KR100332417B1 - Apparatus for detecting STM-16 frame pattern - Google Patents

Abstract

The present invention provides an apparatus for detecting an STM-16 frame pattern, comprising: a 32 latch unit for inputting, latching, and outputting four frame bytes from one channel and sixteen channels constituting each STM-16 frame data; A pattern comparing unit which compares four frame bytes inputted from the 32 latching unit with normal pattern values of the corresponding frame byte to determine whether the frame is a normal or abnormal frame, and outputs a result value; A frame counter for counting and outputting a continuous value of a normal frame or abnormal frame comparison result input from the pattern comparison unit; The alarm declaring unit which declares or releases an alarm according to a normal or abnormal frame count value output from the frame counter enables the latch to be checked by checking only 4 bytes at a predetermined position without checking every byte of the STM-16 frame. This reduces the amount of data that needs to be done, reduces the number of gates in the detector, and reduces overall power consumption.

Description

Apparatus for detecting STM-16 frame pattern}

The present invention relates to a STM-16 (Synchronous Transport Module level 16) frame pattern detecting apparatus, and in particular, ITU-T (International Telecommunications Union, Telecommunication Sector, International Telecommunications Union) Communication standardization section) uses the STM-16 frame detector to check whether the normal frame structure has been delivered, and when determining whether to generate an alarm accordingly, only 4 bytes of the predetermined position are checked. The present invention relates to an STM-16 frame pattern detection device capable of reducing the amount of gates while reducing the number of corresponding gates and reducing the overall power consumption.

The STM-16 frame pattern detecting apparatus to which the present invention is applied is configured to process the corresponding unique function of the overhead by accurately detecting and analyzing an overhead portion of the transmitted data for smooth data transmission between optical communication networks. A device for finding a unique position of.

In general optical network construction, one of the standard connections by data transmission is SDH (Synchronous Digital Hierarchy), which is a digital data transmission by a new standard that transmits signals for communication using a payload. It is a set of ranks. One type of data rate standardized and used in this hierarchy is STM-16.

2 is a structural diagram of a general STM-N frame.

Referring to FIG. 2, the transmitted STM-N frame data is divided into a section overhead (SOH) area and a payload or user area (payload). That is, the position of the SOH byte in the STM-N frame is defined by three vectors S (a, b, c), where a (1 to 3, 5 to 9) represents the number of columns, and b (1 to 9) It represents the number of multiple rows, and c (1 to N) represents the depth in multiple rows.

3 is a structural diagram of a general STM-16 frame.

Referring to FIG. 3, the SOH of the STM-16 frame is A1, A1,... , A1, A2, A2,... , A2, J0, Z0, Z0, X, X,... Composed of bytes of X, where the Framing Byte is a portion denoted by a number of A1 or A2. The plurality of A1 and A2 bytes have already been used, and the X byte is a national use byte, which is a byte allocated for use by a country-specific purpose in data transmission. The above X bytes are not used and may be transmitted by filling in an arbitrary value.

4 is an enlarged structure of a frame byte in FIG.

Referring to FIG. 4, in the SOH structure, A1, A1,... , A1, A2, A2,... When the value of A2 byte is expanded, A1 byte becomes F6 (HEXA), and A2 byte becomes 28 (HEXA). That is, the size occupied by all of the plurality of A1 and A2 bytes in one STM-16 frame is 48 bytes. The value of the A1 byte is F6 (HEXA) / 11110110 (binary), and the value of the A2 byte is 28 (HEXA) / 00101000 (binary).

In the structure of the STM-16 frame data, A1 and A2 are defined as frame bytes, and other bytes are not fixed in their values. Therefore, the normal transmission of the frame is confirmed with only the frame bytes A1 and A2.

When a total of 96 bytes (96 x 8 bits) are normally transmitted on one frame, the structure of one frame (125us) is normally transmitted, that is, the portion occupied by the frame bytes of A1 and A2 in the structure of STM-16 data is fixed. This is because the data of the STM-16 capacity is substantially transmitted serially one bit over the optical cable, but the data rate is 2.48832 Gbps, so the ASIC It is difficult to process a data signal at the bit rate (= 2.48832 Gbps) inside an Applicable Specific Integrated Circuit. Therefore, in order to facilitate internal processing in an ASIC, data is divided into 19.44 Mbps. The frequency division divides 2.48832 Gbps serial data input through the optical receiver into 1:16, converts it into an electrical signal of 155.52 Mbps, and implements it. . Is applied to the input of the ASIC to the character data of 155.52 Mbps is then 1 to the internal processing received as input to the ASIC: 19.44 Mbps is converted into data of a transmission rate which is easy to handle through the 8 Demux process.

