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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 12 SONET Topologies and Upgrades
12.6 12.6 Path-Protected Mesh Networks
Figure 12-18 Path-Protected Mesh Network
PPMN also allows spans with different SONET speeds to be mixed together in “virtual rings.”
Figure 12-19 shows Nodes 1, 2, 3, and 4 in a standard OC-48 ring. Nodes 5, 6, 7, and 8 link to the
backbone ring through OC-12 fiber. The “virtual ring” formed by Nodes 5, 6, 7, and 8 uses both OC-48
and OC-12 cards.
= Primary path
= Secondary path
Working traffic
Protect traffic
Source
Node
Destination
Node
32136
Node 1
Node 11
Node 2
Node 4
Node 5
Node 6
Node 7
Node 8Node 10
Node 9
Node 3