Nortel Networks OPTera Metro 3500 - Manual (Page 57)

Operation, administration, and maintenance (OAM) features 2-19
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-6
BLSR ring switch example
EX1241p
W
P
4
5
Legend
Add/drop multiplexer
One fiber divided into
working and protection
bandwidth
W
P = Working traffic
= Protection traffic
W
W
W
W
P
P
4 3
1 2
P Short path
RR/4/3/S/Idle
Long path
SD/4/3/L/idle
P
W
W
P
P
W
W
P
P
W
UEQ
W W
W
P
P P
P
W W P P
W
W
P
P
Pass-through
state
Idle
state
Node 1 and 2 state change detail