JPH0797783B2 - Fault monitoring control method in switching network - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supervisory control method in a switching network that monitors a fault and manages a connected call during connection.

[Conventional technology]

Conventionally, as a supervisory control system in this type of switching network, for example, there is one disclosed in Japanese Patent Laid-Open No. 59-2467. In this fault control system, each switching device is positioned as an equal device, and faults are monitored by exchanging test packets with each other.

That is, one switching device sends a test request packet, causes another switching device to perform a predetermined test, and then receives a test result notification packet to grasp the failure status in the network, and based on the status. , Determines the routing of packets in the switching device.

[Problems to be solved by the invention]

As described above, the conventional fault monitoring control method in the switching network monitors the faults that naturally recover in each switching device in a distributed manner. If this result is used not only for routing but also for call management, each switching The fault condition recognized by the device depends on its detection timing, and for that reason call management (when terminals in one switching device and terminals in another switching device are communicating through those switching devices,
There is a problem in that there is a possibility that a connection call such as one-sided disconnection may occur due to a difficult difference (such as determination as to whether the call is established or not) in those exchanges.

The present invention has been made in order to solve the above-mentioned problems, and centrally performs call management or the like for a failure of each switching device or a failure of a transmission line to disconnect one side of a call (one switching It is an object of the present invention to obtain a fault monitoring control system in a switching network with high reliability in which a device is in a call connection state and the other switching device does not disconnect the call.

[Means for solving problems]

A fault monitoring control system in a switching network according to the present invention is connected to a plurality of switching devices in the switching network via a fault monitoring path and includes a management device for centralized management, and centralizes management of fault conditions in the switching network. It was done.

[Work]

The fault monitoring control method according to the present invention makes it possible to prevent the recognition of the fault condition of the switching device managed by the management device from occurring.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a ring management device (hereinafter referred to as RME), 2 is a ring switching device (hereinafter referred to as RAE), 3 is a transmission line, 4 is a terminal, 5 is a logical fault monitoring route, and 6 is an in-station. , And 7 is a connection call between stations. The logical fault monitoring path 5 is, for example, a channel secured by the time division multiplexing method in the transmission path 3 or a logical fault formed by adding a fault monitoring command / response to transmitted information. It is realized by various routes.
2 to 5 are diagrams showing an operation example of RME and RAE in the switching network shown in FIG. 1. In each figure, 8 and 12 are health check commands, 9 is a health check response, and 10 is an inter-station communication. Fault recovery processing such as forced call disconnection, 11
RAE failure notification, t ₁ is the time of the health check interval, t ₂
Is RAE and transmission path failure detection time in RME1, t ₃ is RAE
Indicates the transmission path failure detection time in 2.

Next, referring to FIGS. 2 to 5, the RM shown in FIG.
The operation of E and RAE will be described.

First, the RME1 performs fault monitoring with all the RAE2s connected in the ring via the logical fault monitoring route 5, and this fault monitoring can detect faults in the transmission line 3 and RAE2. You can Logical fault monitoring path 5 is RME1
Alternatively, RAE2 sends an information frame to which a destination address and a source address are added to transmission line 3, and RME1 or RAE2 having the same local address as the destination address fetches the information frame from transmission line 3 To do. For example, as shown in FIG. 2, when a failure occurs in a certain RAE2, the health check response 9 to the health check command 8 of the t ₁ time period sent from RME1
Response will not be sent back from that RAE2. Therefore, RME1
Considers the RAE2 to be abnormal after the stipulated t ₂ hours, and to that effect as the RAE failure occurrence notification 11 the RAE that caused the failure.
Notify all RAE2 except 2. Each RAE2 that received the notification
Performs a fault recovery process 10 to forcibly disconnect the inter-station call (for example, the connection call 7 in FIG. 1) between the faulty RAE2. That is, the failure recovery processing 10 means processing for canceling the call connection in the local station between the RAE2 in which the failure has occurred and the other RAE2. This ensures that all RAEs except the failed RAE
The call between and becomes disconnected.

At this time, it is not necessary to disconnect the intra-office call (for example, the connection call 6 in FIG. 1), and the communication between the terminals 4 can be continued as usual.

When the faulty RAE2 recovers, the RAE2 has a health check command 12 that also serves as a fault detection notification from the RME1 (for example, the health check command 8 with information indicating that an abnormality has been detected is added). By receiving the RAE2 itself, the RAE2 itself's fault recovery process 10 (call disconnection process between the faulty RAE2 (in this case, its own station) and another RAE2) is started, and then the health check command 8 The health check response 9 is returned to the normal state.

When a failure occurs in RAE2, a call with another RAE (for communication between two terminals 4 in the system and via the failed RAE2) may be disconnected. Yes, but sometimes it remains connected. But like this, when that RAE2 recovers from the failure,
If the call is disconnected when the health check command 12 is received from RME1, it is always possible to prevent the call from being cut off at this point (as described above, the other RAE disconnects the call with the RAE2). It is in a state).

