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Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2
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Chapter 9 SDH Topologies and Upgrades
Path-Protected Mesh Networks
9.4 Path-Protected Mesh Networks
In addition to single Linear Multiplex Section Protection (LMSP) configurations, terminal point-to-point
or linear ADMs, you can extend ONS 15310-MA SDH traffic protection by creating path-protected mesh
networks (PPMNs). PPMNs include multiple ONS 15310-MA SDH topologies and extend the protection
provided by a single LMSP configuration to the meshed architecture of several interconnecting rings. In
a PPMN, circuits travel diverse paths through a network of single or multiple meshed rings. When you
create circuits, CTC can automatically route circuits across the PPMN or you can manually route them.
You can also choose levels of circuit protection. For example, if you choose full protection, CTC creates
an alternate route for the circuit in addition to the main route. The second route follows a unique path
through the network between the source and destination and sets up a second set of cross-connections.
For example, in Figure 9-8, a circuit is created from the ONS 15454 shown at Node 3 to the ONS 15454
shown at Node 9. CTC determines that the shortest route between the two nodes passes through Node 8
and Node 7, shown by the dotted line, and automatically creates cross-connections at Nodes 3, 8, 7, and
9 to provide the primary circuit path.
If full protection is selected, CTC creates a second unique route between Nodes 3 and 9 which, in this
example, passes through Nodes 2, 1, and 11. Cross-connections are automatically created at Nodes 3, 2,
1, 11, and 9, shown by the dashed line. If a failure occurs on the primary path, traffic switches to the
second circuit path. In this example, Node 9 switches from the traffic coming in from Node 7 to the
traffic coming in from Node 11 and service resumes. The switch occurs within 50 ms.
Figure 9-8 Path-Protected Mesh Network for ONS 15310-MA SDH Nodes
For example, in Figure 9-9, a circuit is created from Node 3 to Node 9. CTC determines that the shortest
route between the two nodes passes through Node 8 and Node 7, shown by the dotted line, and
automatically creates cross-connections at Nodes 3, 8, 7, and 9 to provide the primary circuit path.
= Primary path
= Secondary path
Working traffic
Protect traffic
Source
Node
Destination
Node
124462
Node 1
Node 11
Node 2
Node 4
Node 5
Node 6
Node 7
Node 8Node 10
Node 9
Node 3