JP3535673B2 - Multiplexer backup control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a digital dedicated circuit.
Line (hereinafter referred to as SD-I line) and ISDN public network
(Hereinafter referred to as INS line) between multiplexing devices
Backup control method in data communication of,
When the SD-I line connecting the multiplexing devices fails
Automatically connect the INS line and the data on the SD-I line.
Backup system that guarantees data communication using INS line
Regarding the control method. [0002] 2. Description of the Related Art Conventionally, multiplexing connected by an SD-I line.
The backup function between the devices has an SD-I line failure.
In case of harm, manually perform data communication on the SD-I line
Switch to an INS line that has the same bandwidth as the SD-I line
The data communication of the terminal device
Was. Also, when the SD-I line is restored, the INS operation is performed manually.
The line was switched to the SD-I line. The above conventional technology
According to, switching to backup using INS line
Operation or backup from INS line to S
Operation to switch back to DI line must be performed manually
And the INS line is at least the bandwidth of the SD-I line.
Switch all communication only if it has the same bandwidth as
It was possible. However, INS times for backup
The use of the line is compared with the communication by the SD-I line.
Aim to reduce communication costs due to increased communication costs
To a multiplexer connected by an SD-I line.
There was a problem that resulted. Therefore, a dedicated line
(SD-I line) to reduce communication cost
Not use the INS line when a failure occurs in the leased line.
Wants to reduce communication costs even during backup
Have been. [0003] SUMMARY OF THE INVENTION The present invention has the above problems.
If an SD-I line failure occurs
Backup switching control when a failure or failure is recovered
Or to automatically perform backup failback control
Therefore, backup can be controlled quickly and
By narrowing the bandwidth at backup,
Minimize the communication costs of the INS line used
Multiplexing device backup control method
The purpose is to provide. [0004] [MEANS FOR SOLVING THE PROBLEMS]
In addition, the present invention relates to a multiplexing apparatus in which a terminal device is fixedly connected.
Are digital dedicated lines (hereinafter referred to as SD-I lines) and
And an ISDN public line having a narrower band than the SD-I line
(Hereinafter referred to as INS line)
In the backup control method of the multiplexing device in
The multiplexer detects the occurrence of a failure in the SD-I line.
Based on the SD-I line fault occurrence information
Automatically connect the S line to the opposing multiplexer
Cuts the data flowing on the SD-I line to the INS line
It has a function to change. Further, according to the present invention, a terminal device is fixedly connected.
A dedicated digital line (hereinafter referred to as SD-I)
Line) and I which has a narrower bandwidth than the SD-I line.
Connected via SDN public line (hereinafter referred to as INS line)
Control of multiplexing equipment in closed network
In the system, the multiplexing device is provided with a failure of the SD-I line.
Function to detect the occurrence of an error, and when an SD-I line failure occurs
Also specifies whether data communication is performed or not for each terminal device.
Function to narrow down the bandwidth by selecting
Multiplexer opposing INS line based on harm occurrence information
Automatically connected to and was flowing over the SD-I line
Function to narrow down data and switch to INS line
And had. Further, according to the present invention, a terminal device is fixedly connected.
A dedicated digital line (hereinafter referred to as SD-I)
Line) and I which has a narrower bandwidth than the SD-I line.
Connected via SDN public line (hereinafter referred to as INS line)
Control of multiplexing equipment in closed network
In the system, the multiplexing device is provided with a failure of the SD-I line.
Function to detect the occurrence of an error, and when an SD-I line failure occurs
Also specifies whether data communication is performed or not for each terminal device.
Function to narrow down the bandwidth by selecting
When damage occurs, IN based on failure occurrence information of SD-I line
Automatically connect the S line to the opposing multiplexer
Narrow down the bandwidth of the data flowing on the SD-I line
Function to switch to INS line and SD-
A function to monitor the restoration of the I-line, and when the SD-I line is restored
The data flowing on the INS line is automatically transferred to the SD-I line.
Added a function to switch back dynamically. In addition, this back
In the up control method, the multiplexing device
If the data is out of the allowable backup time,
Provide a function to automatically switch the signal back to the SD-I line
Was. [0007] The back-up of the multiplexing apparatus constructed as described above.
According to the backup control method, data communication is
It is necessary to be able to arbitrarily select terminal devices that can
There is no need to secure more bandwidth for the INS line than necessary.
