JPH07273762A - Communication equipment - Google Patents

Abstract

PURPOSE:To minimize the system down state at the time of the occurrence of a prescribed fault in the middle of data communication. CONSTITUTION:A line releasing means 16a which releases a line at the time of receiving a message for call disconnection from the network side in the middle of data communication, a disconnection reason discriminating means 16b which discriminates whether the disconnection reason of the message for call disconnection is prescribed one, and an automatic call originating means 16c which automatically conducts the call originating operation after a prescribed time are provided. When the call is disconnected because of the occurrence of a fault on the network side in the middle of data communication, the call originating operation is automatically conducted the prescribed time after the disconnection if this disconnection is caused by the prescribed reason, that is, if it can be recovered in a short time, thereby restoring the data communication state as soon as possible.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to communication devices, and in particular
It is suitable to be applied to a communication device compatible with a network that issues a call disconnection message accompanied by a disconnection reason such as an ISDN line network (hereinafter, simply referred to as ISDN network).

[0002]

2. Description of the Related Art For example, when a communication device for an ISDN network requests call setup, the communication device or IS
If the DN network is busy, or if there is a failure in the opposite communication device or ISDN network, the call setup is not naturally performed. Many communication devices compatible with the ISDN network respond by, for example, performing the automatic redialing (recalling operation) in the former case, and informing the failure occurrence in the latter case. In addition, the automatic redial operation is
For example, it is executed under the condition that it is not more than twice in 3 minutes.

On the other hand, in the data communication state, ISD
When a failure occurs in the N network or the opposite device, the line is abnormally disconnected from the network side. In such a case, the communication device notifies that a failure has occurred. As a result, the operator confirms the reason for disconnection (cause of failure), waits for recovery of the failure, and then manually instructs re-calling.

[0004]

As described above, in the conventional communication apparatus, when a failure occurs in the data communication state, the failure occurrence is uniformly notified without distinguishing the cause, and the operator is notified. Has tried to redial after investigating the cause of the failure, so even if the failure is short and the failure has already been recovered before and after the notification of the occurrence of the failure, until the operator restarts the call , The system will not be able to communicate.

Therefore, in the case of a network system in which the system down time (including the time during which communication cannot be executed) is required to be short, it can be said that the measure configuration for the occurrence of a failure is insufficient.

[0006]

In order to solve such a problem, the communication apparatus of the present invention comprises a line releasing means for releasing a line when a call disconnection message is given from the network side in the state of data communication. , A disconnection reason determining means for determining whether the disconnection reason of the call disconnection message (disconnection message or release completion message) is the predetermined reason, and when the disconnection reason corresponds to the predetermined reason, the call is automatically made after a predetermined time. Automatic disconnection means for executing the operation.

[0007]

In the communication device of the present invention, even if a disconnection occurs due to a failure on the network side during data communication, if the disconnection reason is a predetermined reason, that is, there is a possibility of recovery in a short time. In the case of a certain failure, an attempt was made to speed up the return to the data communication state by executing the calling operation automatically after a predetermined time from disconnection. That is, the downtime of the network system can be minimized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a communication device according to the present invention will be described in detail below with reference to the drawings. Here, FIG. 1 is a block diagram showing a detailed configuration of the communication apparatus of this embodiment.

In FIG. 1, a communication device (for example, a communication control device) 10A of this embodiment accommodates one or more data terminal devices (DTE) 20, and an opposite communication device 10B.
In contrast, communication is possible via the dedicated line 30 or the ISDN network 31.

The communication device 10A multiplexes or speed-converts the DTE interface circuit 11 for interfacing with the accommodated data terminal device 20 and the transmission data to the dedicated line 30 or the ISDN network 31 side or the line 30 or. A data transmission / reception circuit 12 that performs transmission / reception processing such as inverse speed conversion and demultiplexing of data from the 31 side.
And a first S / T interface circuit 13 for interfacing with the dedicated line 30 (S / T interface)
And a second S / T interface circuit 1 for interfacing with the ISDN network 31 (S / T interface).
4, a selector circuit 15 that selectively connects the data transmission / reception circuit 12 and the first or second S / T interface circuit 13 or 14, and a control circuit 16 that controls the entire communication device 10A. Has been done.

The control circuit 16 comprises a microprocessor and a memory. The control circuit 16 of this embodiment is
It controls the connection to the selector circuit 15, controls the S / T interface circuits 13 and 14, and controls the operation such as connection and disconnection of the ISDN network. Basically, the dedicated communication line 10B is used to oppose the communication device 10B. Communication is performed, and when a failure occurs in the communication system (including the interface circuit 13 and the like) using the dedicated line 30, the communication is switched to the communication using the ISDN network 31.

That is, in the case of this embodiment, the ISDN network 31 is used as a backup line for the private line 30 and the private line 3 is used when the failure of the private line 30 is recovered.
The communication state using 0 is restored.

The control circuit 16 connects the ISDN network 31 with S /
Messages for various call controls are transmitted and received via the T interface circuit 14. In this embodiment, when a failure occurs on the network side (when a call disconnection message is received) during data communication using the ISDN network 31 as a backup line, the communication device 10A concerned.
Is different from the conventional communication device.

