Troubleshooting
6-28
9124-A2-LB20-00
March 2000
Data Channel Loopbacks on a Frame Relay Link
A network-initiated Data Channel Loopback (DCLB) that 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:
H V.54 Loopback.
H 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.
Framer
Other
T1
Interface
DCLB
The T1
Interface
All
1s
98-16223
CAUTION:
V.54 and FT1 Loopbacks may affect the operation of the 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.