user manual

10-13
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter 10 Circuits and Tunnels
10.7.1 Open-Ended SNCP Circuits
In the SNCP Switch Counts subtab, you can:
• Perform maintenance switches on the circuit selector.
• View switch counts for the selectors.
10.7.1 Open-Ended SNCP Circuits
If ONS 15454 SDHs are connected to a third-party network, you can create an open-ended SNCP circuit
to route a circuit through it. To do this, you create three circuits. One circuit is created on the source
ONS 15454 SDH network. This circuit has one source and two destinations, one at each
ONS 15454 SDH that is connected to the third-party network. The second circuit is created on the
third-party network so that the circuit travels across the network on two paths to the ONS 15454 SDHs.
That circuit routes the two circuit signals across the network to ONS 15454 SDHs that are connected to
the network on other side. At the destination node network, the third circuit is created with two sources,
one at each node 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 SNCP circuit.
10.7.2 Go-and-Return SNCP Routing
The go-and-return SNCP routing option allows you to route the SNCP working path on one fiber pair
and the protect path on a separate fiber pair (Figure 10-5). The working path will always be the shortest
path. If a fault occurs, neither the working fibers nor the protection fibers are affected. This feature only
applies to bidirectional SNCP circuits. The go-and-return option appears on the Circuit Attributes panel
of the Circuit Creation wizard.