JP3131945B2 - Line test apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line test apparatus and a test method capable of specifying a section where an error that does not lead to a failure or an intermittent failure has occurred.

[0002]

2. Description of the Related Art In a conventional line test method, when an error that does not lead to a failure or an intermittent failure occurs, a troublesome operation such as performing a plurality of tests is necessary to specify a section of a failure point. This is necessary, and in some cases, the section of the fault point cannot be specified. FIG. 5 is an apparatus configuration diagram showing an example of a case where a conventional line test method is performed, and FIG. 6 is a detailed block diagram of a test function unit in FIG. here,
A line test method based on the ATM system using fixed-length cells will be described. In FIG. 5, reference numerals 550 and 556 denote terminal devices,
51 and 555 are terminal devices for terminating the communication network, and 552 and 5
Numeral 54 denotes a subscriber exchange that accommodates terminals, 553 a transit exchange that performs transit exchange between the subscriber exchanges, and 501 and 5.
Reference numerals 12, 506 and 507 denote cables connecting the terminal device to the terminating device, 502, 511, 505 and 508 denote transmission lines connecting the terminating device and the local exchange, 503 and 51
0, 504 and 509 are relay transmission lines for connecting the local exchange and the transit exchange, and 513, 514, 515, 51
Reference numerals 6, 517, and 518 denote a return path when the return setting is performed, and T denotes a test function unit including a test cell transmission unit, a test cell reception unit, and a test result determination unit. In FIG. 6, reference numeral 600 denotes a test function unit T; 603 and 604, test cells to be transmitted and received; 601, a sequence number is assigned to a part of a payload field of a test cell to be transmitted; Test cell transmission unit S, 60 having a function of generating and transmitting while increasing the
Reference numeral 2 denotes a test cell receiving unit R having a function of reading out a sequence number written in a part of a payload field of a reception cell, and 605 continuously receives a sequence number read by the test cell receiving unit R without dropping. A test result determination unit C that determines whether the continuity test is successful or not after confirming that the continuity test is performed.

[0003] In the communication between the terminal devices 550 and 556, an error or an intermittent failure that does not lead to a failure occurs, but if a failure point cannot be specified by an alarm transfer or the like, the following (1) to (5) In the procedure of (6), the terminal devices 551 and 55
The simulated section between 5 was specified. (1) First, in order to confirm conduction between the relay switching device 553 and the terminal device 550, T-510-511-512-
A test loop is formed by the path 513-501-502-503-T. Test cell receiver (R) 60 in FIG.
2 in a receivable state, a sequence number is assigned to a part of the payload field from the test cell sending unit (S) 601, and the test cell is increased by, for example, 1,000 while incrementing the sequence number by 1 from an initial value of 1. , 000 are generated and transmitted. The sequence number of the test cell read by the test cell receiving unit 602 is used as the test result determining unit (C) 60 in FIG.
5, the test result determination unit 605 determines that the continuity test was normal by confirming that the sequence numbers of the received cells are continuously received without any loss. (2) Next, the relay switching device 553 and the terminal device 55 shown in FIG.
T-510-511-5 to confirm conduction between
14-502-503-T forms a test loop. The test cell receiving unit 602 in FIG. 6 is set to a receivable state. The test cell transmitting unit 601 assigns a sequence number to a part of the payload field, and generates and transmits, for example, 1,000,000 test cells while increasing the sequence number by one from an initial value of 1. The sequence number of the test cell read by the test cell receiving unit 602 is passed to the test result determination unit 605, and the test result determination unit 605
It is determined that the continuity test was normal by confirming that the sequence number of the received cell was continuously received without any loss.

