XtendLan XL-GDB series User’s Guide
multi-rate capability of the XL-GDB SHDSL access system provides needed flexibility for service
providers deploying today’s digital services.
2.4 Real-time Performance Monitoring
The system provides extensive real-time, non-disruptive monitoring of system performance. DSL
transmission and interface port parameters are continuously monitored. Current and historical
data is available to assist you in identify sources of problems during troubleshooting.
2.4.1 Monitored Parameters
Signal/Noise Ratio:
This is a DSL transmission parameter, measured in dB, which indicates the
Signal-to-Noise (S/N) ratio at a receiver point. The signal-to-noise value is available on the CID’s
status screen and the value is updated every second.
DSL CRC-6:
This is a 6-bit word in every DSL frame, representing a calculation based on all the
bits in that frame except for FAW and CRC-6 bit word. Any mismatch at the receiver, between the
received CRC-6 and the one calculated based on the received data in the frame, indicates one or
more bits were received in error in that second and it is considered and Errored Second (ES).
DSL Sync Loss:
To assure proper synchronization between DSL transceivers, a sync word is
generated in every frame. A sync loss is declared when one or more bits in five consecutive sync
words are detected in error. When this happens, the entire second of data is considered an
Unavailable Second(UAS).
2.4.2 History Reports
Based on detected parameters, the following derived performance
parameters are calculated:
Error Seconds (ES):
a second in which at least 1 CRC-6 error is detected.
Sever Error Seconds (SES):
a second in which at least 150 CRC-6 errors are detected.
Unavailable Seconds (UAS):
a second in which one or more sync loss ebeny has occurred.
Cumulative counts of these parameters are displayed via the console as discussed in Chapter 5
“Configuration/Operation.” The readout displays the total count of each parameter since the last
time the count was cleared.
2.4.3 Status Readouts
In addition to history reports, the XL-GDB provides current status readouts via CID. The Status
menu displays the signal/noise ratio as well as loss of sync or errored CRC. For the synchronous
interfaces such as V.35, the status of clock and control lead is shown. For the G.703 interface,
such status items as HDB3 detected, frame bit error, carrier loss, yellow alarm and sync loss are
indicated if they are present.
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Summary of Contents for XL-GDB101V
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