Optical Loopback - Nortel NTRN10AN Planning Manual

Figure 2-29
Electrical Loopback types
DS1
DS3
EC1

Optical loopback

Optical facility loopbacks
Optical loopback functionality provides maintenance personnel the capability
to test portions of optical circuits for signal continuity by having the OC-n
circuit packs loopback test signals that are sent to them on either the terminal
or facility side of the connection. Sectioning of a SONET path facilitates
remote fault isolation.
Note: Site Manager supports provisioning of optical loopbacks.
Figure 2-30
Planning and Ordering Guide—Part 1 of 2 NTRN10AN
Operation, administration, and maintenance (OAM) features 2-55
Facility Loopback
VT equipped with DS1 AIS
for async mapping or VT AIS
for byte synch mapping
Facility Loopback
STS equipped
with DS3 AIS
Facility Loopback
AIS
illustrates an optical facility loopback.
Terminal Loopback
DS1
DS1 AIS
Terminal Loopback
DS3
DS3 AIS
Terminal Loopback
EC1
Copy of signal on optics
Rel 12.1 Standard Iss 1 Apr 2004