6-3
Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter6 Circuits and Tunnels
Creating Circuits and VT Tunnels
•Size—Select the circuit size (STS circuits on ly ). Th e “c” indicates concatenated STSs.
•Bidirectional—Check this box to create a two-way circuit; uncheck it to create a one-way circuit
(STS and VT circuits only; VT tunnels are bidirectional).
•Number of circuits—Type the number of circuits you want to create. If you enter more than 1, you
can use auto-ranging to create the additional circuits automatically. Otherwise, CTC returns to the
Circuit Source page after you create each circuit until you finish creating the number of circ uits
specified here.
•Auto Ranged—If selected, and you select the source and destination of one circuit, CTC
automatically determines the source and destination for the remaining Number of circuits and
creates the circuits. To determine the source and destination, CTC increments the most specific part
of the end points. An end point can be a port, an STS, or a VT/DS-1. If CTC runs out of choices, or
selects an end point that is already in use, CTC stops and allows you to either select a valid end point
or cancel. If you select a valid end point and continue, auto-ranging begins after you click Finish
for the current circuit.
•Protected Drops—If this box is checked, CTC only displays protected cards and ports (1:1, 1:N, 1+1
or BLSR protection) as choices for the circuit source and destination.
Figure6-1 Creating a circuit
Step 4 (UPSR circuits only) Set the UPSR Selector Defaults:
•Revertive—Check this box if you want traffic to revert to the working path when the conditions that
diverted it to the protect path are repaired. If Revertive is not chosen, traffic remains on the protect
path after the switch.
•Reversion time—If Revertive is checked, set the reversion time. This is the amount of time that will
elapse before the traffic reverts to the working path. Traffic can revert when conditions causing the
switch are cleared (the default reversion time is 5 minutes).
•SF threshold—Set the UPSR path-level signal failure bit error rate (BER) thresholds (STS circuits
only).
•SD threshold—Set the UPSR path-level signal degrade BER thresholds (STS circuits only).
•Switch on PDI-P—Check this box if you want traffic to switch when an STS payload defect
indicator is received (STS circuits only).
Step 5 Click Next.
Step 6 In the Circuit Source dialog box, set the circuit source.