Also, when the SD-I line is restored from the above state,
Is out of backup time, data communication
Automatically switches back to the SD-I line and the INS
Disconnect the line and use the INS line (public network) more than necessary
Can be prevented. [0008] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Will be described. The backup according to the present invention will be described with reference to FIG.
Of the multiplexing equipment network to which the
An overall configuration diagram will be described. In the figure, the reference character A
Or B is a multiplexing device 10A, 10B, respectively.
It belongs to somewhere. The battery according to the present invention
Multiplexer network to which backup control is applied
Multiplexes the multiplexing device 10A and the multiplexing device 10B with the SD-I
Line 40 and INS line whose bandwidth is narrower than SD-I line
50A and 50B. Multiplexer
Terminals 60 are fixedly connected to terminals 10A and 10B, respectively.
Central processing that continues and controls the entire multiplexer
Device (CPU) 20 and a multiplexing device control program, etc.
Record for storing each program, each data, various tables, etc.
The storage device (MEM) 30 is connected. Also multiplex
The multiplexing device 10A and the multiplexing device 10B
Line (SD-I line) 40 and Bandwidth better than SD-I line
INS lines 50A and 50B. Sa
In addition, at least one of the multiplexing devices in the system is an SD
-It has a monitoring function of monitoring the state of the I line 40. The multiplexing device 10 includes a communication path switch 11
And the communication path switch to SD-I line or INS line
A line connecting unit 12 for selectively connecting the SD-I line;
An SD-I line monitoring function 13 for monitoring the
Bandwidth narrowing function 14 that narrows the bandwidth of data communication when
Switch data communication from SD-I line to INS line
SD-I / INS line switching function 15 and data communication
/ SD that switches INS line to SD-I line
An I-line switchback function 16; Next, the operation of the multiplexer will be described.
In this network, the failure of the SD-I line 40
If it occurs, the SD-I line monitoring function of the multiplexer 10
13 detects the failure, and the bandwidth narrowing function 14
Backup information stored in the storage device in the storage device 10
Terminal device 6 that identifies the communication and performs communication even during backup
0, and the SD-I / INS line switching function 15
INS line 50 is connected to the
To send a "call setup" message to the network. Less than,
The multiplexing device that sends out this "call setup" message
Called "backup boot station" and "call setup" message
The multiplexing device that receives data is called the “backup passive station”
Say. This “call setup” message includes the backup
Information indicating that the connection is
Public number of the INS line accommodated in the
Is set). Call setup message via the above network
The opposite multiplexing device that has received the message
Make a backup connection according to the information in the message
Check if the incoming call is from a good multiplexing device.
(Security check), from a connectable multiplexer
If it is recognized that the incoming call is
A message and a response message are sent out.
DI / INS line switching function 15 on SD-I line 40
Is switched over to the INS line 50. In the transmitting side multiplexer 10A, an INS line
50 from the terminating side multiplexer 10B via the
At the point of receiving the “Append” / “Response” message, the SD-I
Switch data communication on line 40 to INS line 50
You. For terminal devices connected to each multiplexer,
Terminal device that is the target of backup switching
By registering whether or not the SD-I line 4
0, the end of backup switching
Identify whether the device is a backup device
Only the target terminal device is used as the backup INS line
By switching, only the minimum necessary terminal devices
It can be switched to the INS network. [0012] By the above processing, on the SD-I line 40
INS times minimum data communication required
Switch to line 50. Also, this backup switch
At the same time, the SD-I line monitoring function 13
Start monitoring for recovery. As a result of restoration monitoring, SD-I line
If it is recognized that 40 has been restored,
"Disconnect" message, which is a message for disconnecting the INS line from
Send message to INS line 50, and
Data communication back to SD-I line 40 and
The INS line 50 disconnection sequence starts. Also back
The up passive station sends a “disconnect” message via the INS line 50.
INS / SD-I line switchback function 1
6 transmits data on the INS line 50 to the SD-I line 40
Switch back up and disconnect sequence of INS line 50
Enter. With the above control, the SD-I line 4
0 when a failure occurs on the INS line 50
Backup switching and SD-I times
Switch to INS line 50 when line 40 is restored
Return the obtained data communication to the SD-I line 40
Backup failback is performed. Referring to FIG. 2, the backup switching control will be described.
And multiplexing device 10 that performs backup failback control
The configuration of the line connection unit 12 accommodated in the server will be described. Multiplexing
The device 10 has a terminal device 60 in addition to the functions shown in FIG.
