KR0123250B1 - Method for locating defects using the relative position values - Google Patents

Abstract

The defect location recognizing method by using a relative location value comprises the steps of: determining location of a network element of VP/VC connection; in case of the network element of VP/VC connection, remaining at an on-failure state; recognizing a relative location of the defect in accordance with an OAM(Operation And Maintenance) function type of an OAM cell; and in case of a terminal network element of the VP/VC connection, recognizing a relative location of the defect in accordance with the OAM(Operation And Maintenance) function type of the OAM cell, received in the on-failure state, to thereby produce or discard a remote defect indication(RDI) OAM cell.

Description

How to locate fault using relative position value

1 is a format diagram of a fault management OAM cell.

2 is a diagram illustrating a failure management OAM flow.

3 is a diagram illustrating a fault location processing flow according to the present invention.

4 is a fault location processing flowchart using a relative position value in accordance with the present invention.

* Explanation of symbols for main parts of the drawings

1: cell header 2: OAM type field

3: OAM function type field 4: Fault type field

5: fault location field 6: EDC field

In the present invention, when a failure occurs in the B-ISDN network, a failure using a relative position value that enables all network elements in the network affected by the failure to recognize the occurrence of the failure and to quickly and clearly identify the location of the failure. Defect location.

In general, in order to find out the location of a failure in the B-ISDN network, when a failure occurs, failure management signals (AIS: Alarm) are used as network elements including the connection affected by the failure by using the OAM (Operation And Maintenance) function. By transmitting Indication Signal, RDI: Remote Defect Indication, it recognizes the failure of connection.

However, the signal recommended by the International Telecommunication Union (ITU-T) only indicates the occurrence of a failure on a given connection and cannot indicate where the failure occurred. Therefore, in order to identify the location of the fault, a separate fault localization process must be performed, which is also not clearly defined, which makes it difficult to accurately identify the location of the fault.

In order to solve the problems of the prior art, the present invention uses a position value relative to a fault location field of a fault signal to recognize that all network elements including a connection affected by the fault are faulty. The purpose of this is to provide a method for locating faults using relative position values that makes it possible to clearly and simply identify the faults and to perform prompt action on them.

The present invention for achieving the above object, Fixed management AIS / RDI (Alarm Indication Signal / Remote Defect Indication) OAM (Operation Maintenance) cell including a defect location field indicating the location on the failed VP / VC connection A method for determining a location of a fault using a method comprising: a first step of determining a position of a network element of a VP / VC connection, and a VP in the case of a fault detection VP / VC connection network element that first detects a failure after performing the first step. AIS OAM cell is transmitted by entering the first specific value in the fault location field in the VC-AIS OAM cell, and it is in an on-failure state. After performing the second step and the first step, the failure detection VP / VC connection network element or the connection network element of the VP / VC connection, which first detected a failure, is applied to the OAM function type of the failure management OAM cell received in the failure state. According to the relative position of the obstacle After performing the first step and performing the first step, the vice verifies the relative fault location according to the OAM function type of the failure management OAM cell received in the failure state in the case of the end network element of the VP / VC connection and generates the RDI OAM cell. Or a fourth step of discarding.

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

FIG. 1 is a diagram illustrating a format of a fault management AIS / RDI (Alarm Indication Signal / Remote Defect Indication) OAM cell applied to the present invention, wherein a failed virtual path (VP) or virtual channel (VC) connection is A 5-byte cell header (1) containing a VPI (VP Identifier) value or a VPI / VCI value and a 4-bit next to the cell header (1) are used to indicate a fault management function. OAM type field (2) giving up the performing OAM cell and OAM function time field (3) giving up the OAM cell 'AIS OAM' or 'RDI OAM' cell among fault management OAM types using the following 4 bits A fault type field 4 indicating whether a fault has occurred in the physical layer or a fault in the ATM layer, a fault location field 5 indicating a position on the VP / VC connection in which the fault occurs; Finally, the EDC field of the error detection code (6) Is made by the entire 53 bytes including the failure type field (4), and a fault location field (5) has not yet been determined recommended by ITU-T.

