JP2001326654A - Protection switching method for pon, and changeover device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection switching memory for PON, that can always use transmission paths of two systems to effectively utilize a physical resource. SOLUTION: A 0-system transmission reception 1a and a 1-system transmission reception section 1b of an OLT 6 are connected to separate ports of a switch 4, 0-system transmission reception sections 31a-31na and 1-system transmission receptions 31b-31nb of ONU 71-7n are respectively connected to other ports of switches 81-8n and a transmission path up to object subscriber terminals 911-91n is established, even if via any of the 0 system and 1 system transmission receptions and operation transmission paths, by changing switching setting of the switch 4 and the switches 81-8n and setting of a frequency band of each transmission path can be set freely.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an OLT (Opt)
PON (Passive), which connects a plurality of optical subscriber units (hereinafter referred to as ONUs (Optical Network Units)) with an optical coupler via an optical coupler.
The present invention relates to a PON protection switching method and a switching device applied to an Optical Network) system.

[0002]

2. Description of the Related Art Conventionally, a duplex configuration as shown in FIG. 4 has been generally used to ensure reliability in a PON system. FIG. 4 shows a completely duplicated PON system as shown in FIG.
First, the configuration of the single basic PON system shown in FIG. 3 will be described. In the OLT 6 in FIG. 3, a transmission / reception unit 1 is connected to a port of a switch 4, and the transmission / reception unit 1 is connected to an optical coupler 2 and an optical fiber. Through multiple ONUs 71-O
NU7n is connected to the transmission / reception units 31 to 3n,
U71 to 7n are connected to a single OLT 6 in a star configuration.

When communication is performed between the OLT 6 and the subscriber terminals 91 to 9n, the same signal is distributed from the optical coupler 2 to the ONUs 71 to ONUs 7n, and the ONUs 71 to ONUs are distributed.
7n is extracted by determining that it is a signal addressed to itself.

In this case, for example, when the ONU 71 determines that the signal is addressed to itself and extracts the signal, the OLT 6
A virtual path has been established between the transmitting / receiving unit 1 of the OLT 6 and the subscriber terminal 91, and communication between the transmitting / receiving unit 1 of the OLT 6 and the subscriber terminal 91 becomes possible. That is, O
The transmission / reception unit 1 in the LT 6 enables communication with the subscriber terminal 91 via the transmission / reception unit 31 of the ONU 71 through the optical coupler 2 and the optical fiber.

When the PON system having such a basic configuration is duplexed in order to ensure the reliability, the configuration is as shown in FIG. 4, and FIG. 4 shows the duplex configuration of the PON shown in FIG. The conventional PON shown in FIG.
In order to provide a redundant configuration, the OLT 6 is provided with two systems of a system 0 transmitting / receiving unit 1a and a system 1 transmitting / receiving unit 1b. Similarly, the subscriber units 71 to 7n are provided with the 0-system transmission / reception units 31a to 3na and the 1-system transmission / reception units 31b to 3nb, respectively, to provide two systems. As described above, by using two systems, the OLT 6 includes the switch 4 and the control unit 10.
In addition, a selector (hereinafter, referred to as SEL) 5 is provided.

The SEL 5 selectively switches between the system 0 transmission / reception unit 1a and the system 1 transmission / reception unit 1b, so that the system 0 transmission / reception unit 1a is connected to the optical coupler 2a and the optical fiber via the ONU.
The 1-system transmission / reception units 31a to 3na of the ONUs 71 to 7n are connected to the 0-system transmission / reception units 31a to 3na of the ONUs 71 to 7n through the optical coupler 2b and the optical fiber.
b to 3nb. These ONUs 71 to 7
The 0-system transmission / reception units 31a to 3na in 1n and the 1-system transmission / reception units 31b to 3nb correspond to each S in the ONUs 71 to 71n in accordance with the selection of the 0 system or 1 system by the SEL5 in the OLT 6.
Selected by the ELs 81 to 8n, the selected 0-system transmission / reception units 31a to 3na and 1-system transmission / reception units 31b to 3nb
Are connected to the subscriber terminals 91 to 9n, respectively.

Further, the ONUs 71 to 7n are provided with control units 111 to 11n, respectively. These control units 111 to 11n provide 0-system transmission / reception units 31a to 3na for SELs 81 to 8n in the ONUs 71 to 7n, respectively.
And 1-system transmission / reception units 31b to 3nb for performing switching selection control or switching selection control in the reverse direction.

