JP3501965B2 - Transmission line termination device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to SDH (Synchronou
s Digital Hierachy) The present invention relates to an optical path signal transmission line terminating device for accommodating signals in an optical path network, and particularly to a transmission line terminating device including a switching system for improving the reliability of the transmission line.

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of an optical path transmission line terminating device which is a network node of an optical path network. To facilitate understanding, the optical path network technology will be briefly described first. The optical path network is a network based on wavelength division multiplexing (WDM) technology and wavelength routing technology, and is characterized in that light is introduced into the path layer. FIG. 9 is an explanatory diagram showing an example of the relationship between the optical path network and the conventional network.

A conventional network is, for example, SDH (Synchronous Dielectric).
gital Hierachy) network, ATM (Asynchronous Transfer)
Mode) network, PDH (Plesiochronous Digital Hierach)
y) A conventional optical communication network represented by a network or a point-to-point WDM transmission system. Considering the current situation of SDH in the world network, S
Of particular importance are DH steel or SDH based WDM systems. FIG. 9 shows an example in which a large number of locally introduced networks are connected to a wide area by an optical path network. Further, in FIG. 9, reference numerals 30-1 to 30-4 are attached to the conventional communication network.

The optical path network is an optical bus cross connect device (OPXC) 32-1 to 32-32 as a network node.
4. Optical path transmission line terminator (OLT) 34-1 to 34-34
4 and the WDM transmission technology is applied to the links between the nodes. The optical path is defined between two OLTs and OPX
Switching of paths, editing, etc. are performed by C. In FIG. 9, when there is a transmission line failure, the working path P1 to the protection path P
2 Path switching in path units (or wavelength units)
It is shown that resetting is possible.

The advantage of the optical path is that the capacity of the path can be increased, and a recovery means for a WDM transmission line failure can be provided for each wavelength (Protection / Restora of the optical path.
Basically, since it is independent of the format of the electric signal that is the client, it is possible to easily cope with future changes and evolution of the transmission format of the electric signal.As a result, depending on the traffic capacity, It is to be able to flexibly construct a network with high failure recovery capability. (For the concept of the optical path network, see K. Sato,
S.Okamoto, and H. Hamada, "Network performance and
integrity enhancement with optical pathlayer techn
ologies ", IEEE JSAC, vol.SAC-12, no.1, pp.159-170,
Details on Jan. 1994.).

OLTs 34-1 to 34-4 are devices arranged at the contact points of the optical path network and the conventional optical communication networks 30-1 to 30-4, and are optical input signals from the conventional networks 30-1 to 30-4. Is converted to an optical path signal and wavelength-multiplexed, and then a WDM optical signal matched to the optical path network is output, or conversely, a WDM optical input in which an optical path signal coming from the optical path network is wavelength-multiplexed. It has a function of performing wavelength separation on a signal, format-converting it into a signal of a conventional optical communication network, and outputting it as an optical signal.

FIG. 10 shows an optical path transmission line terminating device (OL).
It is a figure which shows one structural example of T). Lower half of the drawing (Fig. 10
The side denoted by the middle code D1) is a portion that receives a signal from the optical path network and passes it to the conventional network side. Inputs # 1 to #n of n-series M-wavelength multiplexed signals and wavelength-multiplexed signals of each series are input. N optical amplifiers 40-1 to 40-n for collectively amplifying, n wavelength demultiplexing circuits 42-1 to 42-n for performing wavelength separation, and n × M for performing format conversion between an optical path network and a conventional network. Format converters 43-11 to 43-1M, ..., 43-n1 to 4
3-nM, which consists of M × n optical output to the conventional network side.

Here, the format conversion units 43-11 to 43-11.
43-1M, ..., 43-n1 to 43-nM are assumed to be performed at an electrical level, and an optical receiving circuit (OR), an optical path signal terminating circuit (OPOH), a conventional network terminating circuit (for example, SOH).
Etc.), an optical transmission circuit (OS), and the like. That is, the optical signal of each wavelength is once converted into an electrical signal,
The optical path is terminated in the electric signal format, and then the conventional network side is also terminated by the electric signal (for example, SDH or ATM), then converted into an optical signal and transmitted to the conventional network side.

