JPH04207544A - Loopback test system for atm exchange - Google Patents

Abstract

PURPOSE:To test and measure a switch function of an ATM exchange by allowing a test section to evaluate a function of a switch section based on a sent cell and a received cell. CONSTITUTION:When a control section 2 gives a command of production of a test cell having a specific virtual path/virtual channel (VPI/VCI) for a line interface section 3 to a test section 5, the test section 5 uses a test cell generating means 50 to generate the test cell having the specific VPI/VCI and inputs it to an ATM switch 1. A test cell is inputted to an interface section 3 via an outgoing highway by the switch operation of the switch 1. Upon the receipt of the cell having the specific VPI/VCI, a loopback means 30 of the interface section 3 extracts the cell and loops back it to an incoming highway. The looped back cell is subject to VPI/VCI conversion by a VCC 4 so as to be directed to the test section 5 and the result is inputted to the switch 1. Thus, the test cell outputted from the switch 1 is inputted to the test section 5 and evaluated by an evaluation means 51.

Description

[Detailed description of the invention] [W required] Concerning the return test method for ATM switching equipment.

The purpose of this invention is to provide a loopback test method for ATM exchanges that can test and measure the switch function, police function, and transmission quality of ATV exchanges.

A loop-back means is provided in the line interface section to return a cell having a specified VPI/VCI value from among the cells on the down-bound highway to the up-bound highway.
/VCI value is generated from the test cell generation means and sent out toward the down highway, and the test section receives the test cell returned by the return means of the line interface section, and the test section is configured to transmit the test cell. The function of the switch unit is evaluated based on the received cell and the received cell.

[Industrial application field] 1 The present invention relates to a loopback test method for ATM switching equipment.

In recent years, B-I SDN (Broadband
ATM (Asynchronous
Research and development of switching equipment (transfer mode) is actively underway. This ATM switch performs extremely high-speed switching in units of cell format. On the other hand, A.T.
It is desired that V exchanges, like other exchanges, be able to test and monitor whether the exchange is operating normally.

[Prior Art] A conventional ATM switch converts data sent from a subscriber into cells at a line interface in which the subscriber line is accommodated. The cell contains information of a predetermined length (48 bytes),
Hander with control information such as VPI/VCI (Harchar path/Harchar channel) set corresponding to the destination (
5 Hyde) is added. Such cells are exchanged by an ATM switch from a line interface and output to a destination.

In addition, in order to make effective use of the switching function, ATV exchanges require subscribers to declare their communication bandwidth (cell generation rate) etc. when receiving call requests from subscribers in advance. Consideration is being given to adopting a method that allows communication when it can be processed. Thereby, cell discard and delay can be minimized. A device called a police mechanism is used to monitor this declared value, and if cells exceeding the declared band are generated, processes such as cell disposal are carried out to prevent an excessive load on the ATM switch. conduct.

In conventional electronic exchanges, various tests were performed by physically connecting lines back and forth.

However, ATM switching equipment performs transmission and switching on a cell-by-cell basis, exchanging low-speed cells for voice and other high-speed cells for video and other high-speed cells, so conventional technology cannot be used as is.

[Problems to be Solved by the Invention] As described above, in an ATM switch, the ATM switch executed on a cell-by-cell basis must operate normally. However, with the conventional technology 3, there is a problem in that it is not possible to perform loopback tests online to check whether the ATM switch is operating normally or to detect which part is abnormal when a failure occurs. there were.

Another problem is that there is no way to check whether the police system, which monitors the amount of transmission such as the communication band declared by the subscriber when making a call, has a normal monitoring function.

The present invention provides an A
The purpose is to provide a loopback test method for TM exchanges.

1 A means to solve a problem FIG. 1 shows the basic configuration of the present invention.

FIG. 1 shows three basic configurations A6 to C1. In FIG. 1, 1 is an ATM switch (ATM-3W), 2 is a control section, 3 and 7 are line interface sections connected to subscriber lines, respectively. 30 is a folding means, 4 and 8 are VPI/V
CI converter (■CC), 5 is test section (TE), 50
51 represents a test cell generation means, 51 represents an evaluation means, and 6 represents a police mechanism.

The present invention provides means for selectively looping back specific cells from the downhill highway to the uphill highway in the line interface section of an ATM switch, supplies the specific cells from the testing section to the downhill highway, and tests the looped back test cells at the line interface section. The test is carried out by receiving the information at the department, and the monitoring function of the police system is also tested using the test cell sent from the testing department.