The control circuit 16 is a component that realizes such a characteristic function. In a functional block diagram, as shown in FIG. 1, the line releasing means 16a and the disconnection reason determining means 16 are provided.
b and automatic calling means 16c after disconnection.

Here, the line releasing means 16a uses the ISDN.
This is to release the line when a call disconnection message is given from the network side during data communication using the network 31, and the disconnection reason determining means 16b is a call disconnection message (disconnection message or release completion message). The disconnection automatic calling means 16c automatically executes the calling operation after a predetermined time when the disconnection reason corresponds to the predetermined reason. is there.

FIG. 2 is a flowchart showing the processing of the control circuit 16 of the calling side communication device 10A (more precisely, an SDL diagram showing from the state during data communication to the state during data communication). is there. Further, FIG. 3 shows the calling side communication device 10A, the ISDN network 31, and the called side communication device 1.
It shows an example of a sequence in a layer 3 message between 0B.

2 and 3 in addition to FIG.
ISDN network 3 during data communication, also referring to
The process at the time of failure 1 will be described. In the following description, reference numerals in the 100's indicate processes in FIG.
The numbers in the 00s indicate the sequence and the like in FIG.

As described above, in the communication device (10A) of this embodiment, when a failure occurs in the private line 30, data communication is performed using the ISDN network 31 as a backup line (100, 200). . That is, in the communication device 10A, the route of the DTE interface circuit 11, the data transmission / reception circuit 12, the selector circuit 15 and the second S / T interface circuit 14 causes the user data between the data terminal device 20 and the ISDN network 31 to be transmitted. Transfers are made.

In such a data communication state, I
When a failure occurs in the SDN network 31 (201), a disconnection message clarifying the disconnection reason (cause of failure) is issued to the ISDN.
It is sent from the network 31 side to the calling side communication device 10A (101, 202), and is also sent to the receiving side communication device 10B (203).

In the communication device 10A on the calling side, when the control circuit 16 receives the disconnection message via the S / T interface circuit 14, the control circuit 16 determines the disconnection reason inserted in this message (102) and corresponds to the predetermined reason. If so, the recalling flag is set (103). When the re-call flag is set in this way or when the disconnection reason does not correspond to the predetermined reason, the control circuit 16 releases the call and then sends a release message via the S / T interface circuit 14 to the ISDN network. Send to 31 (10
4, 204).

Here, the predetermined disconnection reason for setting the recalling flag is "network failure", "temporary failure",
"Switch congestion" can be mentioned. ISDN network 31
However, for example, in the case of a service network provided by Nippon Telegraph and Telephone Corporation, the disconnection message includes at least a protocol identifier, a call number, a message type and a reason display as shown in FIG. The display shows "#
38 "is inserted,"# 41 "is inserted in the reason display in the case of" temporary failure ", and"# 42 "is inserted in the reason display in the case of" switch congestion ".

The reason for disconnection is that the ISDN network 3
It is due to 1. "Temporary failure" and "switch congestion" are the reasons why it is highly possible to return to the communication-enabled state in a short time, and "network failure" can also be returned to the communication-enabled state in a short time by switching to a bypass route. This is the reason why

In the following description, the disconnection reason inserted in the disconnection message will be described as one of these predetermined reasons.

On the other hand, in the receiving side communication device 10B,
If there is no re-call flag setting operation and a disconnection message is received, the release message is sent to ISDN after the call release operation.
It is transmitted to the network 31 (205).

On the ISDN network 31 side, when a release message is received from both communication devices 10A and 10B, a release operation is performed in the network, and then a release completion message is sent to the calling communication device 10A and the receiving communication device 10B. (105, 206, 207).

The receiving side communication device 10B enters the idle state upon receiving the release completion message.

On the other hand, in the calling side communication device 10A, the control circuit 16 determines the state of the recalling flag when the release completion message is received (106), and if the recalling flag is in the reset state, the call control state is set to idle. State (10
7) On the other hand, if the recalling flag is set, the built-in timer for recalling is activated (108, 20).
8). That is, if the disconnection reason is any one of "network failure", "temporary failure", and "switch congestion", the recalling timer is started, and if not, the idle state is set.
Here, since the disconnection reason is any one of "network failure", "temporary failure" and "switch congestion", the recalling timer is started.

FIG. 3 shows a case (209) in which the fault is recovered before the re-call timer is timed out.

In the communication device 10A on the calling side, the control circuit 16 causes the re-calling timer to expire (10
9, 210), the call setup message is transmitted to the ISDN network 31, that is, the call is reestablished (110, 211). At this time, since the failure has been recovered in the ISDN network 31, the ISDN network 31 accepts the call setup and returns a call setup acceptance message to the communication device 10A on the calling side (111, 212), and the receiving side. A call setup message is transmitted to the communication device 10B (213).