The upper half of the drawing (the side labeled D2 in FIG. 10) shows the converter in the opposite direction (signal transmission from the conventional network side to the optical path network side). Such a transmission line device is equipped with a redundant system and a backup system in order to quickly restore the network in the event of a transmission line network failure, etc., and plays an important role. In the SDH network, the redundant system and the backup system have been introduced into the current system (the redundant system and the backup system of the SDH network are familiar with Sadako Shimada's "SDH transmission system" Ohmsha Co., Ltd.), and also proposed in the optical path network. (For redundant / standby systems for optical path networks, S. Okamoto et al., "Netwo
rk Architecture for Optical Path Transport Networ
k ", IEEE Trans. on Commun., vol45, No.8, pp.968-97
7 has been proposed). FIG. 11 shows an example of the configuration of the OLT shown in FIG. 10, including a redundant system and a standby system in the format conversion part between the optical path signal and the conventional network signal.

FIG. 11 is a block diagram showing a configuration example of an OLT relating to a format conversion portion between an optical path signal and a conventional network signal. In the example shown in FIG. 11, both the optical path network and the conventional network are redundant systems (the transmitting side transmits exactly the same signal to two systems of 0 system / 1 system, and the receiving side selects 0 system / 1 system).
This is an example of a case in which the system is configured to be switched and a system for instantaneously responding to a transmission line failure or the like is provided.

The format conversion part of the OLT is a 0-system /
Optical path signal termination circuits 50-0, 52-0 and 5 for each system
0-1, 52-1, conventional network signal terminating portion (SDH network is assumed in the example shown in FIG. 11, and SDH section signal terminating circuits 62-0, 64-0 and 62-1, 6 are used.
(Corresponding to 4-1), SDH path signal monitoring / processing circuits 56 and 58 provided between them, and an optical path side switching circuit 54 and an SDH side switching circuit 60 for switching redundant systems.

The optical path signal termination circuit 5 shown in FIG.
0-0, 52-0 and 50-1, 52-1 correspond to OPOH in FIG. 10, and SDH section signal termination circuit 62
−0, 64-0 and 62-1, 64-1 correspond to SOH in FIG. Further, although omitted in FIG. 10 for simplification (a configuration may be omitted), the SDH path signal monitoring / processing circuits 56 and 58 in FIG. 11 are the optical path signal termination circuits 50-0, 52-0 and 50-1, 52-1
And SDH section signal terminating circuits 62-0, 64-0 and 62-1, 64-1.

SDH path signal monitoring / processing circuits 56 and 58
Is for monitoring the status of an SDH path signal, which is a client signal transmitted / received between the path network and the SDH network, and processing it as necessary, and improves the OLT function and network reliability. Is. In FIG. 11, the 0 system / 1 system corresponds to the working / spare system, and is in the upstream direction (in this specification, the direction in which signals are transmitted from the SDH network side to the optical path network side) / downward direction (main). In the specification, it is assumed that a signal is transmitted from the optical path network side to the SDH network side).

In the example shown in FIG. 11, since the SDH path signal monitoring / processing circuits 56 and 58 have only one system, in this configuration a redundant system is constructed in the signal terminating circuit on both the optical path side and the SDH side. ing. In other words, the optical path side switch circuit 54 switches the 0 system / 1 system on the optical path network side, and the SDH side switch circuit 60 switches the 0 system / 1 system on the SDH network side. Since the 0-system / 1-system is divided into package (PKG) units which are maintenance units, a minimum of seven PKGs are required if the switch circuit PKG is also included as shown in FIG.

Next, FIG. 12 is a block diagram showing another configuration example of the OLT relating to the format conversion portion between the optical path signal and the conventional network signal. In the configuration example shown in FIG. 11, S
The DH path signal monitoring / processing circuits 56 and 58 were provided only in one system, but in the configuration example shown in FIG. 12, SDH is used.
Two path signal monitoring / processing circuits are also available. That is, the SDH path signal monitoring / processing circuits 56-0, 58-0
And 56-1 and 58-1 are provided.

