JP2002094493A - Transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission system for preventing functions of a control network from being impaired by accurately performing inter-node device time synchronization. SOLUTION: A client is provided with a time information requesting means C1 with a time request message for requesting the notification of the present time being transmittable to a server. The server is provided with a time information transmitting means S1, and the origin of transmission of the time request message can be notified of the present time; a time information receiving means C2 for receiving the time information and a time information setting means C3; inter-server/client transmission delay d is calculated by the time information setting means C3; and the time acquired by correcting the received present time only by the transmission delay d is set as a self (client) operation time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission system having a long transmission distance between node devices, such as an optical submarine cable system, and a supervisory control device and a node device.

[0002]

2. Description of the Related Art In a transmission system including a plurality of node devices and a supervisory control device, a slave synchronization method is often used. In this method, one time supply device (time server)
A plurality of node devices operate subordinately at the time provided by. However, in this method, when the node device receives the operation time from the time server, a time lag may occur due to a transmission delay due to a transmission distance.

In the conventional transmission system, no measure has been taken against time lag due to transmission delay, in particular, because the system scale is relatively small. However, in recent years, the scale of the system has increased, and in particular, in an international transmission network constructed across the oceans such as the Pacific Ocean and the Atlantic Ocean, the distance between the node devices is several hundred to several thousand km, so that the time lag may occur. It has grown to a level that cannot be ignored.

[0004] If the time lag exceeds the allowable value, the following inconveniences occur, particularly in terms of network management. For example, CMIP
In a network management system using (Common Management Information Protocol), a node device attaches a time stamp to notification information when notifying a monitoring control device, and also notifies an event occurrence time. At this time, if the time between the node devices is not accurately synchronized, when events occurring in different node devices are arranged in chronological order, the context is out of order, and it becomes difficult to analyze the events.

[0005] That is, the difference in operation time between the node devices has a particularly large adverse effect on the network management system.
In a recent large-scale transmission system, it is necessary to take some measures to prevent time lag between node devices.

[0006]

As described above, in recent years, the scale of a transmission system has been increasing, and the synchronization shift between node devices due to transmission delay has become remarkable. For this reason, there is a possibility that the function of the management network may be impaired, and some measures are desired.

[0007] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a transmission system that can accurately synchronize time between node devices and does not impair the function of a management network.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of node devices divided into a plurality of groups and a plurality of node devices for monitoring and controlling these node devices in each group. 1 supervisory control device and the first
A second supervisory control device that receives information provided from the supervisory control device and the node device and performs supervisory control in a unit wider than the first supervisory control device; and the node device, the first supervisory control device, and the second supervisory control. The present invention is directed to a transmission system including a time providing device that provides a time at which devices should operate synchronously, and in the transmission system, at least the first monitoring control device, the second monitoring control device, and the time providing device. In between, the relationship between the server and the client related to the time distribution and supply are set to each other, and when the server receives a time information provision request message requesting notification of the current time from the client, Time information transmitting means for transmitting time information including the current time in the own device, and the client needs to be notified of the current time. Sending the time information request message to the server, sending the time information request message to the server, receiving the time information corresponding to the sent time information request message from the server, and sending the time information request message to the server. The transmission delay in the section between the server that sent the time information and the own device is calculated from the time that has elapsed since the reception of the time information, and the transmission delay is obtained from the server based on the transmission delay. An operation time setting means for setting a time obtained by correcting the current time as an operation time of the own apparatus.

As a form of realizing the client-server relationship between the first monitoring and control device, the second monitoring and control device, and the time providing device, one second monitoring and control device is configured such that the time providing device is a server, Is the client and one of the first
There is a mode in which the monitoring control device uses the one second monitoring control device as a server and its own client, and the other first monitoring control devices sequentially form a client-server relationship with each other.

[0010] Alternatively, one second monitoring and control device uses the time providing device as a server and self as a client, and the plurality of first monitoring and control devices respectively control the one second monitoring and control device as a server and self. There is a form to be a client.

[0011] Alternatively, there is a form in which the plurality of first control devices and the second monitoring control devices each use the time providing device as a server and its own client.

