CN1477796A - Protection method and device for electrical interface unit of synchronous transfer module - Google Patents

Abstract

The invention discloses a method for protecting the electrical interface unit of a synchronous transmission module. The method comprises: the system judges whether there is a failure of the working board according to the request signal output from each working board and the protection board, and if so, sends the All services on the signal processing board of the faulty working board are switched to the signal processing board of the protection board for processing; otherwise, each board continues normal signal processing. The present invention also discloses a device for realizing the above method at the same time, which includes a protection switching processing module, and the protection switching processing module further includes a branch protection receiving board, a branch protection sending board and a cross board, and each board has a A field programmable gate array (FPGA) chip is used to complete the processing of protection switching logic. The method and device can improve the receiving sensitivity of the coaxial cable and greatly reduce the protection switching time.

Description

Protection method and device for electrical interface unit of synchronous transfer module

technical field

The invention relates to a self-healing protection technology of a Synchronous Digital Hierarchy (SDH) network, in particular to a method and a device for protecting an electrical interface unit of a synchronous transmission module.

Background technique

SDH network has high transmission rate and large capacity, so we must pay full attention to its survivability. The solution to this problem is to adopt 1+1 or 1+n backup protection for important units of equipment and optical fiber lines, and to perform protection switching on network routes. Self-healing is the most prominent requirement of a survivable network. The so-called self-healing refers to the ability of the network to automatically switch to an alternative route, reconfigure services, and maintain communication for some local failures without human intervention.

With the extensive application of Synchronous Transport Module (STM) electrical interface boards in SDH transmission products, it is necessary to quickly and reliably protect the electrical interface boards. In the existing first-level STM (STM-1) electrical interface protection technology, the general application method is 1:n protection, that is, there are n working board positions and 1 protection board position in the system. When damaged, the single board on the working board handles important services, and the single board on the protection board handles unimportant services. When a single board of a working board fails, the system transfers the business of the working board to the single board of the protection board for processing, and the unimportant business on the protection board stops processing.

Referring to FIG. 1 , FIG. 1 is a schematic diagram of using relays in the electrical interface unit of the synchronous transmission module to complete protection switching logic processing. As shown in the figure, there are four working boards, one protection board, one main control board and one electrical interface protection switching board (EPS). There are five relays C1~C5 on the EPS board, of which C1, C2, C3, C4 They correspond to working board 1, working board 2, working board 3, and working board 4 respectively, and C5 corresponds to the protection board. The 155Mbit/s STM-1 signal is transmitted on the 75-ohm coaxial cable. In the normal state, that is, when there is no single board failure, the business is transmitted according to the solid line in Figure 1. If the working board 1 fails, the relay The working status of C1 changes, and the business originally processed on the working board 1 is transferred to the protection board for processing along the path shown by the dotted line in Figure 1. The business originally processed on the protection board is cut off, and the business on the working board 1 is thus be protected.

In the prior art, the protection switching is completed by the relay. Since the switching time of the relay can be as long as tens or even hundreds of ms, the switching time is too long, which leads to a long service interruption time; in addition, the signal attenuation of the EPS board Too large, because the signal cannot be reproduced on the EPS board, and the final result is that the signal reaches the receiving chip on the working board after the attenuation of the EPS board and the working board, which leads to the coaxial cable, one of the test indicators of the electrical interface of the synchronous transmission module. The receiving sensitivity is not enough.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a protection method for the electrical interface unit of the synchronous transmission module, so as to shorten the protection switching time and improve the switching efficiency.

Another object of the present invention is to provide a device for realizing the protection of the electrical interface unit of the synchronous transmission module, which can shorten the protection switching time and improve the receiving sensitivity of the coaxial cable.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

A protection method for an electrical interface unit of a synchronous transfer module, characterized in that: the system judges whether any working board is faulty according to the request signal output from each working board and protection board, and if so, the faulty working board will be All services on the signal processing board at the protection board are switched to the signal processing board at the protection board for processing; otherwise, each board continues normal signal processing.

The method further includes:

A. The system performs logical processing according to the request signal output from the working board position and the protection board position, determines the faulty working board position, and generates a decoding signal;

B. According to the decoding signal generated in step A, switch the synchronous transfer module (STM) signal sent from the electrical interface lead-out board of the faulty working board to the protection board for processing, and then broadcast the processed STM signal to n working board positions;

C. The n working board positions select according to the current state of their own broadcast selection signals to send the STM signal broadcasted from the protection board position to the electrical interface lead-out board of the faulty working board position.