FIG. 2 is a diagram illustrating a failure management OAM flow in which failure information is transmitted hierarchically when a failure occurs in a physical layer and an ATM layer to which the present invention is applied. It is recognized that a failure has occurred in the connection involved.

First, when a failure occurs in the transmission path layer or lower layer of the physical layer, the corresponding failure signal (TP-AIS / LOP / LOS) terminates the transmission path OAM flow, that is, the transport path layer of the physical layer, and the VP layer. Detected by the VP connection network element that performs the OAM function connection function.

The VP connection network element that detects the failure generates a Transmission Path-RDI (TP-RDI) signal and transmits it in the opposite direction of transmission in order to indicate that the AIS recognizes the failure for the received resource. Then, by generating and transmitting a VP-AIS OAM cell for all VP connections affected by the corresponding failure of the physical layer, the failure is raised to perform failure management for all VP connections affected by the failure. The VP-AIS OAM cell passes through all network elements included in the VP connection, notifies that there is a failure in the corresponding VP connection, and eventually arrives at the network element terminating the VP connection.

The network element terminating the VP connection transmits a VP-RDI OAM cell in the opposite direction of transmission, indicating that it has recognized a failure on the corresponding VP connection, and then raises the failure for all VC connections included in the failed VP connection. By creating and transmitting the VC-AIS OAM cell, fault management functions up to all VP connections and VC connections affected by physical layer failures are performed. The VC-AIS OAM cell informs that a failure occurs on the VC connection while passing through the network element forming the VC connection, and eventually arrives at the network element terminating the VC connection.

The VC connection termination network element receiving the VC-AIS OAM cell generates a VC-RDI OAM cell and transmits it in the opposite direction of transmission so that all network elements in the direction of failure on the corresponding VC connection recognize the connection failure. The VC-RDI OAM is transmitted in the opposite direction of the failing connection so that all network elements in the failing direction are also aware of the connection failure. This ensures that all network elements that make up a connection recognize the failure in the connection and perform procedures for each failure.

In the present invention, as described above, the fault generated simultaneously with the recognition of the fact of occurrence of a failure by using the unidentified failure location field 5 in the contents of the AIS and RDI OAM cells informing the occurrence of the failure is located at a certain position from each network element. Make sure you know.

3 is a view showing an example of the fault location processing flow according to the present invention, by applying a relative position value to the fault location field 5 of the fault management AIS / RDI OAM to simultaneously identify the fault occurrence position and the fault occurrence position. An example can be shown.

As shown in the figure, the connection between user-A and user-B in the network is VF layer network elements VP-A, VP-N, VP-C and VC layer network elements VC-A, VC-B, VC- It is made through C and VC-D network elements. Among these, when a failure occurs on the physical layer in the transmission direction from the VP-B network element between the VP-B and the VP-C network element to the VC-C network element, the failure of the physical layer is caused by the VP-C network element. Is detected (31).

As soon as the VP-C network element detects a fault, it transmits a VP-RDI signal in the opposite direction of transmission to perform fault management OAM function on the physical layer, and to all affected VP connections from the failed physical link. In the fault position field 5 of the VP-AIS OAM cell, a value of '1' is written and transmitted in the transmission direction.

This VP-AIS OAM cell is delivered to the VC-B network element through the VP connection. The VC-B network element is a network element that performs the termination function of the VP layer connection and a connection network element of the VC layer connection. Therefore, first, the value of the failure location field of the received VP-AIS OAM cell is increased by '1' (33). After that, since the VC-B network element is an end device of the VP connection, a VP-RDI OAM cell is generated and transmitted in the opposite direction of transmission (34). At this time, the value of the received location field of the VP-AIS OAM cell, which is received in the disabled location field 5 in the VP-RDI OAM cell, is written as it is in the disabled location field in the VP-RDI OAM cell. In operation 35, '1' is decreased and then transmitted. In addition, since the VC-B network element is also a connection network element of the VC layer connection, a VC-AIS OAM cell is created and a value of '1' is entered in the fault location field and transmitted on all VC connections affected by the fault ( 36). The VP-RDI OAM cell transmitted in the opposite direction of the failure direction by the VC-B network element arrives at the VC-A network element through the VP-C, the VP-B, and the VP-A (37). . At this time, the VP-C, VP-B, and VP-A network elements first decrease the value of the failure location field of the received VP-RDI OAM cell by '1'. After reducing, the VP-C, VP-B, and VP-A network elements continue to transmit the VP-RDI OAM cell in the transmission direction since they are not end network elements of the VP connection (38).

