Loopback Diagnostics

Loop Back Configure/Query message

The Loop Back Configure/Query message can help to determine whether the cause of a problem is inside or outside of the CSP. The message works by looping signals from the E-ONE, T-ONE, and DS3 cards back to the network. To enable remote loopback, first take the span you want to use out of service. In the Loop Back Configure/Query message, specify a logical span ID and set the action flag to enable loop back.

The E-ONE and T-ONE cards also include card diagnostics for carrier group alarm detection and generation, loss of frame and signal detection, and loop timing support. The host uses the Span Status Query message to retrieve the following statistics:

• Bipolar/Code violations

• Excessive zeroes

• Slips

• Cyclic Redundancy Check (CRC) errors

• Out Of Frame (OOF) defects

• Alarm Indication Signal (AIS) defects