JP2000013349A - Transmission rate conversion method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a circuit scale and to suppress increase of the capacity of hardware of a circuit setting part itself by setting a circuit of plural element signals multiplexed from the multiplex signals while separating these element signals and then executing a prescribed receiving process for each element signal. SOLUTION: A 1st circuit setting part 13A separates a synchronous transport signal level STS-192 into the levels equivalent to the STS-1 levels and at the same time sets a circuit for each STS-1 level under the control of a circuit control part 14A. An OH 15A of an operation system performs overhead processing in response to an instruction of an OH selection part 17A and then performs pointer processing at a level equivalent to the STS-1 level. At the same time, the OH 15A detects the faults including the fault caused by the part 13A, an OR 12A or the OH 15A itself an also the fault caused by an SDH device of an ADM device 10, etc., that is placed at the left side of another device 10 in a transfer network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission rate conversion method and apparatus, for example, a synchronous optical communication network (SONET).
onous Optica1 Network) or Synchronous Digital Hierarchy (SDH) to drop low-order group signals from high-order group signals,
This can be applied to a case where a low-order group signal is added to a high-order group signal.

[0002]

2. Description of the Related Art FIG. 2 shows a simplified conceptual diagram of a conventional ADM apparatus 50.

In FIG. 2, an OR (optical receiving unit) 51 that has received an optical signal of a high-order group signal from an optical fiber cable is
This is photoelectrically converted to a DE-MUX (demultiplexing circuit) 52.
To supply.

In order to parallelize the next OH process, the D
The E-MUX 52 separates the higher-order group signal into a lower-order group signal.

[0005] The O receiving the plurality of separated low-order group signals
The H53 performs processing such as reception termination of overhead for each low-order group signal.

The low-order group signals that have been processed by the OH 53 are multiplexed by a MUX (multiplexing circuit) 54 to obtain a high transmission rate again.

The next line setting section 55 separates the signal multiplexed by the MUX 54 into low-order group signals and sets a line for each low-order group signal. The low-order group signal dropped by this line setting is supplied to the low-speed interface unit 56. The low-order group signal that is not dropped is directly T / I
(Through or Insert) unit 57.

On the other hand, when there is a low-order group signal added from the low-speed interface unit 56, the low-order group signal is also supplied to the T / I unit 57.

The T / I section 57 inserts the added low-order group signal into the time slot of the low-order group signal provided from the line setting section 55, and passes the signal to the next-stage MUX 58. If no lower order group signal is added, T
The / I unit 57 passes the low-order group signal provided from the line setting unit 55 as it is.

M which receives the low-order group signal from T / I section 57
The UX 58 multiplexes these low-order group signals and outputs them.

The output signal of the MUX 58 is sent to a line setting unit 59
The line is set and the data is further multiplexed. And OH60
Then, the multiplexed signal is subjected to processing such as transmission termination of overhead.

After this processing, the MUX 61 performs multiplex processing corresponding to the overhead to obtain the transmission speed of the high-order group signal transmitted through the optical fiber cable.

The high-order group signal is supplied to an OS (optical transmission unit) 62
Is converted to an optical signal and sent to an optical fiber cable.

[0014]

However, in the ADM device 50 described above, since the line is set after the signal is first separated into low-speed low-order group signals by the DE-MUX 52, there is a problem that the circuit scale becomes large. Was. In order to maintain the service to be provided to the user and the amount of information to be processed per unit time even when the transmission speed is reduced, each unit in the ADM device 50 requires a parallel signal line in proportion to the decrease in transmission speed. This is because the number of parallel hardware such as the number and the number of parallel circuits for processing signals increases.

In order to increase the signal transmission speed, the MU
A multiplexing circuit such as X54 may be provided to multiplex the low-order group signals. For this purpose, the amount of hardware for the multiplexing circuit must be increased. Some require multiplexing immediately after separation, and it has been difficult to reduce the circuit scale with this type of device.

For example, the structure of the portion P in FIG.
When the UX 58 is removed, the amount of hardware of the MUX 58 itself decreases, but the increase in hardware between the T / I unit 57 and the line setting unit 59 is unavoidable, and the line setting of low-speed low-order group signals is performed. Is performed without reducing the amount of information processing per unit time, the number of parallel components for line setting in the line setting unit 59 increases, and the amount of hardware of the line setting unit 59 itself increases. I will.

[0017]

According to a first aspect of the present invention, there is provided a method for receiving a multiplexed signal comprising a plurality of component signals multiplexed and receiving a corresponding component signal from the multiplexed signal. In the transmission rate conversion method of dropping, a plurality of element signals multiplexed from the multiplexed signal are separated while setting the lines of these element signals. It is performed for each signal.

Further, in the second invention, when transmitting a multiplex signal formed by multiplexing a plurality of element signals, the transmission rate conversion method of adding the corresponding element signal to the multiplex signal (1) Adds If there is an element signal, the element signal to be added is inserted and passed through among the plurality of element signals, and if there is no element signal to be added, the element signals are passed without change. (2) Here, a predetermined transmission process is performed for each of the plurality of passed element signals, and (3) after that, the plurality of passed element signals are multiplexed and transmitted while setting a line. .

