JP2002198904A - Optical multidrop communication system and switchover and restoration control method of transmission line therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease communication interruption time caused by a short break, particularly a short break by a backbone line switchover, etc., irrespective of bandwidth allocation amount allocated for each slave station. SOLUTION: Master station equipment 1 is provided with a start/stop controller 13 for initiating and suspending slave station equipment 5, a timer for counting a predetermined time corresponding to communication break time caused by switching over backbone optical fibers L2a, L2b, and a switchover instruction transmitter 31 for accepting a switchover initiation notification of the backbone lines to start time count by the timer. The start/stop controller 13 starts initiation control against each of slave station equipment when the time count by the timer expires.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a master station apparatus and a plurality of slave station apparatuses connected by an optical splitter, and at least a trunk line between the master station apparatus and the optical splitter is redundantly configured. A plurality of slave station devices share a transmission medium and a transmission band, the master station device controls allocation of a used transmission band of each slave station device, and each slave station device allocates a used transmission band of the master station device. An optical multi-branch communication system for transmitting transmission information to the master station device and a transmission line switching recovery control method thereof, particularly, it is possible to perform recovery from an instantaneous interruption due to switching of the trunk transmission line in a short time. The present invention relates to an optical multi-branch communication system and a transmission line switching recovery control method thereof.

[0002]

2. Description of the Related Art Conventionally, a plurality of slave stations share a transmission medium and a transmission band, and each slave station performs data transmission to a master station by controlling the bandwidth of the master station. -T Recommendation G. 983.1 (Broa
dband optical access systemsbased on Passive Optic
al Network (PON) 1998/10) Figure 5 / G.983.1-Gener
ic physical configuration of the Optical Distribut
n ONUs (Optical Netwo
rk Unit) and one OLT (Optical Distribution Term)
An optical network having an ination) is known.

[0003] In this optical network, a frame format (ITU-T Recommendation G. 983.1 (Figure 11 / G.
983.1-Frame format for 155.52 / 155.52 Mbit / s PO
N)), data is transmitted from the master station device to each slave station device (downward direction) or from each slave station device to the master station device (upward direction). In this frame format,
It is assumed that the downstream direction is transmitted by a 53-byte fixed-length cell (ATM cell), and the upstream direction is transmitted by a 56-byte fixed-length cell in which a 3-byte overhead is added to a 53-byte ATM cell. .

[0004] A downstream frame is composed of 54 ATM cells and 2 monitoring control (PLOAM: Physical Layer O).
PLOAM cells are inserted at a cycle of 28 cells. P
LOAM cells are in accordance with ITU-T Recommendation G. 983.1 (Tabl
e 8 / G.983.1-Payload content of downstream PLOAMcel
As shown in l), "GRANT1" to "GRANT2" are assigned to the first PLOAM cell as the band allocation information.
7 ”is inserted, and“ GRA ”is inserted in the second PLOAM cell.
NT28 "to" GRANT54 "are inserted.

[0005] The upstream frame has 53 ATM cells, each of which forms a time slot. "GRANT1"-described in the above-mentioned PLOAM cell
“GRANT53” corresponds to each time slot.
The “GRANT” value is identification information associated with each slave station device, and each slave station device holds the associated identification information in advance. Therefore, each "GRANT1" ~
As "GRANT53", "GRAN53"
By inserting the "T" value, each slave station device can recognize the time slot position of the ATM cell to be transmitted by its own slave station device, thereby controlling the bandwidth allocation of each slave station device. become.

Here, the line between the master station device and the slave station device may be momentarily interrupted due to a line fault between the master station device and the slave station device. When such an instantaneous interruption occurs, the slave station apparatus transmits the optical signal input interruption “LOS (Loss Of Sign)”.
al) ”, cell synchronization is lost,“ LCD (Loss of Cell
Delineation) ”and“ OAM ”which is a PLOAM cell loss.
L (PLOAM cell loss), and an alarm such as "FRML (FRML Loss of downstream frame)" which is out of frame synchronization. When this alarm is detected, the operation state transits to the POPUP (pop-up) state. After that, the pop-up message is received from the master station apparatus, and the slave station apparatus transitions to the start-up standby state, and the master station apparatus receives the pop-up message. It will wait for start control.

FIG. 11 is a block diagram showing a configuration of a conventional optical multi-branch communication system, in which a master station apparatus 1 and a plurality of slave station apparatuses 5 (5-1 to 5-n) are connected via an optical splitter 4. Are connected, the master station device 1 and the optical splitter 4 are connected.
The trunk line between and is redundantly configured. This redundant configuration
One optical switch 3a, 3b is interposed between the master station device 1 and the optical splitter 4, and the distance between the optical switches 3a, 3b is 2
They are connected by the optical fibers L2a and L2b.
The switching instruction unit 6 controls switching of the optical switches 3a and 3b. As a result, the optical transmission path between the master station device 1 and the optical splitter 4 includes the paths of the optical fibers L1, L1a, L3 and the optical fibers L1. A redundant configuration is formed in which two routes, the routes L1b and L3, are formed. On the other hand, between the optical splitter 4 and each of the slave station devices 5, a branch optical fiber L4
(L4-1 to L4-n).

[0008] The master station apparatus 1 has a registration management section 17 for managing registration of each slave station apparatus 5 and a communication interface section 2. The communication interface unit 2 performs transmission / reception processing of an optical signal to / from each slave station device 5 via the optical fiber L1 and conversion processing of an optical signal and an electric signal.

The band control unit 10 controls the allocation of the used transmission band to each slave station device 5. Upward alarm monitor 12
Monitors the upstream signal 15 sent from each slave station device 5,
Detects an upward alarm and sends the detected information to the start / stop controller 13
To send to. The start / stop control unit 13 controls the start and stop of each slave station device 5 based on an instruction from the registration management unit 17 and an alarm notification from the uplink alarm monitoring unit 12. The management signal sending unit 14 adds the band information from the band control unit 10 and the start / stop instruction from the start / stop control unit 13 to the downlink signal 16 and sends the down signal 16 to each slave station device 5.

