Nortel Networks OPTera Metro 3500 - Manual (Page 218)

2-180 Operation, administration, and maintenance (OAM) features
OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Figure 2-67
Improper use of STS path bridge and select on a shared VT-managed STS results in VT traffic loss
in case of a fiber cut
EX1553p
OM3500
OM3500
OC-3/12/48
UPSR ring
Note 1: When an STS path bridge & select is applied to a shared VT-managed
STS between multiple sites, OPTera Metro 3500 (W/STX) might have to choose between
two STS paths each containing different failed VTs, resulting in some VT traffic loss.
Note 2: For simplicity only one direction is shown.
X X
X
OK
Fail
OK
Fail
VT#1, STS-1 #1
STS-1 #1
STS-1 #1
STS-1 Path
bridge & select
VT#2, STS-1 #1
VTs
VTs
OM3500
(W/STX)
Backbone
Network