For convenience of explanation, the system 0 transmission / reception unit 1a and system 1 transmission / reception units 31a to 3na are set to the active system, and the system 1 transmission / reception unit 1b and the system 1 transmission / reception units 31b to 3nb are set to the standby system.
It is assumed that an ON system is operated. The 0-system transmission / reception unit 1a, the 0-system transmission / reception units 31a to 3na, and the 1-system transmission / reception unit 1b and the 1-system transmission / reception units 31b to 3nb are names given for physical identification. 1a and 0
The system transmission / reception units 31a to 3na are not always the active system, the system 1 transmission / reception unit 1b and the system 1 transmission / reception units 31b to 3nb are not always the standby system, but the system 0 transmission / reception units 1a and the system 0 transmission / reception unit 31
a to 3na, 1-system transmission / reception unit 1b and 1-system transmission / reception unit 31b
3nb is not particularly related to the active system and the standby system, but for convenience of explanation, the active system is a currently used system. In this case, the standby system is a system operated when switching from the active system. It means that.

Now, as described above, the description will proceed assuming that the PON system is operated with the 0-system transmission / reception unit 1a as the active system and the 1-system transmission / reception unit 1b as the standby system. The system transmitting / receiving unit 1a is an optical coupler 2
a, 0 system transmission / reception units 31a to 3na of ONUs 71 to 7n,
Communication with the subscriber terminals 91 to 9n is possible through the SELs 81 to 8n. Now, the O-system transmitting / receiving unit 1a of the OLT 6 is the optical coupler 2a and the O-system transmitting / receiving unit 31 of the ONU 71.
a, It is assumed that a virtual path is established between the subscriber terminal 91 and the subscriber terminal 91 through the SEL 81, and the two are in a communication state. In this communication state, for some reason,
If an abnormality occurs in the virtual path between the OLT 6 transmission / reception unit 1a and the subscriber terminal 91, the OLT 6
Data from the subscriber terminal 91 is no longer transmitted / received to / from the 0-system transmission / reception unit 1a at T6. The 0-system transmission / reception unit 1a detects the occurrence of an abnormality in the virtual path, and sends an alarm signal to the control unit 10.

[0010] The control unit 10 which has received the alarm signal outputs
A switching command is issued to EL5, and SEL5 switches from the 0-system transmitting / receiving section 1a to the 1-system transmitting / receiving section 1b. As described above, after the control unit 10 outputs the switching command to the SEL5, the control unit 10 connects through the system 1, that is, SE.
L5-1 transmission / reception unit 1b-optical coupler 2b-ONU 71-
ON through 7n 1-system transmission / reception units 31b to 3nb
A switch command is issued to U71 to 7n, and ONUs 71 to 7n are issued.
The control units 111 to 11n perform switching control to the SELs 81 to 8n, and the transmission paths are restored to the target subscriber terminals 91 to 9n.

Thus, the OLT 6 and the subscriber terminals 91 to 91
All the virtual paths between 9n are simultaneously switched to the first system. That is, a virtual path is established between the first transmission / reception unit 1b of the OLT 6 and the subscriber terminals 91 to 9n through the optical coupler 2b, the first transmission / reception units 31b to 3nb of the subscriber units 1 to 7n through the optical fiber, and the SELs 81 to 8n. You.
Accordingly, the communication between the OLT 6 and the subscriber terminal 91 which has been interrupted due to an abnormality is instantaneously transmitted to the ONU 71 via the 1-system transmission / reception unit 1b / optical coupler 2b / optical fiber with the OLT 6.
1st transmission / reception unit 31b, subscriber terminal 9 via SEL81
1 can be resumed and the communication can be continued.

[0012]

However, in the configuration shown in FIG. 4, the working system and the backup system are physically distinguished from each other, and the backup system is not used until it is selected by the selector 5 and the selectors 81 to 8n. Can not do it. In addition, since only the physical transmission medium is replaced, the connection to be restored is the same as before the switching.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to always use both the 0 system and the 1 system in accordance with the switching setting for the switches in the OLT and the ONU. A PON that can freely set up a transmission path and a transmission band of which band can be set freely, and can flexibly provide a transmission path to be restored as a backup according to a service. It is an object of the present invention to provide a protection switching method and a switching device.