[0010] Here, a conventional transmission path restoration processing procedure accompanying a trunk line switching will be described with reference to a flowchart shown in FIG. In FIG. 12, first, the optical switches 3a and 3b are switched based on the switching instruction of the switching instruction unit 6, and the connection switching of the optical fibers L2a and L2b is executed (step S400). Then, an instantaneous interruption occurs with the execution of this switching, and a down warning is detected (step S411). After that, each slave station device 5 becomes the master station device 1
A process for stopping transmission of uplink data to is performed (step S412).

On the other hand, the upstream alarm monitor 12 of the master station device 1
Detects an upward alarm due to an instantaneous interruption accompanying the execution of the trunk line switching (step S401), and the activation stop control unit 13 performs slave stop control such as sending a transmission stop signal to the slave station device 5 (step S401). Step S402). Here, depending on the uplink band of the slave station device 5, there may be a case where the uplink warning is not detected due to only the momentary interruption, but since the slave station device 5 stops the transmission of the uplink data by detecting the downlink alert,
As a result, an upward warning is detected. After that, the start / stop control unit 13 starts a built-in slave station stop timer (not shown) (step S403). The timer time set in the slave station stop timer is a time obtained by adding a predetermined margin to the time when the switching of the trunk line is completed.

Thereafter, the start / stop controller 13 determines whether the timer time counted by the slave station stop timer has expired (step S404). The start-stop control unit 13 determines that the timer time has expired (step S404, YES).
Next, the slave station device 5 is restarted (step S405), and the slave station device 5 is restarted by the slave station start control (step S413).

[0013]

In the above-described conventional optical multi-branch communication system, a used transmission band is allocated to each of the slave station devices 5. In addition, in order to protect the uplink alarm, the uplink alarm monitoring unit 12 outputs the uplink alarm to the start / stop control unit 13 only when the uplink alarm is detected a predetermined number of times, for example, 8 or more times, and Stop control is performed. Therefore, the time required from the switching of the trunk line to the detection of the uplink warning varies depending on the allocated amount of the used transmission band. In particular, when the allocated amount of the used transmission band is small, there is a problem that the time required from the switching of the trunk line to the detection of the uplink warning and the restart of the slave station device 5 becomes long.

For example, 64 kb for voice information
In the bandwidth allocation with a small ps, the interval between the upstream time slots is about 6.6 ms, and it takes about 53 ms at maximum from the switching of the trunk line to the detection of the upstream alarm.
On the other hand, the instantaneous interruption time due to switching of the normal optical switch is 10
About 20 ms.

FIG. 13 shows the processing from the execution of trunk line switching to the start of the slave station activation control for the slave station device 5-1 to which the small band is assigned and the slave station device 5-2 to which the large band is assigned. It is a timing chart shown.
In the case of the slave station device 5-1, a small band is allocated, and therefore, the time slot cycle Tc1 of the slave station device 5-1.
Becomes longer. On the other hand, in the case of the slave station device 5-2, since a large band is allocated, the time slot period Tc2 of the slave station device 5-2 becomes longer.

As a result, the time Tu1 required for the slave station device 5-1 to detect the eighth uplink warning after the instantaneous interruption caused by the trunk line switching execution tx is equal to the time Tu2 for the slave station device 5-2. It becomes larger than. Here, since the time set in the slave station stop timer is constant, it takes from the detection of the eighth rising alarm (t41, t51) to the start of the slave station activation control (t44, t54). The time will be the same. As a result, in the slave station device 5-1 having a small amount of allocated band, a large amount of time is spent from the switching execution tx to the restart.

The present invention has been made in view of the above,
An optical multi-branch communication system capable of reducing a time in which communication is interrupted due to an instantaneous interruption, particularly an instantaneous interruption associated with switching of a main line, regardless of the amount of bandwidth allocated to each slave station device, and its transmission line switching. The purpose is to obtain a recovery processing method.

[0018]

To achieve the above object, an optical multi-branch communication system according to the present invention comprises a master station device and a plurality of slave station devices connected by an optical splitter. The trunk transmission line between the optical splitter is configured redundantly, the plurality of slave station devices share a transmission medium and a transmission band, and the master station device controls the allocation of the used transmission band of each slave station device, In an optical multi-branch communication system in which each slave station device transmits transmission information to the master station device based on allocation of a used transmission band by the master station device, the master station device starts and stops the slave station device. Slave station start / stop control means for controlling a main station, a timer for measuring a predetermined time corresponding to the interruption time accompanying the switching of the trunk transmission path, and a switching instruction transmitting means for receiving a switching start notification of the trunk transmission path. Prepared, said When the switching instruction transmitting means receives the switching start instruction, the station activation stop control means starts the time counting by the timer, and after the time counting by the timer expires, starts the activation control of each slave station device. It is characterized by the following.

According to the present invention, the switching instruction transmitting means includes:
When the switching start notification of the trunk transmission line is received, and the slave station start / stop control means receives the switching start notification, the timer is started by the timer, and after the time counted by the timer expires, the start of each slave station device is started. Control is started.

[0020] In the optical multi-branch communication system according to the next invention, the master station device and the plurality of slave station devices are connected by an optical splitter, and at least a trunk line between the master station device and the optical splitter is redundant. Wherein the plurality of slave stations share a transmission medium and a transmission band, the master station controls allocation of a used transmission band of each slave station apparatus, and each slave station apparatus uses transmission by the master station apparatus. In an optical multi-branch communication system that transmits transmission information to the master station device based on band allocation, the master station device includes a slave station start / stop control unit that controls start and stop of the slave station device; Uplink alarm monitoring means for detecting an uplink alarm of each slave station device associated with switching of the trunk transmission line, and trunk line switching determining means for determining whether or not uplink alerts have been detected for all active slave station devices, The main transmission line A timer for measuring a predetermined time corresponding to the interruption time associated with the switching, the slave station start / stop control means, when the trunk line switching determination means detects an uplink warning for all the active slave station apparatuses, The time measurement by the timer is started, and after the time measured by the timer expires, the activation control of each slave station device is started.

