Nortel Networks OPTera Metro 3500 - Manual (Page 65)

Operation, administration, and maintenance (OAM) features 2-27
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-12
OC-48 BLSR node failure example
F2140
Ring ADM
C-D C-B
C
D-B
D-A
A-D A-B
A
(Add-drop)
D
B-D
B-A
B
Fiber 1
Fiber 2
= Working STS-1 timeslots (1 through 24)
= Protection STS-1 timeslots (25 through 48)
Legend:
= Single fiber cable with 24 working
and 24 protection timeslots
Node
failure
Bridge
(B-D)
B-C (AIS)
D-C (AIS)
= Alarm indication signal AIS