating that it is normal.
Next, the same polling is performed on SV1, and a normal response is similarly received. The so-called polling cycle until polling SV0 again is, for example, about 10 seconds.

By the way, there is no normal response from the SV0 to the polling from the NSP (dashed arrow), since the failure occurs with the cross mark. The NSP then polls again, for example after 5 seconds. This is a so-called retry. This is because if there is an instantaneous failure, a normal response should be returned by retrying. In addition, the NSP polls at the next timeout (after 5 seconds) to make sure, and waits until the next timeout to confirm that no response has been received, and issues a system switching command from SV0 to SV1. . After that, SV1 becomes active and data transmission is continued. On the other hand, the fault search and restoration in the SV0 system are performed.

[Problems to be solved by the invention]

As is apparent from the sequence diagram of FIG. 7, the polling cycle is as long as about 10 seconds and the retry interval is as long as about 5 seconds. The reason is that the line speed via the modem cable 13-0 (13-1) is slow. Therefore, in the example of FIG. 7, there is a problem in that the system switching is finally performed 20 seconds after the occurrence of the failure, and the reliability of the system is considerably hindered. It goes without saying that in any case removal of obstacles should be done promptly.

On the other hand, referring to FIG. 6, the electrical / optical converter (E /
O) and optical / electrical converter (O / E) are one monitoring device 1
You also need 8 sets in 4. However, there is a problem in that these converters are expensive and result in high cost of the monitoring device.

The present invention has been made in view of the above-mentioned problems, and an optical loop monitoring apparatus satisfying both rapid system switching and cost reduction by reducing converters (E / O, O / E). The purpose is to provide.

[Means for solving problems]

FIG. 1 is a diagram showing the principle configuration of an optical loop monitoring device according to the present invention. In the figure, the same components as those already described are denoted by the same reference numerals or symbols (the same applies hereinafter). The optical loop monitoring device 30 includes an active monitoring control unit 31-0, a standby monitoring control unit 31-1, and a network monitoring processor 12 for detecting the presence / absence of a failure in these units 31-0 and 31-1. , The optical / electrical converter 3 shared by these units 31-0, 31-1
2 and these are integrated into a single device and housed in one node 16.

As described above, the main part of the supervisory control unit 31-0 (31-1 is the same) is the demultiplexing unit (CC) 25-0 (25-1) and the control unit (PC) 26-0 (26-1). Consists of. Also,
The optical / electrical converter 32 is composed of an optical / electrical converter and an electric / optical converter, and is used for the optical transmission lines 18-
0,18-1.

[Work]

As shown in FIG. 1, the supervisory control units 31-0, 31-
1, the processor (NSP) 12, the optical / electrical converter 32, etc. are all assembled into a single device and housed in the same node 16. Here, the single device is, for example, an IC group mounted on one wiring board, and therefore, data exchange between the unit 31-0 and the unit 31-1,
Data can be exchanged between the units 31-0 and 31-1 and the processor (NSP) 12 in real time by a signal line wired on the same board. As a result, a command from the processor (NSP) 12 for detecting a failure in the supervisory control unit 31-0 of the active system and switching to the standby system is performed very quickly.

On the other hand, since the units 31-0 and 31-1 are provided on a single device, it is not necessary to provide an optical / electrical conversion unit for each unit, and a single shared optical / electrical conversion unit is not required. The part 32 can be introduced. This allows the converter (O /
The total number of (E, E / O) is halved compared to the case of FIG. 6, and the cost of the optical loop monitoring device is greatly reduced.

〔Example〕

FIG. 2 is a diagram showing a specific example of the optical loop monitoring apparatus according to the present invention, and particularly shows the optical / electrical converting section 32 in detail. The optical / electrical converter 32 is an electric / optical converter (E /
O) 21,22 and optical / electrical converter (O / E) 23,24. These are the optical transmission lines 18-0 for the active system and the standby system,
Connected as shown in 18-1.

Since the optical / electrical conversion unit 32 is shared, it is necessary to selectively use the monitor / control unit 31-0 or 31-1 of the active system or the standby system. For this purpose, changeover switches 33-0 and 33-1 are provided, and the processor (NS
Under the control of P) 12, either the active system or the standby system is selected.

As mentioned above, a single device (IC on one wiring board
Group), the control unit (PC0) 26-
The first path 41 may be provided between 0 and the processor (NSP) 12 as well as the control unit (PC1) and the processor (NSP).
It is extremely easy to form the second path 42 between the first and second terminals 12 and 12 and further form the third path 43 between the control section 26-0 and the control section 26-1. Then, it becomes possible to quickly detect a failure and generate a switching command using these paths.

FIG. 3 shows a first system switching procedure applicable in the present invention.
It is a sequence diagram which shows an example. How to read this diagram This is the same as the case of FIG. 7 described above. First, the network supervisory processor (NS) 12 polls the supervisory control unit (SV0) 31-0 via the first path 41 (FIG. 2) and receives a response indicating normality through the path. This point is the same as the conventional procedure. At this time, the processor NSP is the supervisory control unit (SV1) of the standby system.
31-1 requests polling. This is done via the second pass 42 (FIG. 2). This polling request is issued from the standby system unit SV1 to the active system unit SV0.
To poll. By this instruction, polling is performed to SV0 via the third path 43 (FIG. 2), and if normal, a response is received through the same path. In addition, the processor NSP uses the second pass 4
It also polls SV1 via 2 and receives a response that it is normal.