[0014]

In order to achieve the above object, a PON protection switching method according to the present invention is characterized in that a working transmission / reception unit and a protection transmission / reception unit provided in an intra-office device are respectively connected to the first transmission / reception unit of the intra-station device. Connected to a different port of the switch, the active transmitting / receiving unit and the standby transmitting / receiving unit respectively provided in the plurality of subscriber units are connected to the plurality of subscriber terminals via the second switch of the subscriber unit, An optical signal from the working transmission / reception unit of the intra-office device is distributed to the working transmission / reception unit in the subscriber unit by a first optical coupler, and the working transmission / reception unit of the intra-office device and the current operation of the subscriber unit are used. The transmission / reception unit transmits / receives signals to / from each other, distributes an optical signal from the standby transmission / reception unit of the intra-station device to the standby transmission / reception unit of the subscriber unit by a second optical coupler, and Reserve system transmission and reception Parts and pre system transceiver and mutual transmission and reception of the subscriber unit, a second first controller in the first switch setting control and the subscriber unit switches the station device
By changing the switching control of the second switch by the control unit, the transmission path between the working transmission / reception unit and the protection transmission / reception unit of the intra-station device and the subscriber terminal is simultaneously established.

Therefore, the optical signal from the active transmission / reception unit of the intra-station device is distributed to the active transmission / reception unit in the subscriber unit by the first optical coupler, and the active transmission / reception unit of the intra-station device and the current operation of the subscriber unit are used. System transmitting and receiving signals from each other,
A second optical coupler distributes the optical signal from the standby transmission / reception unit of the intra-station device to the standby transmission / reception unit of the subscriber unit,
The backup transmission / reception unit of the intra-office device and the backup transmission / reception unit of the subscriber device transmit and receive each other. Further, by changing the switching setting of the first switch in the first control unit of the intra-office device and the switching setting of the second switch in the second control unit of the subscriber unit, the active transmission / reception unit and the standby system of the intra-station device are changed. By simultaneously establishing a transmission path between the transmission / reception unit and the subscriber terminal, the active transmission / reception unit of the intra-office device and the subscriber unit and the transmission / reception unit of the standby system can be connected to the target transmission unit via any transmission path. Since the transmission path to the user terminal is established, the OLT and O
Both the working system and the standby system can be used at all times in accordance with the switching setting for the switch in the NU, and the transmission path can be freely established through which system, and the transmission path of any band can be established. In this case, the transmission path to be restored as a spare can be flexibly provided according to the service.

Further, the PON protection switching device of the present invention comprises an intra-office device provided with a working transmission / reception unit and a protection transmission / reception unit, and a first optical coupler for transmitting an optical signal of the working transmission / reception unit of the intra-office device. And a backup transmission / reception unit connected through a transmission path to a working transmission / reception unit connected through a transmission path and an optical signal of the backup transmission / reception unit of the intra-station device to the intra-station device. A plurality of subscriber devices star-connected to each other, a subscriber terminal connected to the active transmission / reception unit and the standby transmission / reception unit of each subscriber device, and the active transmission / reception provided in the intra-office device. A first switch for connecting the unit and the standby transmission / reception unit to different ports to switch the transmission path to establish a transmission path between the intra-office device and the subscriber terminal;
A second switch that is provided in each of the plurality of subscriber devices and switches between the working transmission / reception unit and the protection transmission / reception unit of the subscriber device and connects to the subscriber terminal; A first control unit that performs switching setting control of the first switch; and a second control unit that is provided in each of the subscriber devices and that performs switching setting of the second switch. And

[0017] Therefore, an intra-office device provided with a working transmission / reception unit and a protection transmission / reception unit, and an optical signal of the working transmission / reception unit of the intra-station device are transmitted and received by the subscriber unit through a first optical coupler and a transmission line. And send in the opposite direction,
The optical signal of the standby transmission / reception unit of the intra-office device is transmitted to the standby transmission / reception unit of the subscriber device via the second optical coupler and the transmission line and transmitted in the opposite direction, and the first control unit of the intra-station device controls the first signal. By changing the switching setting to the switch and changing the switching setting of the second switch by the second control unit of the subscriber unit, the switching between the working transmission / reception unit and the standby transmission / reception unit of the intra-office device and the subscriber terminal is performed. A transmission path is established at the same time, and a transmission path is established between the in-station device, the active transmission / reception unit of the subscriber unit, the backup transmission / reception unit, and the intended subscriber terminal via any transmission path. So O
In accordance with the switching settings for the switches in the LT and the ONU, both the working system and the protection system can be used at all times, and the transmission path can be freely set through any of them. The transmission path to be restored as a spare can be freely set.
It can be flexibly provided according to the service.