According to a third aspect of the present invention, there is provided a transmission rate converter for receiving a multiplexed signal formed by multiplexing a plurality of component signals and dropping the corresponding component signal from the multiplexed signal. First line setting means for setting the lines of these element signals while separating a plurality of multiplexed element signals, and receiving processing for executing predetermined reception processing for each of the element signals after the line setting Means.

According to a fourth aspect of the present invention, there is provided a transmission rate conversion device for adding a corresponding element signal to the multiplexed signal when transmitting a multiplex signal formed by multiplexing a plurality of element signals. If there is an element signal to
Passing insertion means for inserting the element signal to be added into the plurality of element signals and passing the signal, and when there is no element signal to be added, passing the plurality of element signals as they are; (2) passing the element signal here Transmission processing means for performing predetermined transmission processing for each of the plurality of element signals; (3) after that,
A second line setting unit for multiplexing the plurality of passed element signals while setting a line, and transmitting an output of the second line setting unit.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment Hereinafter, a transmission rate conversion method and apparatus according to the present invention will be described in which a UPSR which does not return a signal in the apparatus even when a failure is detected.
The first embodiment of the present invention will be described by taking a case where the invention is applied to an ADM (Add Drop Multiplexer) of the SDH in a (Uni-directional Path Switched Ring) system.

(A-1) Configuration of First Embodiment FIG. 3 shows an ADM apparatus 10 according to this embodiment. The size of the ADM apparatus 10 is, for example, a so-called rack level in terms of dimensions, and the number of the boards is, for example, about 4 shelves, each of which includes 20 to 30 boards which can be inserted and removed. The ADM apparatus 10 separates and drops (drops) a low-order group signal having a lower transmission rate from a higher-order signal having a lower transmission rate from a higher-order group signal having a higher transmission rate and a higher-order group signal. It also has an add function of multiplexing (adding).

Such an ADM apparatus is, for example, one synchronous optical communication network, which is a network having a ring (loop) type wiring topology, along one ring along the ring.
About 0 stations are arranged at intervals. This ring-type synchronous optical communication network functions as a transfer network for providing various services supplied from a service node, which is a base for providing information network services, to a distribution network, which is a branch line to a user's home, for example. .

In FIG. 3, for example, a transmission speed of 10 Gbps
The optical fiber cable 11A for transmitting the higher-order group signal SNN1 of OC-192 (Optical Channel-192 Optical Carrier-Level 192) along the ring, for example, clockwise, is connected to an OR (optical receiving unit) 12A. I have.

The OR 12A is a 10 Gbps electrical signal STS-192 obtained by photoelectrically converting a received optical signal.
(Synchronous Transport Signal-level 192)
An O / E converter that sends out after the establishment of frame synchronization, and has its output terminal connected to the first line setting unit 13A.

The first line setting unit 13A separates the multiplexed high-order group signal SNN1 into the minimum unit for line setting according to the control from the line control unit 14A connected to the control terminal. The output terminal is connected to OH (overhead processing unit) 15A, 16A. Here, this minimum unit is equivalent to, for example, STS-1 corresponding to a transmission rate of 1/192 of STS-192.
The signal may be a signal at a middle stage between the STS-192 and the STS-192.

Here, the STS-1 “equivalent” is defined as the separated STS-1 to STS other than the highest-order STS-192.
S-48 and the like are multiplexed and overhead processed ST
This is because the overhead allocation differs between SX and each separated STS-X. For example, the multiplexed S
Although one B1 byte exists in TS-X, the B1 byte does not exist in each separated STS-X frame.

OH15A which is a component of the duplex configuration
Is the operation W currently functioning as the overhead processing unit.
(Working) overhead processing unit for clockwise operation. The overhead processing unit of the protection P (Protection) system corresponding to the OH 15A is the OH 16B for counterclockwise rotation. That is, when a transmission line failure or a device failure is detected by a clockwise signal, the OH 15A replaces the standby system,
System switching in which the OH 16B becomes the active system is performed.

Similarly, the clockwise and backup P OH 16A, which is a component of the duplex configuration, is an overhead processing unit corresponding to the working W OH 15B for counterclockwise use.

In the operation state, the OH 15A (or 15
B) is a pointer process for correcting jitter and wander for each STS-1, and an overhead process (reception termination).
I do.

In this pointer processing, in order to transfer (synchronize) a VC (Virtual Container) included in the received signal to an in-apparatus frame such as the STS-1 equivalent frame, a clock transfer and a VC with respect to the frame position are performed. Is replaced with a pointer value indicating the head position of. As a result, a state in which information can be identified even when jitter or wander occurs, that is, a synchronization state can be secured.

At the receiving end of the overhead, SDH
Among the various overheads in the frame, for example, selection regarding section overhead, that is, section overhead reconfiguration in accordance with demultiplexing in the first-stage first line setting unit 13A is performed.