A communication path switch 11 for connecting the communication path and the line connection unit 12;
A line connection unit 12, a central processing unit 20;
Storage device 30, SD-I line 40, INS line 50
And connected to. Further, the multiplexing device 10 is a terminal device.
Fixedly connected to the device 60. The line connection unit 12
Trunk (TRK) 121, trunk 121 and SD-
Switch to connect I line 40 or INS line 50
The memory 122 is provided. Switching of line connection unit 12
Alternatively, the backup operation can be
A backup switching control or a backup switching control is performed. Next, the backup switching control and the multiplexing device
The operation of backup switchback control will be described. Ma
Control when backup switching operation occurs
When the processing device 20 performs the backup switching operation, the line connection unit 1
2 sends a “backup switch” command. life
The line connection unit 12 that has received the command switches to the line included in the command.
Switch from backup target trunk information to backup
Recognize the trunk that can be
Switch to the backup switchover destination switch
The data communication on the SD-I line 40 is INS
Switch to line 50. SD-ILineMonitoring function 13 is SD-I line
Upon detecting 40 failures, the central processing unit 20SD−
Multiplexer to determine whether to back up when an I line failure occurs
Refer to the table described for each terminal device accommodated in the device
And only for terminals that need backup.
By issuing the "backup switch" command,
The band is narrowed down. Next, when a backup switchback operation occurs,
In this case, the central processing unit 20 performs a backup switchback operation.
To the line connection unit 12
Send the order. Upon receiving the command, the line connection unit 12
The trunk to switch back from the switchback target trunk information contained in
Switch for SD-I line that recognizes
The switching on the INS line 50
Data communication is switched back to the SD-I line 40. Referring to FIG. 3, when a failure occurs on the SD-I line
Explains the data structure required for switching to the INS line
I do. FIG. 3A shows a state in which a failure of the SD-I line 40 is detected.
Multiplexing device (backup boot station) 10A storage device
Multiplexing device (backup) stored in the
Start the passive station) 10B by connecting the INS line 50
31 related to the route number, which is necessary information
An example of the configuration will be shown. Route stored in storage device 30
Data 31 concerning the number arrives at the opposing multiplexer.
Public network number (calling number / calling sub-address)
It faces the public network number storage area 311 to be stored.
Store the node number assigned to the multiplexer.
And the node number storage area 312
Channel information on the INS line 50 to be used is stored.
Channel information storage area 313 is stored separately.
You. Multiplexer 10 detecting failure of SD-I line 40
A is stored in the public network number storage area 311 of the data 31
Public network number and channel information storage area 3
13 is stored in the INS line 50.
"Call setup" message sent to (network) via Dch
Set to. By sending this "call setup" message
Start up the multiplexing device 10B to be connected,
An effective channel can be connected to the network. Node number
After the backup switching is completed, the storage area 312
Used for monitoring the recovery of the dedicated line (SD-I line). Referring to FIG. 3B, an INS line (network)
Multiplexing device that receives incoming calls (backup passive station)
Security data 32 stored in the storage device of 10B
Will be described. This security data
Backup reception that received an incoming call from the INS line (network)
It is determined whether or not the mobile station 10B can accept the incoming call.
It consists of the information needed to Security
The data 32 is composed of a plurality of opposing data allowing a backup connection.
The calling number (including the calling subaddress) of the multiplexing device 10A
Calling number storage area 321 to be stored and at the time of backup
To store the channel information on the INS line 50 used for
And stored in the channel information storage area 322.
You. Multiplexing that received an incoming call from the INS line 50 (network)
The caller ID and the calling number in the "call setting" message
And the calling sub address, and the number is stored in the calling number storage area.
Check if it is registered in a 321
If it is, the call is accepted.releaseComplete
MessageToSend and reject incoming calls. This security
The integrity check process allows you to communicate with illegal callers
INS line connection can be prevented. Also receive
Channel information in the “call setup” message
Whether it matches the information stored in the report storage area 322
And if they match, select that channel.
Sends a "call setting accepted" message. Of said judgment
As a result, the channel information in the
Does not match the information stored in the file information storage area and
If the channel can be changed, the “call setup” message
Channel negotiation to change to channel of channel information
Perform an action. As a result, the receiving-side multiplexing device (batch
Backup passive station).
Channel connection becomes possible. Referring to FIG. 4, an INS line is used for backup.
A description will be given of an example of use in a line when 50 is used. I
The NS line 50 is an INS line call between the multiplexer and the network.
Band of D channel (Dch) for exchanging control information
51 and the bandwidth of the B channel (Bch) of the INS line.
