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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
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 9-9 Path-Protected Mesh Network for ONS 15310-MA SDH Nodes
PPMN also allows spans with different SDH speeds to be mixed together in “virtual rings.” Figure 9-10
shows an ONS 15310-MA SDH with Nodes 1, 2, 3, and 4 in a standard STM16 ring. Nodes 5, 6, 7, and
8 link to the backbone ring through the STM4 fiber. The virtual ring formed by Nodes 5, 6, 7, and 8 use
both the STM16 and STM4 cards.
= Primary path
= Secondary path
Working traffic
Protect traffic
Source
Node
Destination
Node
145956
Node 1
Node 11
Node 2
Node 4
Node 5
Node 6
Node 7
Node 8Node 10
Node 9
Node 3