This section overhead in the SDH frame is generated, detected, and calculated for error monitoring, frame synchronization, and the like.

When the OH 15A, 16
In A, failure detection is also performed on the signal supplied from the first line setting unit 13A.

The input / output interfaces of the OHs 15A and 16A are multiplexed to reduce the number of wires. Here, it is assumed that the output of OH 15A is equivalent to STS-3 obtained by multiplexing three STS-1 equivalents. in this case,
The number of output signal lines can be reduced to one-third as compared with the case where STS-1 equivalent is output as it is without multiplexing.

Since each of the OHs 15A and 16A is provided with, for example, eight element overhead processing units having the same structure in parallel, the above processing is performed for each element overhead processing unit.

In the low-order group interface unit 21 receiving the supply corresponding to STS-3 from the OHs 15A and 16A,
It is also possible to use only one STS-1 equivalent multiplexed to TS-3, for example, four STSs.
-3 equivalents may be multiplexed and treated as higher order STS-12 equivalents. The outputs of the OHs 15A and 16A may be higher-order signals than those corresponding to STS-3.

The OH selector 17A connected to the OHs 15A and 16A, on the basis of an instruction from the line controller 14A, relates to the overhead exchanged by the line controller 14A for the overhead processed by the OH 15A or 16A. Control the selection behavior.

Here, OH 15A is directly connected to OH selector 1
7A, and similarly, the OH 16A is directly connected to the OH selector 17A. That is, OH1
5A and 16A are connected in parallel to the OH selector 17A. The directions of arrows 15AA and 16AA in the figure indicate the directions in which the overhead moves.

From each of the components denoted by reference numerals 11A to 17A, a clockwise receiving side block 18 surrounded by a broken line is shown.
A is configured.

On the other hand, a total of 8 connected to the output terminals of the respective element overhead processing units in the OH 15A one by one.
The bus 20A including the signal lines includes a low-order group interface unit 21 and a T / I (Through or Insert) unit 22A.
Connected to these to send signals to

The internal structure of the low-order group interface unit 21 will be described later. The low-order group interface unit 21 shown at the top of FIG. 3 and the low-order group interface unit 23 shown at the bottom of FIG. Are actually integrated into one circuit in terms of hardware. However, functionally, it can be shown in two parts as shown.

The T / I section 22A whose input terminal is also connected to the output terminal of the low-order group interface section 21 by the bus 21A.
If there is a low-order group signal added from the low-order group interface unit 21, the S
While inserting the low-order group signal into the TS-3 equivalent signal,
If there is no lower-order group signal to be added, the STS-3 equivalent signal transmitted through the bus 20A is directly used as the OH35 signal.
A is a circuit that passes through A. The T / I unit 22A performs this insertion or passage for each pass.

This insertion is performed by multiplexing the low-order group signal supplied from the low-order group interface unit 21 into an arbitrary time slot in the SDH frame of the signal supplied from the OH 15A. The low-order group signal to be inserted may be lower order or higher order than STS-3 equivalent.

The output terminal of this T / I section 22A is OH3
5A.

From OH 15A, bus 20A, T / I section 2
A standby circuit having the same configuration and the same function as the operational circuit up to the OH 35A via the bus 21A and the bus 21A is OH1.
6A, a bus 23A, a T / I unit 24A, and a bus 25A
And OH36A. The clockwise bus 23A is connected to the OH when the standby circuit becomes active.
In order to supply a signal output from 16A, it is connected to an input terminal of the low-order group interface unit 23. At this time, in order to transmit a signal from the low-order group interface unit 23 to the T / I unit 24A, the output terminal of the low-order group interface unit 23 is connected to the T / I unit 24A via a bus 25A.

The buses 20A, 21A, 23A, 25
The number of signal lines constituting A may be larger or smaller than the above eight as required. These buses may be replaced with only one signal line. In this case, OH15
The number of the eight element overhead processing units provided inside A or the like may be the same as the number of signal lines.

The clockwise transmitting side block 30A enclosed by a broken line has a configuration and a function symmetric to the receiving side block 18A.

OH35A, which is a component of the duplex configuration,
36A, the T / I unit 2
A circuit for terminating the transmission of the overhead by multiplexing the overhead of the transmission frame with the signals supplied from 2A and 24A.
A is connected.

The OH 35A is an overhead processing unit of the working W system currently functioning as an overhead processing unit, and is for clockwise use. Spare P corresponding to this OH35A
The overhead processing unit of the system is OH36B for counterclockwise rotation. That is, when a transmission line failure or a device failure is detected by a clockwise signal, the OH 35A is replaced by the standby system,
System switching in which the OH 36B becomes the active system is performed.

Similarly, the clockwise backup OH 36A, which is a component of the duplex configuration, is an overhead processing unit corresponding to the working W OH 35B for counterclockwise use.

The second line setting unit 33A includes an OH 35A,
STS-3 corresponding to STS-3 equivalent signal supplied from 36A
This is a circuit for setting a line by multiplexing in an arbitrary time slot of the STS-192 signal in -1 units. This line setting is executed under the control of the line control unit 34A. An output terminal of the second line setting unit 33A is connected to an input terminal of an OS (optical transmission unit) 32A.

