Specifications

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Cisco ONS 15530 Planning Guide
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Chapter 2 Protection Schemes and Network Topologies
Supported Topologies
Meshed Ring
A meshed ring is a physical ring that has the logical characteristics of a mesh. While traffic travels on a
physical ring, the logical connections between individual nodes are meshed. An example of this type of
configuration, which is sometimes called a logical mesh, is shown in Figure 2-17. Nodes 1 and 2
communicate using band A and nodes 1 and 3 communicate using band B.
Figure 2-17 Meshed Ring Topology Example
For example configurations of meshed ring topologies, see Chapter 6, “Example Shelf Configurations
and Topologies.”
Path Switching in Point-to-Point and Ring Topologies
The Cisco ONS 15530 supports per-channel unidirectional and bidirectional 1+1 path switching. When
a signal is protected and the signal fails, or in some cases degrades, on the active path, the system
automatically switches from the active network path to the standby network path.
Signal failures can be total loss of light caused by laser failures, by fiber cuts between the
Cisco ONS 15530 and the client equipment, or by other equipment failure. Loss of light failures cause
switchovers for both splitter protected and y-cable protected signals. Switchovers based on an alarm
threshold can also automatically occur when the signal error rate reaches an unacceptable level.
Cisco ONS 15530
Cisco ONS 15530
Cisco ONS 15540
Active path
Standby path
Node 1
Node 2
Node 3
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