[0018]

Next, an embodiment of a PON protection switching method and a switching device according to the present invention will be described with reference to the drawings. FIG. 1 shows a P according to the invention.
It is a block diagram showing composition of a 1st embodiment of an ON protection switching device. In FIG. 1, FIG.
The same parts as those of the conventional PON protection switching device shown in FIG.

In FIG. 1, the OLT 6 is provided with a 0-system transmitting / receiving section 1a and a 1-system transmitting / receiving section 1b. The 0-system transmitting / receiving unit 1a and the 1-system transmitting / receiving unit 1b are connected to different ports of the switch 4. The 0-system transmitting / receiving unit 1a in the OLT 6 is connected to the ONUs 71 to 7n via the 0-system optical coupler 2a.
Are connected to the 0-system transmission / reception units 31a to 3na. O
The first transmission / reception unit 1b in the LT 6 is connected to the first transmission / reception units 31b to 3nb in the ONUs 71 to 7n via the first optical coupler 2b.

The ONUs 71 to 7n are provided with switches 81 to 8n, respectively. The OMU transmitting / receiving unit, the 1-system transmitting / receiving unit, and the subscriber terminals 911 to 9nm in the OMU are provided.
Are connected. The 1-system transmitting / receiving unit 1a in the OLT 6 and the 0-system transmitting / receiving units 31a to 3na in the ONUs 71 to 7n are:
Send and receive signals to and from each other. The 1-system optical coupler 2a branches the optical signal from the 1-system transmitting / receiving section 1a and sends it to the 0-system transmitting / receiving sections 31a to 3na in the ONUs 71 to 7n.

Similarly, the 1-system transmitting / receiving section 1b in the OLT 6 and the 1-system transmitting / receiving sections 31b to 3nb in the ONUs 71 to 7n are
Send and receive signals to and from each other. The first-system optical coupler 2b branches the optical signal from the first-system transmitting / receiving unit 1b and sends it to the first-system transmitting / receiving units 31b to 3nb in the ONUs 71 to 7n. Also, OLT6
The 0-system transmission / reception unit 1a and the 1-system transmission / reception unit 1b have a function of always monitoring signals, and notify the control unit 10 when an abnormality under the subordinate is detected.

The switch 4 in the OLT 6 discriminates the header information of the input ATM cell in accordance with the switching setting from the control unit 10, and outputs it to a target port. ON
Switches 81-8n in U71-7n are ONU71-
7n, the header information of the ATM cell received from the 0-system transmission / reception unit and the 1-system transmission / reception unit is determined according to the switching setting from each of the control units 111 to 11n, and is output to the target port. ~ Subscriber terminal 9
The connection to nm has been established.

The switches 81 in the ONUs 71 to 7n
.About.8n is not limited to an ATM switch, but may be other signal switching means. The control unit 10 in the OLT 6 is an OL
Control of each part in T6 is performed. In addition, ONU71-
Each control unit 111-11n in 7n controls each part in ONU71-7n, respectively.

Next, the operation of the first embodiment of the PON protection switching apparatus according to the present invention having the above-described configuration will be described. The description of this operation also serves as the description of the first embodiment of the PON protection switching method according to the present invention. In describing this operation, as an example, a case where virtual paths VP1 and VP2 are set from the OLT 6 to the subscriber terminal 911 is shown in FIG.
Shown in

Now, the switch 4 in the OLT 6 is set to the control unit 1
0, the switching control is performed, and the virtual path V
P1 and VP2 are set, the signal of the virtual path VP1 is connected between the ports P1 and P3 of the switch 4, and the signal of the virtual path VP2 is connected between the ports P1 and P4 of the switch 4. The switch 81 in the ONU 71 is controlled by the control unit 111 to connect the signal of the virtual path VP1 between the 0-system transmitting / receiving unit 31a and the subscriber terminal 911, and to transmit the signal of the virtual path VP2 to the 1-system transmitting / receiving unit. 31b and the subscriber terminal 911.

