VeEX UX400, User Manual

Page: 133 / 209

A graphical timeline on the horizontal axis indicates when the event occurred while the vertical axis indicates the logarithmic scale of errors. The upper left and right arrows
allow the user to scroll through the measurement period, while the + and – keys allow zooming in/out of the time axis.
Go back to top Go back to TOC
7.2.7 Performance Analysis
The Analysis tab displays measured objectives from ITU-T performance tests selected from the Measurements tab (
Setup
>
Measurements
). For a brief description of
supported G-Series and M-Series performance tests as well as setup instructions, please see 7.1.2.2 Performance Analysis .
7.2.7.1 Evaluation According to ITU-T G.821
This recommendation was originally specified for international circuit-switched N x 64kbps connections and later expanded to include higher bit rates.
ES, SES, AS and UAS are evaluated and can be performed on the following events:
FAS bit errors (FAS 2, FAS 34)
CRC errors
E bit errors
Bit errors (TSE, Test Sequence Error)
The following signals can be measured when performing G.821 evaluation of bit errors (TSE):
Unframed patterns
N x 64kbps
Framed patterns and bulk signals
Pass/Fail result is in conjunction with path allocation between 0.1 and 100%
Note:
ITU-T G.821 evaluates bit errors, therefore, facilities for evaluating block errors are disabled. G.821 relies on the evaluation of bit errors, thus the test channel must be
taken out of service to perform the measurement.
Definitions:
Errored Second (ES):
A one-second time interval in which one or more bit errors occur.
Severely Errored Second (SES):
A one-second interval in which the bit error ratio exceeds 10
-3
.
Unavailable Second (UAS):
A circuit is considered to be unavailable from the first of at least ten consecutive SES. The circuit is available from the first of at least ten
consecutive seconds which are not SES.
Available Second (AS):
A one-second time interval in which no bit errors occur.
Errored Free Second (EFS):
A one-second time interval in AS during which no errors and no pattern slips have been detected.
G.821 Analysis
UX400 10G e-Manual D07-00-058P RevA00 Page 133 of 209