(3) Next, in order to confirm the continuity between the transit exchange unit 553 and the subscriber exchange unit 552 in FIG.
A test loop is constituted by 510-515-503-T.
The test cell receiving unit 602 in FIG. 6 is set to a receivable state. Next, the test cell sending unit 601 assigns a sequence number to a part of the payload field, and increases the sequence number by one from the initial value, and assigns a test cell to the test cell.
For example, 1,000,000 are generated and transmitted.
The sequence number of the test cell read by the test cell receiving unit 602 is passed to the test result determination unit 605, and the test result determination unit 605 confirms that the sequence number of the received cell is continuously received without loss. By doing so, it is determined that the continuity test was normal. (4) On the other hand, the relay switching device 553 and the terminal device 55 of FIG.
In order to confirm the continuity between the six, T-504-505-5
A test loop is formed by the route of 06-518-507-508-509-T. The test cell receiving unit 602 in FIG. 6 is set to a receivable state. A sequence number is assigned to a part of the payload field from the test cell transmitting unit 601 in FIG.
For example, 1,000,000 test cells are generated and transmitted while increasing the sequence number by one from the initial value 1. The sequence number of the test cell read by the test cell receiving unit 602 is passed to the test result determination unit 605, and the test result determination unit 605 confirms that the sequence number of the received cell is continuously received without loss. Thus, it is determined that the continuity test was normal.

(5) Next, in order to confirm the continuity between the relay switching device 553 and the terminating device 555 in FIG.
A test loop is constituted by the path of -505-517-508-509-T. The test cell receiving unit 602 in FIG. 6 is set to a receivable state, a sequence number is assigned to a part of the payload field from the test cell transmitting unit 601, and the test cell is increased while the sequence number is incremented by one from an initial value of 1, for example. 1,000,000 are generated and transmitted. The sequence number of the test cell read by the test cell receiving unit 602 is passed to the test result determination unit 605, and the test result determination unit 605 confirms that the sequence number of the received cell is continuously received without loss. Thus, it is determined that the continuity test was normal. (6) Next, in order to confirm the continuity between the transit exchange apparatus 553 and the subscriber exchange apparatus 554 of FIG.
A test loop is formed by the route 6-509-T. The test cell receiving unit 602 in FIG. 6 is set to a receivable state. A sequence number is assigned to a part of the payload field from the test cell transmitting unit 601 in FIG.
Generate and send out 00,000. Test cell receiver 6
02 is passed to the test result determination unit 605, and the test result determination unit 605 confirms that the sequence number of the received cell is continuously received without any loss, thereby providing conduction. Judge that the test was normal.

[0006]

However, when the above-described line test method is performed, the following problems occur. That is, it is necessary to carry out a line test while changing the turning point a plurality of times, in the case of intermittent failure, that the simulated section cannot be specified, it is difficult to perform a long test, and It is difficult to carry out the test. SUMMARY OF THE INVENTION An object of the present invention is to solve these conventional problems, and to specify a simulated section in which an error that does not lead to a failure or an intermittent fault has occurred. It is to provide an apparatus and a method.

[0007]

In order to achieve the above object, in the circuit test apparatus of the present invention, a field for writing a sequence number is provided in a payload section (user data section) of a test cell or a frame, and a sequence is written in the field. FIG. 1 shows a test cell (frame) transmission / reception function having a function of generating and transmitting a test cell or frame by writing a number while increasing the number by one from an initial value, and a function of receiving and erasing the test cell or frame. Are provided in the relay switching device 153 shown in FIG. 1, and A, B, C, D,
A monitor function for monitoring test cells or frames passing through E, F, G, H, I, J, K, L; a lost cell (frame) storage area for storing the sequence numbers of lost test cells or frames; The loss is determined by the continuity of the sequence number for each test cell or frame,
The test cell (frame) monitoring function of writing the sequence number in the lost cell (frame) accumulation area only when it is found that the sequence number is missing is shown in FIG.
C, D, E, F, G, H, I, J, K, L And, as a line test configuration, as shown in FIG.
ST-J-110-KL-115-AB-103-
CD-104-EF-116-GH-109-I
-TST test loop, or TST-J-110-K
-L-111-114-102-AB-103-C-
D-104-EF-105-117-108-GH
-109-I-TST test loop or TST-J
-110-KL-111-112-113-101-
102-AB-103-CD-104-EF-1
05-106-118-107-108-GH-10
A, B, C, D, E, F, G, H, I, J, K on the test loop that constitutes the test loop of 9-I-TST and holds the sequence number of the lost test cell , L are identified by comparing the lost cell storage areas provided in each of the lost cell storage areas.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, a case will be described in which the present invention is applied to an ATM system using fixed-length cells. It should be noted that the frame relay system using a frame can be implemented in exactly the same manner. FIG. 1 is a configuration diagram of a line test loop using a line test method according to an embodiment of the present invention. In FIG. 1, 150 and 156 are terminal devices, 151 and 155 are terminating devices terminating a communication network, 1
52 and 154 are local exchanges accommodating terminals, 153.
Is a transit exchange that relays the subscriber exchange, 101,
112, 106 and 107 are cables connecting the terminal and the terminating device, 102, 111, 105 and 108 are transmission lines connecting the terminating device and the local exchange, 103, 11
Reference numerals 0, 104 and 109 denote transit transmission lines for connecting the local exchange and the transit exchange, and 113, 114, 115 and 11 respectively.
6, 117 and 118 are return paths in the return setting state, A, B, C, D, E, F, G, H, I, J, K,
L is a monitoring function, a test cell monitoring function, and a test function unit including a lost cell storage area, 160 is an operation device for operating and monitoring each switching device, and TST is a test cell transmission / reception function.