Thus, the switch 4 in the OLT 6
By setting the switching of the switch 81 in the ONU 71 by the control unit 10 and the control unit 111, respectively,
A connection can be established in either a transmission path via the 0-system transmission / reception unit 1a in the OLT 6, that is, a path (virtual path VP1) or a path via the 1-system transmission / reception unit 1b in the OLT 6 (virtual path VP2). In this case, 0
Unlike the conventional configuration in which the transmission paths of the system 1 and the system 1 are selectively used, the present invention has a configuration in which both systems can always be used. Can be set via the system and used simultaneously. The bandwidth of the virtual path can also be set independently.

An example of switching a virtual path using this configuration will be described below. As described above, the virtual paths VP1 and V
It is assumed that P2 has been set. As a first example, it is assumed that during normal operation, the virtual path VP1 is used for communication, and the virtual path VP2 is reserved as a backup and only the transmission band is not used. In this case, when a failure occurs in the optical transmission line and the 0-system transmitting / receiving unit 1a constituting the 0-system, the communication on the virtual path VP1 is disconnected.

Therefore, communication can be resumed by switching to the virtual path VP2 secured as a backup. Since the parameters such as the bandwidth of the virtual path VP2 can be set independently regardless of the virtual path VP1 used for the communication up to that point, not only the connection on the virtual path VP1 can be restored as it is, but also The virtual path VP2 can perform various services such as providing a narrow band.

As a second example, it is assumed that during normal operation, the virtual paths VP1 and VP2 are allocated to different communications and are used simultaneously. In this case, when a failure occurs in the 0-system transmission / reception unit 1a and the optical transmission line that constitute the 0-system, communication on the virtual path VP1 is disconnected. Therefore, a new virtual path VP3 for resuming communication with the first transmission / reception unit 1b via the optical transmission path is newly secured.

At this time, the priorities of the virtual paths VP1 and VP2 are determined in advance, and the virtual paths VP2 and VP2 are determined.
When the priority of the virtual path VP2 is low, the bandwidth of the virtual path VP2 is narrowed, a sufficient band is secured for restoring the virtual path VP1, and the restoration virtual path VP is established. When the priority of the virtual path VP2 is higher, a flexible use such as newly securing a virtual path VP3 of a narrow band that can resume the minimum communication becomes possible.

As described above, in the first embodiment according to the present invention, the 0-system transmission / reception unit 1a and the 1-system transmission / reception unit 1b are connected to different ports of the switch 4, and the ONUs 71 to 7n are connected to the 0-system transmission / reception unit 1a. Switch 1 transmission / reception unit 1b to switch 8
1 to 8n, and sets the switching settings for the switch 4 in the OLT 6 and the switches 81 to 8n in the ONUs 71 to 7n.
By changing it to 0 and the control of the control units 111 to 11n in the ONUs 71 to 7n, a transmission path to a target subscriber terminal can be established through either the 0-system or 1-system transmission / reception unit or optical transmission path. .

Further, the bandwidths of these transmission paths can be set freely. With this configuration, two physically different transmission paths can always be used without specializing in the role of active / standby. Along with this, in order to make effective use of the physical transmission bandwidth of the device,
There is an advantage that transmission paths for working and protection can be flexibly constructed.

Therefore, in the first embodiment, P
Regarding a protection switching method and a switching device using a duplex configuration in an ON system, a PON that can effectively use a transmission line held as a spare and a band of the device.
It is possible to provide a protection switching method and a switching device using a duplex configuration in a system.

[0034]

As described above, according to the PON protection switching method of the present invention, the switching settings of the OLT and the switches in the ONU are changed by the control of the control unit, so that physically different transmissions are performed. Since the path to the target subscriber terminal is established through the route, two different systems can always be used without distinguishing between the active system and the standby system, and physical resources can be effectively used. . Further, since what kind of connection is established is free, various services such as what kind of backup virtual path is provided can be flexibly provided.

According to the PON protection switching apparatus of the present invention, the OLT and the plurality of ONUs are provided with the 0-system transmitting / receiving unit and the 1-related transmitting / receiving unit, respectively.
The NUs are connected in a star configuration, and the switching setting of the switches is changed by the switching control of the OLT and the control unit in each ONU to establish a path to the target subscriber terminal through a physically different transmission path. Therefore, two different systems can always be used without distinguishing between the active system and the standby system, and physical resources can be used effectively. Further, since what kind of connection is established is free, various services such as what kind of backup virtual path is provided can be flexibly provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of a PON protection switching device according to the present invention.

