KR100350245B1 - Method for discriminating data of switching system - Google Patents

Abstract

PURPOSE: A method for discriminating data of a switching system is provided to prevent the disconnection of a user message by reconstructing the user message with means of data frames received at an upper layer. CONSTITUTION: Where the transmission of a user message in a switching system is required, a control field for discriminating between a specific pattern being transmitted to a physical link and general data of the user message is contained in a unit frame and transmitted(30-56). Where the unit frame containing the control field, restoring the general data of the user message from the received unit frame. The control field uses 2 bits among bits of a field, which stores a block number in the unit frame. The specific pattern is a pattern of E916.

Description

How to distinguish data in the exchange system.

The present invention relates to an exchange system, and more particularly, to a method for distinguishing a specific pattern used for data transmission and general data of the same pattern included in a user message.

In general, a switching system uses a BCH chip device driver for data transmission between switching devices forming a network. The BCH chip device drive (hereinafter referred to as a BCH drive) is used to synchronize synchronization between two exchange periods in which data is exchanged while distinguishing a user's data transfer state and an idle state that are useful on a physical link. Use a specific pattern called 'E916'. FIG. 1 is a schematic block diagram of a BCH drive. Hereinafter, the structure of a BCH drive will be described with reference to FIG. 1. In FIG. 1, the CPU 10 performs the overall control operation of the BCH drive, and the ROM 12 stores the control program and initial data of the CPU 10. The RAM 14 temporarily stores various data generated during the operation of the BCH drive under the control of the CPU 10, and the clock generation unit 16 synchronizes the exchange period under the control of the CPU 10. Generate a clock for The front panel 18 displays the information according to the predetermined message data under the control of the CPU 10. On the other hand, the signal processing unit 20 transmits and receives data information with other exchanges under the control of the CPU 10.

The BCH drive having the above-described configuration continuously transmits the idle pattern 'E916' on the physical link when there is no data frame of the user to be transmitted in hardware to maintain synchronization between the two exchange periods. When the BCH drive receives the 'E916' pattern and receives a pattern other than the idle pattern, it determines that the user data frame has been received. That is, the BCH drive determines that transmission of the unit data frame ends when the data frame of the upper layer is received and the idle pattern is received again. The upper layer refers to a layer 2 or more layers in the 7 layer model of OSI. In this case, if the user's data frame includes a pattern having the same value as the idle pattern, the BCH drive determines that the data frame is over and thus cannot transmit the data frame normally.

In addition, when constructing a user data frame to transmit a message of a higher layer on a physical link, a start header character (SHC) indicating the start of the user data frame and an end of message character (EMC) indicating the end of the user data frame Figure 2 is used as shown in Figure 2. When the STC or EMC is included in the data frame of the upper layer like the idle pattern, the BCH driver sends a message in the middle of the message in the process of reconstructing the received data frame into the message to be sent to the upper layer. Commits a new message to be started when it is judged to have finished or has not received the last block of the message. In this case, it is also a serious error that the message is temporarily misjudged. However, even if a request for retransmission is performed for a message that was not normally received from the layer 2's point of view, the driver continues to make the same error for the received data frame. There is a problem that transmission is not normally transmitted and received.

Accordingly, an object of the present invention is to provide a method for distinguishing a general pattern of the same pattern included in a user message from a specific pattern used in the data transmission of the exchange system.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Also, many specific details, such as the specific process flows set forth in the following description and the accompanying drawings, are presented to provide a more general understanding of the invention, and it is common knowledge in the art that the invention may be practiced without these specific details. It will be obvious to those who have. And detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

Low 3 shows a format diagram of a unit frame according to the present invention. Only 3 bits out of 5 bits of a field storing a block number in a unit frame of physical transmission are used for storing the block number and the remaining 2 bits are controlled. It consists of a field (Control Field). This setting of the control field allows to distinguish the general data of the user's message from the specific pattern transmitted on the physical link. That is, the value copied to the control field is a binary value and is a frame composed only of general data. It can be divided into a frame composed of SHC and general data, a frame composed of EMC and general data, a frame composed only of two EMC data due to filling, and a frame composed of general data having the same value as the idle pattern.

4 shows a flow chart of the CPU 10 for generating a data frame, and FIG. 5 shows a flow chart of the CPU 10 for processing a received user data frame. Hereinafter, operation examples of the present invention will be described in detail with reference to FIGS. 4 and 5.

