8. Troubleshooting

Data Channel Loopbacks on a Frame Relay Link

A network-initiated Data Channel Loopback (DCLB) loops data over the frame relay link (DS0s) received on the network interface through the FrameSaver unit’s framing circuitry and back to the same interface.

A DCLB can be controlled over the frame relay link using one of the following in-band methods:

TV.54 Loopback.

ANSI T1.403 Annex B Fractional T1 (FT1) Channel Loopback.

The frame relay service provider can use DCLB to verify the integrity of the frame relay circuit.

Other

T1 All

Interface 1s

Framer

The T1

DCLB Interface

98-16223

CAUTION:

V.54 and FT1 Loopbacks 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.

8-32

September 2002

9128-A2-GB20-80

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Paradyne CSU, DSU, 9126-II, 9128-II manual Data Channel Loopbacks on a Frame Relay Link