Nortel Networks OPTera Metro 3500 - Manual (Page 59)

Operation, administration, and maintenance (OAM) features 2-21
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-8
BLSR ring switch example
EX1242p
W
P
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
Long path
SD/4/3/L/bridged
P
W
W
P
P
W
W
P
P
'Bridged' state
'Pass-through'
state
'Pass-through'
state
'Idle' state