Nortel Networks OPTera Metro 3500 - Manual (Page 94)

2-56 Operation, administration, and maintenance (OAM) features
OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-30
Facility loopback
Ex1394t
Optical terminal loopbacks
During a terminal loopback, a signal received on the switch card (STX-192 or
VTX-series) side of the facility is looped back towards the associated
incoming transmitter. To operate a terminal loopback, the facility must be
manually put out of service (OOS).
Figure 2-31 illustrates an optical terminal
loopback.
Figure 2-31
Terminal loopback
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Engineering rules
• Facility and terminal loopbacks are supported on DS1, DS3x3, DS3x12,
DS3VTx12, EC-1x3, EC-1x12, 2x10/100BT, OC-3, 2xGigE/FC-P2P,
OC-3x4, OC-12, OC-12x4 STS, and OC-48, OC-48 STS and OC-192
circuit packs.
Note: Terminal loopback is not supported on the OC-192 circuit packs.
• Terminal and facility loopbacks can not be performed at the same time on
the same optical facility.
• Terminal and facility loopbacks for multi-port optical circuit packs are
done on a per port basis. Only one loopback is allowed per port at any one
time.
• Terminal and facility loopbacks are maintained during;
— circuit pack restarts (warm/cold) if a shelf processor is present in the
shelf
AIS
OOS OCn
Rx
Tx
OOS OCn
Rx
Tx