JP3175571B2 - ATM switch cell continuity test method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cell continuity test system for an ATM exchange. ATM (Asynchronous Trans
fer Mode, asynchronous transfer mode) communication is a high-speed communication technology capable of providing multimedia communication such as image communication, high-speed data communication, and communication of audio signals.

In this ATM communication, information to be communicated is divided into fixed-length data of 48 bytes, and is transferred as fixed-length data called a cell having destination information (referred to as a header) of 5 bytes added to the beginning of the data. I do. And A
In the TM exchange, the destination of the cell is determined from the information in the header of each cell, and communication is performed by transmitting the cell to a specified line or terminal.

[0003] ATM switches used for such multimedia communications are required to have high reliability. Therefore, in order to maintain the high reliability of the ATM switch, it is desired to perform the cell continuity test with high accuracy and efficiency.

[0004]

2. Description of the Related Art FIG. 14 is a diagram for explaining a conventional example. In the figure, 100 is an ATM switch, 110 and 111 are subscriber cards, 121 and 122 are common control units, 130 is a switch unit, 160 is a console for performing maintenance of the ATM switch 100, and 300 is an ATM switch. 100
This is a measuring instrument to be externally attached.

There are subscriber cards for a cell relay system, a frame relay, and the like. For example, when an ATM cell continuity test is performed, a subscriber card 111, a common control unit 121, and a switch unit 130 are supplied from a measuring instrument 300. , And the test cell is turned back by the subscriber card 110 to be tested through the common control unit 122,
The test cell received by the measuring device 300 through the reverse route and returned by the measuring device 300 is checked.

[0006]

The above-mentioned prior art has the following problems. -Since the connection of the measuring device 300 is required each time the test is performed, it takes a long time to prepare for the test.

The test cell transmitted from the measuring device 300 is
Return and check for normality. However, when an abnormality is detected, it takes a long time to specify the location where the failure has occurred.

In the test of the switch unit 130, only the same route as that of the user cell can be tested, so that the route after the system switching by the redundant switch configuration cannot be guaranteed.

[0009] Point-to-multipoint service testing is difficult. APS (Automatic Protection) for switching lines
Switching) service is difficult to test.

[0010] The residual cells in the ATM switch 100 reduce the accuracy of the test. SUMMARY OF THE INVENTION The present invention provides an A switch that can efficiently and efficiently perform a cell continuity test of an ATM switch.
Attempts to implement a cell continuity test system for TM exchanges.

[0011]

FIG. 1 is a diagram for explaining a first principle of the present invention. In the figure, 100 is an ATM switch, 110 is a subscriber card, 140 is a test device that is incorporated in the ATM switch and generates and transmits and receives test cells, and 121 and 122 are test cells from the test device 140. Is a common control unit that replaces the header of the cell and specifies the destination.
It is duplicated with a multi-stage switch configuration that outputs the cell to the destination.
Switch section (details will be described with reference to FIG. 6).
Inputs test information for testing ATM switch
A console 150 receives test information input from the console and transmits the test information to the test apparatus 140 and the common control unit 12.
1 and 122. Also,
Switch section 130 and common control sections 121 and 122
Count the passed cells (not shown) on the input and output sides of
It has a cell counter that switches
The test cell is connected to the switch unit 130 which is duplicated in a switch configuration.
A test cell selection unit (not shown) for selection is provided.

In a cell continuity test of an ATM switch,
From the console 160, a test route and cell continuity test conditions for the number of test cells to be transmitted are set and transmitted to the test device 140 incorporated in the ATM switch 100, and the test device 140 converts the test cells according to the set cell continuity test conditions. The transmitted and returned test cells are received and a cell continuity test is performed.

According to the present invention, the multistage switch configuration is duplicated.
A test cell selection unit (not shown) in the switch unit 130
The test cell display bit of the test cell is
If selected, select a test cell from the standby switch
Output to all the active and standby systems.
Switch can be conducted, and all
The continuity test including the double entangled portion can be performed. And
With such a configuration, the ATM switch 100
The test conditions can be set from the console 160 of the present invention, which eliminates the need for connection of measuring instruments required in the conventional example, the test conditions can be easily set, and an efficient cell continuity test can be performed. Can be.

FIG. 2 is a diagram for explaining the second principle of the present invention. In the figure, 100 is an ATM switch, 110 is a subscriber card, 121 and 122 are common control units, 130 is a switch unit, 140 is a test device, 150 is an interface, 16
Reference numeral 0 denotes a console, which is the same component as that described with reference to FIG. Reference numeral 200 denotes a remote concentrator accommodated in the ATM switch 100, and reference numerals 211 and 212 denote subscriber cards, 2
Reference numerals 21 and 222 denote a common control unit, and reference numeral 230 denotes a concentrator.

