Nortel Networks OPTera Metro 3500 - Manual (Page 217)

Operation, administration, and maintenance (OAM) features 2-179
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-66
Virtual ring (path-in-line) and shared VTmanaged STS - no VT loss in case of a fiber cut
EX1551p
Backbone
Network
OM3500
OM3500
OM3500
OM3500
A
C
B D
Working
time slots
Working
time slots
OC-3/12/48
UPSR ring
OC-3/12/48
UPSR ring
= OM3500 tributary circuit pack
= Path bridge & select
= Traffic A - B, VT#1, STS-1 #1 on a virtual ring (path-in-line), working
= Traffic C - D, VT#2, STS-1 #1 on a virtual ring (path-in-line), protected
Note: For simplicity, only one direction is shown.
X
VT#1,
STS-1 #1
VT#2,
STS-1 #1
Traffic C-D switched
to protected path
Legend
OM3500
(W/STX) OM3500
(W/STX)
OM3500
(W/STX) OM3500
(W/STX)
UPSR, 2 way
(unprotected)
UPSR, 2 way
(unprotected)