Fig. 5 is a structural diagram of 8-bit parallel data in general 19.44Mbps processing.

Referring to FIG. 5, the Out Of Frame state is generated from the viewpoint of monitoring control for normal operation when five or more consecutive frames are delivered, that is, the positions of A1 and A2 are not constant positions, When the value indicates something other than F6, 28. The occurrence condition of Los Of Frame refers to when the time is longer (3ms / 24 frames) than Out Of Frame. The state of In Frame indicates that a frame structure in a normal state is being transmitted, not occurrence of Out Of Frame or Los Of Frame. The measurement time is 250us (2 frames continuous).

6 is a block diagram of a conventional STM-16 frame pattern detecting apparatus, and FIG. 7 is a detailed block diagram of the 768 latch unit in FIG.

6 and 7, the 768 latch unit 31 for latching STM-16 frame data of 16 channel capacity six times; A pattern comparison unit (32) for comparing the F628 (HEXA) pattern with 768 data, which are all framing bytes latched by the 768 latch unit (31); A frame counter (33) which stores the result of the frame counter compared by the pattern comparison section (32); The alarm declaration unit 34 is configured to perform alarm declaration / cancellation related to a frame according to the number of frames stored in the frame counter 33.

Referring to the operation of the conventional device configured as described above in detail as follows.

In order to confirm that the STM-16 frame structure is normally transmitted, every frame byte included in the frame should be examined every frame 125us.

In order to examine all the framing bytes in each frame, since the data processing bit rate is 19.44 Mbps, six latches are required for each bit of the 19.44 Mbps data arranged as shown in FIG. That is, in FIG. 7, six latches 41 to 46 are required for channels 1 to 16 to simultaneously check the first to third F6 values and the first to third 28 values of the channel. .

Therefore, a total of 16 (channel) × 8 (bit) × 6 latches = 768 latches are required. That is, the 768 latch unit 31 latches all 96 bytes corresponding to the frame byte in one frame.

The data latched by the 768 latch unit 31 respectively examines the frame byte at the corresponding position. The number of latches corresponding to one channel is 8 bits x 6 latches = 48 latches. The number of latches required to check all 16 channels is 768 latches, and the frame pattern detector is configured by the 768 latches. Will be.

In this way, the 768 latch unit 31 measures the latched value, and the pattern comparison unit 32 compares the value with the normal case of the In frame state. When the abnormal number of frames is counted by the frame counter 33, the alarm declaration unit 34 determines whether the frames are normally delivered according to the number of frames counted.

If it is declared as a normal frame in the alarm declaration unit 34 with the result of the above test, it is declared as In Frame when two frames (250us) are normally normal, and when an incorrect frame is input for more than five frames (625us), it is declared as Out Of Frame. . If Out Of Frame lasts more than 24 consecutive frames (3ms), it is declared as Loss Of Frame. Each frame, when transmitted normally, has a form that includes frame bytes. And one frame has a cycle of 125us.

However, the above-described conventional technique analyzes all framing bytes to determine whether frames are normally delivered, and thus results of analysis of abnormality caused by an error of only one bit among framing bytes regardless of whether data payload is normally transmitted. By determining the damage or error of the entire frame, and also latching all the framing bytes, the number of gates (Gate) is increased a lot of heat generation, causing the performance degradation of the ASIC there was.

The present invention has been proposed to solve the above-mentioned conventional problems, and confirms whether the frame data having a structure specified on the ITU-T is normally transmitted through the STM-16 frame pattern detector when transmitting the STM-16 frame data. When checking whether or not an alarm is generated accordingly, by checking and latching only 4 bytes at a predetermined position without checking all the frame bytes, the amount of data to be processed is reduced, the number of gates required and the total power consumption are reduced. It is an object of the present invention to provide an STM-16 frame pattern detection apparatus that can be reduced.

