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Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2
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Chapter 7 Circuits and Tunnels
Subnetwork Connection Protection Circuits
• Edit the reversion time.
• Set the hold-off timer (HOT) for linear multiplex section protection selector switching.
• Edit the Signal Fail (SF)/Signal Degrade (SD) bit error rate (BER) thresholds.
• Change path payload defect indication (PDI-P) settings.
Note On the Subnetwork Connection Protection Selectors tab, the SF Ber Level and SD Ber Level columns
display “N/A” for those nodes that do not support VC low-order path signal BER monitoring.
In the Subnetwork Connection Protection Switch Counts subtab, you can:
• Perform maintenance switches on the circuit selector.
• View switch counts for the selectors.
7.6.1 Open-Ended Subnetwork Connection Protection Circuits
If ONS 15310-MA SDH nodes are connected to a third-party network, you can create an open-ended
Subnetwork Connection Protection circuit to route a circuit through the network. To do this, you create
four circuits. One circuit is created on the source network. This circuit has one source and two
destinations, with each destination provisioned to the 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 node. 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
Subnetwork Connection Protection circuit.
7.6.2 Go-and-Return Subnetwork Connection Protection Routing
The go-and-return Subnetwork Connection Protection routing option allows you to route the Subnetwork
Connection Protection working path on one fiber pair and the protect path on a separate fiber pair
(Figure 7-2). The working path will always be the shortest path. If a fault occurs, neither the working or
protection fibers are affected. This feature only applies to bidirectional Subnetwork Connection
Protection circuits. The go-and-return option appears on the Circuit Attributes page of the Circuit
Creation wizard.