The OS 32A is an E / O converter for transmitting an optical signal obtained by electro-optically converting a received electric signal, and an optical fiber cable 31A connected to an output terminal thereof.
To send the optical signal.

The OH distribution unit 37A connected to the OHs 35A and 36A performs overhead processing (transmission termination) in the operating OH 35A or 36A based on an instruction from the line control unit 34A.

At the transmission end of the overhead, for example, the section overhead is distributed, that is, the section overhead is reconfigured in accordance with the multiplexing process performed by the second line setting unit 33A in the next stage.

The OH distribution unit 37A is connected to the line control unit 3
The overhead processing performed by the OH 35A or 36A is controlled based on the instruction from 4A.

Here, the OH 35A is directly connected to the OH
7A, and similarly, the OH 36A is directly connected to the OH distribution unit 37A. That is, OH3
5A and 36A are connected in parallel to the OH distribution unit 37A. The directions of arrows 35AA and 36AA in the figure indicate the directions in which the overhead moves.

On the other hand, the counterclockwise receiving block 18B enclosed by a broken line at the lower right of FIG. 3 is composed of the same components as the clockwise receiving block 18A described above.
Each component is denoted by a reference numeral corresponding to each component of the receiving side block 18A, and detailed description thereof will be omitted.

That is, the optical fiber cable 11B corresponds to the optical fiber cable 11A, the OR 12B corresponds to the OR 12A, the first line setting section 13B corresponds to the first line setting section 13A, and the line control section. 14B corresponds to the line control unit 14A, and OH 15B is the OH
15A, arrow 15BB corresponds to arrow 15AA, OH16B corresponds to OH16A, arrow 16
BB corresponds to the arrow 16AA, and the OH selector 17B corresponds to the OH selector 17A.

Similarly, the counterclockwise transmission side block 30B shown by a broken line at the lower left of FIG. 3 is composed of the same components as the above clockwise transmission side block 30A, Are denoted by the same reference numerals as those of the components of the transmission side block 30A, and the detailed description thereof is omitted.

That is, the optical fiber cable 31B corresponds to the optical fiber cable 31A, the OS 32B corresponds to the OS 32A, the second line setting unit 33B corresponds to the second line setting unit 33A, and the line control unit 34B corresponds to the line control unit 34A, and OH 35B is the OH
35A, the arrow 35BB corresponds to the arrow 35AA, the OH 36B corresponds to the OH 36A, the arrow 36
BB corresponds to the arrow 36AA, and the OH distribution unit 37B corresponds to the OH distribution unit 37A.

Further, a counterclockwise receiving side block 18B,
The counterclockwise buses 20B and 23B and the T / I units 22B and 24B provided between the transmitting side block 30B and the T / I units 22B and 24B have the same configuration and functions as the clockwise bus and the T / I unit described above. , And the detailed description thereof is omitted.

That is, the bus 20B corresponds to the bus 20A, the bus 23B corresponds to the bus 23A, and the T / I
The section 22B corresponds to the T / I section 22A, and the T / I section 24
B corresponds to the T / I unit 24A, bus 21B corresponds to the bus 21A, and bus 25B corresponds to the bus 25A.

As described above, inside the low-order group interface sections 21 and 23, which are one circuit, the OS, OR, OH, line control section, line control section, and the like as in the reception block 18A and the transmission block 30A. Although components such as a setting unit are provided, all of them have specifications for a low transmission rate corresponding to low-order group signals.

The low-order group signal is supplied via the optical fiber cable 26 connected to the low-order group interface section 21 to the distribution network including necessary SLTs (Subscriber Line Terminals) and the like. Is supplied to the terminal device in the user's home. Then, in the upstream direction, the signal transmitted from the terminal device is transmitted to the ADM device 10 along the reverse route, and is added to the higher-order group signal SNN1.

The low-order group interface units 21 and 2
Reference numeral 3 denotes a not-shown protection switch (path selector) provided therein, and a clockwise bus 20
A, 23A or the counterclockwise buses 20B, 23B can be selected, and the drop source and the add destination can be selected.

The fact that the path selector selects an add destination or a drop source is, in other words, nothing but that the path selector is executing the system switching.

The same signal as that of the corresponding active system is transmitted to the constituent parts of the standby system such as the OH 16A, but since the corresponding signal is not selected by the path selector, the standby system is the standby system. is there.

The ADM device 10 also has a function of performing system switching in response to a notification of a failure detection result in another SDH transmission device disposed on both the left and right sides of the transfer network.

The ADM apparatus 10 having the above configuration
1 is simplified to the same level as that of the conventional ADM device 50 shown in FIG.

That is, in the ADM apparatus 10C of FIG.
From the ADM apparatus 10 in FIG. 3, the redundant configuration of the active system and the standby system is unified, and only the configuration for clockwise or clockwise is shown, and the line control unit, OH selection unit, OH distribution unit, etc. Omitted.

