Cisco Cisco ONS 15454 SONET Multiservice Provisioning Platform (MSPP) Guía De Diseño
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Figure 2-29: Nonrevertive Switching
Network Topologies
There are several ways that ONS 15454 nodes may be connected together to form a network.
The ONS 15454 supports point-to-point terminals, linear add/drop multiplexers, Path Protection
Configuration, 2-fiber and 4-fiber bi-directional line switched rings (BLSRs), subtending rings,
path protected mesh network (PPMN), and virtual rings.
Terminal Mode
In a Terminal Mode (TM) topology, the entire SONET payload is terminated at each end of the
fiber span. The nodes are connected by 2 fibers. Protection spans can be added by installing
another trunk card, such as an OC-48, or by using additional ports on a multiport optical card,
such as an OC-3 or OC-12. TM systems are generally deployed for basic transport applications
calling only for a single system solution routed point-to-point. Figure 2-33 shows the traffic flow
for a typical TM configuration.
Final State
Protect
OC-N
Working
OC-N
W
E
W
E
Standby is
now working.
System will
not revert.
now working.
System will
not revert.
1+1
Initial State
Protect
OC-N
Working
OC-N
W
E
W
E
Working
line fails
line fails
1+1
Working
Protect
STS-N
STS-N
STS-N
STS-N
Final State
Protect
OC-N
Working
OC-N
W
E
W
E
Standby is
now working.
System will
not revert.
now working.
System will
not revert.
1+1
Initial State
Protect
OC-N
Working
OC-N
W
E
W
E
Working
line fails
line fails
1+1
Working
Protect
STS-N
STS-N
STS-N
STS-N