Cisco ASR 9000 Series - Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference

Examples
In the following example, all packets are looped back to the DWDM controller:
RP/0/RSP0/CPU0:router(config)# controller dwdm 0/0/0/0
RP/0/RSP0/CPU0:router(config-dwdm)# loopback internal
Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference,
Release 5.3.x
27
Dense Wavelength Division Multiplexing Commands on the Cisco ASR 9000 Series Router
loopback (DWDM)