FIG. 2 is a diagram illustrating a first example of the protection switching device of the PON of FIG. 1;
OL for explaining the operation of the embodiment and the first embodiment of the PON protection switching method according to the present invention
FIG. 5 is an explanatory diagram showing a virtual path setting state between T and an ONU.

FIG. 3 is a block diagram showing a basic configuration of a PON system.

FIG. 4 is a block diagram of a conventional PON system of FIG. 3 having a duplex configuration;

[Explanation of symbols]

1a, 31a to 3na... 0 system transmitting / receiving section (active system transmitting / receiving section), 1b, 31b to 3nb... 1 system transmitting / receiving section (standby system transmitting / receiving section), 2a... 0 system optical coupler, 2b. Couplers, 4, 81 to 8n... Switches, 6... OLT (intra-office device), 71 to 7n... ONU (subscriber device), 91
1 to 91n ... subscriber terminals, 10, 111 to 11n ...
Control unit, P1 to P4 ... port, VP1, VP2 ... virtual path.

Claims (24)

[Claims] An active transmission / reception unit and a protection transmission / reception unit provided in an intra-office device are connected to different ports of a first switch of an intra-office device, respectively. Unit and the standby transmission / reception unit are connected to a plurality of subscriber terminals via a second switch of the subscriber unit, respectively, and an optical signal from the working transmission / reception unit of the intra-office device is transmitted to the first terminal.
The optical coupler distributes the signal to the working transmission / reception unit in the subscriber unit, and mutually transmits / receives the signals of the working transmission / reception unit of the intra-station device and the working transmission / reception unit of the subscriber unit. An optical signal from the standby transmission / reception unit is distributed to the standby transmission / reception unit of the subscriber unit by a second optical coupler, and the standby unit transmission / reception unit of the intra-office device and the standby transmission / reception unit of the subscriber unit are interconnected. The first control unit of the intra-office device controls switching setting of the first switch and the second control unit of the subscriber unit transmits the second switch.
Changing the switching control of the switches (1) and (2) to simultaneously establish a transmission path between the working transmission / reception unit and the protection transmission / reception unit of the intra-station device and the subscriber terminal. 2. The transmission / reception unit of the working unit and the protection transmission / reception unit of the protection unit have a function of monitoring signals, respectively, and notify the control unit of the communication unit when detecting an abnormality under the control. The PON protection switching method according to claim 1, wherein: 3. The ATM switch according to claim 1, wherein the first switch is configured to input an ATM signal according to a switching setting from the first control unit.
2. The PON protection switching method according to claim 1, wherein the header information of the cell is determined and output to a target port. 4. A second switch in each of the subscriber units receives a signal from each of the active transmission / reception unit and the standby transmission / reception unit in each of the subscriber units according to the switching setting by the second control unit. 2. The PON protection switching method according to claim 1, wherein the connection to the subscriber terminal is established by discriminating the header information of the ATM cell and outputting it to a target port. 5. The PON protection switching method according to claim 1, wherein the second switch in each of the subscriber units switches signals other than ATM. 6. A transmission path between the intra-office device and the plurality of subscriber units, wherein a working transmission / reception unit of the intra-station device and the subscriber are set by switching setting of the first switch and the second switch. A first virtual path is set between the active transmission / reception unit of the device and a second virtual path is set between the protection transmission / reception unit of the intra-office device and the protection transmission / reception unit of the subscriber device. 2. The PON protection switching method according to claim 1, wherein the first virtual path and the second virtual path can be used simultaneously. 7. The PON protection switching method according to claim 6, wherein bands of the first virtual path and the second virtual path are set independently of each other. 8. The first virtual path is used for communication during normal operation, and the second virtual path is used for the first virtual path.
7. The PON protection switching method according to claim 6, wherein only a transmission band is reserved and used as a backup for said virtual path. 9. The PON protection switching method according to claim 6, wherein the first virtual path and the second virtual path are allocated to different communications during normal operation and used simultaneously. . 10. The first virtual path and the second virtual path
7. The virtual path according to claim 6, wherein, when one of the virtual paths is disconnected and the other virtual path is disconnected when the virtual paths are allocated to different communications and used simultaneously during normal operation, communication is resumed. The PON protection switching method described in the above. 11. The first virtual path and the second virtual path