[Operation] In the case of the configuration shown in A of the first session, from the control section 2 to the test section 5
A specific VPI/V for the line interface section 3 that becomes
Instructs to generate a test cell with CI and 1
The specified VPI/VCI for the line interface section 3
Give instructions to wrap cells with . Test part 5 is this O
Accordingly, a test cell having a specific VPI/VCI is generated from the test cell generating means 50 and inputted to the ATM switch 1. The switch operation of the ATV switch 1 sends the test cell to the line interface section 3 on the down highway (AT
The signal is input to the line interface unit 3 via the highway (from the M switch 1 to the line interface unit 1).

When a cell having the specific VPI/VCI is input to the loopback means 30 of the line interface section 3.

Take out the cell and turn back to the up highway (the highway heading towards ATM Swissotto). The folded cell is connected to VPI/VC so that it goes to the test section 5 at VCC4.
It is converted to I and input to ATM switch 1. The test cell output from the ATM switch 1 is input to the test section 5 and evaluated by the evaluation means 51.

Next, in the case of the configuration shown in FIG. 1B, the police mechanism 6 determines whether the cell communication amount actually generated by the subscriber is within an appropriate range with respect to the communication band (communication amount) declared by the subscriber in advance. It has the ability to monitor.

If the declared value of the band (cell amount) is exceeded, the cell is discarded or priority control is performed (control to allow only priority cells to pass).

When testing whether this police mechanism 6 operates normally, the control unit specifies the VPI/VCI value of the cell to be looped back to the line interface unit 3, and the same VPI/VCI value is specified for the police mechanism 6. is specified as the monitoring target, and the band of the declared value (test band) is specified.

The VP addressed from the testing section 5 to the line interface 3
When a test cell with an I/VCI value is generated, it is transmitted from the down highway of the ATV switch 1 to the line interface section 3.
When the test cell is input to the uplink highway by the return means 30, the test cell is input to the police mechanism, and the amount of cells is monitored to determine whether or not the band is within a pre-designated band. If the bandwidth is exceeded, the controller is notified. Test section 5
The amount of cells sent out from

By changing the declared value etc. instructed to the police mechanism 6, it is possible to test whether the function of the police mechanism 6 is normal or not. In this case, the test cells input to the police mechanism 6 do not need to be sent to the testing section 5, but may be output as they are.

Next, in the case of the configuration shown in C1 of FIG.
3 shows the loopback for measuring the transmission quality of the path between the two line interfaces 3 and line interface unit 7 in the figure. In this case, one-line interface sections 3 and 7 are each instructed to return a cell having a specific VP I/VCI, and test section 5 sends a test cell to one of the line interface sections 3.

Then, the test cell is inputted to the line interface section 3 through the ATM switch 1, and the test cell turned back here is inputted to the line interface section 7 at the VCC 4.
It is converted into a VPI/VCI value addressed to and supplied to the ATV switch. This test cell is further looped back at the line interface unit 7, converted into a VP I/VCN direct signal and sent to the test unit 5 at the vccs, and then inputted to the ATM switch 1.

In this way, the test cell sent out from the test section 5 returns to the test section again via the two line interface sections 3 and 7, so by evaluating the returned test cell, the error rate, etc. of the target path can be determined. quality is measured.

[Example 1] Figure 2 is a system configuration diagram of the embodiment, Figure 3 is a configuration diagram of a line interface section, Figure 4 is a configuration diagram of a loopback circuit,
FIG. 5 is a block diagram of the test section, and FIG. 6 is a block diagram of the police mechanism.

In FIG. 2, 1, 3 to 6 represent the same devices as in FIG. 1, and l is an ATM switch (ATM-3W).

3 is a line interface section, 4 is a VPI/VCI conversion section (VCC), 5 is a test section, 6 is a police mechanism, and 20
．． 21 corresponds to the control section in FIG.

20 is a CPR interface unit (CP-IF).

21 is a call processing processor (CPR); 9 is a subscriber terminal;
10 is a multiplexing/distributing unit (MDX).

FIG. 2 shows an ATV switch 1 and a test section 5. ATM switch 1, multiplexing/distributing section 10, and line interface section 3
Although only one line is shown between them, in reality there are tracks for the up and down highways, and signals are transmitted in both directions.

To explain the configuration of the line interface section 3 with reference to FIG. 3, 30 is an optical-to-electrical conversion circuit (0/E) that connects to the subscriber line made of optical fiber, and 31 is a physical layer termination circuit that controls the electrical level. .

32 is an ATM layer termination circuit that controls cell creation and disassembly, and 33 is a return circuit.