In the present invention, when testing the subscriber card 211 accommodated in the remote concentrator 200, a test cell is transmitted from the test device 140 accommodated in the ATM switch 100, and the remote concentrator 200 receiving the test cell is transmitted. A test cell indicating bit (hereinafter, referred to as a T bit) indicating that the cell is a test cell is added to the test cell on the side thereof, and is returned to the subscriber card under test 211 through the common control unit 222. Send to 100.

At this time, since the test cell passes through the line L, the test cell needs to be in a format that does not include the T bit, and the common control unit 222 clears the T bit and sends it out to the line L.

The test apparatus 140 of the ATM switch 100 counts test cells received via the line L and performs a cell continuity test.

[0018]

FIG. 3 is a diagram for explaining a cell format according to the present invention. The cell continuity test of the present invention uses the ATM switch 1 to maintain the reliability of the ATM switch 100.
During the operation of 00, a test cell is inserted between user cells used for communication between users and transmitted to perform a continuity test. Therefore, in order to distinguish a user cell from a test cell, a test cell identification bit (hereinafter, referred to as a T bit) indicating that the cell is a test cell is given to the test cell.

The test device 140 sends a test cell with a test ID. In the present invention, the test ID is assigned to 6 octets, and the entire test cell is set to 54 octets.

Further, a pseudo random pattern is inserted into 8 to 54 octets, and the number of bit errors can be counted by checking the pseudo random pattern for errors.

The use of such a test cell enables the cell continuity test of the present invention. FIG. 4 is a diagram illustrating an embodiment (1) of the present invention. AT of the present invention
The M exchange 100 has a switch unit 130 having a three-stage configuration, and includes switches 131 to 133. The cell counter is provided in each component of the ATM switch 100, and includes a subscriber card 110, a common control unit 121,
22 is provided on the entrance side and the exit side, and when the result of the cell continuity test is NG, by comparing the count values of the cell counters before and after each of them, it is possible to easily identify the place where the cell has dropped out can do.

Further, since the test cell passes along with the user cell, the cell counter described in FIG. 4 may be constituted by a test cell counter (not shown) having a function of selecting and counting only the test cells. Accordingly, it is possible to eliminate the influence of the user cell.

FIG. 5 is a flowchart of cell reception according to the embodiment (1) of the present invention. Hereinafter, according to the steps of the flowchart (indicated by S in the figure), the test apparatus 140
Will be described.

S1: It is determined whether the VPI and VCI written in the header of the received cell match the designated values. S2: It is determined whether or not the value of PTI (Payload Type) matches the specified value.

S3: It is determined whether or not the value of CLP (Congestion Level) matches a specified value. S4: Determine whether or not the TEST-IDs match. S
If the result is 1 to S4, the process proceeds to S11.

S5: The count value of the received cell is counted up by "+1". S6: The CRC of the sequential number (shown as SN in the figure) of the test cell is checked.

S7: It is checked whether the sequential number is the sequential number of the previously received cell + 1 (the expected value of the sequential number is shown as SNR in the figure).

S8: If the sequential number does not match the expected value, the error cell counter is incremented by "+1". S9: If the sequential number matches the expected value, the sequential number + 1 is set as the next expected value.

S10: C of the sequential number of S6
If an error occurs in the RC check, the sequential number error counter is counted up by "+1", and the expected value of the sequential number is held as it is.

S11: If S1 to S4 are negative,
Discard the cell. By such processing, the number of normal receptions of the test cell, the number of occurrences of the CRC error of the sequential number, and the number of occurrences of the sequential number error are counted, and the cell continuity test is performed.

Such a test cell is inserted between user cells and transmitted and received, and can be automatically executed during operation of the ATM switch 100. Therefore, it is also possible to provide a cell continuity test scheduler and perform the cell continuity test at an arbitrary timing.

FIG. 6 is a diagram for explaining a test cell selector according to the present invention. In the present invention, the switch unit 130 has a three-stage configuration as described with reference to FIG.
In order to further enhance the reliability of the ATM switch 100, a duplex configuration is adopted, and the switch unit 130 is composed of a plurality of switches 131A to 133A and 131B to 133B.