The relationship between the two is shown as follows: OR12C corresponds to OR12A, line setting section 13C corresponds to first line setting section 13A, and OH15C corresponds to OH15A.
A, the T / I unit 22C corresponds to the T / I unit 22A, the OH 35C corresponds to the OH 35A, the line setting unit 33C corresponds to the second line setting unit 33A,
The OS 32C corresponds to the OS 32A.

The ADM device 10C is connected to the ADM device 10C shown in FIG.
When compared with the DM device 50, it is obvious that the circuit size can be reduced by the present invention.

The operation of the first embodiment having the structure shown in FIG. 3 will be described below.

(A-2) Operation of the First Embodiment First, the OR 12A, which has received the OC-192 higher-order group signal SNN1 from the optical fiber cable 11A, performs photoelectric conversion and performs an electrical signal operation at the same speed as the OC-192. The STS-192 is sent to the first line setting unit 13A.

The first line setting unit 13A is provided with a line control unit 14
A in accordance with the control from A.
The line is set for each STS-1 while separating the line into S-1.

The operation system OH is used for the STS-1 equivalent.
15A performs the overhead processing according to an instruction from the OH selection unit 17A, and performs the pointer processing.

At this time, the OH 15A also detects a failure. In the detection of the failure of the OH 15A, the failure is caused by the operation of the first line setting unit 13A, the OR 12A or the OH 15A itself, the failure is caused by the optical fiber cable 11A, or is disposed on the left side of the ADM apparatus 10 on the transfer network. A failure due to an SDH transmission device such as another ADM device is detected.

When the OH 15A detects a failure, system switching is performed and the left-handed OH 16B becomes the active system, so that clockwise and counterclockwise switching also occurs. As a result, the high-order group signal SNN1 transmitted from the left side (including the receiving side block 18A) including the location where the failure has occurred is not used in the ADM apparatus 10 and the counterclockwise high-order group signal SNN2 supplied from the right side without a failure. Can be used.

Of the STS-3 equivalents transmitted to the bus 20A after being multiplexed by the OH 15A, the first line setting unit 1
The STS-3 equivalent signal in which the line to be dropped to the low-order group interface unit 21 in 3A is set is dropped to the low-order group interface unit 21 in accordance with the line, and the same as described above in the low-order group interface unit 21. Similar overhead processing and various processing such as demultiplexing and multiplexing are performed, sent to the optical fiber cable 26, and supplied to the distribution network.

On the other hand, among the STS-3 equivalents transmitted from the OH 15A to the bus 20A, the first line setting unit 13
The STS-3 equivalent in which the line to be dropped to the low-order group interface unit 21 in A is not set is transmitted as it is on the bus 20A and supplied to the T / I unit 22A.

When there is a low-order group signal added from the low-order group interface unit 22A, the T / I unit 22A converts the low-order group signal transmitted via the bus 21A into the STS.
By multiplexing the signal into an arbitrary time slot corresponding to STS-3, a low-order group signal is inserted corresponding to STS-3. Then, the STS-3 equivalent having received the insertion of the low-order group signal is supplied to the OH 35A.

If there is no low-order group signal to be added, T /
Since the I section 22A passes the STS-3 equivalent as it is, the STS-3 equivalent is supplied to the OH 35A.

Under the control of the OH distribution unit 37A, the active OH 35A performs the overhead processing in preparation for the multiplexing process in the second line setting unit 33A at the next stage.

In response to this, the second line setting unit 33A controlled by the line control unit 34A performs line setting while multiplexing the STS-3 equivalent to the higher order group signal STS-192.

Therefore, the higher-order group optical signal SNN1 of the OC-192 is transmitted from the OS 32A to the optical fiber cable 31A.

The operation related to the clockwise signal has been described above.
And the optical fiber cable 31B via the receiving block 18B, the bus 23B, the transmitting block 30B, etc.
The same operation is carried out for the counterclockwise signal sent to.

Note that the above-mentioned path and path built in the low-order group interface section in each ADM apparatus on the ring type transfer network is used.
When the selector selects an add destination (that is, system switching), it is determined whether certain information is carried by a counterclockwise signal or a clockwise signal. The information carried in the counterclockwise signal may be the same.

On the other hand, a notification of failure detection in another SDH transmission device arranged on the right side of the transfer network, for example,
When the ADM device 10 receives the data through the counterclockwise optical fiber cable 11B, the ADM device 10 performs the system switching using the active OH 15A as the standby system and the standby OH 16B as the active system.

When a failure is detected in the adjacent SDH transmission device on the left side, the failure location may be the transmission block 30A, T / I section 22A, optical fiber cable 31A, and the SDH transmission device of the ADM device 10. ADM device 10
If the ADM device has the same configuration as
It is highly possible that the part is one of the parts corresponding to the receiving block 18A in the H transmission apparatus. So in this case,
The effect of the failure can be suppressed by the system switching.