FIG. 2 is a detailed block diagram of the monitor function, test cell monitoring function, and lost cell storage area in FIG. 2, reference numeral 200 denotes a test function unit; 201, a monitor function unit that monitors test cells passing through the test function unit 200; 203, a storage device in the switching device; 204, a lost cell storage area assigned to the storage device 203; It is. Further, SEQ1 and SEQ1 in the lost cell accumulation area 204
2,..., SEQn are accumulation tables holding the sequence numbers of the lost test cells, 202 is to monitor the continuity of the sequence numbers of the payload portions of the test cells read out by the monitor function, Only a test cell monitoring function unit having a function of retaining the sequence number of the test cell in the lost cell storage area 204. Four of these test function units 200 are provided in each of the transit exchange 153 and the subscriber exchanges 152 and 154.
FIG. 3 is a detailed block diagram of the test cell transmission / reception function in FIG. In FIG. 3, reference numeral 300 denotes a test cell transmission / reception function unit, and 301 has a function of assigning a sequence number to a part of the payload field of the test cell, generating and transmitting the sequence number while increasing the initial value by one from an initial value. A test cell transmission unit, 302 is a test cell reception quenching unit,
Reference numeral 303 denotes a test cell transmitted with a sequence number from a part of the payload field and transmitted from the test cell transmitting unit 301, and reference numeral 304 denotes a test cell returned from the above-described test route. It should be noted that the test cell reception annihilation unit 302 can include functions equivalent to those of the test function unit 200 shown in FIG. Such a test cell transmission / reception function 300
It is provided in the relay switching device 153.

FIG. 4 is a diagram showing a configuration example of a test cell used in the present invention. In FIG. 4, reference numeral 400 denotes an SEQ field for writing a sequence number of a test cell, which has a length of, for example, 5 bytes. Payload is a payload field. Test cell header (Hea
der) is based on ITU-T Recommendation I.D. 361, wherein the VPI is Virtual Path I
D and VCI are Virtual Connection
ID and PT are PayloadType, CLP is Cel
l Loss Priority, HEC is Heade
r Error Control. FIG. 7 shows FIG.
3 is a detailed block diagram of an operation device for operating and monitoring the switching device shown in FIG. 7, reference numeral 700 denotes an operation device; 701, a storage device provided in the operation device; 702, a test result collection area;
A, 702B,..., 702L are test result collection flags indicating the presence or absence of loss of the test cell.

An example of the ATM system using fixed-length cells will be described below. In FIG. 1, one terminal 1
In the communication between the terminal 50 and the other terminal 156, an error that does not lead to a failure, an intermittent failure, or the like has occurred. , The simulated section is specified by the following procedures (1) to (5). (1) The TS shown in FIG.
TJ-110-KL-111-114-102-A
-B-103-CD-104-EF-105-11
7-108-GH-109-I-TST.
For example, as a logical path for a line test, a logical path for a line test is configured on the same physical line as the user path using the same VPI value and VCI value as the user path. As a logical path for a line test, it is also possible to configure a logical path for a line test using a VPI value and a VCI value separately for the line test on the same physical line as the user path. (2) Each switching device 152, 153, 154 shown in FIG.
Test function units A, B, C, D, E, F, G, H, I,
Test cell monitoring function 201 provided for J, K, L
Then, the test cell monitoring function 202 (see FIG. 2) is operated to initialize all the lost cell accumulation areas 204 to “0”.