For example, on the input side of the switch 132A, A
CT-based switch 131A and SBY-based switch 131
B is connected. Here, the cell monitoring unit 130A in the switch 132A monitors the T bit of the incoming cell, and when detecting a cell in which the T bit is set, selects the cell from the SBY system switch 131B at that timing. To the cell selection unit 130B.

With such a configuration, it becomes possible to select and flow a test cell from the SBY-system switch 131B. Although the upper diagram illustrates the switch 132A, all the switches 131A to 133A and 131B to 133B have the same configuration. With such a configuration, the test cell can be made conductive to both the ACT system and the SBY system. It is also possible to test the duplex confounding part, and the normality after system switching can be guaranteed.

FIG. 7 is a view for explaining an embodiment (2) of the present invention. The figure shows the subscriber card 1 from the test equipment 140.
11 and 12 show diagrams for performing a point-to-multipoint cell continuity test for sending test cells to the test cells 11 and 112. FIG. In the embodiment (2), the subscriber cards 111 and 112 are provided with a test cell discarding unit for discarding test cells and the cell counter described in FIG.

In the present invention, a test cell is transmitted from the test apparatus 140, and the common control units 121 and 122, the switch unit 13
0, a plurality of subscriber cards 111, 112 (3
The same is true for more than one. ). The subscriber cards 111 and 112 check the normality of each path by counting the number of test cells received by the cell counter. Also, if there is an abnormality,
A failure location can be easily specified from the count value of the cell counter provided in each device.

A broken line in the drawing indicates a route through which a test cell passes. Here, a state in which a cell copy is performed by the switch unit 130 and multipoint communication is performed is shown. Further, by discarding the test cells in the test cell discarding units of the subscriber cards 111 and 112, it is possible to prevent the used test cells from being mixed into other paths.

FIGS. 8 and 9 show diagrams (1) and (2) for explaining the embodiment (3) of the present invention. In ATM communication, since high reliability is required as a system, the line has a duplex configuration. One of the duplexed lines is called a working line, and the other line is called a protection line.The communication line is normally used for the working line, and when a failure occurs, the protection line is used. Switch to use. In order to maintain high reliability, it is necessary to check the normality of the protection line even while the working line is operating.

In the present invention, the T bit is identified by the common control unit 121 so that the test cell control unit 12 that allows the test cell from the non-service state subscriber card 112 to pass therethrough.
0B is provided.

The loopback test shown in FIG. 8A is performed by the line control unit of the common control unit 121 corresponding to the working line. The loopback test shown in FIG. Card 111
9C, a loopback test in the line corresponding section of the common control unit 121 corresponding to the protection line by the loopback setting shown in FIG. 9C, and a subscriber corresponding to the protection line by the loopback setting shown in FIG. 9D. A folding test with the card 112 can be performed.

9 (C) and 9 (D), the test cell from the protection line side is turned back to the common control unit 121, but since the T bit is "ON", it is confirmed that the test cell is a test cell. , And passes the test cell control unit 120B to the test apparatus 140.

In each loop-back setting, the test cell transmitted to the side where loop-back is not set is referred to by the header in each test cell discarding unit, and the test cell is discarded there because the T bit is on.

With such a setting, the working line and the protection line can be individually tested. FIG. 10 is a diagram for explaining the embodiment (4) of the present invention. In the figure, the common control unit 121 is provided with a T bit deletion unit 120A, and the subscriber card 110 is provided with a T bit addition unit 110A for adding a T bit.

In the subscriber card 110, the test cell with T bit = 1 is discarded without being sent to the line side. In FIG. 10, the T bit of the test cell transmitted from the test apparatus 140 is set to “0” by the T bit deletion unit 120A of the common control unit 121 in order to transmit the test cell to the line side. The test cell in which the T bit is set to “0” is specified by the header.
The data is output to the line via the subscriber card 110 to be tested.

The test cell output to the line is looped back at the line and input to the subscriber card 110. In the subscriber card 110, in order to indicate that the cell is a test cell, the T bit is set to "1" by the T bit adding unit 110A and transmitted, so that the cell is recovered by the test apparatus 140 and a cell continuity test is performed. be able to.

FIG. 11 is a diagram for explaining the embodiment (5) of the present invention. As described above, the ATM switch 100 is required to have a high degree of reliability, and each device constituting the ATM switch 100 is duplicated. One of the duplicated systems is referred to as a system 0, and the other system is referred to as a system 1. The system is switched and used when a failure occurs.

In the present invention, such a 0-system, 1-system AT
The test equipment 140 is mounted on each of the M exchanges 100 and 101, and the test cells are sent and returned independently from the test equipment 140 of the system 0 and the system 1 so that the continuity test of the routes of the ACT system and the SBY system is simultaneously performed. Can be.