(A-3) Effects of the First Embodiment As described above, according to the present embodiment, the OHs 15A and 16A
Since the line setting is performed in the previous stage such as the above, it becomes possible to cause the same first line setting unit to perform the demultiplexing and the line setting which were conventionally performed by another circuit, and to cope with the drop function. The circuit scale of the part can be reduced.

Further, since the line setting is performed in the next stage such as the OH 35A, 36A, etc., the multiplexing and the line setting (after inserting the low-order group signal) conventionally performed by another circuit are the same as the second line. This can be performed by the line setting unit, and the circuit scale of the part corresponding to the add function can be reduced.

On the other hand, by performing system switching, in the present embodiment, the clockwise receiving side and transmitting side blocks 18A
And 30A can be disconnected simultaneously or counterclockwise receiving and transmitting blocks 18B and 30B
Can be disconnected at the same time, so even when a failure is detected,
Normal service provision to the user can be continued, and the reliability is high.

(B) Second Embodiment Next, a transmission rate conversion method and apparatus according to the present invention is applied to a BLSR for transmitting a signal by returning a signal in the apparatus when a failure is detected.
A second embodiment of the present invention will be described with an example in which the present invention is applied to the ADM of the SDH in the (Bi-directional Line Switched Ring) system.

(B-1) Configuration and Operation of Second Embodiment BLDM ADM apparatus 40 according to the second embodiment
Is shown in FIG. The configuration of the ADM device 40 is a BLSR
Since the configuration is the same as that of the ADM apparatus 10 shown in FIG. 3 except for a configuration for folding back a signal corresponding to the system, FIG.
The same reference numerals are given and the detailed description is omitted.

That is, in FIG.
A, 13A, 14A, 15A, 15AA, 16A, 16
AA, 17A, 18A, and 20A, 2
1, 21A, 22A, 23, 24A, 25A, 26, and reference numerals 30A, 31A, 32A, 33A,
34A, 35A, 35AA, 36A, 36AA, 37A
1 correspond to the respective parts in FIG. 1 denoted by the same reference numerals.

In FIG. 4, reference numerals 11B, 12B,
13B, 14B, 15B, 15BB, 16B, 16B
B, 17B, and 18B, and reference numeral 20B (, 2
1), 22B (, 23), 24B, and 25B, and reference numerals 30B, 31B, 32B, 33B, 34B,
The counterclockwise configuration of each part of 35B, 35BB, 36B, 36BB, and 37B corresponds to each part of FIG.

Next, a configuration for folding back a signal corresponding to the BLSR system will be described.

In FIG. 4, a protection switch 41 provided in the middle of the bus 20A, a protection switch 42 provided in the middle of the bus 23A, and a protection switch 4 provided in the middle of the bus 23B.
3 and the protection provided in the middle of the bus 20B.
The switch 44 is a configuration for the return.

The protection switch 41 normally includes a clockwise transmission side block 30A and a T / I
The unit 22A is connected to the clockwise receiving circuit block 18A, but when a failure is detected, the clockwise transmitting circuit block 30A and the T / I unit 22A are connected to the counterclockwise receiving circuit block 18B. Switch.

By this connection switching, a signal is looped back in the ADM device 40. That is, the signal supplied from the counterclockwise optical fiber cable 11B is transmitted to the clockwise optical fiber cable 31A instead of the counterclockwise optical fiber cable 31B. In the return, the protection switches 41 and 42 are linked to switch the connection,
Alternatively, it is executed by the protection switches 43 and 44 interlocking and switching the connection.

By the return, it is possible to set a detour route on the ring-type transfer network and in the ADM device 40 that avoids a location where a failure such as a signal interruption or a transmission error occurs.

The return of such a signal is performed when the right-handed OH 15A or 16A or the left-handed OH 15B or 16B in the ADM device 40 detects a failure.

For example, if the OH 15A, which is currently in operation, detects a failure, the protection switches 41 and 4
2 is switched to the illustrated state.

As a result, the signal output from the OH 16B is input to the T / I unit 22A, and the signal output from the OH 15B is input to the T / I unit 24A.
The signal is looped back.

The protection switch (that is, the path selector) in the low-order group interface section 21 is used as a protection switch 4 as a drop source.
The same bus 20B as that before the switching of 1, 42 is selected, and as an add destination, the T / I section 24B before the switching is not selected, and the T / I section 24A is selected.

Like the protection switch 41, the protection switch 42 normally connects the clockwise transmission block 30A and the T / I section 24A to the clockwise reception circuit block 18A. ,
When a failure is detected, the clockwise transmission side circuit block 30A is used.
And a switch for connecting the T / I unit 24A to the counterclockwise receiving side circuit block 18B.

In addition, the protection switch 43 normally operates the counterclockwise transmission side block 30B and the T / I
The unit 22B is connected to the counterclockwise receiving side circuit block 18B, but when a failure is detected, the counterclockwise transmitting side circuit block 30B and the T / I unit 22B are connected to the clockwise receiving side circuit block 18A. Switch.