The configuration example of FIG. 12 seems to have introduced redundancy in this portion as well to improve reliability, but this portion is originally only electrical processing and is already a highly reliable portion. is there. Rather, the intention of the configuration example shown in FIG. 12 is from the viewpoint of effective use of resources. That is,
When the 0 system is the current system and the 1 system is the backup system, if the 0 system fails, the 1 system is used for restoration, but normally, low priority traffic is also passed to the 1 system and the backup system is used. Make effective use of system resources. In this case, SDH path signal monitoring / processing circuits 56-0, 58-0 and 56-1, 58-1
If the two systems are divided into PKGs, a minimum of 8 PKs
G is needed. Of course, if only one system of the SDH path signal monitoring / processing circuit is used in this configuration, it is the same as the redundant system shown in FIG. 11, and both the redundant system and the standby system are compatible.

[0017]

By the way, in the configuration example of the OLT in consideration of switching to the redundant system / standby system according to the conventional technique described above, both the optical path network and the SDH network are provided with the redundant system / standby system, Although there is a merit of improving the reliability of, there are two switches on the optical path side and SDH side, and there are many PKGs that are maintenance units.
There is a drawback that the amount of hardware is increased, which in turn increases the cost of the device.

The present invention has been made in view of the above circumstances, and a redundant / standby system on the optical path side and the SDH side can be configured, and the required hardware amount is small, and therefore, the transmission of a low-cost device configuration is possible. An object is to provide a road terminating device.

[0019]

In order to solve the above-mentioned problems, the present invention considers the necessity of a redundant / standby system, and shares two switches with one
The number of Gs is reduced, and eventually the size and cost of the device are reduced.

Specifically, according to the present invention, an optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, the SDH signal or an SDH path signal included in the optical path signal. In a transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing the above, a redundant system or a standby system for these, and a switch means for switching these redundant systems or the standby system, said switch means is Provided between the optical path signal terminating means and the SDH path signal monitoring / processing means, and commonly used for switching the redundant system or standby system of the optical path signal and switching the redundant system or standby system of the SDH signal. It is characterized by being done. Further, the present invention provides an optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and monitoring or processing the SDH signal or an SDH path signal included in the optical path signal. In the transmission line terminating device including the SDH path signal monitoring / processing means, the redundant system or the standby system, and the switch means for switching the redundant system or the standby system, the switch means includes:
It is installed between the SDH path signal monitoring / processing means and the SDH signal terminating means, and is commonly used for switching the redundant system or standby system of the optical path signal and switching the redundant system or standby system of the SDH signal. It is characterized by Also, the present invention provides an optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and an SDH signal or an SDH included in the optical path signal.
A transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing a path signal, a redundant system or a backup system for these, and a switch means for switching the redundant system or the backup system, wherein the switch The means transmits the signal transmitted from the optical path network to the SDH network to the optical path network in response to the optical path signal terminating means and the SDH path signal monitoring / processing means. For signals, the SDH path signal monitoring / processing means and the S
It is arranged between the DH signal terminating means and the redundant system or standby system for switching the optical path signal and the redundant system or standby system for switching the SDH signal. Further, the present invention provides an optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and monitoring or processing the SDH signal or an SDH path signal included in the optical path signal. In the transmission line terminating device including the SDH path signal monitoring / processing means, the redundant system or the standby system, and the switch means for switching the redundant system or the standby system, the switch means includes:
For signals transmitted from the optical path network to the SDH network, between signals transmitted from the SDH network to the optical path network between the SDH path signal monitoring / processing means and the SDH signal terminating means. Is the optical path signal terminating means and the SDH
It is installed between the path signal monitoring / processing means and is commonly used for switching the redundant system or the standby system of the optical path signal and for switching the redundant system or the standby system of the SDH signal.