Dp channel existing on the SD-I line 40 to be defined
(Dpch) band 52 for control information and SD-I times
Bandwidth 53 is set to ensure data communication on line 40
Is done. Dpch 52 exists on the INS line 50
The line is switched from the SD-I line 40 to the INS line 50
Even after the backup has been switched, the SD-I
It is necessary to continuously control the exchange of data on the line 40.
It becomes possible. Also, data communication on the INS line 50
Bandwidth 53 exists, so that the SD-
Data communication on the I line 40 is guaranteed. Referring to FIG. 5, backup switching is performed.
Layer 3 connection sequence of the INS line 50 and the line
"Backup switching" command for data communication to connection unit 12
The command transmission timing will be described. Backup boot station and
Multiplexing device 10A fails SD-I line 40
Is detected (S10), the route number data 3
8 with respect to the network via the INS line 50A with reference to FIG.
"Call setup" message including backup information 33 shown in
Is sent out (S11). The network receives the “call setup”
Multiplexer that opposes messages (backup passive station)
10B (S12). "Call setting" message from the network
The opposite multiplexing device 10B that has received the message
Number of the backup information 33 in the "Set" message33
2And the security shown in FIG.
Backup connection possible by comparing with the check data 32
If it recognizes that the
To send (S13)Send "response" message
It is issued (S15).Network is backup passive multiplexing equipment
Activate the "call setting accepted" message received from the device 10B
Is transmitted to the side multiplexer 10A (S14).. networkIs
Response message from the passive passive multiplexer 10B.
Message is received, the acknowledgment message is backed up.
With transmission to the passive-side multiplexer 10B (S16)
The received response message to the backup initiator
The data is transmitted to the multiplexer 10A (S17). The backup start-side multiplexing device 10A
"Call setting accepted" message and "answer" message from the network
The connection is considered completed when the page is received, and the central processing unit
20A is "backup switching" to line connection unit 12A
An instruction is sent (S18). Similarly, backup passive
The side multiplexer 10B sends a “response confirmation” message from the network.
Is received, the connection is considered to be completed, and the central processing unit 20
B issues a "backup switching" command to the line connection unit 12B.
Is transmitted (S19). The backup process
The sequence at the time of switching the group is completed, and the
After turning the switching to the INS line 50, the INS line
The normality of Dpch 52 is checked on 50 (S2
0) If normal, the backup switching is completed and IN
Continue data communication on the S line 50 and the SD-I line 40
Is executed (S21). The backup start-side multiplexing device 10A
If a connection incomplete message is received from the network,
After the timing has been set, the “call setup” message is sent to the network again.
Send (retry) the message. In step S20, I
Checking the normality of the Dpch 52 on the NS line 50
As a result, if it is not normal, the INS line 50 is temporarily disconnected, and
The connection (retry) of the INS line 50 is started. Referring to FIG. 6, backup switching is completed.
Of the dedicated line recovery monitoring control performed during backup after
I will explain Kens. During backup, one multiplexing device
The device 10A is connected to the opposing multiplexing device 10B in FIG.
(A) is stored in the node number storage area 312.
"Dedicated" in which the node number of the opposing multiplexer is set.
Line recovery monitoring request ”message of INS line 50
h52 (S30). "Dedicated line restoration monitoring required
Request message received by the
The multiplexing device 10B sends a “dedicated line restoration monitoring request” message.
The node number in the field matches the node number set for itself.
Is determined (S31).
Is recognized as a “leased line recovery monitoring request” message.
You. If they do not match, the received “Dedicated line recovery monitoring
Request message. In the determination of step S31,
The “Dedicated line recovery monitoring request” message is sent to the own multiplexer.
To monitor leased line restoration.
It is determined whether the state is the state (S32), and the dedicated line restoration monitoring is performed.
If the request is not possible, the "Request NG" message
Via the Dpch 52 to the multiplexing device 10A facing the
Is transmitted (S33), and the determination in step S32 is made.
Repeat at predetermined intervals. Dedicated in step S32
If line recovery monitoring is possible, a "Request OK" message
Via the Dpch 52 to the multiplexing device 10A facing the
Is transmitted (S34) and transmitted to the line connection unit 12B.
The “dedicated line restoration monitoring” instruction is notified (S35), and the SD-I
The normality of the line 40 is checked (S36). On the other hand,
In step S33, the “request NG” message is multiplexed by the multiplexer.
