8. Troubleshooting

Line Loopback

The Line Loopback (LLB) loops the information received on the selected interface back to the source of the loopback. When used with a pattern test at the remote node, LLB determines whether the problem is with the sending device or the T1 facility.

Main Menu TestNetwork Physical Tests

Other

All

T1

Interface

1s

 

Framer

LLB

The T1

Interface

 

97-15336

CAUTION:

This test may affect operation of frame relay PVCs assigned to the selected port. While in loopback, the frame relay link will be down so any IP data being sent while this test is active will be disrupted.

An LLB cannot be started when one of the following tests is active:

Payload Loopback, Send Remote Line Loopback, or an active Monitor Pattern on this network interface.

Repeater Loopback on any other T1 interface with DS0s assigned to this network interface.

Send Pattern Test on this network interface or any synchronous data port (Port

TUse set to Synchronous) assigned to this interface.

Send V.54 or FT1 Loopback, or Data Channel Loopback on any synchronous data port (Port Use set to Synchronous) assigned to this network interface.

9128-A2-GB20-80

September 2002

8-27

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Paradyne CSU, DSU, 9126-II, 9128-II manual Line Loopback, Main Menu → Test→ Network Physical Tests, Llb