In the figure, system 0 conducts the continuity test on the route in system 0 (shown by a thick line), and system 1 performs the continuity test on the route in system 1; Of course it can be done.

Further, in the configuration of FIG.
Reference numeral 40 denotes an independent configuration, and test conditions can be set independently from the console 160. For example,
The number and transmission speed of test cells can be set arbitrarily.

In the present invention, the test device 140 for transmitting a test cell is provided with a test identification number assigning unit (not shown). In general, the cell continuity test specifies a plurality of continuity routes and continuously performs them. ATM switch 100
The switch unit 130 has a buffer for temporarily storing cells and then transmitting the cells at a specified speed.

In the cell continuity test, when the test route is switched, the buffer of the switch unit 130
If the previous test cell for the continuity test remains, in the next test, the test cells are mixed, and the number of passed test cells cannot be correctly counted.

Therefore, in the present invention, a test identification number assigning section is provided, and a TEST-ID is assigned for each continuity test.
The T-ID makes it possible to separate the residual cells of the previous test, and to count the number of test cells accurately.

FIG. 12 shows a flowchart of the test route setting section according to the embodiment of the present invention. For example, as described with reference to FIG.
133, there are a plurality of routes from one terminal to another terminal. When all of the continuity tests are performed on a plurality of routes, a test of an overlapped route is performed, and the efficiency of the continuity test is reduced.

Therefore, in the cell continuity test, a test route is set by the test route setting unit so as not to test the duplicate route that passes through all the switches. S1: It is determined whether the switch unit 130 has a three-stage configuration.

S2: In the case of a three-stage configuration, the same input / output route in the second-stage switch (indicated by ICSW in the figure) is tested. (Same switch system) S3: A cross route test in the second-stage switch is performed. (Same switch system) S4: The same ingress / egress route in the second stage switch is tested. (Confound switch system) S5: A cross route test in the second stage switch is performed. (Confounding Switch System) S6: If not a three-stage switch configuration, an n × n intersection test is performed.

For example, in a conduction test of a three-stage switch using four 8-input, 8-output switches,
The number of continuity test routes can be reduced to about 1/4.
FIG. 13 is a view for explaining the embodiment (6) of the present invention. The figure shows a cell continuity test of the remote concentrator 200 accommodated in the ATM switch 100.

In the figure, the ATM switch 100 and the remote concentrator 200 are connected by a line L. In the cell format on the line L, the T bit is “0” and the remote concentrator 2
00 in the common control unit 12
It is set to "0" by the T bit deletion unit of 1.

The subscriber card 2 of each of the remote concentrators 201 and 202 that has received the test cell with the T bit set to "0"
Reference numeral 12 is set to T bit “1” by a T bit assigning unit. Then, the test cell set to the T bit “1” is transmitted to the subscriber card under test 211, and the subscriber card under test 2 is transmitted.
Turn around at 11. The common control unit 222 sets the T bit to “0” and sends it out to the line L.
Of the remote concentrator 200 by performing the cell continuity test.

Also in this configuration, the continuity test of the ACT system and the SBY system can be performed simultaneously by selectively passing the test cell by the selector 200A.

[0060]

According to the present invention, the test equipment for transmitting and receiving test cells is mounted in the ATM exchange, so that test conditions can be easily set from the console of the ATM exchange and the cell continuity test can be performed efficiently. Can do it.

Further, the test equipment is mounted on each of the duplicated ATM exchanges of the system 0 and the system 1 and independently set back, so that the cell continuity test of the ACT system and the SBY system can be performed simultaneously. Normality can also be guaranteed.

Further, a T bit indicating that the cell is a test cell is added to the test cell, and the T bit is monitored, and a passing and discarding process is performed. , APS line test, etc., necessary for the operation of the ATM exchange can be performed.

Further, the remote concentrator accommodated in the ATM exchange can simultaneously perform the ACT and SBY cell continuity tests.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first principle of the present invention.

FIG. 2 is a diagram illustrating a second principle of the present invention.

FIG. 3 is a diagram illustrating a cell format according to the present invention.

FIG. 4 illustrates an embodiment (1) of the present invention.

FIG. 5 is a flowchart of cell reception according to the embodiment (1) of the present invention.

FIG. 6 is a diagram illustrating a test cell selection unit according to the present invention.

FIG. 7 illustrates an embodiment (2) of the present invention.

FIG. 8 illustrates Embodiment (3) of the present invention (part 1).