With this configuration, for example, a plurality of node devices are provided in a station that is installed apart from each other, and a first monitoring control device that monitors and controls the node device belonging to the station is provided for each individual station. In such a transmission system, the operation time between the first monitoring and control devices can be accurately synchronized with the time provided by the time providing device, regardless of the transmission delay caused by the distance between the stations. That is, by taking the above-described means, it is possible to achieve at least mutual synchronization between the first monitoring and control devices.

Since the first supervisory control devices and the node devices to be monitored and controlled belong to the same station, the first supervisory control devices are synchronized with each other so that time synchronization between the node devices is achieved. Can be taken accurately. This makes it possible to construct a transmission system that does not impair the function of the management network.

As a mode for establishing synchronization between the first monitoring and control devices and the node device to be monitored and controlled, for example, the plurality of first monitoring and control devices are provided with time setting means. The own time may be forcibly set in each node device to be monitored and controlled. The function of the time setting means can be realized using, for example, a SET command in CMIP.

Alternatively, there is a form in which the plurality of node devices each use a first monitoring and control device that monitors and controls itself as a server, and each of the plurality of node devices as a client.

[0016] Further, there is provided a relay means for exchanging the time information request message and the time information between the server and the client, wherein the plurality of node devices, the first control device and the second monitoring control device each include: There is a form in which the time providing device is a server and the self is a client. With this configuration, the node device, the first control device, and the second monitoring control device operate in synchronization with the time of the original time providing device, and the time synchronization between the node devices can be accurately performed as described above. It is possible to take.

A series of procedures performed by the time information transmitting means, the time information requesting means, the time information receiving means, and the operation time setting means can be realized by, for example, mounting the NTP protocol on the server and the client. it can.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, SDH (Synchronous Digital Hierarchy) as a global standard is used.
Assume a system that conforms to

FIG. 1 is a system diagram showing a configuration of a transmission system according to the present invention. In FIG. 1, for example, a plurality of stations (Stations) ST-1 to ST1 to be installed across the ocean
Each of ST-m has a plurality of node devices (NODE)
1-1 to 1-n are provided. Node device 1-1
1-n are connected in a ring shape by a high-speed line OF extending between stations, and are connected between a plurality of node devices 1-1 and node devices 1-2.
A ring network is formed between the node devices 1-n. That is, there are n ring networks, and each ring network is formed from m node devices 1-1, 1-2, ..., 1-n.

Each of the node devices 1-1, 1-2,..., 1-n
The interface of the high-speed line OF connecting
M-64 (Synchronous Transfer Module-level 64: 1
(Equivalent to 0 Gbps). Each high-speed line OF transmits an optical signal, and its transmission wavelength differs from one ring network to another. These lines are wavelength-multiplexed to form a wavelength multiplex line FL.

The node devices 1-1 to 1-n in the stations ST-1 to ST-m are connected to an in-station supervisory control device (SSE) 2 in each station. SSE2 is
Furthermore, it is connected via a LAN to a supervisory control device (NME) 3 responsible for supervisory control over the entire area of the network. Also the above LAN
Is connected to a router 4, and a management network ML connecting the NMEs 3 in each station is formed through the router 4. Note that this management network ML is logically the SOH of the SDH frame transmitted through the wavelength multiplex line FL.
DCC (Data Commu) in H (Section Over Head)
communication channel).

At this time, it should be noted that a predetermined transmission delay occurs in information transmission between adjacent node devices depending on the distance between the node devices.

Here, one NME 3 (in FIG. 1, ST-
The time server 8 is connected to the NME 3). The time server 8 acquires the time calculated by the GPS (Global Positioning System) device 9, and obtains the other NMEs 3 in the network, the node devices 1-1, 1-2,.
The operation time is distributed and supplied to the SSE2, the router 4, and the like.

FIG. 2 shows the configuration of the time server 8. The time server 8 includes an input / output unit 81 serving as a human-machine interface, and an interface unit (I / F) serving as a connection interface between the GPS device 9 and the NME 3.
82 and a storage unit 83 storing various operation programs and the like
And a clock function unit 84 that synchronizes with the time provided by the GPS device 9, and a control unit 85.