The VC-A network element is an end network element of the VP connection and a network element of the VC layer. Accordingly, the VC-A network element receives the VP-RDI OAM cell, decreases the value of the fault location field by '1', recognizes only the value, and deletes the VP OAM cell from the connection (39). In this way, a failure that occurs between the VP-B and VP-C network elements is that all network elements in the VP layer are aware of the occurrence. In addition, the value of each fault location field received at this time allows the relative position of the fault to be known.

That is, since the VC-A network element received the VP-RDI OAM cell and the value of the fault location field was '-3', it means that the fault occurred in the third section in the RDI OAM receiving direction of the VC-A network element. In the same way, since the VP-A network element is '-2', in the second section in the receiving direction of the OAM cell, and the VP-B network element is '-1', in the next section in the receiving direction of the OAM cell, the VP-C The network element is the first section in the VP AIS receiving direction because the value of the fault location field of the VP-AIS OAM cell is '1', and the second section is the VP-AIS receiving direction because the value of the VP-D network element is '2'. In the event of a fault, network elements on all VP connections can see their location.

Next, we look at the ongoing fault management at the VC link layer. Like the VP layer, the VC-B network element writes '1' in the fault location field and transmits it in the transmission direction (36). This VC-AIS OAM cell is delivered to user-B via VC-C and VC-D network elements. In this case, since the VC-C and the VC-D are not end network elements of the VC connection, the VC-AIS OAM cell increases the value of the failure location field by '1' and continues transmitting (310). Since user-B is an end network element of the VC connection, after receiving the VC-AIS OAM cell, '1' is incremented and the value is written into the fault location field of the VC-RDI OAM cell as it is. In operation 311, the VC-RDI OAM cell is transmitted in the opposite direction while the value of the fault location field is decreased by '1'.

The VC-D, VC-C, VC-B, and VC-A network elements receiving the VC-RDI OAM cell continue to transmit after decreasing the value of the fault location field of the VC-RDI OAM cell by '1', respectively (312). ). Since the user-A network element is another end network element of the VC connection, the value of the failure location field of the received VC-RDI OAM cell is reduced to '1' and stored, and the corresponding cell is deleted from the VC connection (313). In this case, since the user-A network element has a value of '-2' in the content of the VC-RDI OAM cell, a failure occurs in the second section in the direction of receiving the VC-RDI OAM cell. Since the contents of the VC-RDI OAM cell have a value of '-1', a failure occurs in the first section in the direction of receiving the VC-RDI OAM cell. VC-B, VC-C, VC-D, and User-A The network element has '1', '2', '3', '4' for the contents of the VC-AIS OAM cell, respectively, so that the VC-AIS OAM cell receives the first, second, third and fourth directions. By determining that the failure occurred in the first section, all network elements included in the VC connection can simultaneously identify the location of the failure on the VC connection and recognize the fact of the failure.

4 is a flow chart for processing fault location using relative position values according to the present invention, and shows a series of procedures for each network element.

As shown in the figure, the present invention first determines the position of a network element (400), and in the case of a VP / VC connected network element which first detected a fault, a '1' is indicated in the fault position field in the VP / VC-AIS OAM cell. After writing (410), the AIS OAM cell is transmitted (402), and the failure state (On-Failure) (403), the determination result, if the connection network element of the VP / VC connection failure state (403) When receiving the failure management OAM cell in the AIS or RDI check whether (405), VP / VC-AIS OAM cell is increased to the value of the failure location field (5) '1' (406) and other failure location field ( After determining the relative position with the value of 5) (407), continue to transmit the failure management OAM cell (410), in the case of the VP / VC-RDI OAM cell, the value of the fault location field (5) is reduced to '1' (408) ), The relative position is determined by the value of the fault location field 5, except for the fault detection network element (409), and the failure management OAM cell is continuously transmitted, and then the state is again failed (411). .

