JPH1168716A - Path switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase adjusting function and switching function of a phase adjusting part only by exchanging the low-speed interface substrate of a low-speed part regardless of no interruption or interruption by centralizing these functions at a low-speed interface section. SOLUTION: Concerning the configuration of a main signal part 33, a system is composed of low-speed interface parts 34 and 36 having the phase adjusting function, non-interruption switching function and NNI processing function and high-speed interface parts 35 and 37 having the NNI processing function. A common part 40 is composed of a clock part 41 for receiving a clock from a clock supplier 44 and generating a clock to be used inside the device, a control part 42 for executing the command of operation setting or switching control from a controller 45, an alarm part 43 for receiving fault information such as transmission alarm, line alarm or intra-device alarm, and an alarm monitor device 46. Then, the phase control parts as the phase adjusting function and non-interruption selective switching function of the low-speed parts 34 and 36 are excluded so that the interruption bus switching device can be easily provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission apparatus in an SDH network composed of a transmission side apparatus and a reception side apparatus, and is configured by being connected via two transmission lines having different distances. Operational transmission path (path) /
The present invention relates to a path switching device that performs switching with a backup transmission line.

[0002]

2. Description of the Related Art In a recent SDH transmission system, a transmission speed in an optical fiber transmission line is 600 Mbps.
The speed is increased to 4 Gbps or the like, and the effect when a transmission line failure occurs is very large. In this case, two transmission lines, a working line and a protection line, are installed as a relay transmission network. Generally, these transmission line distances are different, but the same signal information is transmitted in these transmission lines. The reliability of the network is improved by configuring a redundant system having a function of selecting the working / spare. SDH
In the system, VC (virtual) multiplexed with the main signal of the STM frame of the working transmission line and the protection transmission line is used.
lContainer) path is managed as a unit, and alarm detection, alarm transfer, and the like are performed using a VC path as a processing unit.

[0003] The VC path is multiplexed in an arbitrary phase by an instruction of a pointer in an STM frame. Therefore,
When signals from the working transmission line and the protection transmission line are received, even if the same signal is transmitted on the transmission side, the phase of the VC path transmitting the same information is different on the reception side. In this case, if any failure occurs in the active transmission path, a line data error or line disconnection alarm will be generated. It is necessary to select and switch the system transmission path.

In recent years, the content of information multiplexed as a main signal has been required to have extremely high line reliability due to the progress of inter-computer communication, and even momentary interruptions have become unacceptable. In this case, if switching is performed by an electronic circuit such as a selector in a situation where the phases of the VC paths are different, instantaneous interruption is inevitable. Therefore, in recent years, in a circuit section that passes through a VC path, a delay is provided by a memory to which one of the phases of the active or standby VC path is advanced via a memory or the like, so that the phases of the two paths are the same. Non-instantaneous interruption switching devices that perform switching after matching are being introduced.

[0005] With regard to the conventional device having a non-stop switching function, NTT Technical Journal 199 describes a device for selecting an active transmission line and a standby transmission line of an SDH transmission system.
As a function to realize the instantaneous interruption switching function as described in the September 2005 issue “Development of Module AY”, NNI (Network Node Interface) on the high-speed side and the low-speed side
ce) A high-speed interface unit and a low-speed interface unit having processing functions, and a phase adjusting unit between these functions.

A general configuration for realizing the instantaneous interruption function is disclosed in the above document. Therefore, when realized as a device, the three block configuration is a normal configuration method due to the relationship of component mounting and the like. In the prior art,
Various SDH transmission devices have been put to practical use in Japan, but domestic telecommunications carriers use devices whose external dimensions are standardized. Further, there is a premise that the instantaneous interruption switching device according to the present invention must be realized by the same printed circuit board, unit, and mounting structure. Therefore, if there is a method that can be reduced in size while being restricted by the external dimensions, advantages such as cost and flexibility in configuration will appear.

However, in the prior art, attention has been paid to a device that switches without instantaneous interruption, and in fact, no attention has been paid to a switching device that allows instantaneous interruption. Conventionally, attention has been paid only to the effect of the instantaneous interruption switching, and the demerit has not been mentioned.

[0008] The instantaneous interruption switching device also has a drawback, and the biggest drawback is that a delay must be inserted into the main signal portion. When a large number of these hitless switching devices are provided in a network, a considerable propagation delay occurs end-to-end, and when the main signal data is a voice signal, the voice quality is greatly deteriorated. Therefore, in a network related to telephone exchange and the like, the effect of instantaneous interruption is small, and delay is a problem.