According to the present invention, the main line switching determining means includes:
It is determined whether or not uplink warnings have been detected for all of the active child station devices, and the child station activation stop control means has detected that the trunk line switching determination means has detected an uplink alarm for all of the active child station devices. If you do, start the time measurement by the timer,
After the time measured by the timer expires, the start control of each slave station device is started.

In the optical multi-branch communication system according to the next invention, the master station device and the plurality of slave station devices are connected by an optical splitter, and at least a trunk line between the master station device and the optical splitter is redundant. Wherein the plurality of slave stations share a transmission medium and a transmission band, the master station controls allocation of a used transmission band of each slave station apparatus, and each slave station apparatus uses transmission by the master station apparatus. In an optical multi-branch communication system that transmits transmission information to the master station device based on band allocation, the master station device includes a slave station start / stop control unit that controls starting and stopping of the slave station device; Uplink alarm monitoring means for detecting an uplink alarm of a slave station apparatus, band information holding means for holding band information that is information on a used transmission band allocated to each slave station apparatus, and a plurality of timers corresponding to each slave station apparatus And before From a predetermined time corresponding to the switching time from the start of switching of the main transmission line to the completion of the switching, each slave station device detects an upward alarm from the occurrence of switching of the main transmission line according to the size of the used transmission band indicated by the band information. Calculating the remaining time obtained by subtracting the elapsed time until the slave station device has a timer setting means for setting the remaining time corresponding to each of the slave station devices; When data is detected, a timer corresponding to the slave station device that has issued the uplink alarm data is started to measure time, and after the time counted by the timer expires, start control of the slave station device is started. I do.

According to the present invention, the timer setting means starts the predetermined time corresponding to the switching time from the start of the switching of the trunk transmission line to the completion of the switching according to the size of the used transmission band indicated by the band information. Calculate the remaining time by subtracting the elapsed time from the occurrence of switching to the time when each slave station device detects an uplink warning, set the corresponding remaining time to the timer corresponding to each slave station device, and stop the slave station activation. When the control unit detects the uplink warning, the control unit starts time counting by the timer corresponding to the slave station device that has issued the uplink warning, and after the time counting by the timer expires, starts the start control of the slave station device. Like that.

[0024] In a transmission path switching recovery processing method for an optical multi-branch communication system according to the next invention, a master station device and a plurality of slave station devices are connected by an optical splitter, and at least the master station device and the optical splitter are connected. The trunk transmission path between them is redundantly configured, the plurality of slave station devices share a transmission medium and a transmission band, the master station device controls the allocation of the use transmission band of each slave station device, and each slave station device In the transmission line switching recovery control method for an optical multi-branch communication system that transmits transmission information to the master station device based on the allocation of a used transmission band by the master station device, the switching for receiving a notification of the start of switching of the trunk transmission line is performed. A notification receiving step, and, when receiving a notification of the start of switching of the trunk transmission line, timing start to start timing by a timer for timing a predetermined time corresponding to a non-transmission time accompanying the switching of the trunk transmission line. And extent, after the counting of a predetermined time by the timer has expired, characterized in that it comprises a starting control step of starting the activation control of the slave station apparatuses.

According to the present invention, when the notification of the start of switching of the trunk transmission line is received by the switching notification receiving step, and the notification of the start of switching of the trunk transmission line is received by the timing start step, the switching of the trunk transmission line is performed. By starting the time measurement by a timer that measures a predetermined time corresponding to the interruption time accompanying the switching, by the start control step, after the time measurement of the predetermined time by the timer expires, to start the start control of each slave station device. I have.

In the transmission path switching recovery processing method for an optical multi-branch communication system according to the next invention, a master station device and a plurality of slave station devices are connected by an optical splitter, and at least the master station device and the optical splitter are connected. The trunk transmission path between them is redundantly configured, the plurality of slave station devices share a transmission medium and a transmission band, the master station device controls the allocation of the use transmission band of each slave station device, and each slave station device In the transmission line switching recovery control method for an optical multi-branch communication system that transmits transmission information to the master station device based on the allocation of a used transmission band by the master station device, each slave station associated with switching of the trunk transmission line is provided. A main line switching determination step of detecting whether or not an uplink alarm for the device has been detected for all active sub-station devices; and Road switching A timer starting step for starting time measurement by the timer for measuring a predetermined time corresponding to the interrupted time involved, after the counting of the predetermined time period has expired by the timer,
A start control step of starting start control of each slave station device.

According to the present invention, it is determined whether or not, in the trunk line switching determination step, an upward alarm for each slave station device accompanying the switching of the trunk line transmission line has been detected for all active slave station devices. Detecting, by the timing start step, when detecting an uplink alarm for all the active slave station devices, start timing by a timer that counts a predetermined time corresponding to the interruption time accompanying the switching of the trunk transmission line, and start In the control step, after the time measurement of the predetermined time by the timer has expired, the start control of each slave station device is started.

In the transmission path switching recovery processing method for an optical multi-branch communication system according to the next invention, a master station device and a plurality of slave station devices are connected by an optical splitter, and at least the master station device and the optical splitter are connected. The trunk transmission path between them is redundantly configured, the plurality of slave station devices share a transmission medium and a transmission band, the master station device controls the allocation of the use transmission band of each slave station device, and each slave station device In the transmission path switching recovery control method of the optical multi-branch communication system for transmitting transmission information to the master station device based on the allocation of the used transmission band by the master station device, information on the used transmission band assigned to each slave station device is provided. A band information holding step of holding band information, and a predetermined time corresponding to a switching time from the start of switching of the main transmission line to the completion of switching, according to the size of the used transmission band indicated by the band information. A timer that calculates the remaining time obtained by subtracting the elapsed time from the occurrence of switching of the trunk line transmission line to the time when each slave station device detects an upward alarm, and sets the corresponding remaining time to the timer corresponding to each slave station device. The setting step, when detecting an uplink warning from the slave station device, starts counting time by a timer corresponding to the slave station device that has issued the uplink warning, and after the time counted by the timer expires, sets the slave station device. And a start control step of starting the start control of (1).