In addition, in the case of an end network element of the VP / VC connection, if a failure management OAM cell is received in a failure state 412 (413), it is checked whether it is AIS or RDI (414).

As a result of the check, if the VP / VC-AIS OAM cell, the value of the fault location field 5 is increased by 1 (415), the fault location is identified (416), and the value is left as it is. (417), again decrease the value of the fault location field of the VP / VC-RDI OAM cell by '1' (418), then transmit the VP / VC-RDI OAM cell in the opposite direction of transmission (419), In a failed state (423).

If the received fault management OAM cell is a VP / VC-RDI OAM cell, the value of the fault location field 5 is decreased by 1 (420), and after determining the relative position of the fault (421), the fault management OAM cell is discarded. (422) and fail again (423).

According to the above procedure, network elements on each VP / VC connection receive the value of the failure location field (5) of the AIS OAM cell when the AIS cell is received, and the RDI OAM cell when the RDI OAM cell is received. The value of the location field 5 is unique to the location of the failure, and it is recognized that a failure occurs in a section separated by an absolute value of the failure location value in the direction in which the AIS or RDI OAM cell is received, respectively.

As described above, according to the present invention, when a failure is found in the B-ISDN network, it is possible to automatically recognize the occurrence of the failure and simultaneously identify the location without requiring an additional test function to identify the location of the failure. have.

Claims (5)

Fault management method including fault management AIS / RDI (Alarm Indication Signal / Remote Defect Indication) OAM (Operation Maintenance) cell including fault location field (5) indicating the location on faulty VP / VC connection. In the first step of determining the position of the network element of the VP / VC connection, and after performing the first step, in the case of the failure detection VP / VC connection network element first detected a failure in the VP / VC-AIS OAM cell A second step of transmitting the AIS OAM cell by entering a first specific value in the failure location field and turning on the failure, and in case of the connection network element of the VP / VC connection, immediately failing; After performing step 1, determine the relative position of the fault according to the OAM function type of the fault management OAM cell in which the fault detection VP / VC connection network element or the connection network element of the VP / VC connection is received in the failure state. And performing the first step Thereafter, a fourth step of identifying a relative failure position and creating or discarding the RDI OAM cell according to the OAM function type of the failure management OAM cell received in the failure state in the case of the end network element of the VP / VC connection. Disability location identification method using relative position value. The method of claim 1, wherein the third step comprises: determining whether the OAM function type is AIS or RDI when a failure detection OAM cell is received in a failure state of a failure detection VP / VC connection network element or a connection network element of the VP / VC connection. After performing the fifth step and the fifth step, in the case of the AIS OAM cell, the failure location field value is increased by '1', the relative location is determined by the value of the failure location field, and the sixth step of continuously transmitting the failure management OAM cell is performed. And a seventh step of reducing the failure location field value by '1' and continuing to transmit the failure management OAM cell in the case of an RDI OAM cell after performing the fifth step. How to grasp. The method of claim 2, wherein in the seventh step, in the case of the connection network element of the VC / VP connection, the relative location field value of the RDI OAM cell is decreased by '1', and the relative location is determined by the value of the failure location field. Disability positioning method using a relative position value, characterized in that it further comprises an eighth step. The method of claim 1, wherein the fourth step comprises: a fifth step of identifying an OAM function type of a failure management OAM cell received in a failure state in the case of an end network element of a VP / VC connection, and after performing the fifth step; In case of the AIS OAM cell, the relative position of the fault is determined and the RDI OAM cell is generated and transmitted in the opposite direction. After performing the fifth step, if the RDI OAM cell is performed, the value of the fault location field 5 is set to '1'. Method for identifying the location of a failure using a relative position value comprising the seventh step of reducing the relative location of the failure by reducing the RDI OAM cell. 5. The method of claim 4, wherein the sixth step comprises: an eighth step of determining a relative position of the failure by increasing the value of the failure location field 5 of the AIS OAM cell by '1', and the failure location of the AIS OAM cell; A ninth step of generating an RDI OAM cell using the value of the field 5, and a tenth step of decreasing the value of the fault location field 5 of the generated RDI OAM cell by 1 and transmitting in the opposite direction; Disability positioning method using the relative position value, characterized in that.