Cisco ONS 15600 Reference Manual page 162

8.4 Path-Protected Mesh Networks
Figure 8-11
Node 1
Node 11
If full protection is selected, CTC creates a second unique route between Nodes 3 and 9 that 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 fiber from Node 7 to the fiber from Node 11 and service
resumes. The switch occurs within 50 ms.
PPMN also allows spans of different SONET line rates to be mixed together in virtual rings.
shows Nodes 1, 2, 3, and 4 in an OC-192 ring.
Cisco ONS 15600 Reference Manual, R8.0
8-12
Path-Protected Mesh Network
Node 2
Node 10
Protect traffic
Node 9
Source
Node
Node 3
Node 4
Node 8
Node 7
Destination
Node
Chapter 8 SONET Topologies and Upgrades
Node 5
Node 6
= Primary path
= Secondary path
Figure 8-12