Multiplexer 10A received from 10B receives a certain time
Multiplexing device 10B
Sends a “dedicated line restoration monitoring request” message (S3
0). The multiplexing device 10A executes this processing in parallel.
To determine whether it is possible to monitor
Judgment (S37), if the dedicated line recovery monitoring is possible
For example, a "dedicated line restoration monitoring" instruction is sent to the line connection unit 12A.
(S38), and checks the normality of the SD-I line 40
(S36). In the judgment of step S37, the request is OK.
If it is, notify the line control unit of the "dedicated line restoration monitoring" instruction.
I do. Dedicated line restoration monitoring is not possible in the judgment of step S37
If it is in a state of being able to perform
Repeat at intervals. By this processing, both multiplexing devices
Thus, it is possible to monitor the restoration of the leased line. Many
The multiplexing device 10A and the multiplexing device 10B are
Check the normality of the line and check the SD-I line 40 for abnormalities.
During the detection (S39), both multiplexers respectively
Continue checking the normality of the SD-I line (S35),
S38). At least one of the multiplexing devices is SD-I
When it is detected that the line 40 has been restored to normal (S39).
Then, the process shifts to the backup failback control (S40). Next, normality check of the SD-I line 40 is performed.
Will be described in detail. Received "Dedicated line restoration monitoring" instruction
Multiplexer 10AofLine connection unit 12A and multiplexer
10BThe line connection unit 12B is connected to the line of the SD-I line 40.
Check layer 1 status and if layer 1 is not restored
Information indicating "line error"EachCentral control unit 20A,
20BNotify to Also, if layer 1 is restored
For example, data is sent out on the SD-I line 40,
CostumePlace ofLine connectionDepartment andExchange of data between
Sequence). Thereby, the SD-I line 40
Communication test at the layer 2 level
You. Whether data exchange can be performed normally by this check
IfEachLine connectionDepartment isSD-I line 40 is abnormal.
Is determined to beEachCentral control unitIn placeOn the other hand,
Information indicating "always" is notified. Also, the data exchange
If successful,EachLine connectionDepartment is, SD-I
Determines that line 40 is normal, EachCentral control unitIn place
On the other hand, information indicating "line normal" is notified. Line connection unit 1
2AFrom the "line normal" information of the SD-I line 40 or
The central control device 20A that has received the “line abnormality” information
I took a certain timing for "line error" information
The multiplexing device 10B that is facing the “Recovery line recovery monitoring
It enters a sequence for sending a “viewing request”. "Line normal" information
If the information is information, the backup switchback control is started. This dedicated line
In the recovery monitoring sequence of
Or "line error" information triggers backup switching
Valid only on the backup start-up multiplexer 10A
Yes, the multiplexing device 10B on the backup receiving side
Ignore information. This allows both multiplexers to be
Can be prevented from starting backup failback
Wear. Referring to FIG. 7, as a result of the dedicated line restoration monitoring,
Backup off after DI line 40 is recognized as normal
The return sequence will be described. Multiplexing backup initiator
Device 10A has recognized that the SD-I line 40 is normal.
In this case (S50), the INS line 50 being backed up is disconnected.
Send "disconnect" message to network to disconnect INS
A line disconnection sequence is entered (S51), and the line is disconnected.
Sends "backup failback" request to connection unit 12A
Then, the switching directed to the INS line 50 is changed to SD-
It returns to the I line 40 (S52). The network is
"Disconnect" message to backup passive-side multiplexer 10B
To (S53). Receive a “disconnect” message from the network
Backup passive sideManyThe weighting device 10B has an IN
Switching that was directed to the S line 50 is changed to the SD-I line 4
Switch back to 0 (S54), complete backup switchback
Then, the data communication on the SD-I line 40 is continued (S
55). Further, the backup passive-side multiplexer 1
0B is the callreleaseAfter executing the processing, backup
Sends a "release" message to the startup multiplexing device 10A.
It is issued (S56). "release'' Message
The backup activation-side multiplexing device 10ACallofreleaseProcessing
After runningreleaseCompleted message is backed up over the network.
Is sent to the passive-side multiplexer 10B (S57), and IN
The disconnection of the S line 50 is completed. Referring to FIG. 8, multiplexing on the backup start side is performed.
Set in the “call setup” message sent from device 10A.
The configuration of the backup information 33 to be set will be described. back
The up information 33 includes a calling number identifier 331 and a calling number 33
2, the originating subaddress 333, and the node of the own multiplexer.
