Cisco Systems 15454 11.9.1 Open-Ended Path Protection Circuits, 11.9.2 Go-and-Return Path Protection Routing

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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 11 Circuits and Tunnels
11.9 11.9.1 Open-Ended Path Protection Circuits
Figure 11-7 Editing Path Protection Selectors
11.9.1 Open-Ended Path Protection Circuits
If ONS 15454s are connected to a third-party network, you can create an open-ended path protection
circuit to route a circuit through it. To do this, you create four circuits. One circuit is created on the
source ONS 15454 network. This circuit has one source and two destinations, each destination
provisioned to the ONS 15454 interface that is connected to the third-party network. The second and
third circuits are created on the third-party network so that the circuit travels across the network on two
diverse paths to the far end ONS 15454. At the destination node, the fourth circuit is created with two
sources, one at each node interface connected to the third-party network. A selector at the destination
node chooses between the two signals that arrive at the node, similar to a regular path protection circuit.
11.9.2 Go-and-Return Path Protection Routing
The go-and-return UPSR routing option allows you to route the path protection working path on one
fiber pair and the protect path on a separate fiber pair (Figure 11-8). The working path will always be
the shortest path. If a fault occurs, both the working and protection fibers are not affected. This feature
only applies to bidirectional path protection circuits. The go-and-return option appears in the Circuit
Attributes panel of the Circuit Creation wizard.