In order to achieve the above object, STM-16 frame pattern detection apparatus according to the present invention,

A latch unit for inputting, latching, and outputting four frame bytes from one channel and sixteen channels constituting each STM-16 frame data; A pattern comparing unit which compares four frame bytes inputted from the latch unit with normal pattern values of the corresponding frame byte to determine whether the frame is a normal or abnormal frame, and outputs a result value; A frame counter for counting and outputting a continuous value of a normal frame or abnormal frame comparison result input from the pattern comparison unit; The technical configuration is characterized by consisting of an alarm declaration unit for declaring or releasing an alarm by the normal or abnormal frame count value output from the frame counter.

1 is a block diagram of a general optical transmission equipment,

2 is a structural diagram of a general STM-N frame,

3 is a structural diagram of a general STM-16 frame,

4 is an enlarged structure of a frame byte in FIG.

5 is a structural diagram of 8-bit parallel data in general 19.44 Mbps processing;

6 is a block diagram of a conventional STM-16 frame pattern detection apparatus,

7 is a detailed block diagram of the 768 latch unit in FIG. 6;

8 is a block diagram of an STM-16 frame pattern detecting apparatus according to the present invention;

9 is a detailed block diagram of the 32 latch unit in FIG. 8;

FIG. 10 is a detailed block diagram of a frame counter in FIG.

Explanation of symbols on the main parts of the drawings

51: 32 latch portion 52: pattern comparison portion

53: frame counter 54: alarm declaration unit

Hereinafter, an embodiment according to the technical spirit of the present invention STM-16 frame pattern detection apparatus as follows.

FIG. 8 is a block diagram of the STM-16 frame pattern detecting apparatus according to the present invention. FIG. 9 is a detailed block diagram of the 32 latch unit in FIG. 8, and FIG. 10 is a detailed block diagram of the frame counter in FIG.

As shown in FIG. 8, a 32 latch unit 51 for inputting, latching, and outputting four frame bytes from one channel and 16 channels constituting each STM-16 frame data; A pattern comparison unit 52 which compares four frame bytes inputted from 51 and normal pattern values of the corresponding frame bytes, respectively, and determines whether the frame is a normal or abnormal frame, and outputs a result value; A frame counter 53 for counting and outputting a continuous value of a normal frame or abnormal frame comparison result inputted from the frame counter; and an alarm declaration for declaring or releasing an alarm based on a normal or abnormal frame count value output from the frame counter 53. It consists of a part 54.

In the above, the 32 latch unit 51 detects and latches the first and 49th frame bytes of the first channel and the 48th and 96th frame bytes of the 16th channel from the STM-16 frame data.

Referring to the STM-16 frame pattern detection apparatus according to the present invention configured as described above in detail with reference to the accompanying drawings as follows.

A general optical transmission device will be described with reference to FIG. 1.

Reference numerals 10 and 20 of FIG. 1 are optical transmission apparatuses for transmitting and receiving optical signals in units of frames, 21 is a block for aligning frame signals, and 22 is a frame pattern of the STM-16 from frame aligned data. STM-16 frame pattern detection unit for detecting, 23 is a block to declare a frame alarm when an error occurs by analyzing the detected frame pattern, 24 is to check the error (error) from the signal detected the frame pattern and section communication It is a block that performs the function, the auto-protection switching function, and the pruning line function, and 25 is a demultiplexer.

As shown in FIG. 1, when two optical transmission apparatuses 10 and 20 of A and B are connected, the transmitted data undergoes a frame alignment process and checks whether a predetermined byte is a normal value from the aligned frame data. In the alarm declaration section, the alarm associated with the frame is declared. The overheads are inherent to the error check (B1, B2), section communication (DCC1, DCC2), auto-protection switching (K1, K2), and tripping line (E1, E2: section 1: 1 communication). It will play a role.

In order to play this unique role, it is important to know the location of each byte correctly. This role of positioning can be performed by checking the frame alignment bytes A1 and A2. Here, DCC1, DCC2 and E1, E2 are different in software communication and hardware communication (operator voice). In addition, each overhead plays a unique role, and the payload, which is a portion corresponding to the actual data, is composed of low bit rate data through a demux process.

The present invention is used to determine whether data used in a network constructed by an optical communication system normally transmits a corresponding structure, and is used in general optical communication network configuration.