The control section 85 has a time information transmitting means S1. When receiving a time information provision request message from a client requesting notification of the current time, the time information transmitting means S1 performs control for transmitting time information including the current time in the own device to the client. .

FIG. 3 shows the configuration of the NME 3. NME3
Is an input / output unit 31 serving as a human-machine interface, and an interface unit (I / F) 3 serving as a connection interface between the SSE 2 and the router 4 via the LAN.
2 and a storage unit 33 storing various operation programs and the like.
, A clock function unit 34, and a control unit 35.

FIG. 4 shows the configuration of SSE2. SSE2
Stores an input / output unit 81 as a human-machine interface, an interface unit (I / F) 82 for connecting to the node devices 1-1 to 1-n and the NME 3 via a LAN, and various operation programs. A storage unit 83, a clock function unit 84, and a control unit 85.

The time server 8, NME3, SSE
Reference numeral 2 denotes a general-purpose workstation in which a dedicated function is mounted, and the main function is implemented by software.

FIG. 5 shows a node device 1 according to this embodiment.
1 shows the configuration of -1 to 1-n. Node devices 1-1 to 1-n
Are provided with a working transmission line SL and a protection transmission line PL.

The node devices 1-1 to 1-n are provided with a working high-speed interface (HS) for terminating the working transmission line SL.
(I / F) 1-0 and a standby high-speed interface unit 1-1 for terminating the standby transmission line PL. The STM-64 signal drawn into the device via the active high-speed interface unit 1-0 and the standby high-speed interface unit 1-1 is transmitted to a time slot exchange unit (TSA).
gnment) 2-0. Time slot exchange unit 2
-0 drops a predetermined time slot among the time slots multiplexed to the STM-64 signal and sets the low-speed interface unit (LS I / F) 3-1 to 3-k
Give to. Conversely, the low-speed interface units 3-1 to 3-k
Is supplied to the time slot switching unit 2-0, added to a predetermined time slot of the STM-64 frame, and transmitted via the high-speed line OF.

It should be noted that the time slot switching section 2-0 is duplexed with the time slot switching section 2-1 as a pair, and the time slot switching section 2-0 operates as a working system in a normal state. When a failure occurs in the time slot exchange unit 2-0, switching within the device is performed to operate the time slot exchange unit 2-1 as a standby system. The operation of the time slot exchange unit 2-1 is as follows.
This is the same as the operation of −0.

Here, the high-speed interface units 1-0, 1
-1, the time slot exchange units 2-0 and 2-1 and the low speed interface units 3-1 to 3-k are connected to the main control unit 5 via the sub-controllers 4H, 4T and 4L, respectively. The sub-controllers 4H, 4T, and 4L are the main control unit 5
Is to assist in giving various operation control by
Various controls, such as redundancy switching control, are executed hierarchically by the cooperative operation of the sub-controllers 4H, 4T, 4L and the main control unit 5. The main control unit 5 includes a storage unit 6 storing various control programs and the like, and a management network interface (I / O).
F) 7.

The functional units provided in the control unit 35 of the NME 3, the control unit 25 of the SSE 2, and the main control unit 5 of the node devices 1-1 to 1-n in the above configuration vary depending on the system configuration. That is, regarding the distribution of operation time, NME3, SSE2, node devices 1-1 to 1-n
The configuration of the control unit 35, the control unit 25, and the main control unit 5 changes depending on the setting of which device becomes a server and which device becomes a client.

Also, the same device may be a server or a client depending on the situation. For example, the NME 3 connected to the time server 8 is a client when viewed from the time server 8, but is a server when viewed from the SSE 2. Such a setting can be arbitrarily determined by implementation at the time of system design.

With reference to FIG. 6, a description will be given of functional means to be provided in the server and the client relating to time distribution in the present embodiment. That is, the server transmits the time information transmitting means S
1 is provided. This has the same function as that of the time server.