According to the present invention, the band information holding step holds band information, which is information on the used transmission band allocated to each slave station device, and the timer setting step
From a predetermined time corresponding to the switching time from the start of the switching of the trunk line to the completion of the switching, each slave station device issues an upward alarm from the occurrence of switching of the trunk line in accordance with the size of the used transmission band indicated by the band information. The remaining time calculated by subtracting the elapsed time until detection is calculated, the timer corresponding to each slave station device is set to the corresponding remaining time, and the start-up control process detects an uplink warning from the slave station device. In this case, time counting by a timer corresponding to the slave station device that has issued the uplink warning is started, and after the time counted by the timer expires, start control of the slave station device is started.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an optical multi-branch communication system and a transmission line switching recovery processing method according to the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of an optical multi-branch communication system according to Embodiment 1 of the present invention. In FIG. 1, the optical multi-branch communication system is the same as that of FIG.
1, the master station device 1 and a plurality of slave station devices 5 are connected via the optical splitter 4, and the trunk line between the master station device 1 and the optical splitter 4 is redundant. It is configured.

The master station device 1 has a switching instruction transmitting unit 31. The switching instruction unit 6 issues a switching instruction to the optical switches 3a and 3b that switch the trunk transmission line by the optical fibers L2a and L2b.
1 is also input. When a switching instruction is input from the switching instruction unit 6, the switching instruction transmitting unit 31 outputs to the start / stop control unit 13 that the switching instruction has been issued. Other configurations are the same as those of the conventional optical multi-branch communication system shown in FIG. 11, and the same components are denoted by the same reference numerals. However, the start / stop control unit 13 illustrated in FIG. 1 performs a different control process from the start / stop control unit 13 illustrated in FIG.

FIG. 2 is a block diagram showing a detailed configuration of the slave station device 5 shown in FIG. In FIG. 2, an optical transceiver 21 performs a transmission / reception process of an optical signal transmitted / received to / from the master station device 1 and a conversion process between an optical signal and an electric signal. The downstream alarm monitoring unit 22 monitors a downstream alarm from the downstream signal output from the optical transceiver 21 and outputs a monitoring result to the upstream data transmission control unit 28. The uplink data transmission control unit 28 performs control to stop transmission of uplink data transmitted from the optical transceiver 21 to the master station device 1 when the downlink alarm monitoring unit 22 detects a downlink alarm.

The allocation identifying section 23 obtains information on band allocation from the downlink signal output from the optical transceiver 21,
Based on the information on the bandwidth allocation, the data reading unit 24
a, 24b to control data reading. The buffer memories 25a and 25b temporarily store data input from a terminal device or the like connected to the slave station device 5. The data reading units 24a and 24b read data from the buffer memories 25a and 25b at the timing of being output to their own time slots and output the data to the multiplexing unit 27 under the control of the assignment identifying unit 23. The multiplexing unit 27 includes the data reading units 2
The data output from 4a and 24b is multiplexed, and optical transceiver 21 outputs the multiplexed data to master station device 1 as an optical signal.

Here, with reference to the flowchart shown in FIG. 3, a description will be given of a transmission path restoration processing procedure in the case where the switching of the trunk line by the switching instructing unit 6 has occurred. In FIG. 3, first, the optical switches 3a, 3b are switched based on the switching instruction of the switching instruction unit 6, and the optical fibers L2a, L2
When the connection switching of 2b is executed (step S100),
The switching instruction transmitting unit 31 is notified of the switching instruction, and the switching instruction transmitting unit 31 notifies the activation / stop control unit 13 that the trunk line has been switched (step S101).

Thereafter, the start / stop control unit 13 performs a slave station stop control such as sending a transmission stop signal to the slave station device 5 irrespective of the uplink warning result monitored by the uplink warning monitoring unit 12 ( Step S102). Further, the start / stop control unit 13 starts a built-in slave station stop timer (not shown) (step S103). The timer time set in the slave station stop timer is a time obtained by adding a predetermined margin to the time when the switching of the trunk line is completed.

Thereafter, the start / stop controller 13 determines whether or not the timer time counted by the slave station stop timer has expired (step S104). The start / stop control unit 13 determines that the timer time has expired (step S104, YES).
Next, slave station start control for restarting the slave station apparatus 5 is performed (step S105), and the slave station apparatus 5 restarts by the slave station start control (step S113).

On the other hand, each slave station device 5 detects a down warning due to an instantaneous interruption that occurs with the execution of trunk line switching (step S111). Thereafter, each slave station device 5 performs a process of stopping transmission of uplink data to the master station device 1 (step S112). Thereafter, each slave station device 5 is restarted by the slave station start control from the master station device 1 (step S113).

Here, based on the timing chart shown in FIG. 4, a specific transmission line restoration process when the switching instruction unit 6 switches the trunk line will be described.
FIG. 4A shows a slave station device 5 having a small allocated band.
4 illustrates the flow of uplink data, and FIG. 4B illustrates the flow of uplink data of the slave station device 5-2 to which the allocated band is large.

When the optical switches 3a and 3b switch the optical fibers L2a and L2b at time tx according to the switching instruction from the switching instruction section 6, a momentary interruption occurs. Regardless of the above, the activation stop control unit 13 activates the slave station stop timer at time t1 according to the switching instruction notified from the switching instruction transmission unit 31. The slave station stop timer times out at time t2, and at time t3 after the time-out, the start / stop control unit 1
3 starts slave station activation control. In this case, the slave station stop control and the slave station activation control are performed based on the switching instruction sent from the switching instruction unit 6 irrespective of the presence / absence of an uplink alarm, particularly, the count number of the uplink alarm.