With the above-mentioned structure, the present invention is characterized by the optical path side and the S
The basis of the means is to combine the functions of the two switches arranged on the DH side into the function of one switch. Originally, the switch of the meridian crossing system shown in FIG. 12 has a function of switching between both sides with one switch. As a condition for consolidating two switches into one switch, the redundancy of the SDH path signal monitoring / processing circuit portion will be deleted. That is, the optical path signal terminating circuit and the SDH section terminating circuit are in the active system, and when a failure occurs in the active system of the SDH path signal / monitor processing circuit, eliminate the redundancy meaning that only this part is switched to the standby system. However, as described above, this portion is a highly reliable portion as compared with the circuit portion including the transmission line and the optical component, so that there is no serious problem.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A transmission line terminating device according to an embodiment of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram showing a configuration of a transmission line terminating device according to a first embodiment of the present invention. The transmission line terminating device according to the first embodiment of the present invention shown in FIG. 1 differs from the conventional transmission line terminating device shown in FIG. 11 or 12 in that an optical path signal terminating circuit and an SDH path signal monitoring /
The point is that one optical switch signal PKG installed between the processing circuits switches between the optical path signal terminating circuit and the SDH section signal terminating circuit so that it can be used for both redundant and standby systems.

More specifically, the transmission line terminating device according to the first embodiment of the present invention has a structure corresponding to the structure shown in FIG. That is, the optical path signal terminating circuits 2-0, 4-0 and 2-1, 4-1 are respectively the optical path signal terminating circuits 50-0, 52-0 and 50- in FIG.
1, 52-1 corresponding to SDH path signal monitoring / processing circuits 8-0, 10-0 and 8-1, 10-1, respectively.
SDH path signal monitoring / processing circuit 56-0, 58- in 2
0 and 56-1, 58-1 corresponding to SHD section signal termination circuits 12-0, 14-0 and 12-1, 14-
1 corresponds to the SHD section signal termination circuits 62-0, 64-0 and 62-1, 64-1 in FIG. 12, respectively.

The optical path signal terminating circuits 2-0, 4-are different from the conventional transmission line terminating device shown in FIG. 12 and the transmission line terminating device according to the first embodiment of the present invention shown in FIG. 0
, 2-1 and 4-1 and the SDH path signal monitoring / processing circuits 8-0, 10-0 and 8-1, 10-1 for switching the optical path and the SDH path. The point is that the switch circuit 6 is provided. Depending on the type of SDH path signal, SDH path signal monitoring / processing circuits 8-0, 10-
0 and 8-1, 10-1 and SDH section signal termination circuit 12-0, 14-0 and 12-1, 14-1 are the same P
It becomes possible to mount on a KG, and in the conventional configuration shown in FIG. 12, a minimum of 8 sheets is required, but in the present embodiment, it can be reduced to 5 sheets.

Next, a modification of the transmission line terminating device according to the first embodiment of the present invention will be described. FIG. 2 is a block diagram showing a modification of the transmission line terminating device according to the first embodiment of the present invention. The difference between the transmission line terminating device shown in FIG. 1 and the transmission terminating device shown in FIG. 2 is that the optical path / SDH switch circuit 6 in FIG.
The optical path network side PKG and S are divided into -01 to 16-12.
It is arranged on the DH network side PKG to eliminate the switch PKG. The distribution circuit includes SDH path signal monitoring / processing circuits 10-0 and 10-1 and an optical path signal terminating circuit 2-.
It is provided within 0, 2-1. With the configuration shown in FIG. 2, the number of PKGs is at least four. Therefore, FIG.
It is possible to reduce the number of sheets by one compared with the configuration shown in FIG.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram showing the configuration of the transmission line terminating device according to the second embodiment of the present invention. The transmission line terminating device according to the second embodiment of the present invention shown in FIG. 3 is different from the transmission line terminating device according to the first embodiment of the present invention shown in FIG. Switch circuit 6
Are optical path signal termination circuits 2-0, 2-1, 4-0, 4-1
And SDH path signal monitoring / processing circuit 8-0, 8-1, 10
In the present embodiment, the SDH path signal monitoring / processing circuit 8-
This is a point provided between 0, 8-1, 10-0, 10-1 and the SDH section signal terminating circuits 12-0, 12-1, 14-0, 14-1. In this embodiment, the optical path / SDH switch circuit 6 includes an optical path signal termination circuit and an S
The DH section signal terminating circuit is switched so that it can be used for both a redundant system and a standby system.