Further, the protection switch 44
Normally, the counterclockwise transmission side block 30B and T /
The I unit 24B is connected to the counterclockwise receiving side circuit block 18B. When a failure is detected, the counterclockwise transmitting side circuit block 30B and the T / I unit 24B are connected to the clockwise receiving side circuit block 18A. Switch to connect.

(B-1-1) The UP to the BLSR
Upgraded low-order group interface unit 21 from SR
By selecting the drop source and the add destination by the path selectors provided in and 23, the protection switch for signal return such as the protection switch 41 is switched while the operation of the UPSR ADM apparatus 10 is continued. Can be added.

For example, first, a clockwise bus 20A, 2
Select 3A and unselect left-handed buses 20B, 23B
, A return protection switch is added, and then the counterclockwise buses 20B and 23B are selected, and a return protection switch is added to the unselected clockwise buses 20A and 23A.

Thus, the ADM device 10 of the UPSR system is upgraded to the ADM device 40 of the BPSR system while the operation of the ADM device 10 is continued.

The ADM device 40 having the above-described configuration is the same as the ADM device 10 in FIG.
Simplified to the same level as the DM device 50,
This is the ADM device 10C shown in FIG.

(B-2) Effects of the Second Embodiment As described above, according to the present embodiment, the circuit size of the portion corresponding to the drop function in the ADM device 40 is exactly the same as in the first embodiment. Can be reduced, and AD
The circuit scale of a portion corresponding to the add function in the M device 40 can be reduced.

On the other hand, by performing the loopback, in the present embodiment, the blocks 18A and 30B of the clockwise receiving side and the counterclockwise transmitting side can be simultaneously separated, or the counterclockwise receiving side and the clockwise transmitting side can be separated. Block 18B
And 30A can be disconnected at the same time, so that even when a failure is detected, normal service provision to the user can be continued, and the reliability is high. Also, since a detour route can be set on the transfer network, the optical fiber cable 3
Even when 1A and 11B are one cable, highly reliable operation is possible.

Further, the difference between the ADM device 40 according to the present embodiment and the ADM device 10 according to the first embodiment is only the presence or absence of the return protection switches 41 to 44. While the ADM device continues to operate, the UPS
It can be upgraded to R and is economical, flexible and reliable.

(C) Other Embodiments In the first and second embodiments described above, the case where the wiring topology of the network is ring-shaped has been described. It is also applicable to topologies, for example, tree type, star type, and the like.

Further, in the above description, one ADM apparatus has both the drop function and the add function. However, an apparatus having only the add function and an apparatus having only the drop function may be separately configured. . In this case, by combining them, the same functions as those of the first and second embodiments can be provided. If necessary, a device having only an add function or only a drop function can be used alone.

In the ADM apparatuses of the first and second embodiments, the high-order group signal is received from the clockwise optical fiber cable 11A, and the clockwise optical fiber cable 31 is received.
The high-order group signal is transmitted to A, the high-order group signal is simultaneously received from the counterclockwise optical fiber cable 11B, and the high-order group signal is transmitted to the counterclockwise optical fiber cable 31B. That is, the optical fiber cables 11A and 3
When 1A is regarded as one optical fiber and the optical fiber cables 11B and 31B are regarded as one optical fiber, ADM
The devices 10 and 40 were of the two-fiber type,
A four-fiber system using two optical fibers may be used.
Further, if necessary, six or more optical fibers may be used, or one optical fiber may be used.

To explain clockwise, in the two-fiber system, the higher-order group signal supplied from one optical fiber is (multiplex-demultiplexed) loaded on one of the buses 20A or 23A which is the operating system. When this becomes, for example, a four-fiber system, both of the two higher-order group signals supplied from the two optical fibers are transferred to the bus 20A or 2B.
It will be put on one of the buses of the operation system of 3A.

Further, since these devices and the method used therewith can arbitrarily exchange the time slots of the low-order group signals multiplexed with the high-order group signals, they can also be applied to cross connectors and the like.

In the first and second embodiments, an SDH frame is used as a transmission frame of a signal to be transferred.
The transmission frame that can be used in the present invention is not limited to SDH. It may be a digital signal of another transmission frame,
Further, the signal may be an analog signal.

Further, in applying the present invention, matching of the clock frequencies of the respective low-order group signals, that is, synchronization is not always an essential condition.

That is, according to the present invention, a multiplexed signal constituted by multiplexing a plurality of component signals is received, the corresponding component signal is dropped from the multiplexed signal, and / or the plurality of component signals are multiplexed. When transmitting a multiplexed signal configured by the above-described method, the present invention can be widely applied to a case where a corresponding element signal is added to the multiplexed signal.

[0125]

As described above, according to the present invention, the scale of a circuit having a function of dropping a corresponding element signal from a multiplex signal and / or a function of adding a corresponding element signal to a multiplex signal is provided. Can be made smaller than a conventional circuit having the same function.

[Brief description of the drawings]

FIG. 1 is a simplified block diagram showing a configuration of an ADM device according to first and second embodiments.

FIG. 2 is a block diagram showing a conventional ADM device.

FIG. 3 is a block diagram illustrating an ADM device according to the first embodiment.