(3) Test cell transmission / reception function unit T shown in FIG.
The test cell receiving unit R in the ST is operated to provide a field (400) for writing a sequence number in the payload from the test cell transmitting / receiving function TST, and the sequence number is incremented by one from the initial value 1 in the field. For example, 1,000,000 test cells are generated and transmitted to the line test route. (4) For example, in FIG. 1, the test cell transceiver TS
It is assumed that one test cell to which the sequence number 1000 transmitted from T is assigned has been lost in the relay transmission line 109. At this time, the test cell monitoring function unit 202 in the test function unit I in the relay switching apparatus 153 does not detect the sequence number 1000. Therefore, it is determined that the test cell to which the sequence number 1000 has been assigned has been lost. The number 1000 is stored in the storage table S of the lost cell storage area 204 (see FIG. 2) in the test function unit I.
Write to EQ1 and hold it. However, in the test function units J, K, L, A, B, C, D, E, F, G, H,
Since no lost cell is detected, the lost cell storage area 20
No. 4 does not hold a sequence number.

(5) After the transmission of the test cell is completed, the operation device 700 shown in FIG.
52, 153, and 154, the storage tables SEQ1 and SEQ of the lost cell storage area 204 (see FIG. 2).
It is determined whether a sequence number is held in SEQn by J, K, L, A, B, C, D, E, F, G,
Confirm in the order of H and I. For example, when a sequence number is held in the lost cell accumulation area 204, the storage device 701 provided in the operation device 700
(See FIG. 7), each monitor point A, B, C, D,
Flag 1 is written to test result collection flags 702A, 702B,... 702L for each of E, F, G, H, I, J, K, and L. In this embodiment, J, K, L, A, B, C, D,
When the loss sequence numbers are confirmed in the order of E, F, G, H, I, J, K, L, A, B, C, D, E, F, G, H
Since the sequence number is not held in the lost cell accumulation area 204 in the test result collection area 204, the test result collection flags 702A, 702B, 702C, and 7 in the test result collection area 702 are stored.
702L, 1 is not written, but in the description of (4) above, on the assumption that the test cell has been lost in the relay transmission line 109, the lost cell storage area 204 in the test function unit I is stored. Since it is determined that the sequence number 1000 is held in the accumulation table SEQ1,
The flag 1 is written to the test result collection flag 702I.

The test result collection flag 702 of the test function unit I
A flag indicating that the test cell has been lost is held in I, and the section HI is not set before the test result collection field of the test function unit H in the preceding stage because the flag is not held. Specify as a simulated section. The test result collection area 702 of the operation device 700 can be included in the switching devices 152, 153, and 154 to determine the test result. That is, in the present embodiment, it is possible to specify an simulated section in which an error that does not lead to a failure or an intermittent failure has occurred by performing only one line test. In the embodiment, the case where the present invention is applied to the ATM system using fixed-length cells has been described. However, it is needless to say that the same applies to the case where the present invention is applied to the frame relay system using frames. In addition, as a test route, the terminal device 15
1, 155, but in addition, TST-J-110-KL-115-AB-1
03-CD-104-EF-116-GH-10
9-I-TST test route, ie, local exchange 1
Route to be turned back at 52,154 and TST-J-11
0-KL-111-112-113-101-102
-AB-103-CD-104-EF-105-
106-118-107-108-GH-109-I
-TST test route, ie, terminal devices 150 and 156
It goes without saying that a line test using a route that is turned back can also be performed. Further, in the embodiment, the test cell or the frame transmission / reception function TST is arranged in the relay switching device 153. However, the transmission / reception function can be attached to the outside of the switching device.

[0015]

As described above, according to the present invention,
A line test to identify an erroneous section in which an error or an intermittent failure that does not lead to a failure has occurred, without performing a line test while changing the turning point multiple times,
It can be implemented with low operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a line test route showing one embodiment of the present invention.

FIG. 2 is a detailed block diagram of a test function unit having a monitor function, a lost cell monitoring function, and a lost cell storage area provided in each switching device in FIG. 1;

FIG. 3 is a detailed block diagram of a test cell transmitting / receiving function in FIG. 1;

FIG. 4 is a structural diagram of a test cell used in the present invention.

FIG. 5 is a configuration diagram of a test route showing a conventional line test method.

FIG. 6 is a detailed block diagram of a test cell transmitting / receiving function unit in FIG. 5;

FIG. 7 is a detailed block diagram of the operation device in FIG. 1;

[Explanation of symbols]

101, 112, 106, 107... Cables connecting terminals and terminating devices; 102, 111, 105, 108... Transmission lines between terminating devices and local exchanges;
104,109 ... Transmission path between transit exchange and subscriber exchange, 150,156 ... Terminal, 151,154 ... Subscriber exchange. 153: relay switching device, 160: operation device, A, B, C, D, E, F, G, H, I,
J, K, L: test function unit, TST: test cell (frame) transmission / reception unit, 200: test function unit, 201: monitor function unit, 202: test cell (frame) monitoring unit, 203:
Storage device, 204: lost cell (frame) storage area,
205: Test cell, SEQ1, SEQ2, ..., SEQ
n: accumulation table, 300: test cell (frame) transmission / reception unit, 301: test cell transmission unit, 302: test cell reception unit, 303, 304: test cell (frame) 400: sequence field unit, 700: operation device, 701 ... storage device, 702 ... test result collection area, 701A, 701B, ..., 701L ... test result collection flag.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-327753 (JP, A) JP-A-7-15432 (JP, A) JP-A-58-97941 (JP, A) JP-A-4- 81046 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 H04L 12/28 H04L 12/26 H04L 12/42

Claims (3)

(57) [Claims] 1. A line test apparatus provided in an exchange that performs communication by an ATM system using fixed-length cells or a frame relay system using a frame, wherein a test cell or a frame having a sequence number written in a payload portion. In order to determine the loss of the test cell, the continuity of the sequence number for each test cell or each frame is determined at each of the test loops, and the test cell or frame determined to be lost due to the lack of the sequence number is determined. A test cell or frame monitoring function unit for holding a sequence number in a storage area; and generating a plurality of test cells or frames while increasing the sequence number of the test cell or frame by one from an initial value, and generating the test cell or frame. The frames are sequentially transmitted to the test loop, and the test loop is traversed. And with said test cell or test cell to receive and eliminate the frame or the frame transmission and reception function unit that has returned to the sequence number of the missing test cells or frames are held in the storage area of the test cell or frame monitoring unit, Loss in the order of test cell travel on the test loop
A test result collection function unit that reads the presence or absence of a lost sequence number, stores the presence or absence of the read sequence number in a storage area corresponding to the test cell or the frame monitoring function unit, and uses it as information for specifying a simulated section. A line test apparatus characterized by having: 2. The line test apparatus according to claim 1, wherein a field for writing a sequence number is provided in a payload portion of the test cell or the frame, and the test cell is incremented by one from an initial value in the field. Or a line test characterized in that a test cell or a frame transmitting / receiving function unit for generating a frame, transmitting the test cell or the frame to the test loop, and receiving / erasing the cell or the frame is provided outside the switching equipment. apparatus. 3. A line test method for a communication system in which communication is performed by an ATM system using fixed-length cells or a frame relay system using a frame by using a switching device having a line test function unit. communication line or the user communication line folded state as disconnecting the user terminal in the network unit or Te subscriber switching device smells that accommodates the user terminal, the user communication line of the folded state as disconnecting the user terminal, and each configuration A test cell or a frame transmission / reception function unit for transmitting / receiving a test cell or a frame is arranged at one point on a test loop to be performed, and a test cell or frame to which a sequence number is assigned is generated from the test cell or the frame transmission / reception function unit to perform the test. the cell or frame is sent to the test loop, the The test cell or frame passes above test loop
Monitoring by the line test function unit, the test cell or
Of the sequence number written in the payload
Monitor continuity and if the sequence number is missing
Is considered to be a loss of the test cell or frame and
The sequence number of the test cell or frame
Lost cell or frame storage area provided in Nobu
And loops around the test loop including the line test function section and returns.
The test cell or frame that has been
After receiving / erasing by the frame transmission / reception function unit and completing transmission of the test cell or frame, the test loop
The test cell or frame in the above line test function
Direction of the test cell on the test loop
Check for the presence of a loss sequence number in the order
Lost cell or frame storage error
Line test function unit of switching equipment having rear and in front of this function unit
The section between the line test function sections of the switching equipment
Line testing method, characterized by a constant.