FIG. 4 is a block diagram showing a modification of the transmission line terminating device according to the second embodiment of the present invention. The difference between the transmission line terminating device shown in FIG. 4 and the transmission line terminating device shown in FIG. 3 is that the optical path / SDH switch circuit 6 in FIG. 3 has a distribution circuit and selector circuits 16-01 to 16-. The switch PKG is eliminated by arranging the optical path network side PKG and the SDH network side PKG by dividing them into 12. The distribution circuit is an SDH path signal monitoring / processing circuit 8-0, 8-1.
And SDH section signal terminating circuit 14-0, 14-1
It is provided inside. With this configuration, the same PKG reduction as that of the modification of the transmission line terminating device according to the first embodiment shown in FIG. 2 can be expected.

Next, a third embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the transmission line terminating device according to the third embodiment of the present invention. First shown in FIG.
In the embodiment and the third embodiment shown in FIG. 3, the circuits mounted on the same PKG in the upstream direction and the downstream direction have the same configuration. From the viewpoint of device operation and management, it is desirable that the same upstream and downstream circuits be mounted on the same PKG. On the other hand, from the viewpoint of increasing the versatility of the hardware (in this case, the versatility of the PKG), the configuration shown in FIG. 5 is also possible.

That is, regarding both the 0-system and the 1-system, the optical path signal terminating circuits 2-0, 2 are applied to the downstream signals.
-1 and the SDH path signal monitoring / processing circuits 8-0, 8-1 and SDH path signal monitoring / processing circuits 10-0, 10-1 and SDH section signal terminating circuit for upstream signals. The optical path / SDH switch circuit 6 is installed between the optical path 14-0 and 14-1 so that the optical path signal termination circuit and the SDH are connected.
By switching to the section signal terminating circuit, the configuration will be compatible with both redundant and standby systems. When an SDH format-based optical path signal is used, the optical path signal terminating circuit and the SDH section signal terminating circuit have almost the same functions, so the four PKGs shown in FIG. 5 have the same circuit configuration and one type of PKG. Can be realized with.

FIG. 6 is a block diagram showing a modification of the transmission line terminating device according to the third embodiment of the present invention. The transmission line terminating device shown in FIG. 6 is different from the transmission line terminating device shown in FIG. 5 in that the optical path / SDH switch circuit 6 in FIG. 5 has a distribution circuit and selector circuits 16-01 to 16-1.
The switch PKG is eliminated by dividing the optical path network side PKG and the SDH network side PKG into two parts.
The distribution circuit is provided in the optical path signal termination circuits 2-0 and 2-1 and the SDH section signal termination circuits 14-0 and 14-1.

Next, a fourth embodiment of the present invention will be described. FIG. 7 is a block diagram showing the configuration of the transmission line terminating device according to the fourth embodiment of the present invention. In the transmission line terminating device according to the fourth embodiment of the present invention shown in FIG.
For both the 0-system and the 1-system, SDH path signal monitoring / processing circuits 8-0, 8-1 and S are used for signals in the downstream direction.
Between the DH section signal terminating circuits 12-0 and 12-1, an optical path signal terminating circuit 4-is provided for upstream signals.
0,4-1 and SDH path signal monitoring / processing circuit 10-0,
An optical path / SDH switch circuit 6 is installed between the switch 10-1 and 10-1 so as to be compatible with both the redundant system and the standby system. With this configuration, the same effect as that of the third embodiment shown in FIG. 5 can be expected.

FIG. 8 is a block diagram showing a modification of the transmission line terminating device according to the fourth embodiment of the present invention. The transmission line terminating device shown in FIG. 8 is different from the transmission line terminating device shown in FIG. 7 in that the optical path / SDH switch circuit 6 in FIG. 7 is a distribution circuit and selector circuits 16-01 to 16-1.
The switch PKG is eliminated by dividing the optical path network side PKG and the SDH network side PKG into two parts.
The distribution circuit is an SDH path signal monitoring / processing circuit 8-0,
8-1 and SDH path signal monitoring / processing circuit 10-0, 1
It is provided in 0-1. With this configuration, the same effect as that shown in FIG. 7 can be obtained.