In the first embodiment, regardless of the bandwidth allocation amount assigned to each slave station device 5 and the uplink warning, each slave station device 5 Are forcibly controlled to stop, and are further controlled to be restarted, so that each of the slave station devices 5 is controlled to stop in substantially the same time, and the restart is controlled.
Quick restart control is performed.

Embodiment 2 Next, a second embodiment of the present invention will be described. In the first embodiment described above,
Although the master station device 1 forcibly performs the stop control and the start control of the child station device 5 based on the switching instruction from the switching instruction unit 6, in the second embodiment, all the child station devices 5
When one or more uplink warnings are detected, it is recognized that switching of the trunk line has occurred, and thereafter, the stop control and the start control for the slave station device 5 are performed.

FIG. 5 is a diagram showing a schematic configuration of an optical multi-branch communication system according to the second embodiment of the present invention. In FIG. 5, in the optical multi-branch communication system, as in the conventional optical multi-branch communication system shown in FIG. 11, a master station device 1 and a plurality of slave station devices 5 are connected via an optical splitter 4,
The trunk line between the master station device 1 and the optical splitter 4 has a redundant configuration.

When the uplink alarm detected by the uplink alarm monitoring unit 12 is detected at least once from all of the slave station devices 5, the master station device 1 determines that the switching of the trunk line has occurred. Is output to the start / stop control unit 13. Other configurations are the same as those of the conventional optical multi-branch communication system shown in FIG. 11, and the same components are denoted by the same reference numerals. Note that the output of the upstream alarm monitoring unit 12 is output to the main line instantaneous interruption determination unit 19, and the start / stop control unit 1
3 is not output.

Here, with reference to the flowchart shown in FIG. 6, a description will be given of a transmission path restoration processing procedure by the master station device 1 when the switching of the trunk line by the switching instruction unit 6 occurs. In FIG. 6, first, the optical switches 3a and 3b are switched based on the switching instruction of the switching instruction unit 6, and the connection switching of the optical fibers L2a and L2b is executed (step S200). , An uplink warning, that is, an instantaneous interruption of the uplink signal is detected (step S20).
1).

Thereafter, the main line instantaneous interruption determination unit 19 determines whether or not an upward warning has been detected for all of the slave units 5 that are currently connected to the master unit 1 and that have been activated (step S202). If an uplink warning has been detected for all of the active child station devices 5 (step S202, YES), the activation stop control unit 13 sends a transmission stop signal to the child station device 5 or the like. Stop control is performed (step S203). Further, the start / stop control unit 13 starts a built-in slave station stop timer (not shown) (step S20).
4). The timer time set for this slave station stop timer is
This is a time obtained by adding a predetermined margin to the time when the switching of the trunk line is completed.

Thereafter, the start / stop controller 13 determines whether or not the timer time counted by the slave station stop timer has expired (step S205). The start / stop control unit 13 determines that the timer time has expired (step S205, YES).
Next, slave station start control for restarting the slave station device 5 is performed (step S206), and the slave station device 5 is restarted by the slave station start control.

Here, based on the timing chart shown in FIG. 7, a specific transmission line restoration process in the case where the switching of the trunk line by the switching instructing unit 6 has occurred will be described.
FIG. 7 shows the flow of uplink data of each slave station device 5 to which various bandwidth allocation amounts are allocated.

When the optical switches 3a and 3b execute switching of the optical fibers L2a and L2b at time tx in response to the switching instruction from the switching instructing unit 6, an instantaneous interruption occurs.
Is detected as an upward alarm. In this case, the timing at which an uplink warning is first detected differs depending on the bandwidth allocation amount allocated to each slave station device 5. For example, for the slave station devices 5-1, 5-2, 5-n, the time t
An upward warning is detected at timings x1, tx2, and txn. However, this timing difference is smaller than the time difference of detecting the uplink warning eight times or more for each slave station device 5.

Here, as described above, when the main line instantaneous interruption determination unit 19 detects one or more uplink warnings for all the slave stations 5, at the time ty, the instantaneous upstream It is determined that the disconnection has occurred, and the slave station stop timer is started at time t11. This slave station stop timer operates at time t
Time out at 12 and time t1 after this time out
In 3, the start / stop control unit 13 starts the slave station start control. That is, in order to protect the uplink warning, the slave station stop control and the slave station activation control are performed only by detecting one or more uplink warnings without detecting eight or more uplink warnings. In addition, it is determined that an uplink instantaneous interruption has occurred only once for each slave station device 5, but in the case of an instantaneous interruption of the main line, the number of uplink alerts is not the number of uplink alerts, but all slave station devices 5 are notified. On the other hand, it is important whether or not an upward alarm is generated. Conversely, if no uplink alarm is generated for only one slave station device 5, it cannot be determined that there is an instantaneous interruption due to main line switching.

In the second embodiment, all the slave stations 5
Is determined to be an instantaneous interruption due to the switching of the trunk line at the point in time when one or more uplink warnings are generated, and thereafter, the respective slave station devices 5 are controlled to be stopped, and the start control is further performed to restart them. The slave station device 5 is controlled to stop at substantially the same time, and is further controlled to restart, so that quick restart control is performed.

Embodiment 3 FIG. Next, a third embodiment of the present invention will be described. In Embodiments 1 and 2 described above, the slave station stop control and the slave station start control for each slave station device 5 are performed using one slave station stop timer. A plurality of slave station stop timers corresponding to each slave station device 5 are provided, and an appropriate timer setting time corresponding to the bandwidth allocation amount is set for each slave station stop timer,
The slave station stop control and the slave station activation control are performed for each slave station device 5.

