KR100195063B1 - Ring Alarming Method in Branch Coupling Network of Synchronous Optical Transmission Device - Google Patents

Abstract

The present invention relates to a ring alert method in an ADM network of a synchronous optical transmission device, comprising: initializing nodes (200 to 203) connected to the network; Reading (204) each node from the F1 byte belonging to the interval overhead of a synchronous multiplex frame; Checking (205) the F1 byte to determine an alert; Setting (DMA) and setting a ring alarm bit (RING_ALM_BIT) when the alarm is detected as a result of the determination; If it is determined that the alarm is not detected and the device is in the DMA state, setting the DM2 bypass state to the DMA2BYPASS state and resetting and transmitting the ring alarm bit RING_ALM_BIT; Setting (210, 211) a bypass state when a predetermined time elapses in the DMA2BYPASS state without detecting an alarm as a result of the determination; As a result of the determination, if an alarm is not detected and the master station is a bypass state, the ring alarm bit RING_ALM_BIT is periodically reset and transmitted, otherwise the ring alarm bit RING_ALM_BIT is passed through as it is. To step (213 to 218); And turning on or off the LEDs according to the ring alarm bit RING_ALM_BIT (219 to 226). Therefore, all nodes display the corresponding alarm according to the ring alarm bit to indicate the failure state of the transmission line, thereby facilitating maintenance.

Description

Ring Alert Method in Branch Coupling (ADM) Network of Synchronous Optical Transmission Devices

1 shows a general synchronous multiplexing structure.

2 is an STM-n frame format of a general synchronous digital hierarchy.

(A) of FIG. 3 shows the section overhead (SOH) of the frame format shown in FIG.

(B) of FIG. 3 shows a path overhead (POH) of the frame format shown in FIG.

4 is an example of an ADM ring topology of an optical synchronous transmission apparatus to which the present invention is applied.

5 is an example of a synchronous transmission apparatus to which the present invention is applied.

6 is an operating state diagram according to the present invention.

7 is a flow chart illustrating the flow of processing a ring alert in accordance with the present invention.

* Explanation of symbols for main parts of the drawings

10,20,30,40: Node S: Service Line

P: Reserve Line T: Optical Transmitter

R: Optical receiver 11,21,31,41: Multiplexing device

111: low speed multiplexer switching unit 112: low speed multiplexer

113: high speed multiplexer 114: network node matcher

115: clock supply 116: multiplexing control unit

117: system control unit 118: network control unit

119: mashing line matching unit 120: mashing board

121: Alarm

The present invention relates to a method for generating a ring alert using F1 bytes of section overhead (SOH) in a synchronous optical transmission device.

In general, a synchronous optical transmission device converts an asynchronously multiplexed signal (eg, DS-1, DS-1E) into an optical signal in an optical transmitter and transmits the optical signal to an opposite station through an optical cable, and transmits the optical signal received from the opposite station. The optical receiver converts an electrical signal and then synchronous demultiplexes to output an asynchronous demultiplexed signal. A process of forming an STM-n frame by synchronous multiplexing an asynchronous multiplexed signal is shown in FIG. 1. In FIG. 1, AM denotes an asynchronous multiplexing process, SM denotes a synchronous multiplexing process, and multiplexes in the direction of an arrow to form an STM-n frame. For example, a DS-1 frame is mapped to a box (C: Container) to be C-11, and when a path overhead (POH: path OverHead) is added thereto, it is a virtual container VC-11. When the pointer PTR is added, it becomes the Uributary Unit (TU) TU-11. In addition, TU-11 is grouped into four groups and multiplexed into VC-3 and VC-4 in the form of a hierarchy signal unit group (TUG-2), and three VC-3s are managed through an administrative unit (AU) AU-3. It is multiplexed to become a management unit group (AUG), and SOH is added to it and finally STM-1. At this time, the European DS-1E is mapped to C-12 and then a path overhead (POH) is added to become a virtual box VC-12.

Here, the box (C) is a basic unit constituting the synchronous multiplexing structure, and the existing asynchronous digital hierarchy signals are synchronously multiplexed by being mapped in the corresponding boxes, and correspond to C-1, C-2, C-3, There is C-4, and C-1 is again divided into C-11 to map North American DS-1 and C-12 to map European DS-1E. The virtual box VC is a signal unit for supporting connection between path layers in synchronous transmission, and the level signal unit TU is a lower path layer VC-1, VC-2 and an upper path layer VC-. When the pointer is used to adapt 3, VC-4), the hierarchy signal unit group (TUG) combines one or more hierarchy unit signals (TU) and aligns them with a predetermined position in the upper VC payload space. The management unit (AU) is used as an AU pointer as a signal unit to provide the adaptive function between the upper path layer and the multiplexer section layer, and the management unit group (AUG) combines one or more management unit (AU) signals to pay STM. It is aligned at a fixed position in space.