On the other hand, the client sends time information requesting means C
1, time information receiving means C2, and operation time setting means C3
And The time information requesting means C1 sends a time information request message requesting notification of the current time to the server. The time information receiving means C2 receives time information for the transmitted time information request message from the server.
The operation time setting means C3 calculates a transmission delay in a section between the server that has transmitted the time information and the own device, based on a time elapsed from when the information request message is transmitted to when the time information corresponding thereto is received. Using the current time obtained from the server based on this transmission delay, the time of the own device is corrected.

The processing procedure between the server and the client in the above configuration will be described with reference to the flowchart of FIG. First, in step 71, the client sends a time request message to the server. The transmission time at this time is defined as T1. This time request message is mainly transmitted to the server via the management network ML, and at this time, a transmission delay d corresponding to the transmission distance occurs.

On the other hand, the server receives the time request message in step 72. Then, the server returns the time information in which the time (T2) at that time is described as the current time to the client in step 73. Again,
A transmission delay d occurs.

The client receives the time information from the server in step 74. The time at this time is defined as T3. Next, the client calculates the transmission delay d in step 75. The equation used at this time is T3−T1 = 2 × d. After calculating the transmission delay d in this step, the client sets the time to be set to T2 + d in step 76, and resets this time to the clock function unit of its own device in step 77. In this way, it is possible to set a time at which the transmission delay d is guaranteed for the client.

In the above description, the configuration shown in FIG. 6 and the processing procedure shown in FIG. 7 can be realized, for example, by mounting NTP on a device serving as a server and a device serving as a client. Next, the state of implementation of the time distribution function in the present embodiment will be described for several cases.

(Case 1) FIG. 8 is a diagram showing a system configuration in Case 1. In this case, the station building ST
At -2, the time server 8 and the NME 3 are connected by NTP. At this time, regarding the time distribution, the time server 8 becomes the server and the NME 3 becomes the client.

In the same station ST-2, NME3 and SME
SE2 is connected by NTP. At this time, NME3 is the server and SSE2 is the client. In addition, SSE
The two are connected to each other by NTP across stations.
At this time, for example, the SSE2 of the station ST-2 becomes the server of the SSE2 of the station ST3, and conversely, the SSE2 of the station ST-3.
Becomes a client of SSE2 of the station building 2. Further, SSE2 of the station ST-3 is a server of the SSE2 of the station 4 and conversely, SSE2 of the station ST-4 is SSE2 of the station 3
Become a client. Thus, the station ST-2 S
With the SE2 as the origin, the other SSEs 2 sequentially form a client-server relationship with each other.

In summary, the NME 3 can be both a server and a client. Therefore, as shown in FIG. 9A, the control unit 35 of the NME 3 controls the time information transmitting unit S1.
(As a server), time information requesting means C1 (as a client), time information receiving means C2 (as a client), and time information setting means C3 (as a client). Similarly, SSE2 can be a server or a client. Therefore, as shown in FIG. 9B, the control unit 25 of the SSE2 also includes a time information transmitting unit S1, a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3.

The control unit 25 of the SSE 2 includes a time setting unit 251. The time setting unit 251 is a node device 1-1 that is subject to monitoring and control by itself (SSE2).
.About.1-n is forcibly set to its current time. This is because in case 1 SSE2 and node device 1
-1 to 1-n are not connected in a NTP client-server relationship. That is, as shown in FIG. 8, the time setting for the node devices 1-1 to 1-n is performed by the CMIP command “SE” transmitted from the SSE2.
T ". The time setting means 251 has such a function.
The time between the SSE 2 and the node devices 1-1 to 1-n can be accurately adjusted, but this is possible only when the distance between the two is not long and the transmission delay can be ignored.

In the above case, first, the NME 3 of the station ST-2 is synchronized with the time of the time server 8. Further, at the time of NME3, SSE2 of the station ST-2 is synchronized. The time of SSE2 of this station ST-2 is distributed to other SSE2 via NTP, and all SSE2
Synchronize with the time of SSE2 of T-2. At this time, SSE2
The transmission delay of the information transmission between the time information transmitting means S1, the time information requesting means C1,
It is compensated by the processing procedure of FIG. 7 executed by the time information receiving means C2 and the operation time setting means C3. That is,
The operation times of all the SSEs 2 can be accurately synchronized with the current time of the time server 8.