FIG. 8 is a diagram showing a schematic configuration of an optical multi-branch communication system according to the third embodiment of the present invention. 8, in the optical multi-branch communication system, as in the conventional optical multi-branch communication system shown in FIG. 11, a master station device 1 and a plurality of slave station devices 5 are connected via an optical splitter 4,
The trunk line between the master station device 1 and the optical splitter 4 has a redundant configuration.

The band control unit 10 of the master station device 1 has band information 20 which is information on band allocation to each slave station device 5.
Is output to the start / stop control unit 13. Start / stop control unit 13
Has a plurality of slave station stop timers (not shown) corresponding to each slave station device 5. In addition, the start / stop control unit 13 sets each of the slave station devices 5 to issue an upward alarm from the occurrence of trunk line switching from a predetermined time corresponding to the switching time from the start of trunk line switching to the completion of switching according to the magnitude of the bandwidth allocation amount. It has a timer setting unit 13a that calculates the remaining time by subtracting the elapsed time until the detection is performed eight times, and sets the remaining time corresponding to each of the slave station stop timers corresponding to each slave station device 5. Start / stop control unit 1
3 is to start measuring the timer time set in the slave station stop timer for the slave station device that has detected the uplink alert, when an uplink alert is detected for each slave station device 5, and the slave station stop timer After the expiration of the clock time of the slave station device, the activation of the slave station device is controlled. Other configurations are the same as those of the conventional optical multi-branch communication system shown in FIG. 11, and the same components are denoted by the same reference numerals.

Here, with reference to a flowchart shown in FIG. 9, a description will be given of a transmission path restoration processing procedure in the case where the switching of the trunk line by the switching instructing unit 6 has occurred. In FIG. 9, first, the optical switches 3a and 3b are switched based on the switching instruction of the switching instruction unit 6, and the optical fibers L2a and L2 are switched.
When the connection switching of 2b is executed (step S300),
The upward alarm monitoring unit 12 detects an upward alarm (step S301). In this case, the up-alarm monitoring section 12 outputs the up-alarm warning to the activation / stop control section 13 only when the up-alarm alert is detected eight times.

After that, when the upstream alarm monitoring unit 12 notifies that the upstream alarm has been detected, the main line instantaneous interruption determination unit 19 sends a transmission stop signal to the slave station device 5 where the upstream alarm has been detected. A slave station stop control such as transmission is performed (step S302). Further, the start / stop control unit 13 acquires the band information 20 output from the band control unit 10 (step S303), and sets the timer value, which is the remaining time, to the slave station stop timer corresponding to the uplink warning. (Step S304).

Thereafter, the start / stop control unit 13 starts the slave station stop timer (step S305). further,
The start / stop controller 13 determines whether or not the timer time counted by the slave station stop timer has expired (step S30).
6). When the timer time has expired (step S306, YES), the activation stop control unit 13 performs slave station activation control for restarting the slave station device 5 (step S30).
7) The slave station device 5 is restarted by the slave station start control.

Here, based on the timing chart shown in FIG. 10, a specific transmission line restoration process when the switching of the trunk line by the switching instruction unit 6 occurs will be described. FIG. 10 shows the flow of uplink data of the slave station device 5-1 to which the allocated bandwidth allocation is small, and the flow of uplink data of the slave station device 5-2 to which the allocated bandwidth allocation is large.

When the optical switches 3a and 3b switch the optical fibers L2a and L2b at the time tx in response to the switching instruction from the switching instruction unit 6, an instantaneous interruption occurs.
Is detected as an upward alarm. From the point of time when this uplink warning is detected, the timer setting unit 13 calculates the remaining time of the child station stop timer corresponding to the child station device 5 from which this uplink alarm was detected, and sets the remaining time to this child station stop timer. Alternatively, the bandwidth information 20 is periodically sent to each slave station stop timer.
The remaining time is calculated based on the above, and the remaining time is set in each slave station stop timer.

Since the amount of bandwidth allocated to the slave station device 5-1 is small, the time slot period Tc1 of the slave station device 5-1 is long. The timer setting unit 13a calculates the time slot cycle Tc1 from the band information 20 and also calculates a time Tu1 until eight uplink warnings are counted, and sets a predetermined margin between the time from the start of trunk line switching to the completion of switching. From the time (t23−tx) where
The remaining time (t23-t22) is calculated by subtracting the time obtained by adding the predetermined time (t22-t21) to 1 and the remaining time is set in the slave station stop timer corresponding to the slave station device 5-1. On the other hand, since the amount of bandwidth allocated to the slave station device 5-2 is large, the time slot cycle Tc2 of the slave station device 5-2 is short. Similarly, the timer setting unit 13a sends a long remaining time (t3) to the slave station device 5-2.
3-t32), and calculates the remaining time by using the slave station 5-
Set the slave station stop timer corresponding to 2. That is, a short timer time is set when the time required to detect the uplink alarm corresponding to the bandwidth allocation is long, and a long timer time is set when the time required to detect the uplink alarm corresponding to the bandwidth allocation is short. Thus, the times t23 and t33 at which the slave station stop timer expires are made substantially the same.

In the third embodiment, the number of detections of
The timer time of each slave station stop timer is set in accordance with the length of time until the execution is repeated, and the timeout time of each slave station stop timer is set to be substantially constant. The stop control and restart control of each slave station device 5 can be performed without being affected by the allocated bandwidth allocation amount, and quick restart control is executed.

In the third embodiment, each slave station device 5
Since an uplink alarm is detected every time and the stop control and the start control are performed for each slave station device 5, not only the instantaneous interruption due to the switching of the trunk line, but also the connection between the optical splitter 4 and each slave station device 5 is performed. It is possible to individually cope with an instantaneous interruption of the optical fiber L4 which is a branch line, and a quick line restoration process is realized.

[0063]

As described above, according to the present invention, when the switching instruction transmitting means receives the switching start notification of the main transmission line and the slave station start / stop control means receives the switching start notification, Start timing by the timer,
Since the start control of each slave station device is started after the time measured by the timer expires, the instantaneous interruption caused by the switching of the main transmission line is performed independently of the detection of the uplink alarm accompanying the switching of the main transmission line. Therefore, there is an effect that the stop control and the start control of the slave station device can be reliably performed.