A detailed configuration of the STM-16 frame pattern detection unit 22 shown in FIG. 1 will be described with reference to FIG. 8. The data transmitted through the optical cable is reframed by the frame alignment block 21. The frame data byte of each channel transmitted by the reframe is aligned. Among the aligned frame bytes, the 32 latch unit 51 latches 4 byte data values of 1 channel and 16 channels to be detected and measured. Then, the pattern comparison unit 52 confirms whether the latched four byte values coincide with the normal byte values. In other words, it is checked whether or not data composed of normal STM-16 frames is transmitted. [0057] The frame counter 2 for inputting a result of comparing a value of a byte input by the pattern comparing unit 52 with a value of a normal byte 2 (5/24) 53 to determine the alarm state.

Referring to FIG. 9, a detailed configuration diagram of the 32 latching unit 51 and the pattern comparing unit 32 shown in FIG. 8 is provided. It detects and analyzes four bytes. That is, from the STM-16 frame data structure consisting of 16 channel data of 19.44Mbps, the first and 49th byte data of one channel and the 48th and 96th byte data of 16 channels are latched.

That is, among the 96 frame bytes of the frame data constituting the first channel, F6 data of the first byte and 28 data of the 49th byte are latched to the latches 61 to 63, and the pattern comparison unit 71 is latched. The 16th channel latches the F6 data of the 48th byte and the 28th data of the 96th byte in the latches (64 to 66) in the 16th channel, and the pattern comparison unit 72 By comparing the same with the normal pattern.

As described above, the four bytes to be checked must be checked at the same time. That is, the result of latching 8-bit parallel data twice for each of the two channels (once shifted in synchronization with one clock) is examined, which means a total of 8 bits x 2 latches x 2 channels = 64 latches are required, such as 64.

The pattern comparison unit 52 or 71 or 72 determines whether the latched frame byte value is 1st = F6, 48th = F6, 49th = 28, 96th = 28. At this time, the latched values of the four bytes are simultaneously determined. If the four bytes are normally transmitted, it is determined that the corresponding STM-16 frame data is normally delivered. With the result of the error transmission determination in the frame unit as described above, it is determined whether the alarm is established by counting the frame counter 53 for a predetermined period of time.

The types of alarms based on the above error determination on a frame basis are as follows.

Out Of Frame: 625us (Continuous transmission error for 5 frames)

Los Of Frame: 3ns (Continuous transmission error for 24 frames)

In Of Frame: Continuous normal transmission for 2 frames

The alarm type as described above is determined by counting errors in units of frames by the frame counter 53 shown in detail in FIG. 10.

The frame counter 53 is a frame unit cycle, which is a counter that repeats for a predetermined period (125us), and consists of three types of counters: 2 counters, 5 counters, and 24 counters. For example, the frame is stored in a frame counter for periodic simultaneous checks. For example, the stored frame is an error. When an abnormal frame accumulates 5 or more consecutively, OOF is declared and when 24 or more accumulates, LOF is accumulated. Is declared. The release of the OOF is when two normal frames are transmitted, and the LOF is released when the normal frames are continuously transmitted over 24 frames. That is, the frame counter 53 is used to declare / release the alarm associated with the frame.

That is, the two frame counter 81 is used for counting normal frames, the five frame counter 82 is used for OOF declaration by successive abnormal frames, and the 24 frame counter 83 is LOF due to the accumulation of OOF. The 24 frame counter 84 is used to release the LOF by accumulating normal frames.

The present invention having the above-described configuration reduces the amount of data to be latched by checking only four bytes of a predetermined position without checking every byte constituting the frame byte.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the STM-16 frame pattern detection apparatus according to the present invention does not check all the frame bytes (96 bytes), but checks only four bytes at a predetermined position, so that the amount of data to be latched is small. This results in industrial utilization that reduces the overall gate of the ASIC and reduces the overall power consumption.

Claims (2)

A latch unit for inputting, latching, and outputting four frame bytes from one channel and sixteen channels constituting each STM-16 frame data; A pattern comparing unit which compares four frame bytes inputted from the latch unit with normal pattern values of the corresponding frame byte to determine whether the frame is a normal or abnormal frame, and outputs a result value; A frame counter for counting and outputting a continuous value of a normal frame or abnormal frame comparison result input from the pattern comparison unit; And an alarm declaration unit for declaring or releasing an alarm based on a normal or abnormal frame count value output from the frame counter. The method of claim 1, wherein the latch unit, An STM-16 frame pattern detection apparatus, characterized by detecting and latching the first and 49th frame bytes of the first channel and the 48th and 96th frame bytes of the 16th channel from the STM-16 frame data.