The time synchronization between the SSE 2 and the node devices 1-1 to 1-n to be monitored and controlled is performed via a SET command.
The operation time of −n can be accurately synchronized with the current time of the time server 8.

(Case 2) FIG. 10 is a diagram showing a system configuration in Case 2. What is different from case 1 of FIG. 8 is that SSE2 and node devices 1-1 to 1-n
The point is that they are connected by NTP. In this case, each SS
E2 is a server for another SSE2, and is also a server for the node devices 1-1 to 1-n immediately below. Each of the node devices 1-1 to 1-n becomes a client of the SSE2 under its control, and the SSE2
It operates by referring to the time.

In this case, as shown in FIG. 11A, the control unit 35 of the NME 3 controls the time information transmitting means S1,
It comprises a time information requesting means C1, a time information receiving means C2, and a time information setting means C3. Similarly, SSE2 can be a server or a client. Therefore, FIG.
As shown in (b), the control unit 25 of the SSE2 also includes a time information transmitting unit S1, a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3.

Further, the node devices 1-1 to 1-n
Since it operates as a client of E2, the main control unit 5 sends the time information requesting means C as shown in FIG.
1, a time information receiving means C2 and a time information setting means C3.

In the above configuration, the time server 8, the NME
3. SSE2 performs time synchronization via NTP as in Case 1. The time synchronization between the SSE 2 and the node devices 1-1 to 1-n to be monitored and controlled is also performed via the NTP. Thereby, the node devices 1-1 to 1--1
n can be accurately synchronized with the current time of the time server 8.

(Case 3) FIG. 12 is a diagram showing a system configuration in Case 3. In this case, the station building S
At T-2, the time server 8 and the NME 3
Connected by At this time, regarding the time distribution, the time server 8 becomes the server and the NME 3 becomes the client.

The difference from cases 1 and 2 is that the station building ST-2
NME3 and all SSE2 across stations
This is the point connected by. At this time, NME3 of the station building ST-2
Is a server, and all SSE2 are clients to the NME3.

In this case, the NME 3 of the station ST-2
Acts as a server and a client. Therefore, as shown in FIG. 13A, the control unit 35 of the NME 3 includes a time information transmitting unit S1, a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3. on the other hand,
SSE2 becomes a client of NME3. So SS
The control unit 25 of E2 includes a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3, as shown in FIG. In this way, the operation times of all SSEs 2 can be synchronized with the time of the time server 8.

Each SSE 2 and each of the node devices 1-1 to 1-1
Between -n, synchronization may be performed using a CMIP SET command as in Case 1, or synchronization may be performed using NTP as in Case 2. In order to perform synchronization by CMIP, the control unit 25 of the SSE2 may include the time setting unit 251. To synchronize by NTP,
As in Case 2, the node devices 1-1 to 1-n are clients of the SSE2, and the main control unit 5 has time information requesting means C1, time information receiving means C2, and time information setting means C3.
Should be provided. Which form to choose,
It can be arbitrarily selected according to system requirements.

(Case 4) FIG. 14 is a diagram showing a system configuration in Case 4. In this case, all NMEs 3 and SSEs 2 in the network are connected to the time server 8 via NTP. At this time, regarding time distribution, the time server 8 is a server, and all NMEs 3 and all SSEs 2 are clients.

In this case, the control unit 35 of the NME 3
As shown in FIG. 5A, a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3 are provided. Similarly, the control unit 25 of the SSE2 includes a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3 as shown in FIG.

Each SSE 2 and each of the node devices 1-1 to 1-1
As with Case 3, synchronization with −n can be performed using a CMIP SET command or NTP. In this case, the control unit 25 (SSE) and the main control unit 5 (node device)
Is the same as case 3.

(Case 5) FIG. 16 is a diagram showing a system configuration in Case 5. In this case, all NMEs 3, SSEs 2, and node devices 1-1 to 1-n in the network are connected to the time server 8 via the NTP. That is, regarding the time distribution, the time server 8
Is a server, all NME3s, all SSE2s, and all node devices 1-1 to 1-n are clients.