The present invention also provides a device for implementing the above protection method, which is used to control the protection switching between the working board position and the protection board position, and each working board position and protection board position are composed of a signal processing board and an electrical interface lead-out board , the key lies in: including a protection switching processing module, connected to a protection board position and at least one working board position, the broadcast selection signal Si output by the protection switching processing module is respectively connected to the electrical interface lead-out board of the protection board position and each working board position The input broadcast selection signal is connected in one-to-one correspondence, the output transmission signal Ti is connected in one-to-one correspondence with the transmission signal input by the electrical interface lead-out board in each working board position, and the output receiving signal Rp is connected to the electrical interface lead-out board in the protection board position The input receiving signal; the request signal REQi output by the signal processing board in the protection board position and each working board position is respectively connected to the protection switching processing board, and the receiving signal R _i output by the electrical interface lead-out board in each working board position is respectively input The protection switching processing board, the transmission signal Tp output by the protection board is directly input to the protection switching processing board.

The protection switching processing module further includes a branch protection receiving board, a branch protection sending board, and a cross board; the request signal REQi output by the signal processing board in the protection board position and each working board position is directly input into the cross board, and the broadcast signal output by the cross board The selection signal Si is respectively input to the protection board position and the electrical interface lead-out board in each working board position, and the decoding signal output by the cross board is connected to the input of the branch protection receiving board; the receiving signal Rp output by the branch protection receiving board is directly input The electrical interface lead-out board in the protection board position, the receiving signal R _i output by the electrical interface lead-out board in each working board position is respectively input into the branch protection receiving board; the sending signal Tp output by the protection board position is directly input into the branch protection sending board , the branch protects the transmission signal Ti output by the transmission board to be directly connected to the electrical interface lead-out board in each working board position.

The branch protection receiving board, the branch protection sending board and the cross board are respectively provided with a Field Programmable Gate Array (FPGA) chip for processing protection switching logic.

Because the present invention cancels the EPS protection switching board and the relay switching logic, adopts the branch protection receiving board, the branch protection sending board and the cross board, and realizes the protection switching logic in the very fast FPGA chip, thereby improving the coaxial cable The receiving sensitivity greatly reduces the protection switching time.

Description of drawings

Fig. 1 is a schematic diagram of using relays to complete protection switching logic processing in the electrical interface unit of the synchronous transmission module.

FIG. 2 is a schematic diagram of a protection switching logic process implemented by using a field programmable gate array (FPGA) in the electrical interface unit of the synchronous transmission module.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to FIG. 2 , FIG. 2 is a schematic diagram of the protection switching logic processing implemented by using FPGA in the electrical interface unit of the synchronous transmission module. It can be seen from the figure that the protection board position 201 and each working board position 202 are composed of an STM-1 signal processing board and an STM-1 electrical interface lead-out board. This embodiment uses 8-way STM-1 signal processing boards SP08 and 8 STM-1 electrical interface lead-out board EU08. In this embodiment, the protection switching processing module of the present invention is composed of a tributary protection transmitting board (TPT) 203, a tributary protection receiving board (TPR) 204 and a cross-connect board (XCS) 205. The protection board position 201 is connected with n working board positions 202 . Among them, the TPT board is connected to the EU08 board at the protection board position through the Tp terminal, the TPT board is connected to the n EU08 boards at the working board position through T1~Tn terminals respectively, the TPR board is connected to the EU08 board at the protection board position through the Rp terminal, and the TPR board is connected to the EU08 board at the protection board position through the Rp terminal. The board and the n pieces of EU08 boards on the working board are connected through the R1 ~ Rn terminals respectively, the XCS board is connected to the SP08 board on the protection board through the REQp terminal, and the XCS board is connected to the n SP08 boards on the working board through the REQ1 ~ REQn terminals respectively . There is an FPGA chip on the TPT board, TPR board, and XCS board respectively. When the working board fails, the system will switch the services of the working board to the protection board. The protection switching logic processing is performed by the TPT board, TPR Board and the FPGA chip on the XCS board are completed together. What needs to be pointed out here is that the working board is composed of one EU08 board and one SP08 board. A failure of the working board means that the SP08 board is faulty, but the EU08 board is not faulty and is still in a normal state.