FIG. 9 is a view for explaining an embodiment (3) of the present invention (part 2);

FIG. 10 is a diagram illustrating Embodiment (4) of the present invention.

FIG. 11 illustrates an embodiment (5) of the present invention.

FIG. 12 is a flowchart of a test route setting according to the present invention.

FIG. 13 is a diagram illustrating Embodiment (6) of the present invention.

FIG. 14 illustrates a conventional example.

[Explanation of symbols]

100, 101 ATM switch 110, 111, 112, 211, 212 Subscriber card 110A T-bit assigning unit 121, 122, 221, 222 Common control unit 120A T-bit deleting unit 120B Test cell control unit 130 Switch unit 131-133, 131A ~ 133A, 131A ~ 13
3B switch 130A cell monitoring unit 130B cell selection unit 140 test equipment 150 interface unit 160 console 200, 201, 202 remote concentrator 200A selector 230 concentrator 300 measuring instrument L line

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-268668 (JP, A) JP-A-7-38573 (JP, A) JP-A-7-15462 (JP, A) JP-A-4- 157841 (JP, A) JP-A-7-38565 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/24-12/28 H04L 12/56

Claims (8)

(57) [Claims] 1. A test cell integrated in an ATM switch.
A test device that performs generation, transmission and reception, and a test cell header from the test device are replaced, and the
And a common control unit for designating the cell and outputting the cell to an output destination designated from the header of the cell
The multi-stage switch configuration has redundant switches for the active and standby systems.
The switch unit is connected to the ATM switch and tests the ATM switch.
And console for inputting test data for a test information input from the console the test instrumentation
And an interface for sending to the common control unit
And the input and output sides of the switch unit and common control unit.
And a cell counter that counts cells that have passed
In the ATM exchange having, in the switch unit, which is duplicated in a multi-stage switch configuration, trial
A test cell selection unit for selecting a test cell, and the test cell selection unit of the switch unit
If a test cell indication bit is detected, the test cell selection
Select the cell input from the standby switch in the selector
A cell of an ATM exchange characterized by conducting a continuity test
Continuity test method. (2) A cell continuity of the ATM switch according to claim 1.
In the test method, The passage of test cells from a non-serviced subscriber card,
A test cell control unit for controlling disposal is provided, The cell indicates that it is a test cell, and the active system on the line side
A protection system on a working line or line side
To the working line,
Make a loopback setting on one side of the
The test cell is wrapped on the side where the wrap is set, and the other
On the side that is not set repeatedly, the test cell control unit
Cell for ATM exchange characterized by discarding test cells
Continuity test method. (3) A cell continuity of the ATM switch according to claim 1.
In the test method, Check that the cell turned back from the line side is a test cell.
Add bit to display Test cell display bit assigning section
Provided, Display the test cell in the cell turned back on the line side.
To perform a test cell continuity test
Characteristic ATM cell exchange cell continuity test method. (4) A cell continuity of the ATM switch according to claim 1.
In the test method, Incorporated into redundant system 0 and system 1 ATM switch
0-system and 1-system test equipment Make independent loopback settings for system 0 and system 1
The continuity test of the test cell of the auxiliary system is performed simultaneously.
A cell continuity test method for ATM exchanges. (5) A cell continuity of the ATM switch according to claim 4.
In the test method, The 0-system and 1-system test equipment are independently provided for the test cells.
The transmission rate and the number of test cells to be transmitted are set.
Cell continuity test method for ATM exchanges. 6. A cell continuity of the ATM switch according to claim 1.
In the test method, All of the switch sections that are duplicated in a multi-stage switch configuration
Route that passes through all switches and does not
The test route setting section that sets the test route to the test route is provided.
A cell continuity test method for an ATM exchange, characterized in that: 7. A cell continuity of the ATM switch according to claim 1.
In the test method, Test that assigns a test identification number within the test cell format
An identification number assigning unit is provided, When conducting a cell continuity test, the number of transmission test cells and the reception test
The number of cells is managed in test identification number units.
3. The cell continuity test system for an ATM exchange according to claim 2. Claim 8. A cell continuity of the ATM switch according to claim 1.
In the test method, A remote concentrator is housed in an ATM switch, A test cell is received from the test equipment accommodated in the ATM switch.
The remote concentrator that transmitted the test cell and received the test cell
Test bit and send it to the subscriber card under test.
The entrance card turns the test cell back, and the inside of the ATM switch
Of the test cell and conducts a continuity test of the test cell.
A cell continuity test method for an ATM exchange, characterized in that: