Intelligent line testing

Details Intelligent line testing Intelligent line testing

2000-08-02

2004-10-12

Nguyen, Duc (Department: 2643)

Telephonic communications

Diagnostic testing, malfunction indication, or electrical...

Of trunk or long line

C379S022030, C379S029010

Reexamination Certificate

active

06804328

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to line testing in a telephony system, and in particular to intelligent and automated line testing.
BACKGROUND OF THE INVENTION
Subscribers to the public switched telephone network (PSTN) are typically connected to a local switching system via groups of wires, commonly referred to as subscriber lines or subscriber loops. Telephone companies serving these subscribers must test these lines for operability and quality. Such testing may occur when known problems exist, or during preventative maintenance to monitor line quality or detect outages. Given the ever-increasing number of subscribers and lines necessary to service these subscribers, significant time and resources are dedicated to providing routine, automated line testing (ALT) for the subscriber lines.
Traditionally, automated line testing was conducted, by instructing a switch to sequentially test a range of numbers associated with a group of subscriber lines handled by the particular switch. As shown in
FIG. 1
, an operational support system (OSS)
10
is used to decide which subscriber lines to test. Testing occurs when the OSS
10
sends instructions to one of the test heads
12
to test a group of subscriber lines
14
handled by switch
16
. As depicted, the subscriber lines
14
connect a line interface
18
with a subscriber
20
. Exemplary line testing capable OSS's are Nortel Networks' AccessCare, Lucent Technologies' LMOS-MLT, and Teradyne's 4TEL.
The test heads
12
connect to a metallic test access cross-connect (MTACC)
22
over dedicated analog test trunks or pairs
24
. The MTACC
22
may selectively connect any one of the analog test trunks directly to a line interface
18
associated with a subscriber line
14
. Notably, the connection between the test head
12
and a selected subscriber line
14
is a direct, metallic connection. Preferably, the test heads
12
are fairly proximate to the switch
16
, and the metallic connection between the test head
12
and the tested subscriber line
14
is as direct as possible.
To test any particular subscriber line
14
, the OSS
10
sends an appropriate instruction to a test head
12
. The test head will dial a number associated with the subscriber line
14
over the analog test pairs
24
. The switch
16
recognizes that the number dialed over the analog test trunk is an instruction to facilitate a line test for the associated subscriber line
14
. The switch
16
then effects a direct connection between the analog test pairs
24
and the line interface
18
associated with the subscriber line to be tested. At this point, the test head
12
has a direct, electrical and mechanical connection to the tested subscriber line
14
and tests the subscriber line
14
in traditional fashion. For automated line testing, the OSS
10
will instruct a test head
12
to test subscriber lines associated with a range of numbers. For example, the OSS
10
may instruct the test head
12
to test all subscriber lines
14
having a local exchange 555-XXXX. As such, all numbers within the exchange from 555-0000 through 555-9999 are tested.
Unfortunately, the OSS
10
has little or no information regarding the actual hardware configuration of the switch or how the various subscriber lines are arranged and placed within the numerous shelves, drawers, and cards used to store the line interfaces
18
. Further, there are typically at least two test heads for any given switch
16
, and the test heads
12
typically test their set of lines concurrently. Since there is no coordination between the OSS
10
and the allocation and assignment of subscriber lines
14
in the switch
16
, there is often contention for common resources between the test heads
12
during automated line testing.
Typically, the test head
12
can only test one subscriber line at a time. Further, the switches
16
are normally configured such that the MTACC
22
can provide only one access path for any group of subscriber lines
14
. For example, the MTACC
22
may only provide one connection for a shelf of line interfaces
18
. Thus, only one test head
12
can gain access to the shelf at any given time. Since the OSS
10
doesn't know the assignment and allocation of the subscriber lines
14
, it may request multiple test heads
12
to simultaneously test subscriber lines
14
that are on a common shelf. When this happens, there is a contention for access to the subscriber lines
14
by the test heads
12
. As such, there is an interruption in the automated line testing for one of the test heads
12
.
Another type of interference with line testing occurs when a subscriber
20
is using the particular subscriber line
14
slated for testing. The automated line testing is interrupted, because the OSS
10
isn't aware that the subscriber line
14
is being used. For smaller switches
16
, contention between test heads
12
and use by subscribers
20
have not posed significant barriers to line testing. Larger switches and media gateways providing switching functions are more greatly affected by decreases in line testing efficiency. For example, the smaller switches may support only 640 lines or less. In contrast, larger gateways may support up to 16,000 lines or more and may be further grouped in clusters where millions of lines require testing on an automatic and periodic basis. As such, there is a need for an efficient and intelligent way to provide automated line testing in an efficient manner that avoids the contention or line use problems described above.
SUMMARY OF THE INVENTION
The present invention provides for intelligent and efficient line testing by allowing a test control entity, such as an operational support system (OSS), to obtain information bearing on testing telephony lines. The information to be obtained relates to the structure or operation of the switching device. Preferably, the information obtained includes suggestions of which lines to test using test heads associated with the switching device. The suggestions may include a list of numbers that can be tested concurrently. Such suggestions may assist the OSS in providing instructions to the test heads to avoid line contention during testing, testing lines that are in use, or any number of scenarios potentially detrimental to efficient line testing. The information or suggestions may be obtained from an element manager or like entity having information about a particular switching device, or may be obtained directly from the switching device.
As such, the OSS will request line test instructions from the element manager or gateway, which will in turn provide line test instructions or suggestions back to the OSS. Based on the received information, the OSS will develop and provide line instructions to one or more test heads, which will carry out line tests at the switching device.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon reviewing the following description of the preferred embodiments of the invention in conjunction with the accompanying figures.


REFERENCES:
patent: 4611320 (1986-09-01), Southard
patent: 4677665 (1987-06-01), Walker
patent: 4939765 (1990-07-01), Benjamin et al.
patent: 5521958 (1996-05-01), Selig et al.
patent: 6061429 (2000-05-01), Clowez
patent: 6209108 (2001-03-01), Pett et al.
patent: 6295339 (2001-09-01), Jollota

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