Nortel Networks OPTera Metro 3500 - Manual (Page 60)

2-22 Operation, administration, and maintenance (OAM) features
OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-9
BLSR ring switch example
EX1233p
W
P
7
8
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
W
W
W
W
P
P
4 3
1 2
P
P
W
W
P
P
W
W
P
P
'Bridged' state 'Bridged' state
'Pass-through'
state
'Pass-through'
state
'Bridged' state
'Bridged and
Switched' state
'Pass-through'
state
'Pass-through'
state