Figure 2 shows the STM-1 frame format of a typical synchronous digital hierarchy (SDH), which occupies 9 rows and 270 columns for 125 μsec, thus having a transmission rate of 9 x 270 x 8 x 8 Kbps = 155.550 Mbps. . Here, 9x9 bytes are the section overhead (SOH) and AU pointer space, and 9x261 bytes are the payload space. In the 9x9 byte, 3x9 (a) is the player section overhead (RSOH), 1x9 (b) is the AU pointer, and 5x9 (c) is the multiplexer section overhead (MSOH). The payload space may be loaded with one VC-4 or three VC-3s. The VC-3 includes a 9 × 1 path overhead (d: POH).

(A) of FIG. 3 is a section overhead (SOH) of the frame format shown in FIG. 2. Rows 1 to 3 are player section overheads, row 4 is an AU pointer, and rows 5 to 9 are multiplexing sections. Is overhead. In (a) of FIG. 3, the player section overhead is a section overhead (SOH) checked for each player, and 'A1' and 'A2' are frame alignment codes for identifying the boundary of the STM frame, where 'A1' = 11110110, 'A2' = 00101000, 'B1' is Bit Interleaved Parity (BIP) byte for player interval error monitoring, and 'D1, D2, D3' can be used in player interval. As a data communication channel (DCC), the capacity of each channel is 64 Kbps, so the total capacity of the data communication channel between playback apparatuses is 192 Kbps. 'E1' is an orderwire that can be used for voice communication in the player section, F1 is a user channel for a user such as a network operator, and 'X' is a space allocated to be defined and used in each country. .

The multiplexer section overhead (SOH) is a section overhead that is checked for each multiplexer and is transparently passed in the players, and is composed of B2, D4 to D12, E2, K1, K2, Z1, and Z2. 'B2' is bit-bit even number check byte for error detection function of multiplexing section, and 'D4 ~ D12' is data communication channel (DCC) for multiplexer section and total capacity is 576Kbps. 'E2' is a line that can be used for voice communication in the multiplexer section, and 'K1, K2' are assigned for APS as Automatic Protection Switching (APS) channels, and 'K2' is an alarm indication signal (AIS). : It is used for displaying interval maintenance signal such as Alarm Indication Signal and FRP, and Z1 and Z2 are reserved bytes for future use.

The path overhead (POH) includes a high path overhead and a low path overhead. FIG. 3 (b) shows a high path overhead (POH) of the frame format shown in FIG. Path overhead attached to the high-level virtual box, VC-3 and VC-4, located in the first column of VC-3 or VC-4, consisting of J1, B3, C2, G1, F2, H4, Z3 ~ Z5 . 'B3' is the bit shift even check byte for path error monitoring function, 'C2' is the signal label to indicate the configuration of VC-3 / VC-4, and 'F2' is for communication between path devices. 'G1' is a channel for informing the VC-3 / VC-4 sender of the path status and performance at the VC-3 / VC-4 receiver side, and 'H4' is used for multi-frame display of component payloads. Used. The low path overhead is a path overhead (POH) attached to the low virtual box, VC-1 and VC-2, and is denoted as 'V5' as the first byte of VC-11, VC-12 and VC-2. Consists of BIP-2, FEBE, PT, L1 ~ L3, FERF.

The general description of such a synchronous transmission method is described in detail in pages 101 to 234 of the book Broadband Information Communication, which was jointly authored by two other people.

However, when a branch / coupling (ADM) type network is constructed using these synchronous optical transmission devices, a ring alarm is required to indicate when an error occurs in the transmission path on the ring network. Conventionally, an alarm indication signal (AIS) is used. Large-scale alarms, such as), were used, and no ring alarm was provided through the entire ring network.

Accordingly, an object of the present invention is to provide a ring alerting method for informing that a serious failure occurs in a transmission path in an ADM type network composed of a synchronous optical transmission device.