[0009] Therefore, in recent years, switching devices that allow instantaneous interruption have also attracted attention again, and devices having both functions of instantaneous interruption switching and instantaneous interruption switching can be realized with a low-cost and flexible configuration. If this is the case, it will be possible to make a significant contribution to industries such as the information and telecommunications industry, leading to lower line charges. The above-mentioned document discloses a technique for a method of configuring a non-interruptible switching device, but does not describe a technology including instantaneous switching.

Here, the structure of the conventional system will be described with reference to FIGS. 7 and 8. FIG. 7 and 8 are block diagrams showing an example of a conventional path switching device.
The first conventional example shows a case of an instantaneous interruption switching device, and the second conventional example of FIG. 8 shows a case of an instantaneous interruption switching device.

First, a description will be given of an example of a non-instantaneous-interruption switching device of a first conventional example in FIG. The conventional path switching device includes low-speed units 200 and 211 of the 0-system / 1 system and high-speed units 400 and 410 of the 0-system / 1 system.
And phase adjustment units 300 and 310 of the 0 system / 1 system. On the transmission side, the low-speed units 200 and 210 include receiving units 202 and 212 that convert optical signals 201 and 211 input from a transmission path such as a terminating device into electric signals, and STM-n.
J1 of POH of each VC-n frame forming a frame
NNI to set multi-frame synchronization pattern in bytes
The phase information is added by the processing units 203 and 213, and the signals are output to the divider units (signal distribution units) 303 and 313 of the phase adjustment units 300 and 310, and the same signal is output by two systems. 1-system selector units 401 and 41
1 and selects one of the selected signals from the low-speed part 0 system / one system, and separates the selected signal into phase information in the NNI processing sections 402 and 412 of the high-speed section. Alternatively, the signals are output as transmission signals 404 and 414 from the transmission units 403 and 413 that convert the signals into optical signals.

The configuration on the receiving side of the path switching device includes an NNI processing unit 402, 4 which receives an electric or optical signal from the received signals 407, 417 and generates an SST-n frame in the device.
At 12, phase information is added, and the signal is transmitted to the low-speed units 200 and 210 of the 0-system / 1 system via the high-speed divider units (signal distribution units) 405 and 415. 0/1 low-speed part 2
The receiving operations of 00 and 210 are based on the phase delay difference generated by the transmission paths 407 and 417 of each VC-n frame, and the VC-n
A phase adjuster reflecting the frame failure detection time, VC-
Phase adjusters 300 and 310 for detecting faults in n frames
And STM-n for transmission from the VC-n frame signal output from the selector from the selectors 302 and 312 for selecting one of the outputs from the phase adjustment unit on a VC-n frame basis.
A transmitting unit 20 that converts an electric signal into an optical signal from the NNI processing units 203 and 213 that generate frames and transmits the optical signal to a transmission path
5, 215.

Next, a description will be given of a case of instantaneous interruption switching in the second conventional example of FIG. When the instantaneous interruption switching is configured, the above-described phase adjustment unit becomes unnecessary, and the low speed unit 5 is used instead of the phase adjustment unit.
In order to connect the high-speed units 700 and 710 with the high-speed units 700 and 710, through connection units 600 and 610 are required.

Therefore, when providing a service that does not require instantaneous interruption switching, a board accommodating the above-mentioned phase adjustment unit is not required, but a simple function of realizing only a through function for connecting a low-speed unit and a high-speed unit is provided. A substrate is required. To provide a service requiring instantaneous interruption switching, a board for accommodating a phase adjustment unit between the high-speed interface unit and the low-speed interface unit is required.

[0015]

As described in the prior art, on the premise that the apparatus is realized under the conditions of the external dimensions such as the printed circuit board and the structural dimensions of the unit, depending on the services to be further provided, It is not advisable to deliberately insert a delay into the main signal to degrade line quality if instantaneous interruption can be tolerated as in the case of voice signal transmission.
Naturally, the cost of the instantaneous interruption switching device is increased by the amount of memory. Therefore, when selecting whether or not to accommodate the line phase adjustment unit, if the same system unit can always be used, there is no need to realize another device regardless of instantaneous interruption or instantaneous interruption, and a flexible device configuration Becomes possible.