FIG. 4 is a block diagram illustrating an ADM device according to a second embodiment.

[Explanation of symbols]

10, 10C, 40, 50 ... ADM device, 13A, 13
B: first line setting unit, 33A, 33B: second line setting unit, 15A, 16A, 35A, 36A, 15B, 16
B, 35B, 36B... OH, 21, 23... Low-order group interface unit, 22A, 24A, 22B, 24B.
Parts, 20A, 21A, 23A, 25A, 20B, 21
B, 23B, 25B ... bus, SNN1, SNN2 ... higher-order group signals.

Claims (10)

[Claims] 1. A transmission rate conversion method for receiving a multiplexed signal formed by multiplexing a plurality of component signals and dropping the corresponding component signal from the multiplexed signal, comprising the steps of: A line for these element signals is set while separating the element signals, and a predetermined reception process is executed for each of the element signals after the line setting. 2. A transmission rate conversion method for adding a corresponding element signal to a multiplexed signal when transmitting a multiplexed signal formed by multiplexing a plurality of elementary signals. The element signal to be added is inserted and passed among the element signals of the above, and if there is no element signal to be added, the plurality of element signals are passed as they are. A transmission rate conversion method characterized by performing a predetermined transmission process, and thereafter multiplexing and transmitting the plurality of passed element signals while setting a line. 3. The transmission rate conversion method according to claim 1, wherein the drop by the transmission rate conversion method and the add by the transmission rate conversion method according to claim 2 are performed together. 4. A transmission rate converter for receiving a multiplexed signal formed by multiplexing a plurality of component signals and dropping a corresponding component signal from the multiplexed signal, comprising: First line setting means for setting the lines of these element signals while separating the element signals, and reception processing means for executing predetermined reception processing for each of the element signals after the line setting. A transmission speed conversion device characterized by the above-mentioned. 5. When transmitting a multiplexed signal formed by multiplexing a plurality of element signals, a transmission rate conversion device for adding the corresponding element signal to the multiplexed signal, if there is an element signal to be added, Passing insertion means for inserting and passing the element signal to be added among the element signals of the above, and when there is no element signal to be added, passing insertion means for passing the plurality of element signals as they are; Transmission processing means for performing predetermined transmission processing, and second line setting means for thereafter multiplexing the plurality of passed element signals while setting a line, the second line setting means A transmission speed conversion device for transmitting an output of a transmission speed. 6. The transmission rate conversion device according to claim 4, wherein the multiplexed signal is a high-order group signal of a digital hierarchy, and the element signal is a low-order group signal of a digital hierarchy. The transmission rate conversion device according to claim 1, further comprising at least an overhead reception termination process, and wherein the predetermined transmission process includes at least an overhead transmission termination process. 7. A transmission rate conversion apparatus, wherein the drop by the transmission rate conversion apparatus according to claim 4 and the add by the transmission rate conversion apparatus according to claim 5 are performed in combination. 8. The transmission rate conversion device according to claim 4, wherein a plurality of drop source circuits including at least the reception processing means or a plurality of add destination circuits including the transmission processing means are provided. If a failure is detected in the active drop source circuit or add destination circuit functioning as the original or add destination, the standby drop source circuit or add destination circuit that is not currently functioning as the drop source is removed. A transmission rate conversion apparatus, comprising: a system switching unit that is used as an active system and uses a drop source circuit or an add destination circuit of the active system in which a failure is detected as a standby system. 9. The transmission rate conversion device according to claim 4, wherein a plurality of said transmission speed conversion devices are arranged in a network having a ring topology, wherein said transmission speed conversion device comprises: A clockwise processing circuit for processing a signal transmitted clockwise through the network; a clockwise processing circuit for processing a signal transmitted counterclockwise through the network; and Detect signal failure,
Or a clockwise failure detecting means for detecting a failure of the signal by receiving a notification of failure detection from the transmission rate converter on the right side of the network that has detected the failure of the transmitted clockwise signal; Detecting the failure of the counterclockwise signal that
Or a counterclockwise fault detecting means for detecting a fault in the signal by receiving a notification of fault detection from the transmission rate converter on the left side of the network that has detected the fault in the transmitted counterclockwise signal; When the clockwise fault detection means or the counterclockwise fault detection means detects the fault, the clockwise processing circuit is separated into an input side and an output side, and the counterclockwise processing circuit is connected to the input side and the output side. Switching to connect the input side of the clockwise processing circuit and the output side of the counterclockwise processing circuit, or to connect the output side of the clockwise processing circuit and the input side of the counterclockwise processing circuit Means for setting a detour route in the network. 10. A drop source circuit or an add destination circuit according to claim 8, a system switching unit according to claim 8, a clockwise processing circuit according to claim 9, a counterclockwise processing circuit according to claim 9, 10. A transmission speed conversion device comprising: a clockwise fault detection unit according to claim 9; a counterclockwise fault detection unit according to claim 9; and a switching unit according to claim 9. A transmission speed conversion device, wherein switching between an active system and a standby system by a switching unit is performed in an interlocked manner.