In order to achieve the above object, the present invention provides a network in which nodes composed of optical transmission devices having a synchronous multiplexing function are formed in a ring-shaped double line and then branch / coupled (ADM) type to be connected to the network. Initializing the nodes; Reading, by each node, an F1 byte belonging to a section overhead of a synchronous multiplex frame; Checking the F1 byte to determine an alert; Setting a DMA state and setting a ring alarm bit when an alarm is detected as a result of the determination; Resetting the ring alert bit after transmitting the DMA2BYPASS state if the alert is not detected and the DMA state is determined; Setting the BYPASS state when 18 seconds have elapsed in the DMA2BYPASS without detecting an alarm as a result of the determination; If it is determined that the alarm is not detected and the home station is in the BYPASS state, the ring alarm is periodically reset and transmitted, and if not, the ring alarm bit is passed through as it is; And turning on or off the LED according to the ring alarm bit.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

First, an example of configuring a ring network having four nodes by using the synchronous optical transmission device to which the present invention is applied is as shown in FIG. 4, where the station A 10, the station B 20, and the station C 30 are shown. And D station 40, each station is provided with two optical transceivers and a multiplexer / demultiplexer, and a ring is formed by two lines. In FIG. 2, S denotes a service line currently in use, P denotes a reserve line, and signal transmission directions are in opposite directions to the service line and the reserve line.

That is, the station A 10 multiplexes its own station signal with the relay signal received from the station D 40 through the receiver 13 or from the station B 20 through the receiver 14, and then the transmitter 12. Converts the optical signal to the B station 20 through the service line S, and converts the optical signal into the optical signal from the transmitter 15 to the D station 40 through the reserve line P, respectively. 20) multiplexes the relay signal received from the station A 10 through the receiver 23 or the station signal received from the station C 30 through the receiver 24 and its own station signal, and then converts the transmitter 22 into an optical signal. Then, the service line S is converted to the station C through the service line S, and the transmitter 25 converts the optical signal into the station A via the preliminary line P, respectively. The signal transmission in the station C and the D is the same as the signal transmission in the A and B stations.

In this ring structure, each node is composed of one master station and the other slave stations. All nodes can be equally main stations, and the main station receives the service line (S) and reserves (P) The sending side should be cut off (called S-cut) or the service line (S) transmission, reserve line (P) receiving side should be cut off (called P-cut), and the sub-stations should use the service line (S) and spare Both transmission and reception of line P must be connected.

The synchronous multiplexer to which the present invention is applied (hereinafter, since the multiplexing of the transmission process in the present invention includes demultiplexing in the reception process, multiplexing and demultiplexing are simply referred to as multiplexing) as shown in FIG. Likewise, low speed multiplexer switching unit (LPSB: 111), low speed multiplexer (LSMB: 112), high speed multiplexer (HSMB: 113), network node matcher (MNIB: 114), clock supply (STGB: 115), multiplexing Control unit (CPCB: 116), system control unit (SPCB: 117), network control unit (DCCB: 118), matching line matching unit (OWIB: 119), matching board (TEL: 120), alarm (ALU: 121) The DS-1 or DS-1E, which is an asynchronous multiplexed signal, is converted into an STM-1 signal which is a synchronous multiplexed signal and inversely converted.

In FIG. 5, a clock supplier (STGB) 115 generates and supplies a clock and timing necessary for a system, and a system controller (SPCP) 117 is responsible for controlling and monitoring the entire system, and a network controller (DCCB); 118 accesses the OAM data by the TMN protocol to the parameters of the large station or the remote station and provides communication through the DCC channel. The low speed multiplexer (LSMB) 112 consists of six operation boards and one avi board, so that the synchronous multiplexing / demultiplexing of the DS1 signal is performed as the TUG2 signal, and the high speed multiplexer (HSMB) 113 connects up to 21 TUG signals. Synchronous synchronization / demultiplexing with VC-3 and AUG signals. In addition, the low speed multiplexer switching unit (LPSB) 111 is composed of relays for switching between 7: 1 circuits and 6: 1 boards (or units) to improve the availability and reliability of the service channel. Transfer according to the transfer command of CPCB: 116, and the network node matcher (NNIB) 114 connects the AUG signal to generate and insert a section overhead (SOH) to form an STM-1 signal to connect to the optical device. It also performs a scramble function to facilitate clock recovery. At this time, the network node matching device (NNIB) 114 to which the present invention is applied has a red LED (not shown) attached to the front to display a ring alarm, and a ring alarm is generated due to an abnormality in the transmission line. When generated, this LED is turned on to indicate it. In addition, the hapb matching unit (OWIB) 119 performs a function of connecting the haptic wire to the network through the system control unit 117, a two-wire (2W) interface function, a multi-way call configuration function, call setup internal function, The E1 / E2 selection function and the like are processed, and the alarm 121 processes the alarm according to the control of the system controller 117.