The problem to be solved in the present invention is to realize these functions only by replacing the low-speed interface board in the low-speed section regardless of instantaneous interruption or instantaneous interruption. In the above prior art, in order to realize the instantaneous interruption function by the method of realizing the device configuration, a board realized as a through connection section must be mounted instead of the phase adjustment section board.

[0017]

In the case of the non-instantaneous switching service, a high-speed unit, a phase adjusting unit and a low-speed unit are required. In the case of the instantaneous switching service, only the high-speed unit and the low-speed unit are required.

Therefore, in order to accommodate them in the same system unit, the phase adjustment function and the instantaneous interruption switching function of the phase adjustment unit, which have conventionally been realized on separate boards, are integrated into the low-speed interface unit, so The configuration of the system unit required for providing the interruption switching service and the instantaneous interruption switching service is only the high-speed unit and the low-speed unit.

In order to achieve this object, it is necessary to mount a phase adjustment unit on a low-speed interface board. The method of realizing the phase adjustment function of the known example document includes a system in which the operating system and the standby system are respectively housed on separate boards, and the phase adjustment between respective signals is controlled by exchanging phase information between these boards. I was taking.

In the present invention, a system is adopted in which both the operation system signal and the standby system signal are accommodated and controlled in the phase adjustment function unit, and these are realized by an LSI. By mounting this LSI on a low-speed interface board, two signals from the high-speed interface board are taken into the low-speed interface board, and the confounding of the signals is only between the low-speed interface board and the high-speed interface board. The configuration is also two on the high-speed side and two on the low-speed side, for a total of four, making it possible to realize both instantaneous interruption and no instantaneous interruption switching functions with a very simple configuration.

Therefore, the technical means for solving the problem is also an important factor in considering the method of forming the substrate. Further, as a method of configuring the LSI, the present invention replaces the method of the configuration of the LSI, which is a means for realizing the functional configuration of the related art,
As a system for accommodating both the working system and the protection system transmission line (0/1 system) in the phase processing unit, a single chip LSI (non-instantaneous switching LSI) is used to realize these functions (number of gates: about 100
KG). In other words, by mounting the LSI according to the present invention on the low-speed interface board of the low-speed section, a system configuration having a two-part configuration of the high-speed section and the low-speed section becomes possible.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a path switching device according to the present invention will be described below with reference to the drawings. First, the configuration of the transmission device and the configuration of the communication network will be described.
1 and 2 are network configuration diagrams showing the configuration of a communication network using the transmission device of the present invention.

FIG. 1 is a diagram showing a network configuration of a point-to-point transmission of a facing type, in which an SDH communication is performed and an end of the transmission lines 1, 3, 5, 6, 7, and 8 performing different relay transmissions. A station A2 and a terminal station B4 are provided. FIG. 2 is a diagram showing a network configuration for loop transmission, in which a terminal station A2
3, a terminal station B24, a terminal station C25, and a terminal station D26.
7, 28, 29, and 30 are connected to form a communication network and provide a high-speed digital communication service.

The network configuration of the path switching device according to the present invention will be described with reference to an example of a point-to-point transmission of the opposite type. The present transmission system includes a path switching device 1, 2 that performs communication in the SDH system and a SDH multiplexing terminal device 3, 4, 5, 6 that performs multiplexing / demultiplexing relay between the path switching devices 1, 2, and a path switching device. 1
Are transmitted to the path switching device 2 via the SDH multiplexing terminal equipment by optical fiber transmission lines 7 and 8.

FIG. 3 is a block diagram illustrating the network configuration of FIGS. 1 and 2 in more detail, and is a diagram illustrating the overall block configuration of the path switching apparatus according to the present invention.

The system of the main signal section 33 comprises a low-speed interface section 34, 36 having a phase adjustment function, a non-interruptible switching function, and an NNI processing function, and a high-speed interface section 35, 37 having an NNI processing function. The common unit 40 receives a clock from the clock supply device 44 and generates a clock to be used in the device. A control unit 42 executes command processing such as operation state setting and switching control from the control device 45. And transmission line alarm,
Alarm unit 4 that receives fault information such as line alarms and in-device alarms
3 and a monitoring device 46 that performs alarm monitoring.

