8. Testing
8-10 March 2001 3160-A2-GB24-10
Payload Loopback (PLB)
The Payload Loopback command (PLB) loops the received signal on the network
interface back to the network. The signal is looped back as close to the DTE
Drop/Insert (DSX-1) port as possible (after it has passed throu gh the framing
circuitry of the DSU/CSU). Framing CRCs and BPVs are corrected.
Procedure
To perform a Payload loopback:
1. From the top-level menu screen, select Test.
2. From the Test screen, select Lpbk.
3. From the Loopback screen, select PLB.
Test Started appears on Line 2. If a Payload loopback is already in
progress, the Already Active message appears. If an invalid combination
of loopbacks is in progress, the error message Invld Test Combo appears
(see Table8-2, Valid Loopback Combinations, for valid loopback test
combinations).
496-14316-02
CSUDSU
NETWORK
INTERFACE
DTE
(DSX-1)
ALL 1s
PLB
PORT 1PORT 2
ALL 1s
ALL
1s
F1 F2 F3
Test:
Rlpbk Lpbk Ptrns
F1 F2 F3
Loopback:
Abort LLB PLB