On the other hand, the cyste control unit 117 and the network control unit 118 is connected to the terminal equipped with a graphical user matching (GUI) function, the matching line matching unit 119 is connected to the matching board (TEL), network node matching The device 114 transmits and receives the STM-1 signal to the service line and the reserve line, respectively.

Next, the present invention will be described based on an understanding of the optical transmission device as described above and the branch / coupled ring structure constructed using the same.

FIG. 6 is a state diagram illustrating a transition of operating states according to the present invention, wherein each node constituting the ADM network has a bypass state, a DMA state, and a DM2 bypass in association with a ring alarm operation. It is in one of the (DMA2BYPASS) states.

First, each node constituting ADM network maintains BYPASS state when it is initialized. At this time, the rang alarm bit (RING_ALM_BIT) indicating the alarm status of the corresponding transmission line is reset and the LED located in the NNIB of each node is reset. The ring alarm flag RING_ALM-flag for turning on is also reset, and the LED is turned off.

In this way, when the nodes remain in the bypass state and one node detects an abnormality in the transmission line (e.g., an alarm or fault occurs in the NNIB or the HSMB is a hernia or alarm), the node becomes a DM ( Transition to DMA) and set ring alarm bit (RING_ALM_BIT) to transmit. Other nodes maintain bypass (BYPASS) and if the received ring alarm bit is set, the corresponding NNIB LED is turned on and ring The alarm bit (RING_ALM_BIT) is passed to the next node as it is. At this time, if the mother station is in bypass (BYPASS) state and no alarm is detected, the ring alarm bit RING_ALM_BIT is reset and transmitted at the beginning of every minute (0-15 seconds).

On the other hand, if any node recognizes the alarm release in DMA state, it transitions to DMA2BYPASS state, resets ring alarm bit (RING_ALM_BIT), and transmits, and releases alarm state more than 18 seconds in DMA2BYPASS state. If it does, it goes to BYPASS state. If the alarm is recognized in the DMA2BYPASS state, the state becomes DMA again and the ring alarm bit (RING_ALM_BIT) is set and transmitted.

Here, the ring alarm bit RING_ALM_BIT uses bit 7 of the F1 byte as shown in Table 1 below, and the ring alarm flag RING-ALM-flag is a control bit for turning on or off the LED of the NNIB.

As shown in Table 1, the F1 byte of the section overhead (SOH) indicates that the bit 7 is used as a ring alarm bit. When bit 7 is reset (0), an alarm is released, and when it is set (1), an alarm is generated.

7 is a flowchart illustrating a ring alert processing flow chart according to the present invention, comprising: initializing nodes 200 to 203 connected to a network; Reading (204) each node from the F1 byte belonging to the interval overhead of a synchronous multiplex frame; Inspecting the F1 byte and detecting an error to determine an alarm (205); If it is determined that an alarm is detected, setting to a DMA state and setting and transmitting a ring alarm bit (206); If it is determined that the alarm is not detected and the DMA is in the DMA state, the ring alarm bit RING_ALM_BIT is reset and transmitted (207, 208, 212) after setting to the DMA2 bypass state (DMA2BYPASS); (209, 210, 211) if the alarm is not detected and 18 seconds in the DMA2BYPASS state has elapsed, the BYPASS state is set; Resetting the ring alarm bit (RING_ALM_BIT) periodically if the mother station is in the BYPASS state as a result of the determination, and passing the ring alarm bit (RING_ALM_BIT) as it is without the mother station (213 to 218); And turning on or off the LED according to the ring alarm bit RING_ALM_BIT (219 to 226).

In general, the ADM network is composed of dual (P, S), and accordingly at least two NNIBs are mounted, so ring alarm related operations are performed for each NNIB board.

First, it is determined whether the NNIB board is mounted, and if not mounted, the same process is performed for the next NNIB (200,201).