First of all, a block containing SHC or EMC uses a minimum of 2 bits in the control field to search for data in the data area after the control field is searched to distinguish whether SHC or EMC is included in this frame. That is, when the transmission of the user message is requested, the CPU 10 loads the user message to generate the user data frame in step 30 and proceeds to step 32. In step 32, the CPU 10 records the SHC and one byte of user data in the user data field in the unit frame structure. Thereafter, in step 34, the CPU 10 sets an open flag in the control field to record that the control field includes the SHC, and records the block number together with the block number. Thereafter, in step 36, the CPU 10 checks whether there is residual data, and proceeds to step 38 when there is no residual data. The CPU 10 then records EMC + EMC in the user data field in steps 38 and 40, respectively, sets the end flag, and records the block number together with the block number. On the other hand, if there is remaining data of the 36th step, the CPU 10 proceeds to step 42 and checks whether the remaining data is 1 byte, and proceeds to step 44 when the remaining data is 1 byte. In step 44, the CPU 10 records one byte of remaining user data and EMC in the user data field. In step 46, the CPU 10 sets an end flag in the control field and records the block number together with the block number. On the other hand, if the remaining data in step 42 is not one byte, the CPU 10 proceeds to step 48 and checks whether the usage data to be recorded is the 'E916' pattern. If the user data is the 'E916' pattern at step 48, the CPU 10 proceeds to step 50, converts the user data, records the data in the user data field, and proceeds to step 52. In step 52, the CPU 10 sets the IDLE pattern in the control field to record the data converted in step 50 as the IDLE pattern, records the block with the block number, and returns to step 36. On the other hand, when terminating the configuration of the user data frame of the user message, the EMC indicating the end of unit message transmission is recorded and transmitted in the user data area. At this time, if one byte data area is left in the user data area, one more EMC is included to terminate the user data frame configuration, and a value for distinguishing data frames containing one or two EMCs in the control field is recorded. The control field has a value that identifies whether it contains two or one EMCs. Therefore, when receiving data, it is possible to check whether two EMCs are included in the frame including the EMC and whether the end of the general data of the user message has the same value as the EMC. Hereinafter, a process of the CPU 10 for processing the received user data frame will be described with reference to FIG. 5.

First, in case of receiving user data frame, similarly to the case of transmission, the type of received frame is distinguished by the control field value.In particular, when a value indicating the idle pattern is received, the user data is restored to the same value as the idle pattern. . That is, the CPU 10 reads the unit frame received through the signal processor 20 in step 60 and proceeds to step 62 to check whether the control field has the SHC or EMC set. If SHC or EMC is set in the test result control field, the CPU 10 proceeds to step 64. In step 64, the CPU 10 checks whether the control field includes SHC. If the SHC is included, the CPU 10 proceeds to step 68 to perform the SHC processing routine and then proceeds to step 70. On the other hand, if no SHC or EMC is set in the test result control field of step 62, the CPU 10 proceeds to step 70. On the other hand, if SHC is not included in the check result control field of step 64, that is, if the EMC is included in the CPU 10 proceeds to step 66 after performing the EMC processing routine proceeds to step 70. In step 70, the CPU 10 checks whether the IDLE pattern is displayed in the control field. If the IDLE pattern is displayed, the CPU 10 proceeds to step 72, restores the received data to the 'E916' pattern, and records the data in the user data buffer. Proceed. On the other hand, if the IDLE pattern is not displayed in the control result field of step 70, the CPU 10 proceeds to step 74 and records two bytes of the user message in the data buffer. In step 76, the CPU 10 checks whether the processing of the received user data frame has ended and returns to step 60 if it is not finished. On the other hand, when the processing of the received user data frame is finished, the CPU 10 proceeds to step 78 to generate a message to send the user data recorded in the data buffer to the upper layer and receives the received data according to the present invention. Terminate user data frame processing.

As described above, the present invention can prevent the BCH driver from determining that the data transmission ends when the same user data message is transmitted as the idle pattern, and even if a special pattern indicating the start and end of the user data frame is included in the user data area. Since this can be selected by the BCH driver, a user message can be reconstructed using a data frame received to a higher layer to avoid shorting and error handling of the user message. In addition, there is a clear distinction between EMC filling and general data indicating the end of a message when constructing a unit data frame, and in configuring these control fields, there is an advantage of clarifying the exchange period protocol without extending the data frame.

1 is a schematic block diagram of a BCH driver.

2 is a user data frame format diagram.

3 is a unit frame format diagram.

4 is a process flow diagram for generating a data frame.

5 is a flowchart of a received user data frame.

Claims (5)

In the data discrimination method of the exchange system, A unit frame transmission step of transmitting a user message during a switching period of the switching system by including a control field in a unit frame for distinguishing a specific pattern transmitted on a physical link from general data of a user message; And a data restoration step of restoring general data of the user message from the received unit frame when the unit frame including the control field is received. The method of claim 1, wherein the control field uses only two bits among fields for storing a block number in a unit frame. The method of claim 2, wherein the specific pattern is an 'E916' pattern. The method of claim 3, wherein the unit frame transmission step; A first step of loading a user message, recording SHC and user data in a user data field in a unit frame structure, and setting an open flag in a control field when the user message transmission request is received; A second step of retrieving residual data from the user message and rewriting the EMC in the user data field if there is no residual data; A third process of recording the residual data and the EMC and setting the end flag in the control field and recording the block data together with the block number when the remaining data of the user message is 1 byte; If the remaining data in the user message is not 1 byte, the pattern of the user data to be recorded is examined and if the pattern is 'E916', the user data is converted and recorded in the user data field, and then an IDLE pattern is set in the control field. If the pattern of the user data is not the 'E916' pattern, the data of the switching system is characterized by resetting the control field after recording two bytes of the user message and recording the block number together. How to distinguish. The method of claim 4, wherein the data restoration step is: The first step of reading the received unit frame to check whether the SHC or EMC set in the control field, A second process of performing a corresponding processing routine set in the control field as a result of the inspection; When the IDLE pattern is displayed in the control field, the data is restored to the 'E9l6' pattern and recorded in the user data buffer, whereas when the IDLE pattern is not displayed in the control field, a third process of recording the user message 2 bytes in the data buffer and, And a fourth step of generating a message for transmitting the user data recorded in the data buffer to a higher layer when the processing of the received unit frame is completed.