The receiving side communication device 10B thereby performs the call setting process and returns the response message to the ISDN network 31 (214). The ISDN network 31 also performs the call setting process, and then sends the response message to the calling side communication. It is returned to the device 10A (112, 215). As a result, the calling communication device 1
The control circuit 16 of 0A transmits a response confirmation message indicating that the call establishing operation is recognized in the communication device 10B on the receiving side and the ISDN network 31 to the ISDN network 31 (113, 216), and further, the ISDN network 31. 31 also transmits a response confirmation message to the receiving-side communication device 10B (217).

When the call (line) setting is completed in this way, data communication is restarted (114, 218).

As described above, the operation itself at the time of the recalling is the same as the recalling performed when the opposite communication device 10B is busy at the time of the first call. Although not shown in FIG. 2 and FIG. 3, the operation when the fault continues or the opposite communication device 10B is busy at the time of the recalling is also performed at the time of the recalling related to the first call. The operation is similar in the same situation. The control circuit 16 controls the data terminal device 20 before the recalling timer times out.
When a call is issued from, the timer for re-calling is reset and the call operation according to the instruction is performed.

Therefore, according to the above embodiment, even if a predetermined network failure occurs during data communication using the ISDN network 31, if the failure is recovered within the time-up time of the recalling timer, Data communication can be automatically restarted, and the system down state can be minimized. In particular, considering that the ISDN network 31 is used as a backup for the dedicated line 30, the system down state is minimized considerably.

Further, according to the above-mentioned embodiment, since the reason for disconnecting the re-calling operation is limited, it is possible to reduce the waste of the re-calling. For example, if a failure occurs in the partner communication device, it is impossible to take measures such as switching to a detour route, and it takes time to recover from the failure, and the recalled call itself is wasted.

In the above embodiment, the case in which the ISDN network 31 as the backup line is used to cope with the failure occurrence during the communication is shown, but the present invention is also applicable to the communication system in which the backup line is a dedicated line. Can be applied
According to the present invention, it is possible to cope with the occurrence of a failure in a communication state using a dedicated line as a backup line. Further, the present invention can be applied to a communication device in a communication system in which there is only one kind of line (no backup line exists) for communication with the opposite communication device. In short, any communication device for a communication system that sends a disconnection message with a disconnection reason may be used, and the content and number of line types are not limited.

In the above embodiment, the calling side communication device makes a call again, but the called side communication device may make an automatic call for returning to the data communication state. Further, in a communication system in which a monitoring device that manages and monitors the entire communication system is connected to a communication device that intervenes in the transmission and reception of user data, it is possible to call again when a failure occurs in the data communication state. The monitoring device may be activated. The term "communication device" in the claims shall include such monitoring devices.

Further, in the above-mentioned embodiment, the disconnection reasons for activating the recalling operation are "network failure" and "temporary failure".
Also, although the "switch congestion" is shown, the call may be recalled for other reasons.

Further, in the above embodiment, the reason for disconnecting the disconnection reason for determining whether to activate the re-call is shown from the disconnection message. However, like the disconnection message, it is one of the call disconnection messages. It may be taken out from the release completion message.

Further, the number of re-calls and automatic calls for returning to the data communication state is not limited to once, but may be two or more.

[0040]

As described above, according to the communication apparatus of the present invention, the line releasing means for releasing the line when the call disconnecting message is given from the network side during the data communication, and the call disconnecting means. A disconnection reason determining means for determining whether or not the disconnection reason of the message is a predetermined reason, and an after disconnection automatic calling means for automatically executing a calling operation after a predetermined time when the disconnection reason corresponds to the predetermined reason. As a result, even if a predetermined network failure occurs during data communication, if the failure is recovered before the start of the recall call, the data communication can be automatically restarted and the system down state can be minimized. Can be turned on.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a communication device according to an embodiment.

FIG. 2 is a processing flowchart of the communication apparatus of the embodiment when a network side failure occurs during data communication.

FIG. 3 is a diagram showing an example of a sequence of exchanging a layer 3 message between a communication device and a network according to an embodiment.

FIG. 4 is an explanatory diagram showing an example of a format of a disconnection message.

[Explanation of symbols]

10A, 10B ... communication device, 12 ... data transmission / reception circuit,
Reference numeral 15 ... Selector circuit, 16 ... Control circuit, 16a ... Line releasing means, 16b ... Disconnection reason determining means, 16c ... Automatic calling means after disconnection, 20 ... Data terminal equipment (DTE), 30 ...
Dedicated line, 31 ... ISDN network.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H04L 12/28 29/14 H04M 11/00 303 9466-5K H04L 11/20 C 9371-5K 13 / 00 311

Claims (2)

[Claims] 1. A line releasing means for releasing a line when a call disconnecting message is given from the network side during data communication, and whether or not the disconnection reason of the call disconnecting message is a predetermined reason. A communication device comprising: disconnection reason determining means and automatic disconnection calling means for automatically executing a calling operation after a predetermined time when the disconnection reason corresponds to a predetermined reason. 2. The communication device according to claim 1, wherein the communication device can communicate with the opposite communication device via a private line or a public line, and one line is used for backup. The disconnection reason determining means and the after-disconnection automatic calling means function only when a call disconnection message is given from the network side in a state of data communication using a backup line. Communication device.