The inside of the folding circuit 33 of FIG. 3 is shown in FIG. The foldback circuit connects a cell with a specific VPI/VCI on the down highway from the ATV switch.
Extract at 4, turn around, and take route 36? , and is configured to input to an inserter 35 provided on the outbound highway 7.

This return control is performed from CPR2+ to CP- shown in FIG.
This is done by control signals provided via the IFI.

Next, the configuration of the test section 5 will be explained using FIG. 5.

In FIG. 5, 58 and 59 are the highway and ATV switch that output test cells to the ATM switch, and the switch interface (SWIF) that connects to the human-powered highway from A, 52 is a delay circuit (DELAY), and 5
3 is a cell circuit (CEL).

54 is a transmit/receive cell comparison circuit (CMP), 55 is a pattern generation circuit (PC), 56 is a control unit (CNT) that controls the operation of each part of the test section, and 57 is an oscillation circuit (OSC).

The control section 56 is connected to the CP-IP (CPR interface section in FIG. 2) 20, is controlled by the CPR 21, executes the test, and sends the results to the CPR 21. When transmitting test cells, when a pattern is generated from the pattern generation circuit 55 under the control of the control unit 56, the cell formation circuit 53 converts the pattern into a predetermined format (specified VPI/
A test cell having a header of the VCI value and consisting of a predetermined number of bytes of data from the pattern generation circuit 55 is generated and output to the ATV switch from the switch interface 5th.

The test cell manually operated from the ATM switch is the comparison circuit 54.
The delay time (A
The comparison circuit 54 compares the cell with a transmission cell input after the time required for transmitting the TM switch or line interface, and the comparison result (coincidence and non-coincidence signal) is input to the control unit 56. The control unit 56 counts the number of matches (or mismatches) for each sent cell.

Data representing transmission quality such as error rate is obtained and output to the CPR 21.

Further, by controlling the delay time of the delay circuit 52 and performing a test, the delay characteristics of the transmission path, etc. are detected.

Next, the configuration of the police mechanism 6 is shown in FIG.

In FIG. 6, 60 is a decoder (DEC) for decoding the VPI/VC1 value of a passing cell and counting up the corresponding counter, and 61 is a counter (CT) provided corresponding to each VP I/VCJ value. ), 62 is a latch circuit (LATCH) that holds the VPI/VCI of the passing cell;
63 holds the declared band (maximum cell inflow amount) corresponding to each vp1/VCI value, and the VP held in the latch circuit 62
A RAM table (RAM TABLE) from which the declared band corresponding to the 1/VCI value is read, 64 a comparator (CMP) that compares the current passing cell amount and the maximum cell amount corresponding to the declared band, 65 a comparator 64; When the amount of incoming cells is smaller than the declared band (corresponding maximum cell amount) and the amount of incoming cells, input cells are selected, and when the amount of incoming cells exceeds the declared band, empty cells are selected and output. This is a selector (SEL) to

The line interface section 3 has the configuration shown in FIGS. 2 to 5.
(hereinafter referred to as the line interface under test). At the start of the test, the CPR21 (Fig. 2) sends test cells to the test section (TE) 5 via the CP-IF20 to the line interface section under test 3. should be given to ~p
1/VCI (11!). At this time, the CPR 21 also notifies the line interface unit under test 3 of the PI/VCI value of the cell to be returned via CP'-IF,
Also, for the VCC 4 corresponding to this line interface section 3, a VPI/VCI conversion value for returning the returned test cell to the testing section 5 is specified.

In response to the subsequent test activation, the test section (TE) 5 starts sending out test cells using the circuit shown in FIG. The sent test cell is switched within the ATV switch 1 according to the VPI/V (l value held in the terminal) and reaches the line interface section 3 under test.

Loopback circuit of line interface 3 under test (Figure 4)
Here, since the test cell matches the VPI/VC value of the return cell specified by the CPR 21, it is returned as is. Thereafter, VCC4 of this line interface section 3 converts the VPI/VCI (i) addressed to the test section 5 specified by CPR21 to A via MDXIO.
The signal is inputted to the TM switch 1 and returned to the testing section 5 where the signal was generated.

The test results in test section 5 (Figure 5) are CP-IF20
The notification is sent to the CPR 21 via .

Next, the operation of testing the police mechanism using this folding method will be explained with reference to FIGS. 2 and 6.

The sequence in this test is the same as the above-mentioned test of the line interface section, but during the test, the police mechanism of the line interface section under test 3 is instructed about the allowable band for VPI/VC1f of the test cell. Specify the band of the test cell to be sent.