If the NNIB board is mounted, it is determined whether 10 seconds have elapsed since the initialization of the NNIB (202), and if the 10 seconds have not elapsed, the ring alarm bit (RING_ALM_BIT) is reset and transmitted (203). If 10 seconds have passed since the NNIB board was initialized, it reads the F1 byte and checks for an alarm related bit (bit 7) of the F1 byte and whether there is a hardware error in its system (204). As a result of the inspection, it is determined whether an alarm has occurred (for example, whether there is an alarm or a fault on the NNIB board, or whether there is an alarm after HSMB is dismounted). ) Is transmitted and F1 bytes are transmitted (205, 206). That is, in the embodiment of the present invention, since bit 7 of the F1 byte is used as the ring alert bit (RING_ALM_BIT), it is set to 1 and transmitted.

If an alarm has not occurred, it is determined whether the current state is a DMA state. If the state is a DMA state, the state is set to DMA2BYPASS state (207, 208), and then the ring alarm bit (RING_ALM_BIT) is reset. In case of DMA2BYPASS, it is determined whether DMA2BYPASS is in the DMA2BYPASS state (209). After setting, the ring alarm bit RING_ALM_BIT is reset and transmitted (step 211).

If no alarm occurs and the DMA state is not DMA2BYPASS, it is determined whether it is BYPASS state (213). If it is BYPASS state, it is determined whether it is the home country (215) and it is the home country, and within 15 seconds per minute (0≤sec). ≤ 15) and resets the ring alarm bit (RING_ALM_BIT) and transmits it (217) .If it is not the home country or after 15 seconds per minute, the received ring alarm bit (RING_ALM_BIT) is bypassed (passed) as it is (218). If not in the BYPASS state, it is set to the bypass state (214).

After the above steps are performed, it is subsequently determined whether the received or transmitted ring alarm bit (RING_ALM_BIT) is set (219). If the ring alarm bit (RING_ALM_BIT) is set, the ring alarm flag (RING_ALM_flag) is set (220). Next, when the ring alarm flag RING_ALM_flag is set, the LED is turned on (224, 225). If the ring alarm bit (RING_ALM_BIT) is not set, it is determined whether the ring alarm flag (RING_ALM_flag) is in the reset state (221). If the reset state is turned off, the LED is turned off (226) and the ring alarm flag (RING_ALM_flag) is not in the reset state. It is determined whether 10 seconds have elapsed since the alarm flag RING_ALM_flag has been set (222). If it has passed, the ring alarm flag (RING_ALM_flag) is reset, and when 10 seconds have passed, the LED is turned on according to the ring alarm flag (RING_ALM_flag) (224, 225).

As described above, when a failure occurs in the ADM ring transmission path according to the present invention, the node which detects this is notified to another node by setting and transmitting a ring alert bit (RING_ALM_BIT), and all nodes correspond to the corresponding ring alert bit. By displaying an alarm, there is an effect of making it easy to maintain and display the fault condition of the transmission line.

Claims (3)

In a network in which nodes consisting of optical transmission devices having a synchronous multiplex function form a double line in a ring shape and then operate in a branch / combination (ADM) type, the nodes connected to the network are initialized (200 to 203); Reading (204) each node from the F1 byte belonging to the interval overhead of a synchronous multiplex frame; Checking (205) the F1 byte and its own system to determine an alert; Setting (DMA) and setting a ring alarm bit (RING_ALM_BIT) when the alarm is detected as a result of the determination; If it is determined that the alarm is not detected and the device is in the DMA state, setting the DM2 bypass state to the DMA2BYPASS state and resetting and transmitting the ring alarm bit RING_ALM_BIT; Setting (210, 211) a bypass state when a predetermined time elapses in the DMA2BYPASS state without detecting an alarm as a result of the determination; If it is determined that the alarm is not detected and the master station is in the bypass state, the ring alarm bit RING_ALM_BIT is periodically reset and transmitted, and if not, the ring alarm bit RING_ALM_BIT is passed as it is. (213-218); And turning on or off the LEDs according to the ring alarm bit (RING_ALM_BIT) (219-226). The method of claim 1, wherein the step of periodically resetting the ring alarm bit RING_ALM_BIT by the mother station resets the ring alarm bit RING_ALM_BIT within 15 seconds per minute, and thereafter passes the received ring alarm bit RING_ALM_BIT as it is. Ring alarming method in branch coupling (ADM) network of synchronous optical transmission device. The method of claim 1, wherein the step of turning on or off the LED sets or resets the ring alarm flag RING_ALM_flag according to a ring alarm bit RING_ALM_BIT, and sets the LED according to the set or reset state of the ring alarm flag RING_ALM_flag. A ring alarming method in a branched coupling (ADM) network of a synchronous optical transmission device, characterized in that the light is turned on or off.