Usually, the 155Mbit/s STM-1 signal pattern transmitted on the external coaxial cable is Mark Inversion Code (CMI). The 155Mbit/s STM-1 signal is transmitted to the EU08 board located on the working board for processing. The EU08 board converts the CMI code into a unipolar non-return-to-zero code (NRZ) and then sends it to the SP08 board for processing. Back to the EU08 board, the EU08 board converts the NRZ code into a CMI code and sends the signal through the coaxial cable from the transmitting end T; at the protection board position, the EU08 board and the SP08 board are connected normally, and some unimportant services can be transmitted. Under normal conditions, no matter in the working board position or the protection board position, the receiving data and sending data in the EU08 board are transmitted in the direction indicated by the bold arrow in Figure 2. At this time, the branch protection receiving board and the branch protection sending No processing is done for boards and cross boards.

In an abnormal state, that is, when a single board fails, the system switches the services of the faulty SP08 board on the working board to the SP08 board on the protection board for processing. Between the protection board and the faulty working board, EU08 The receiving data and sending data in the board are transmitted in the direction indicated by the linear arrow in Figure 2.

When the system is working, the board position indication signals on the n+1 EU08 boards shown in Figure 2 are Xp, X1~Xn respectively, and they indicate the current working status of the board. For example, when Xp is 1, it indicates that the board is currently It is in the working board position. When X1~Xn are 0, it indicates that the board is currently in the protection board position. Each SP08 board outputs a REQ signal, among which the SP08 board located at the protection board position outputs REQp, and the n SP08 boards located at the working board position output REQ1~REQn respectively, and these REQ signals are output to the FPGA chip on the XCS board. Then, the specific protection switching process of the present invention under the abnormal state is as follows: the FPGA chip judges whether there is a SP08 board to break down according to the REQ signal state, if there is no SP08 board to break down, then do not process; if it is found that there is an SP08 board If a fault occurs, the FPGA chip on the XCS board outputs C1, C2, and C3 decoding signals to the FPGA chip on the TPR board, and at the same time outputs the Sp signal to the EU08 board on the protection board, and outputs the S1~Sn signals to the protection board respectively. n EU08 boards, to indicate whether the current EU08 board needs to be bridged. Among them, the values of C1, C2, and C3 signals are combined into a three-bit binary number, which can indicate which SP08 board at the working board position is faulty. In fact, the number of digits of the decoding signal is the same as the current working board position. The number is related, and in the present embodiment it is assumed that there are at most 8 working board positions, so only three bits are used. The n pieces of EU08 boards in the working board position divide the 155Mbit/s STM-1 signal received from the R terminal into two channels, one is sent to the SP08 board in the working board position, and the other is sent to the FPGA chip on the TPR board. The FPGA chip on the TPR board selects a signal sent from the faulty SP08 board from the 155Mbit/s STM-1 signals of the R1~Rn road according to the values of the C1, C2, and C3 signals sent from the XCS board. And transmit it to the EU08 board at the protection board position through the Rp terminal. After receiving the 155Mbit/s STM-1 signal transmitted from the Rp terminal, the EU08 board sends it to the SP08 board at the protection board position for processing and then returns The EU08 board to the protection board position is then transferred to the TPT board through the Tp terminal. The TPT board broadcasts the STM-1 signal transmitted from the Tp terminal to the n pieces of EU08 boards in the working board position through the T1 ~ Tn terminals, and the n pieces of EU08 boards in the working board position are selected according to the broadcast selection signals S1 ~ Sn sent from the XCS board Determine which EU08 board the 155Mbit/s STM-1 signal is sent from. When the broadcast selection signal S1~Sn appears "1" state, the EU08 board corresponding to the working board position will be bridged, and the 155Mbit broadcast from the TPT board will be bridged. /s STM-1 signal is sent out; when the state of "0" appears in the broadcast selection signal S1~Sn, the EU08 board corresponding to the working board will send the signal under normal state.