In the police mechanism (FIG. 6) of the line interface under test, the highest cell amount corresponding to the specified test cell allowable band is taken out from the ram table 63 and supplied to the comparator 64. The comparator 64 compares the inflow amount of test cells outputted from the counter 61 and the amount of cells from the ram table 63, and when the number of test cells that have passed through exceeds a predetermined band, the comparator 64 outputs a signal to the CPR 21 via the CP-IF 20. Give notice.

In this way, by various combinations of the test cell band instructing the police mechanism of the line interface unit 3 under test and the band of the sending test cell instructing the test unit 5, the police mechanism of the line interface unit 3 under test responds to each instruction. The normality of the function of the police mechanism can be tested based on the presence or absence of a test cell bandwidth excess notification from the station.

Next, the operation of measuring the transmission quality of a path within an ATM switch will be explained.

Generally, the path within the ATM switch 1 has different states depending on the route within the switch. Therefore, in order to measure the transmission quality of a particular path, a test cell is passed through the path itself when the path is in use.

At the start of measurement, the CPR 21 sends the test section 5 a V signal for the test cell to transmit to the first line interface section 3.
Specify the PI/VCJ value and the band width of the sending cell. In addition, the first line interface unit 3I instructs the VPI/'VC+ (direct) of the cell to be returned from the CPR 21.
The second line interface unit 7 receives the test cell that has been returned to the VCC 4 of the line interface unit 3.
(See C1 in Figure 1)
Indicates the conversion value of the value.

Further, the CPR 21 specifies the VPI/VCI value of the cell to be looped back to the second line interface unit 7, and returns the looped cell to the VCC 8 of the second line interface unit 7 to the test unit 5. YoniVPI/
Indicates the conversion value of the VCI value.

After this, the test cell is sent out from the test section 5.

The test cells that are manually input from the ATM switch l to the first line interface section 3 are turned back here and transferred to the ATM
It is input to the switch 1, from there it is manually inputted to the second line interface section 7, and after being looped back at the second line interface section 7, it passes through the ATM switch 1 and returns to the test section 5.

The test section 5 can measure the transmission quality of the path between the first line interface section 3 and the second line interface section 7 by observing the error rate and the like of the returned test cells.

[Effects of the Invention] According to the present invention, a function is provided in the line interface section of an ATM switch to loop back cells with a specific VPI/VCI value, and the function test of the single line interface section, the test of the police mechanism, and the measurement of the transmission quality of the path can be performed. It is possible to perform detailed tests such as

Maintenance of the switching equipment becomes easier and reliability can be improved.

[Brief explanation of the drawing]

Figure 1 is a basic configuration diagram of the present invention, Figure 2 is a system configuration diagram of an embodiment, Figure 3 is a configuration diagram of the line interface section, Figure 4 is a configuration diagram of the loopback circuit, and Figure 5 is a diagram of the test section. The configuration diagram, FIG. 6, is a configuration diagram of the police mechanism. 1 in Figure 1 1 ATM switch (ATM-5W) 2. Control section 3.7 Two-line interface section 30, loopback means 4.8: VPl/VCI converter (VCC) 5: Test section (TE) 50: Test Cell generation means 51 = Evaluation means 6: Police mechanism patent applicant Fujitsu Co., Ltd. (one other person) agent patent attorney
Kazuo Hosaka (2 others) Block diagram of the 1st testing department Block diagram of the 5th ward police organization Black 6 Reasons

Claims (3)

[Claims] (1) In the loopback test method for ATM exchanges, a loopback means is provided at the line interface section to loop back a cell with a specified VPI/VCI value from among the cells on the downward highway to the upward highway, and the specified VPI/VCI value is a test section that generates a test cell from a test cell generation means and sends it out toward the down highway, and receives the test cell returned by the return means of the line interface section; A loopback test method for an ATM switch is characterized in that the function of a switch section is evaluated based on received cells. (2) In a loopback test method for an ATM switch equipped with a police mechanism that monitors and controls cells flowing between the line interface and the switch so that they are within the band declared by the subscriber, A loopback means is provided to return cells with a specified VPI/VCI value from among the cells above to the up-bound highway, and a test cell with the specified VPI/VCI value and band is generated and sent out toward the down-bound highway. A test cell generating means is provided, and the normality of the police mechanism can be confirmed by monitoring whether or not the police mechanism performs normal processing according to the band when the test cell returned from the line interface section passes. A return test method for ATM switching equipment featuring the following. (3) In claim (1), the test cell sent from the test section is looped back at the first line interface section and outputted to the second line interface section via a specified path, and An ATM exchange characterized in that a path to be measured is formed in which the cell is returned to a test section after further loopback, and the test section measures the transmission quality of a specific path within the switch based on the transmitted cells and the received cells. fold-back test method.