Number 334 and the like. As described above, the central processing of the multiplexer is performed.
The storage device recognizes the failure of the SD-I line and
The backup information stored in the
Performs line connection control. At this time, connect the INS line
Backup in the signal for the call ("call setup" message)
And send information that can be recognized as a connection for
I do. The opposing multiplexing device transmits the above “call setting” message.
Message and back up in the "call setup" message
Identify information and initiate backup control. Above control
, Backup control is performed by both nodes and SD-I
Transfer data communication on the line to the INS line. Then SD
-Monitor the restoration of the I line, and when the restoration is recognized, INS
Disconnect the line and perform data communication on the SD-I line
To minimize the use of INS lines
Guarantee data communication and minimize communication costs.
Can be minimal. In the above description, the backup switchback operation has been described.
Performed on condition that SD-I line is restored.
Monitor the time since the backup started
After a certain period of time, data communication is automatically switched to the SD-I line.
INS line
(Public Network) to prevent unnecessary use
It can also be configured. Also housed in a multiplexing device
Prioritize terminal backup needs
Make sure that the terminal device that has been backed up has priority
Give a long backup time to a terminal device with a high rank,
Backup time regardless of restoration of DI line
Disconnect the INS line in order from the terminal device where
And use INS lines (public networks) more than necessary.
May be prevented. Further, in the above description
Indicates backup switching operation or backup switchback operation
Operation is automatically performed based on the monitoring results of SD-I line failures.
But manually based on the monitoring results.
May be provided. [0030] As described above, the multiplexing apparatus according to the present invention
According to the backup control method, the data is
Terminal device that can perform data communication
In this way, the bandwidth of the backup INS line
There is no need to secure In addition, SD-
When I line is restored or during backup time
In case of deviation, data communication is automatically switched to SD-I line.
INS line
(Public network) can be prevented from being used more than necessary.
it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing the configuration of an SD-I line to which a backup control method according to the present invention is applied and a network connected by an INS line having a band narrower than the SD-I line. FIG. 2 is a block diagram showing a configuration of a multiplexing apparatus that executes a backup control method according to the present invention. FIG. 3 is a diagram showing a data structure used in the present invention. FIG. 4 is a view for explaining a use mode of an INS line in the present invention. FIG. 5 is a sequence diagram illustrating a line switching procedure according to the present invention. FIG. 6 is a sequence diagram illustrating a line monitoring procedure according to the present invention. FIG. 7 is a sequence diagram for explaining a line recovery procedure according to the present invention. FIG. 8 is a view for explaining the configuration of backup data included in a call setting message. [Description of Reference Codes] 10 Multiplexer 11 Communication path switch 12 Line connection unit 13 SD-I line monitoring function 14 Band narrowing function 15 SD-I / INS switching function 16 INS / SD-I switchback function 20 Central processing unit Reference Signs List 30 storage device 40 dedicated line (SD-I line) 50 ISDN public network (INS line) 60 terminal device

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI H04M 3/22 H04M 11/00 303 11/00 303 H04L 13/00 311 H04Q 11/04 H04Q 11/04 M (56) References JP-A-8-84169 (JP, A) JP-A-6-37731 (JP, A) JP-A-6-37730 (JP, A) JP-A-8-18626 (JP, A) JP-A-8-167908 (JP, a) JP flat 8-70294 (JP, a) JP flat 6-334637 (JP, a) JP flat 7-240771 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ H04J 3/00 H04J 3/14 H04L 1/22 H04L 29/14 H04M 3/22 H04M 11/00 303 H04Q 11/04 JICST file (JOIS) WPI (DIALOG)

Claims (1)

(57) [Claim 1] Multiplexing between multiplexers to which a terminal device is fixedly connected by a digital leased line and an ISDN public line having a band narrower than the digital leased line. In the device backup control method, the multiplexing device has a function of detecting the occurrence of a failure of the digital leased line, a function of selecting a terminal device that performs data communication even when a failure of the digital leased line occurs, and a function of narrowing down the bandwidth. ISDN based on fault occurrence information of digital leased line
A function of automatically connecting a public line to an opposing multiplexer and narrowing the band of data flowing on a digital leased line to an ISDN public line, and giving priority to backup for each of the plurality of terminal devices. Ranking information
And the priority of the registered terminal device.
The ISDN public used for backup in descending order
Set a longer line usage time to
If the line usage time has elapsed, the IS
A backup control method for a multiplexing device, characterized in that it has a function of cutting off communication on a DN public line .