Still referring to Fig. 2, in the normal communication process, the SP08 board of the protection board position and each working board position sends request signals REQp, REQ1～REQn to the XCS board 205; The 155Mbit/s STM-1 signal received by the terminal is divided into two paths, one path is sent to the SP08 board at the working board position, and the other path is sent to the FPGA chip on the TPR board 204. When the SP08 board of the working board position 1 breaks down, the realization process of the protection switching of the present invention is: the FPGA chip on the XCS board 205 performs logical processing on the input REQp, REQ1～REQn signals, and finds the REQ1 corresponding to the working board position 1 After the signal is not normal, the value of the output decoding signal C1C2C3 is 000, indicating that the SP08 board located at the working board position 1 is faulty; the FPGA chip on the TPR board 204 is based on the value of the decoding signal C1C2C3 (000) sent from the XCS board. , from R1～Rn 155Mbit/s STM-1 signals, select one signal R1 transmitted from the SP08 board that has failed, and transmit it to the EU08 board at the protection board position through the Rp terminal, and the EU08 board receives After the 155Mbit/sSTM-1 signal transmitted from the Rp end, it is sent to the SP08 board of the protection board for processing and then returned to the EU08 board of the protection board, and then transmitted to the TPT board 203 through the Tp end. The TPT board 203 broadcasts the STM-1 signal received from the Tp terminal to the n pieces of EU08 boards in the working board position through the T1~Tn terminals, and the n pieces of EU08 boards in the working board position are selected according to the broadcast selection signal S1 sent from the XCS board 205 ～Sn decides which EU08 board the 155Mbit/sSTM-1 signal is sent out from. Bridge, to send out the 155Mbit/s STM-1 signal broadcast from the TPT board 203; and the state of the broadcast selection signals S2~Sn of the EU08 board on the other working boards is "0", so the EU08 corresponding to the working board The board performs signal transmission under normal conditions.

In a word, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (5)

1. A protection method for the electrical interface unit of a synchronous transmission module, characterized in that: the system judges whether there is a fault in the working board according to the request signal output from each working board and the protection board, and if so, it will fail All services on the signal processing board of the working board are switched to the signal processing board of the protection board for processing; otherwise, each board continues normal signal processing. 2. The protection method according to claim 1, characterized in that the method further comprises: A. The system performs logical processing according to the request signal output from the working board position and the protection board position, determines the faulty working board position, and generates a decoding signal; B. According to the decoding signal generated in step A, switch the synchronous transfer module (STM) signal sent from the electrical interface lead-out board of the faulty working board to the protection board for processing, and then broadcast the processed STM signal to n working board positions; C. The n working board positions select according to the current state of their own broadcast selection signals to send the STM signal broadcasted from the protection board position to the electrical interface lead-out board of the faulty working board position. 3. A device for realizing the above protection method, which is used to control the protection switching between the working board position and the protection board position. Each working board position and protection board position are composed of a signal processing board and an electrical interface lead-out board. Its characteristics It consists in: including a protection switch processing module, connected to a protection board position and at least one working board position, and the broadcast selection signal Si output by the protection switching processing module is respectively connected with the electrical interface lead-out board input of the protection board position and each working board position The broadcast selection signals are connected in one-to-one correspondence, and the output transmission signal Ti is connected in one-to-one correspondence with the transmission signal input by the electrical interface lead-out board in each working board position, and the output receiving signal Rp is connected to the input of the electrical interface lead-out board in the protection board position. Receiving signal; the request signal REQi output by the signal processing board in the protection board position and each working board position is respectively connected to the protection switching processing board, and the receiving signal R _i output by the electrical interface lead-out board in each working board position is input into the protection board respectively. The processing board is switched, and the transmission signal Tp output by the protection board is directly input to the protection switching processing board. 4. The device according to claim 3, characterized in that: the protection switching processing module further includes a branch protection receiving board, a branch protection sending board and a cross board; The request signal REQi output by the processing board is directly input to the cross-connect board, the broadcast selection signal Si output by the cross-connect board is respectively input to the protection board position and the electrical interface lead-out board in each working board position, and the decoding signal output by the cross-connect board is connected to the branch circuit protection The input of the receiving board; the receiving signal Rp output by the branch circuit protection receiving board is directly input to the electrical interface lead-out board in the protection board position, and the receiving signal R _i output by the electrical interface leading-out board in each working board position is respectively input to the branch circuit protection receiver board; the transmission signal Tp output by the protection board is directly input to the branch protection transmission board, and the transmission signal Ti output by the branch protection transmission board is directly connected to the electrical interface lead-out board in each working board position. 5. The device according to claim 4, characterized in that: said branch protection receiving board, branch protection sending board and cross board are respectively provided with a field programmable gate array (FPG) for processing protection switching logic FPGA) chip.

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