According to the next invention, the trunk line switching judging means judges whether or not an upward alarm has been detected for all of the activated slave stations, and the slave station start / stop control means judges that the trunk line switching judgment has been made. When the means detects an upward alarm for all the running slave stations, the timer starts counting, and after the time counted by the timer expires, the start control of each slave station is started. Therefore, in addition to the protection of the uplink warning, there is an effect that the instantaneous interruption caused by the switching of the trunk transmission line can be reliably identified, and the stop control and the start control of the slave station device can be quickly performed.

According to the next invention, the timer setting means comprises:
From a predetermined time corresponding to the switching time from the start of switching of the main transmission line to the completion of the switching, each slave station device detects an upward alarm from the occurrence of switching of the main transmission line according to the size of the used transmission band indicated by the band information. The remaining time obtained by subtracting the elapsed time up to is calculated, the timer corresponding to each slave station device is set to the corresponding remaining time, and the slave station start / stop control means detects the uplink warning, Start the timekeeping by the timer corresponding to the slave station device that issued the command, and after the time measured by the timer expires, start control of the slave station device is started. Regardless of the size of the slave station, the stop control and the start control of the slave station device can always be performed within a fixed time, and not only the instantaneous interruption due to the switching of the trunk line but also the slave station device due to the failure of the branch line can be performed. Stop To your and start control is an effect that it can be applied.

According to the next invention, when the notification of the start of switching of the trunk transmission line is received in the switching notification receiving step, and the notification of the start of switching of the trunk transmission line is received in the timing start step, A timer for counting a predetermined time corresponding to the interruption time accompanying the switching of the timer is started, and the startup control step starts the startup control of each slave station device after the timer for the predetermined time expires by the timer. Therefore, it is possible to grasp the instantaneous interruption caused by the switching of the main transmission line regardless of the detection of the upward alarm accompanying the switching of the main transmission line, and to reliably perform the stop control and the start control of the slave station device. It works.

According to the next invention, in the main line switching judgment step, it is determined whether or not an upward alarm for each slave station device accompanying the switching of the main line transmission line has been detected for all of the active slave station devices. Detecting, by the timing start step, when detecting an uplink alarm for all the active slave station device, to start timing by a timer that counts a predetermined time corresponding to the interruption time accompanying the switching of the trunk transmission line, In the activation control step, the activation control of each slave station device is started after the timer of the predetermined time has expired by the timer. Is reliably identified, and the stop control and the start control of the slave station device can be quickly performed.

According to the next invention, in the band information holding step, band information, which is information on the used transmission band allocated to each slave station device, is held, and in the timer setting step, switching from the start of switching of the trunk line is performed. From the predetermined time corresponding to the switching time until completion, the elapsed time from the occurrence of switching of the trunk transmission line to the detection of an uplink alarm by each slave station device according to the size of the used transmission band indicated by the band information was subtracted. The remaining time is calculated, the remaining time corresponding to each of the timers corresponding to the respective slave stations is set, and when the up alarm from the slave station is detected by the activation control step, the slave that has issued the up alarm is set. The start of the timer control by the timer corresponding to the station device is started, and after the time counted by the timer expires, the start control of the slave station device is started. Regardless of the size of the allocated bandwidth, it is possible to always perform the stop control and the start control of the slave station device within a fixed time, and not only the instantaneous interruption due to the switching of the main line, but also each of the slave units due to the failure of the branch line. There is an effect that the present invention can be applied to stop control and start control for the station device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical multi-branch communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a detailed configuration of a slave station device of the optical multi-branch communication system shown in FIG.

FIG. 3 is a flowchart illustrating a transmission path switching recovery control processing procedure by the optical multi-branch communication system illustrated in FIG. 1;

FIG. 4 is a timing chart showing an example of transmission line switching recovery control processing by the optical multi-branch communication system shown in FIG.

FIG. 5 is a diagram showing a configuration of an optical multi-branch communication system according to a second embodiment of the present invention.

6 is a flowchart showing a transmission path switching recovery control processing procedure by the optical multi-branch communication system shown in FIG. 5;

7 is a timing chart illustrating an example of a transmission line switching recovery control process performed by the optical multi-branch communication system illustrated in FIG. 5;

FIG. 8 is a diagram showing a configuration of an optical multi-branch communication system according to a third embodiment of the present invention.

9 is a flowchart showing a transmission path switching recovery control processing procedure by the optical multi-branch communication system shown in FIG.

10 is a timing chart illustrating an example of a transmission line switching recovery control process performed by the optical multi-branch communication system illustrated in FIG.

FIG. 11 is a diagram illustrating a configuration of a conventional optical multi-branch communication system.

12 is a flowchart showing a transmission path switching recovery control processing procedure by the optical multi-branch communication system shown in FIG. 11;

13 is a timing chart illustrating an example of a transmission line switching recovery control process performed by the optical multi-branch communication system illustrated in FIG. 11;

[Description of Signs] 1 master station device, 2 communication interface unit, 3a, 3b
Optical switch, 4 optical splitter, 5,5-1 to 5-n
Slave station device, 6 switching instruction unit, 10 band control unit, 1
1, 21 optical transceiver, 12 uplink alarm monitor, 13
Start / stop control unit, 13a timer setting unit, 14 management signal transmission unit, 15 uplink signal, 16 downlink signal, 17 registration management unit, 19 trunk line disconnection determination unit, 22 downlink alarm monitoring unit, 23 assignment identification unit, 24a, 24b data Reading unit,
25a, 25b buffer memory, 26a, 26b uplink data, 27 multiplexing unit, 28 uplink data transmission control unit, 31 switching instruction transmitting unit L1, L2a, L2b, L
3, L4, L4-1 to L4-n optical fiber.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 9/00 K (72) Inventor Hiroshi Ichigase 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 2-3 F term in Ryo Denki Co., Ltd. (reference) 5K002 BA04 BA06 DA05 DA09 EA05 EA33 FA01 5K014 CA06 FA01 5K033 AA06 BA08 CC01 DA01 DB01 DB22 EA04 EB06 5K042 CA07 CA10 DA18 EA01 FA08 HA13 JA01 NA01 NA02 NA03