FIG. 4 shows an embodiment of the path switching apparatus for instantaneous interruption according to the present invention. The path switching device of the present invention
Low-speed sections 50 and 70 of system / 1 system and high-speed section 6 of system / 1 system
0 and 80. The configuration of the transmission side is each low-speed unit 5
Receivers 52 and 72 for converting optical signals 51 and 71 input from a transmission line such as a terminating device into electric signals,
P of each VC-n frame forming the STM-n frame
The NNI processing sections 53 and 73 for setting a multi-frame synchronization pattern in the J1 byte of the OH add phase information, and output the same signal to two dividers (signal distribution sections) 56 and 76 to output the same signal. The signals are input to selectors 61 and 81 of the 0/1 system of 60 and 80, one of the selected signals is selected from the 0/1 system of the low speed units 60 and 80, and the selected signal is converted to the NNI processing unit 62 of the high speed unit. , 82, the phase information is separated, and the separated signals are output as transmission signals 64, 84 from transmission units 63, 83, which convert the signals into electric signals or optical signals.

The configuration of the receiving side of the path switching device is such that an electric or optical signal is received from the received signals 65 and 85,
The NNI processing sections 62 and 82 that generate T-n frames add phase information, and the signals are passed through high-speed divider sections (signal distribution sections) 67 and 87 and the 0-system / 1-system low-speed section 50,
70. The receiving operation of the low-speed units 50 and 70 of the 0/1 system includes a phase adjustment unit that reflects a phase delay difference generated by the transmission lines 65 and 85 of each VC-n frame and a failure detection time of each VC-n frame. Phase adjusters 57 and 77 for detecting a failure in n frames and selectors 58 and 78 for selecting one of the outputs from the phase adjuster on a VC-n frame basis.
A NNI processing unit 5 for generating an STM-n frame for transmission from the VC-n frame signal output from the selector
The transmission units 55 and 75 convert the electric signals from the signals 3 and 73 into optical signals and transmit the signals to the transmission line.

FIG. 5 shows an embodiment of a path switching apparatus for instantaneous interruption according to the present invention. Fig. 4 shows the path switching device for instantaneous interruption.
In the device block diagram described in FIG.
The instantaneous interruption path switching device can be easily realized by removing the phase control units 57 and 77, which are the phase adjustment function and the instantaneous interruption selection switching function of 20, and the path switching device of FIG. The low-speed units 50 and 70 and the low-speed units 100 and 120 of the path switching device corresponding to the instantaneous interruption shown in FIG. 5 are provided with a compatible function.

FIG. 6 is a block diagram showing the configuration of the phase adjustment unit provided in the path switching device of the present invention. There are synchronization pattern detection units 142 and 152 for detecting a multi-frame synchronization pattern from each VC-n frame signal received from the 0-system / 1-system transmission lines 141 and 151 and generating a head synchronization pulse of the multi-frame. The write addresses of the n-frame delay memories 145 and 155 are generated, and the head frame address of the multi-frame is stored in the address buffer (0) 144 and the address buffer (1) 154. The phase control circuit 48 detects a lag-phase VC-n frame from the multi-frame head synchronization pulse, and
A read reference pulse 149 to which an n-frame failure detection time is added is generated. The read control circuit 150 sets the address buffer (0) 14 at the timing of the read reference pulse.
4. A read head address is set from the address buffer (1) 154, and a read address to the delay memories 145 and 155 is generated. The B3 operation circuit 157 detects a data error of the VC-n frame and generates a B3 quality deterioration signal to the selector 159. The PTR detection circuit 158 generates a PTR error when detecting data other than a predetermined pointer value. The selector 159 outputs the normal output signal 16 from the selector input signals 146 and 156 based on the failure result of the VC-n frame signal of the B3 operation circuit 157 and the PTR detection circuit 158.
Select 0.

[0031]

As described above, according to the present invention, when it is desired to provide the instantaneous interruption switching service and the non-instantaneous interruption switching service, it is not necessary to replace the unit each time for the service, and the instantaneous interruption is performed only by replacing the low-speed interface board. It is possible to provide an instantaneous interruption switching path switching apparatus and an instantaneous interruption switching path switching apparatus that can support the switching service and the instantaneous interruption switching service and that can be exchanged for each system in the unit.

Also, by integrating the functions of the phase adjustment section and the low-speed section into the low-speed section interface board, the number of packages has conventionally been required to be at least 6 in the 0/1 system.
It is possible to reduce the number of packages and the number of products constituting the system, which is very advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a network configuration diagram showing a configuration of a communication network using a transmission device of the present invention.

FIG. 2 is a network configuration diagram showing a configuration of a communication network using the transmission device of the present invention.

