Nortel Networks OPTera Metro 3500 - Manual (Page 55)

Operation, administration, and maintenance (OAM) features 2-17
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-4
BLSR ring switch example
EX1230p
W
W
W
W
P
P
4 3
1 2
P
P
W
W
P
P
W
W
W
P
P
W
Add/Drop tributaries
W
W
W
P
P
Node 1 and 4 detail
'Idle' state 'Idle' state
'Idle' state 'Idle' state
P
P UEQ
UEQ
W
P
1
Legend
Add/drop multiplexer
One fiber divided into
working and protection
bandwidth
W
P = Working traffic
= Protection traffic