At this time, in particular, the NTP
An NTP datagram relay means 100 for relaying datagrams is provided. The NTP datagram relay means 100 is realized by a line setting state and a wiring state between a client and a server.

In this case, the control unit 35 of the NME 3
The control unit 25 of FIG. 2 and the main control unit 5 of the node devices 1-1 to 1-n correspond to FIGS.
As shown in (c), a time information requesting unit C1, a time information receiving unit C2, and a time information setting unit C3 are provided.

As described above, in the present embodiment, the client is provided with the time information requesting means C1, and transmits a time request message requesting a notification of the current time to the server. The server is provided with time information transmitting means S1, and notifies the sending source of the current time in response to the time request message.
The client includes a time information receiving means C2 for receiving time information and a time information setting means C3. The time information setting means C3 allows the transmission delay d between the server and the client.
Is calculated, and the time obtained by correcting the received current time by the transmission delay d is set as the operation time of the self (client).

Thus, even if the distance between the devices is long at the time of distributing the operation time, the time is corrected on the receiving side by the transmission delay d corresponding to the distance. As a result, the time synchronization between the SSEs 2 and further between the node devices can be accurately obtained irrespective of the distance between the devices, thereby providing a transmission system with no risk of impairing the function of the management network. Becomes

The present invention is not limited to the above embodiment. For example, not only one time server 8 but a plurality of time servers may be provided. In time server 8, GPS
Although the time is obtained by the device 9, for example, an atomic clock or the like may be used. In the above cases 1 and 2, all the SSEs 2 are synchronized via the NTP. However, instead of this, the NMEs 3 may be connected to each other via the NTP. In addition, various modifications can be made without departing from the gist of the present invention, such as the implementation form of NTP.

[0064]

As described above, according to the present invention, it is possible to accurately synchronize the time between the node devices, thereby providing a transmission system that does not impair the function of the management network. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a transmission system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a time server 8 according to the present invention.

FIG. 3 is a block diagram showing a configuration of a supervisory control device (NME) 3 according to the present invention.

FIG. 4 is a block diagram showing a configuration of SSE2 according to the present invention.

FIG. 5 is a block diagram showing a configuration of node devices 1-1 to 1-n according to the present invention.

FIG. 6 is a diagram for explaining functional units to be provided in a server and a client related to time distribution in the embodiment of the present invention.

FIG. 7 is a flowchart illustrating a processing procedure between a server and a client related to time distribution in the embodiment of the present invention.

FIG. 8 is a diagram showing a system configuration in case 1 according to the embodiment of the present invention.

FIG. 9 shows a case 1 according to the embodiment of the present invention, in which NM
The figure which shows the functional means with which the control part 35 of E3 and the control part 25 of SSE2 are provided.

FIG. 10 is a diagram showing a system configuration in Case 2 according to the embodiment of the present invention.

FIG. 11 illustrates a case 2 according to the embodiment of the present invention.
The figure which shows the control part 35 of ME3, the control part 25 of SSE2, and the functional means with which 1-1-1-n of a node device are provided.

FIG. 12 is a diagram showing a system configuration in Case 3 in the embodiment of the present invention.

FIG. 13 illustrates a case 3 according to the embodiment of the present invention.
The figure which shows the function means with which the control part 35 of ME3 and the control part 25 of SSE2 are provided.

FIG. 14 is a diagram showing a system configuration in Case 4 in the embodiment of the present invention.

FIG. 15 illustrates a case 4 according to the embodiment of the present invention.
The figure which shows the function means with which the control part 35 of ME3 and the control part 25 of SSE2 are provided.

FIG. 16 is a diagram showing a system configuration in case 5 in the embodiment of the present invention.

FIG. 17 illustrates a case 5 according to the embodiment of the present invention.
The figure which shows the control part 35 of ME3, the control part 25 of SSE2, and the functional means with which 1-1-1-n of a node device are provided.