[0033]

As described above, according to the present invention, it is possible to reduce the number of PKGs or the circuit scale in the interface conversion circuit part including the switching system of the optical path transmission line terminating device, and consequently reduce the size of the device. There is an effect that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a transmission line terminating device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a modification of the transmission line terminating device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a transmission line terminating device according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a modification of the transmission line terminating device according to the second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a transmission line terminating device according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a modification of the transmission line terminating device according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a transmission line terminating device according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram showing a modification of the transmission line terminating device according to the fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an example of a relationship between an optical path network and a conventional network.

FIG. 10 is a diagram showing a configuration example of an optical path transmission line terminating device (OLT).

FIG. 11 is a block diagram showing a configuration example of an OLT regarding a format conversion portion between an optical path signal and a conventional network signal.

FIG. 12 is a block diagram showing another configuration example of the OLT relating to the format conversion part between the optical path signal and the conventional network signal.

[Explanation of symbols]

2-0, 2-1, 4-0, 4-1 ... Optical path signal terminating circuit (optical path signal terminating means), 6 ... Optical path / SDH switch circuit (switching means), 8-0, 8-1, 10-0,1
0-1 ... SDH path signal monitoring / processing circuit (SDH path signal monitoring / processing means), 12-0, 12-1, 14-0,
14-1 ... SDH section signal terminating circuit (SDH signal terminating means).

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Satoshi Okamoto 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) References Japanese Patent Laid-Open No. 10-200495 (JP, A) Open 2000-124872 (JP, A) JP 2000-152292 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04J 3/00 H04B 10/02 H04L 1/22

Claims (4)

(57) [Claims] 1. An optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and an SDH signal or an SDH included in the optical path signal.
A transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing a path signal, a redundant system or a standby system for these, and a switch means for switching the redundant system or the standby system, wherein the switch The means includes the optical path signal terminating means and the S
A transmission line which is installed between the DH path signal monitoring and processing means and is shared by the switching of the redundant system or the standby system of the optical path signal and the switching of the redundant system or the standby system of the SDH signal. Termination device. 2. An optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and an SDH signal or an SDH included in the optical path signal.
A transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing a path signal, a redundant system or a standby system for these, and a switch means for switching the redundant system or the standby system, wherein the switch The means is installed between the SDH path signal monitoring / processing means and the SDH signal terminating means, and switches between the redundant system or the standby system of the optical path signal and the redundant system or the standby system of the SDH signal. A transmission line terminating device characterized by being shared. 3. An optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and an SDH signal or an SDH included in the optical path signal.
A transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing a path signal, a redundant system or a standby system for these, and a switch means for switching the redundant system or the standby system, wherein the switch Means for the signal transmitted from the optical path network to the SDH network, the optical path signal terminating means and the SDH.
As for the signal transmitted from the SDH network to the optical path network, the path signal monitoring / processing means is installed between the SDH path signal monitoring / processing means and the SDH signal terminating means. A transmission line terminating device which is shared by switching of a redundant system or a standby system of an optical path signal and switching of a redundant system or a standby system of the SDH signal. 4. An optical path signal terminating means for terminating an optical path signal, an SDH signal terminating means for terminating an SDH signal, and an SDH signal or an SDH included in the optical path signal.
A transmission line terminating device comprising an SDH path signal monitoring / processing means for monitoring or processing a path signal, a redundant system or a standby system for these, and a switch means for switching the redundant system or the standby system, wherein the switch Means for a signal transmitted from the optical path network to the SDH network, a signal transmitted from the SDH network to the optical path network between the SDH path signal monitoring / processing means and the SDH signal terminating means. Is installed between the optical path signal terminating means and the SDH path signal monitoring / processing means, and switches the redundant system or the standby system of the optical path signal and the redundant system or the standby system of the SDH signal. A transmission line terminating device, which is shared by and.