Multiplex communications – Diagnostic testing – Fault detection
Reexamination Certificate
1998-11-04
2003-01-21
Nguyen, Chau (Department: 2663)
Multiplex communications
Diagnostic testing
Fault detection
C370S252000, C370S395100
Reexamination Certificate
active
06510140
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to an ATM line evaluation system, and more particularly to an ATM line evaluation apparatus and method for performing an evaluation realizing easy understanding of a synthetic quality degree of ATM lines to be evaluated, the ratio of each parameter in the entirety, etc.
As is well known, in an ATM (Asynchronous Transfer Mode) line for use in data translation, cell data comprising a header portion and an information portion is used as a transmission data unit, and the cell data is transmitted to a line associated with address information of the header portion.
If a fault occurs in the process of data transmission, the cell data cannot be exactly transmitted.
It is thus necessary to periodically check the transmission quality of the ATM lines.
In general, the transmission quality of ATM lines is evaluated by the number of occurrence of three parameters: misinserted cell, lost cell, and errored cell. In other words, these three parameters are data considered on the basis of kinds of phenomena of errors. Specifically, these parameters correspond to the following phenomena.
The occurrence of the misinserted cell is
a phenomenon in which cell data is sent due to
a miswrite of address information of the cell data at
a relay portion or a branch portion of the ATM line.
The occurrence of the lost cell is a phenomenon in which cell data is sent to an erroneous address due to the occurrence of the misinserted cell.
The occurrence of the errored cell is a phenomenon in which cell data including an error is sent.
The frequencies of occurrence of such abnormal cells are conventionally specified by the ATM line evaluation standard, etc. as important parameters for evaluating the transmission quality of ATM lines.
In the conventional ATM line evaluation apparatus, in order to evaluate the transmission quality of an ATM line, the number of occurrence of each of misinserted cell, lost cell and errored cell in a predetermined time period is found and each of the obtained parameters is individually displayed on a display device.
In the conventional ATM line evaluation apparatus, however, the obtained parameters are individually displayed, as mentioned above, that is, displayed on the basis of kinds of phenomena of errors. Thus, a synthetic quality degree of lines to be evaluated, the ratio of each parameter in the entirety, etc. cannot easily be understood.
Specifically, in the conventional method of individually displaying the three parameters, the sum of the three parameters cannot easily be determined. Consequently, for example, in a case where the number of occurrence of each parameter is low but the sum of the numbers of occurrence of three parameters is not negligible, this condition may be overlooked.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above circumstances, and its object is to provide a measuring apparatus enabling the user to first understand quantitatively the general quality (or general errors) of an ATM line or the details thereof, i.e. conditions of errors based on kinds of phenomena, and then to easily make a quality judgment or take a measure relating to the quality of ATM line without fail. More specifically, this invention aims at providing an ATM line evaluation system including an ATM line evaluation apparatus and method for performing an ATM line evaluation realizing easy understanding of a synthetic quality degree of ATM lines to be evaluated, the ratio of each parameter in the entirety, etc., by displaying a sum value of three parameters in a predetermined time period.
In order to achieve the above object, according to an aspect of the present invention, there is provided an ATM line evaluation apparatus comprising:
misinserted cell detection means for receiving cell data from an ATM line and detecting a misinserted cell occurring due to a defect in a transmission operation of the ATM line;
lost cell detection means for receiving cell data from the ATM line and detecting a lost cell occurring due to a defect in the transmission operation of the ATM line;
errored cell detection means for receiving cell data from the ATM line and detecting an errored cell occurring due to a defect in the transmission operation of the ATM line;
misinserted cell counting means for receiving an output from the misinserted cell detection means and counting the number of misinserted cells in a predetermined time period;
lost cell counting means for receiving an output from the lost cell detection means and counting the number of lost cells in a time period identical to the predetermined time period;
errored cell counting means for receiving an output from the errored cell detection means and counting the number of errored cells in a time period identical to the predetermined time period;
data preparation means for totaling an output from the misinserted cell counting means, an output from the lost cell counting means, and an output from the errored cell counting means, and preparing data for displaying a strip-shaped graph having a length corresponding to the total value; and
display means for receiving an output from the data preparation means and displaying the strip-shaped graph.
In order to achieve the above object, according to another aspect of the invention, there is provided an ATM line evaluation method comprising the steps of:
receiving cell data from an ATM line and detecting a misinserted cell occurring due to a defect in a transmission operation of the ATM line;
receiving cell data from the ATM line and detecting a lost cell occurring due to a defect in the transmission operation of the ATM line;
receiving cell data from the ATM line and detecting an errored cell occurring due to a defect in the transmission operation of the ATM line;
receiving a detection output of the misinserted cell and counting the number of misinserted cells in a predetermined time period;
receiving a detection output of the lost cell and counting the number of lost cells in a time period identical to the predetermined time period;
receiving a detection output of the errored cell and counting the number of errored cells in a time period identical to the predetermined time period;
totaling a count output of the misinserted cell, a count output of the lost cell, and a count output of the errored cell, and preparing data for displaying a strip-shaped graph having a length corresponding to the total value; and
receiving an output from the data preparation means and displaying the strip-shaped graph.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
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Hideo Murakami et al: “Monitoring Method for Cell Transfer Performance in ATM Networks”, NTT Review, JP, Telecommunications Association, Tokyo, vol. 4, No. 4, Jul. 1, 1992, pp. 38-44, XP000310841—p. 40, paragraph 3—p. 42, paragraph 4.2.
G. Keiser et al: “Test Traffic Generation Equipment and Algorithms for Evaluating ATM Networks”, Computer Communications NL, Elsevier Science Publishers BV, Amsterdam, vol. 19, No. 12, Oct. 1, 1996, pp. 962-971, XP000635579, ISSN: 0140-3664—p. 964, paragraph 2.3—p. 966, paragraph 4.
Anritsu Corporation
Frishauf Holtz Goodman & Chick P.C.
Lee Andy
Nguyen Chau
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