Now, suppose that a failure occurs in SV0 at the time of the X mark in FIG. Then, a normal response is not returned to the same polling 'as the above polling (dotted arrow pointing left in the figure). Further, there is no normal response from SV0 to a polling 'from SV1 to SV0 based on a polling request' similar to the above polling request (right dotted arrow in the figure). Then, SV1 waits for the next polling '(path 42) from the NSP and waits for SV0.
Is returned as an abnormal response to the NSP via the same path 42. Here, the NSP itself is the SV
When the abnormality of 0 is detected and the same abnormality notification is received from SV1, it is determined that the failure of SV0 is certain, and the system switching command is issued to SV1 via path 42.
After that, SV1 becomes active and data transmission is continued. On the other hand, the fault search and restoration in the SV0 system are performed.

In the sequence shown in FIG. 3, the time required from immediately before the occurrence of the fault (x) to the time when the system switching command is issued is as shown at the left end in the figure, and is ten or more seconds. This is half the length of the conventional case (Fig. 7). Such high-speed switching is possible because it is processed in a single unit without using a modem cable as in the past. Similarly, the system switching can be speeded up by the following procedure.

FIG. 4 is a second system switching procedure applicable in the present invention.
It is a sequence diagram which shows an example. However, in executing this system switching procedure, it is convenient to provide an active system register and a standby system register. These registers are
The control units 26-0 and 26-1 of FIG. 2 are designated by reference numerals 51-0 and 51-1 respectively. These registers are, so to speak, stator registers, and are used in the supervisory control unit (S
When V0) 31-0 and (SV1) 31-1 detect an internal failure by their own hardware, a flag bit is set in the corresponding register 51-0, 51-1. A so-called watchdog timer is an example of the above hardware. The processor (NSP) can issue a system switching command at high speed by checking the presence or absence of the flag bit.

The view of FIG. 4 is the same as that of the above-mentioned FIG. 7. First, from the NSP to the active SV0, the first path 41 (second
The register (REG) 51-0 is read out via the figure. If there is no failure, you will receive no error via the same path. The NSP also performs REG reading on the SV1 of the standby system via the second path 42. If normal, you will receive no abnormality through the same pass. Below, above ,,,
Repeat the same exchange as.

Now, suppose that an SV0 failure (indicated by a cross) occurs in any of the periods D in the figure. Then, SV0
Sets a flag bit indicating a fault occurrence in its own register 51-0. This is detected in the REG read 'from the NSP, and the abnormality detection is returned to the NSP via the path 41. The NSP sends a system switching command to the SV1 via the path 42. After that, activate SV1 and
Performs SV0 failure search and recovery. In this case, the time until the system switching command is sent is several 100 ms.

〔The invention's effect〕

As described above, according to the present invention, it is possible to realize an optical loop monitoring device that can shorten the time from the occurrence of a failure to the system switching and reduce the device cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of an optical loop monitoring device according to the present invention, FIG. 2 is a diagram showing one specific example of an optical loop monitoring device according to the present invention, and FIG. 3 is a system applicable to the present invention. First switching procedure
FIG. 4 is a sequence diagram showing an example, and FIG. 4 is a second system switching procedure applicable in the present invention.
Fig. 5 is a sequence diagram showing an example, Fig. 5 is a system diagram showing a conventional optical loop monitoring device and its peripheral equipment, Fig. 6 is a diagram specifically showing the conventional monitoring device, and Fig. 7 is a conventional system switching procedure. It is a sequence diagram shown. 12 ... Network monitoring processor, 15 ... Optical loop, 16 ... Node, 18 ... Optical transmission line, 30 ... Optical loop monitoring device, 31-0, 31-1 ... Supervisory control unit, 32 ... Optical -Electrical converter, 41 ... 1st pass, 42 ... 2nd pass, 43 ... 3rd pass.

Claims (3)

[Claims] 1. A working system and a standby system for monitoring an optical loop (15) comprising an optical transmission line (18) and a plurality of nodes (16) inserted in the optical transmission line (18). Redundant supervisory control units and system switchover that detects the presence or absence of faults in each of these supervisory control units and, when a fault occurs, switches the system from the active supervisory control unit to the standby supervisory control unit. An optical loop monitoring device comprising a network monitoring processor (12) for sending a command, comprising: a monitoring control unit (31-0) of a working system, a monitoring control unit (31-1) of a standby system, and the network. The monitoring processor (12) is integrated into a single device and accommodated in one node (16), and the optical transmission line is further included.
A single optical-electrical converter (3) shared by the unit (31-0) and the unit (31-1) for connection with (18).
An optical loop monitoring device having 2). 2. A first path (41) for polling from the network monitoring processor (12) and receiving a response from the active monitoring and control unit (31-1), and polling from the processor (12). It is a path used to receive the response from the supervisory control unit (31-1) of the standby system, and a polling request from the processor (12) is also made to the standby unit (31-1), A response regarding normality or abnormality of the active system unit (31-0) is returned to the standby system unit (31-).
The second path (42) received from 1), and the standby unit (31-1) polling the active unit (31-0) based on the polling request, and receiving the response. 3 paths (43) are provided in the single device, and the abnormality of the working system unit (31-0) detected through the first path (41) and the second path (42) and Third pass
The optical loop monitor according to claim 1, wherein the system switching command is transmitted from the processor (12) when the abnormality of the working system unit (31-0) detected through the (43) coincides. apparatus. 3. A monitor control unit (31-0) for the active system
A register (51-0) that sets a flag bit for displaying the self-detected fault in itself, and displays the self-detected fault in the standby supervisory control unit (31-1). A register (51-1) for setting a flag bit for setting, a first path (41) for reading the register (51-0) from the network monitoring processor (12), and the processor (12) to A second path (42) for reading the register (51-1) is provided in the single device, and when the flag bit is set in the register (51-0), the processor ( The optical loop monitoring device according to claim 1, wherein the system switching command from the active system to the standby system is transmitted from 12).