Next, an operation example when a failure occurs in the transmission line 3 will be described with reference to FIGS. FIG. 3 shows a case where the transmission line fault condition is shorter than the fault detection time of RME1 and RAE2. In this case, neither RME1 nor RAE2 recognizes the failure, and thus normal operation is continued. The transmission line failure detection time t ₂ in RAE2 shown in FIG. 3 and subsequent figures is a time-out time in which the health check command 8 of t ₁ cycle that seems to come from RME1 is waited for and considered abnormal, and t ₃ > t ₂ The relationship is established. That is, t ₃
From the relation of> t ₂ , the transmission line failure is always detected in RME1 earlier than RAE2.

Here, as shown in FIG. 4, even when the transmission line failure is recovered between the time t ₂ and the time t ₃ , the RME 1 detects the abnormality after the time t ₂ . Then, the RAE failure occurrence notification 11 is sent to another (other than RAE2 in which RME1 could not receive the health check response 9 due to the transmission path failure, that is, the failure is affected.
(Not for RAE2) Notify all RAE2. Then, the RAE 2 which received the notification executes the failure recovery processing 10 as in the case shown in FIG. However, in this case, the RAE fault occurrence notification 11 indicates that the RAE is
E2 is not notified. However, when the transmission line failure is restored, the RAE 2 recognizes the failure at that point by the health check command 12 that also serves as the failure detection notification from the RME 1, and executes the failure recovery processing 10.

It is possible that a plurality of RAE2 cannot receive the health check command 8 normally due to the influence of the transmission path failure, and as a result, those RAE2 do not send out the health check response 9. That is, it is possible that the RME 1 cannot receive the health check responses 9 from a plurality of RAEs 2. In that case, although the RAE failure occurrence notification 11 indicates a plurality of RAEs 2, it is possible to deal with the same situation as in the above embodiment.

Further, if t ₃ <t ₂ , it is obvious that the following inconvenience may occur. In that case,
RAE2 checks health check command 12 before t ₂ hours.
May send back a health check response 9. Then, RAE2 returns to the normal communication state. Then, RME1 can no longer detect the failure (its RAE2
I received Hellscheck Response 9 from), RAE
Do not send fault notification 11. Therefore, the RAE2 disconnects the call, the other RAE2 maintains the call, and the call is dropped.

As shown in FIG. 5, when the transmission line failure is maintained for t ₃ hours or longer, the RAE2 affected by the failure independently detects the failure after t ₃ hours and executes the failure recovery processing 10. . After that, when the transmission line failure is recovered, the RAE 2 receives the health check command 12, but the failure processing such as the connection call between stations is not necessary because it has already been executed, and the normal operation state is restored.

The failure recovery processing 10 shown in FIGS. 3 to 5 is the same as the processing operation described with reference to FIG.

Further, in the above embodiment, the ring type switching network has been described as an example, but the same effect can be obtained when applied to a switching network having other network configuration.

〔The invention's effect〕

As described above, according to the present invention, the fault monitoring control method is used in a system provided with a management device connected to a plurality of switching devices when there is a switching device that cannot receive a check response from the system. When the management device gives an instruction to disconnect the call to the other switching device to the other switching device, and when the management device restores the state in which the command from the management device can be received, the other switching device causes the switching device to Since the method of disconnecting the call with the switching device was adopted,
In the event of a switching device failure or transmission line failure, the management device can concentrate and handle the failure, and in particular, there is a method that can build a highly reliable system that does not cause one-sided call disconnection. There is an effect to be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a ring-type switching network to which a fault monitoring system according to an embodiment of the present invention is applied, and FIG. 2 shows operations of a management device and a switching device when a failure occurs in the switching device in FIG. The sequence diagram and FIGS. 3 to 5 are respectively the first
It is a sequence diagram which shows operation | movement of the management apparatus and the exchange apparatus at the time of the failure of the transmission path in the figure. In the figure, 1 is a ring management device (management device), 2 is a ring switching device (switching device), 3 is a transmission line, 5 is a fault monitoring route, and 6 and 7 are connection calls. In the drawings, the same reference numerals indicate the same or corresponding parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04L 12/437 H04M 3/22 A H04Q 11/04 9466-5K H04L 11/08

Claims (1)

[Claims] 1. A switching network in which a plurality of switching devices are arranged so that they can communicate with each other on a ring type transmission line and terminals are connected to each other via a switching device A management device, which is placed on the transmission line so as to be able to communicate with the device, sends a check command sent to each of the switching devices via the transmission line and a check response returned from each of the switching devices via the transmission line. In the fault monitoring control method in a switching network to be monitored by using the management device, the management device sends a check command to each of the switching devices at regular intervals via the transmission path, and within a check time after sending the check command. If there is a switching device that could not receive the check response from the switching device, it is sent to each switching device other than that switching device via the transmission line. A failure occurrence notification indicating the switching device, and at the same time, at least a check command that also serves as a failure detection notification is sent to the switching device that could not receive the check response from the switching device. Sends the check response when the check command is received via the transmission line,
When the notification of the failure occurrence is received, the call with the switching device indicated by the notification is disconnected, and when the check command is not received after the elapse of the fixed period (t ₁ ), the time is counted from the elapsed time. The time that elapses and the timeout time (t ₃ ) that is longer than the check time (t ₂ ) has elapsed or the check command (12) that also serves as the fault detection notification is received, whichever comes first. , A fault monitoring and control system in a switching network characterized by disconnecting a call from another switching device.