VeEX RXT-6000e, User Manual

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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%
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.
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Evaluation According to ITU-T G.826
G.826 recommendation makes provision for higher bit rates and allows in-service measurement using the evaluation
of block errors.
The following are evaluated: ES, SES, BE, BBE, and UAS.
Pass/Fail result depends on path allocation of 0.1 to 100%.
In-Service Measurement (ISM): Simultaneous in-service measurement of “near end” and “far-end” of a selected
path.
Out-of-Service Measurement (OOS): Out-of-service measurement using bit errors in a test pattern.
Definitions:
Errored Second (ES): A one-second time interval containing one or more errored blocks.
Severely Errored Second (SES): A one-second time interval in which more than 30% of the blocks are errored
Block Error (BE): A block containing one or more errored bits.
Background Block Error (BBE):
An errored block that is not a SES.
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.
The recommended measurement time for G.821 and G.826 is 30 days.
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