When the priority of the second virtual path is lower than the priority of the first virtual path, the virtual path of the second virtual path narrows the bandwidth of the second virtual path when the first virtual path is disconnected. 7. The PON protection switching method according to claim 6, wherein a sufficient bandwidth for restoring the first virtual path is secured and a restoration virtual path is established. 12. The first virtual path and the second virtual path
When the priority of the second virtual path is higher than the priority of the first virtual path, the virtual path of the virtual path of a narrow band that can resume the minimum communication when the first virtual path is disconnected. 7. The PON protection switching method according to claim 6, wherein a new path is secured. 13. An intra-office device provided with an active transmission / reception unit and a protection transmission / reception unit, and an optical signal from an active transmission / reception unit of the intra-station device is transmitted to a first transmission unit.
And a backup transmission / reception section connected to the second optical coupler via a transmission path, respectively, with the working transmission / reception section connected to the second optical coupler via the transmission path. A plurality of subscriber devices star-connected to the intra-station device; subscriber terminals connected to the active transmission / reception unit and the standby transmission / reception unit of each of the subscriber devices; and A first switch for connecting the working transmission / reception unit and the protection transmission / reception unit to different ports to establish a transmission path between the intra-office device and the subscriber terminal; A second switch that is provided in each of the devices and switches between the working transmission / reception unit and the backup transmission / reception unit of the subscriber device and connects to the subscriber terminal; Of the switch A PON protection switching device, comprising: a first control unit that performs switching setting control; and a second control unit that is provided in each of the subscriber devices and that performs switching setting of the second switch. . 14. The transmission / reception unit of the working unit and the protection transmission / reception unit of the protection unit have a function of monitoring signals, respectively, and notify the control unit of the switching device when detecting an abnormality under the control. The PON according to claim 13,
Protection switching device. 15. The first switch according to claim 1, wherein the first switch is configured to receive an input AT according to a switching setting from the first controller.
14. The PON protection switching device according to claim 13, wherein the header information of the M cell is determined and output to a target port. 16. A second switch in each of the subscriber units receives a signal from each of the active transmission / reception unit and the standby transmission / reception unit in each of the subscriber units according to the switching setting by the second control unit. 14. The PON protection switching device according to claim 13, wherein the connection to the subscriber terminal is established by determining the header information of the ATM cell and outputting it to a target port. 17. The PON protection switching device according to claim 13, wherein the second switch in each of the subscriber units switches signals other than the ATM. 18. A transmission path between the intra-office device and the plurality of subscriber units, wherein a working transmission / reception unit of the intra-station device and the subscriber are set by switching setting of the first switch and the second switch. A first virtual path is set between the active transmission / reception unit of the device and a second virtual path is set between the protection transmission / reception unit of the intra-office device and the protection transmission / reception unit of the subscriber device. 14. The PON protection switching device according to claim 13, wherein the first virtual path and the second virtual path can be used simultaneously. 19. The first virtual path and the second virtual path
19. The PON protection switching device according to claim 18, wherein the virtual paths have independent bands. 20. The first virtual path is used for communication during normal operation, and the second virtual path is used by securing only a transmission band as a backup for the first virtual path. The PON according to claim 18,
Protection switching device. 21. The first virtual path and the second virtual path
19. The PON protection switching device according to claim 18, wherein the virtual paths are allocated to different communications during normal operation and used simultaneously. 22. The first virtual path and the second virtual path
19. The virtual path according to claim 18, wherein during normal operation, when one virtual path is disconnected and the other virtual path is disconnected when allocated to different communications and used simultaneously, the communication is resumed on the other virtual path. PON described
Protection switching device. 23. The first virtual path and the second virtual path
When the priority of the second virtual path is lower than the priority of the first virtual path, the virtual path of the second virtual path narrows the bandwidth of the second virtual path when the first virtual path is disconnected. 19. The PON protection switching device according to claim 18, wherein a sufficient bandwidth for restoring the first virtual path is secured and a restoration virtual path is established. 24. The first virtual path and the second virtual path
When the priority of the second virtual path is higher than the priority of the first virtual path, the virtual path of the virtual path of a narrow band that can resume the minimum communication when the first virtual path is disconnected. 19. The PON protection switching device according to claim 18, wherein a path is newly secured.