FIG. 3 is a diagram illustrating a transmission device and a communication network according to the present invention.

FIG. 4 is a diagram for explaining a configuration of a path switching device for instantaneous interruption without interruption according to the present invention;

FIG. 5 is a diagram for explaining a configuration of a path switching device for instantaneous interruption according to the present invention.

FIG. 6 is a diagram for explaining a phase adjusting unit of the path switching device for instantaneous interruption according to the present invention.

FIG. 7 is a block diagram of a conventional path switching device for instantaneous interruption.

FIG. 8 is a block diagram of a conventional path switching device for instantaneous interruption.

[Explanation of symbols]

1, 3, 5, 6, 7, 8, 21, 22 ... transmission path 2,
4, 10, 12, 14, 16 ... terminal stations, 9, 11, 13,
15: Path switching device, 10, 12, 14, 16 ... Multiple terminal device, 27, 28, 29, 30 ... Relay transmission line, 31,
38, 141 ... 0 system transmission line, 32, 39, 151 ... 1 system transmission line, 33 ... main signal unit, 40 ... common unit, 34, 36 ...
Low-speed IF unit, 35, 37 high-speed IF unit, 41 clock unit, 42 control unit, 43 alarm unit, 44 clock supply unit, 45 control unit, 46 monitoring unit, 51, 71,
101, 121, 201, 211, 501, 511... Input signal, 50, 70, 100, 120, 200, 210
... Low speed section, 60, 80, 110, 130, 200, 21
0, 500, 510 ... high-speed section, 54, 74, 64, 8
4, 104, 124, 114, 134, 204, 21
4, 404, 414, 505, 515, 704, 714
... Sending signal, 65, 85, 115, 135, 407, 4
17, 707, 717... Received signals, 52, 72, 66,
86, 102, 122, 116, 136, 202, 21
2, 406, 416, 502, 512, 706, 716
... Receiving units 53, 73, 62, 82, 103, 123,
112, 132, 203, 213, 402, 412, 5
03, 513, 702, 712... NNI processing unit, 61,
81, 111, 131, 401, 411, 701, 71
1. High-speed selector section, 67, 87, 117, 137, 4
05, 415, 705, 715: High-speed divider unit, 5
7, 77, 301, 311... Phase control units, 58, 78,
106, 126, 302, 312, 507, 517 ... low speed selector section, 56, 76, 107, 127, 303,
313, 504, 514 ... low-speed divider unit, 55, 7
5, 63, 83, 105, 125, 113, 133, 2
05, 215, 403, 413, 506, 516, 70
3, 713: transmission unit, 142, 152: synchronization pattern detection circuit, 143, 153: synchronization pulse, 144, 154
... address buffer, 145, 155 ... delay memory, 1
48: phase control circuit, 149: reference pulse, 150: read control circuit, 157: B3 arithmetic circuit, 158: PTR detection circuit, 159: selector, 146, 156: selector input signal, 160: output signal.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masamichi Kawagome 216 Totsukacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture

Claims (4)

[Claims] An SD comprising a transmitting device and a receiving device.
In the H network, there is an active transmission line / standby transmission line configured by being connected via two transmission lines having different distances, and selection switching between the active transmission line and the standby transmission line is performed. In a path-uninterruptible switching device that performs the switching of the active transmission line and the standby transmission line without instantaneous interruption in the path instantaneous interruption switching device that implements The low-speed section having the function, the non-interruptible selection switching function and the NNI processing function is constituted by one board, and the high-speed side is constituted by a high-speed section and a low-speed section by a high-speed interface board having the NNI processing function. A path switching device comprising a system. 2. An SD comprising a transmitting device and a receiving device.
In the H network, there is an active transmission line / standby transmission line configured by being connected via two transmission lines having different distances, and selection switching between the active transmission line and the standby transmission line is performed. To realize a system that allows instantaneous interruption to perform switching between the active transmission line and the protection transmission line in a path non-interruptible switching device that performs switching in units of VC paths multiplexed with the main signal A system comprising a low-speed unit having an NNI processing function and a high-speed unit having an NNI processing function. 3. A system section for accommodating a high-speed section and a low-speed section for realizing the above-mentioned first and second aspects, wherein the low-speed section of the first and second aspects is interchangeable. Path switching device. 4. A path switching device according to claim 2, wherein a low-speed interface board and a high-speed interface board can be constituted by the same board in a system section accommodating a high-speed section and a low-speed section.