The Analysis tab displays measured objectives from ITU-T performance tests selected from the Measurements tab (Setup > Measurements).

 

Evaluation According to ITU-T G.821

This recommendation was originally specified for international circuit-switched N x 64kbps connections.

 

ES, SES, AS and UAS are evaluated and can be performed on the following events:

• Bit errors (TSE, Test Sequence Error)

 

The following signals can be measured when performing G.821 evaluation of bit errors (TSE):

• Unframed patterns

• Pass/Fail result is in conjunction with path allocation between 0.1 and 100%

 

ITU-T 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.