Claims (6)

[Claims] 1. A master station device and a plurality of slave station devices are connected by an optical splitter, at least a trunk transmission path between the master station device and the optical splitter is redundantly configured, and the plurality of slave station devices are A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the allocation of the used transmission band by the master station device. In the optical multi-branch communication system for transmitting transmission information to a device, the master station device includes: a slave station start / stop control unit that controls start and stop of the slave station device; and a disconnection time accompanying switching of the trunk line. A timer for measuring a corresponding predetermined time; and a switching instruction transmitting unit for receiving a switching start notification of the trunk transmission line, wherein the slave station start / stop control unit is configured so that the switching instruction transmitting unit transmits the switching start instruction. Accepted If the timer according to start time counting, after a time measured by the timer has expired, the optical multi-branch communication system, characterized in that to start the start control of the slave station apparatuses. 2. A master station device and a plurality of slave station devices are connected by an optical splitter, at least a trunk line between the master station device and the optical splitter is redundantly configured, and the plurality of slave station devices are A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the allocation of the used transmission band by the master station device. In the optical multi-branch communication system for transmitting transmission information to a device, the master station device includes: a slave station start / stop control unit that controls start and stop of the slave station device; and each slave unit associated with switching of the trunk line. Uplink alarm monitoring means for detecting an uplink alarm of a station apparatus, trunk line switching determining means for determining whether or not an uplink alarm has been detected for all active slave station apparatuses, and interruption time associated with switching of the trunk line transmission path Predetermined time corresponding to A timer for measuring the time, wherein the slave station start / stop control means starts the time counting by the timer when the trunk line switching determination means detects an uplink alarm for all the slave station apparatuses being started. An optical multi-branch communication system characterized by starting activation control of each slave station device after expiration of a time measurement by the optical communication device. 3. A master station device and a plurality of slave station devices are connected by an optical splitter, at least a trunk transmission line between the master station device and the optical splitter is redundantly configured, and the plurality of slave station devices are A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the allocation of the used transmission band by the master station device. In an optical multi-branch communication system for transmitting transmission information to a device, the master station device includes a slave station start / stop control unit that controls start and stop of the slave station device, and an uplink that detects an uplink alarm of each slave station device. Alarm monitoring means, band information holding means for holding band information which is information on a used transmission band allocated to each slave station device, a plurality of timers corresponding to each slave station device, Until switching is completed Remaining time obtained by subtracting from the predetermined time corresponding to the switching time, the elapsed time from the occurrence of switching of the trunk transmission path to the detection of an uplink alarm by each slave station device according to the size of the used transmission band indicated by the band information. And a timer corresponding to each slave station device, a timer setting means for setting a corresponding remaining time, and wherein the slave station start / stop control means, when detecting an uplink warning, the uplink warning An optical multi-branch communication system, characterized by: starting timekeeping by a timer corresponding to an issuing slave station device; and starting the start control of the slave station device after the time measured by the timer expires. 4. A master station device and a plurality of slave station devices are connected by an optical splitter, at least a trunk line between the master station device and the optical splitter is redundantly configured, and the plurality of slave station devices are A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the allocation of the used transmission band by the master station device. In a transmission line switching recovery control method for an optical multi-branch communication system that transmits transmission information to an apparatus, a switching notification receiving step of receiving a notification of a start of switching of a main transmission line, and a notification of a start of switching of the main transmission line are received. In the case, a timing start step of starting time counting by a timer that counts a predetermined time corresponding to a disconnection time accompanying the switching of the trunk transmission line, and after the time counting of the predetermined time by the timer expires, each slave station device. And a start control step of starting the start control of the transmission path switching recovery control method of the optical multi-branch communication system. 5. A master station device and a plurality of slave station devices are connected by an optical splitter, and at least a trunk transmission line between the master station device and the optical splitter is redundantly configured, and the plurality of slave station devices are A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the allocation of the used transmission band by the master station device. In the transmission line switching recovery control method for an optical multi-branch communication system that transmits transmission information to a device, an uplink alarm for each of the child station devices accompanying the switching of the trunk transmission line is issued to all the child station devices that are operating. A main line switching determination step of detecting whether or not the main line transmission line is detected, and a timer for measuring a predetermined time corresponding to a non-conduction time associated with the switching of the main line transmission line when detecting an uplink alarm for all the active slave station devices. Start timing A transmission start switching step of an optical multi-branch communication system, comprising: starting a start-up control of each slave station device after expiration of a predetermined time by the timer. Control method. 6. A master station device and a plurality of slave station devices are connected by an optical splitter, and at least a trunk line between the master station device and the optical splitter is redundantly configured. A transmission medium and a transmission band are shared, and the master station device controls the allocation of the used transmission band of each slave station device, and each slave station device controls the master station based on the allocation of the used transmission band by the master station device. A transmission line switching recovery control method for an optical multi-branch communication system for transmitting transmission information to a device, comprising: a band information holding step of holding band information that is information on a used transmission band allocated to each slave station device; From a predetermined time corresponding to the switching time from the start of the switching to the completion of the switching, from the occurrence of the switching of the trunk line to the detection of the uplink alarm by each slave station device according to the size of the used transmission band indicated by the band information. A timer setting step of calculating the remaining time obtained by subtracting the excess time and setting the remaining time corresponding to each of the timers corresponding to the respective slave station devices, and detecting an uplink alert from the slave station device, Starting the time counting by the timer corresponding to the slave station device that has issued the command, and starting the start control of the slave station device after the time counted by the timer has expired. A transmission line switching recovery control method for a branch communication system.