[Explanation of symbols]

ST-1 to ST-m station building 1-1 to 1-n node device (NODE) OF high speed line FL wavelength multiplexing line ML management network 2 station monitoring and control device (SSE) 3 monitoring Control devices (NME) 21, 31 Input / output unit 22, 32 Interface unit (I / F) 23, 33 Storage unit 24, 34 Clock function unit 25, 35 Control unit 1-0 Active high-speed interface Section (HS I / F) 1-1: standby high-speed interface section 2-0, 2-1 time slot exchange section (TSA) 3-1 to 3-k: low-speed interface section (LS I / F)
F) 4H, 4T, 4L ... sub-controller 5 ... main control unit 6 ... storage unit 7 ... management network interface (I / F) 8 ... time server 81 ... input / output unit 82 ... interface unit (I / F) 83 ... storage Unit 84 clock function unit 85 control unit S1 time information transmitting unit 9 GPS device C1 time information requesting unit C2 time information receiving unit C3 operating time setting unit 251 time setting unit 4 router 100 NTP data Gram relay means

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Claims (9)

[Claims] 1. A plurality of node devices that are divided into a plurality of groups, a plurality of first monitoring and control devices that perform monitoring control on these node devices in units of groups, the first monitoring and control devices, and the node devices A second monitoring and control device that performs monitoring and control in a unit wider than the first monitoring and control device in response to information provided by the first device and the node device, the first monitoring and control device, and the second monitoring and control device operate in synchronization In a transmission system including a time providing device that provides a time to be provided, at least a server for distributing and supplying the time between the first monitoring control device, the second monitoring control device, and the time providing device. When the client relationship is set with each other, the server, when receiving a time information provision request message requesting notification of the current time from the client, Time information transmitting means for transmitting time information including the current time of the own device to the client, wherein the client transmits the time information request message requesting notification of the current time to the server; Requesting means; time information receiving means for receiving time information for the sent time information request message from the server; and time elapsed from sending the time information request message to receiving time information for the time information request message. An operation of calculating a transmission delay in a section between the server that has sent the time information and the own device, and setting a time obtained by correcting a current time obtained from the server based on the transmission delay as an operation time of the own device. A transmission system comprising: time setting means. 2. A second monitoring and control device synchronizes with the current time of the time providing device using the time providing device as a server and a self as a client, wherein one first monitoring and controlling device is the one second monitoring and controlling device. The supervisory control device is synchronized with the current time of the second supervisory control device using the server as a server and the client itself as a client, and the other first supervisory control devices sequentially form a client-server relationship with each other and synchronize with the current time of the server with respect to itself. The transmission system according to claim 1, wherein: 3. The one second monitoring and control device synchronizes with the current time of the time providing device using the time providing device as a server and the self as a client, and the plurality of first monitoring and control devices each include the one 2. The transmission system according to claim 1, wherein the second monitoring and control device is synchronized with a current time of the second monitoring and control device using the server as a server and the client itself as a client. 4. The system according to claim 1, wherein the plurality of first control devices and the second monitoring control device synchronize the current time of the time providing device with the time providing device serving as a server and the client itself as a client. A transmission system according to claim 1. 5. The system according to claim 2, wherein each of the plurality of first monitoring control devices includes time setting means for forcibly setting its own current time in a node device to be monitored and controlled. The transmission system according to any one of the above. 6. The plurality of node devices synchronize with the current time of a first monitoring and control device that monitors and controls itself, respectively, as a server and a first monitoring and control device that monitors and controls itself using the first monitoring and control device as a client. Claim 2
The transmission system according to any one of claims 1 to 4. 7. The plurality of node devices, the first control device, and the second monitoring control device synchronize the time providing device with a current time of the time providing device using the time providing device as a server and the client as a client, respectively. 2. The transmission system according to claim 1, further comprising a relay unit for exchanging the time information request message and the time information between the client and the client. 8. A series of procedures performed by the time information transmitting means, the time information requesting means, the time information receiving means, and the operation time setting means are realized by mounting an NTP (Network Time Protocol) on the server and the client. The transmission system according to any one of claims 1 to 7, wherein: 9. The time setting means includes a CMIP (Comm.
on Management Information Protocol)
The transmission system according to claim 5, wherein the current time is set for the node device by a command.