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Cisco ONS 15454 Procedure Guide, R5.0
August 2005
Chapter 6      Create Circuits and VT Tunnels
NTP-A183 Create a Unidirectional DS-1 Circuit with Multiple Drops
Step 9 Complete the “DLP-A95 Provision a DS-1 Circuit Source and Destination” task on page 17-96.
Step 10 In the Circuit Routing Preferences area, uncheck Route Automatically. When Route Automatically is 
not selected, the Using Required Nodes/Spans and Review Route Before Circuit Creation check boxes 
are unavailable.
Step 11 To set the circuit path protection, complete one of the following:
• To route the circuit on a protected path, leave Fully Protected Path checked and continue with 
Step 12. Fully protected paths might or might not have path protection path segments (with primary 
and alternate paths), and the path diversity options apply only to path protection path segments, if 
any exist.
• To create an unprotected circuit, uncheck Fully Protected Path and continue with Step 16.
• To route the circuit on a BLSR protection channel, if available, uncheck Fully Protected Path, 
check Protection Channel Access, click Yes  in the Warning dialog box, then continue with Step 16. 
Caution Circuits routed on BLSR protection channels are not protected and are preempted during BLSR 
switches.
Step 12 If you selected Fully Protected Path in Step 11 and the circuit will be routed on a path protection, choose 
one of the following: 
• Nodal Diversity Required—Ensures that the primary and alternate paths within the path protection 
portions of the complete circuit path are nodally diverse.
• Nodal Diversity Desired—Specifies that node diversity is preferred, but if node diversity is not 
possible, CTC creates fiber-diverse paths for the path protection portion of the complete circuit path.
• Link Diversity Only—Specifies that only fiber-diverse primary and alternate paths for path 
protection portions of the complete circuit path are needed. The paths might be node-diverse, but 
CTC does not check for node diversity.
Step 13 If you selected Fully Protected Path in Step 11 and the circuit will be routed on a path protection DRI, 
click the Dual Ring Interconnect check box.
Step 14 Click Next. In the Create area of the VT Matrix Optimization panel, choose one of the following:
• Create VT tunnel on transit nodes—This option is available if the DS-1 circuit passes through a node 
that does not have a VT tunnel, or if an existing VT tunnel is full. VT tunnels allow VT circuits to 
pass through ONS 15454s without consuming cross-connect card resources. VT tunnels can carry 
28 VT1.5 circuits. In general, creating VT tunnels is a good idea if you are creating many VT 
circuits from the same source and destination. Refer to the Cisco ONS 15454 Reference Manual for 
more information.
• Create VT aggregation point—This option is available if the DS-1 circuit source or destination is on 
an EC1, DS3, DS3E, DS3i-N-12, DS3XM-6, DS3XM-12, or OC-N port on a BLSR, 1+1, or 
unprotected node. VAPs collect DS-1s on an STS for handoff to non-ONS 15454 networks or 
equipment, such as an IOF, switch, or digital access and cross-connect system (DACS). It allows 
VT1.5 circuits to be routed through the node using one STS connection on the cross-connect card 
matrix rather than multiple VT connections on the cross-connect card VT matrix. If you want to 
aggregate the DS-1 circuit you are creating with others onto an STS for transport outside the 
ONS 15454 network, choose one of the following:
–
STS grooming node is [source node], VT grooming node is [destination node]—Creates the 
VAP on the DS-1 circuit source node. This option is available only if the DS-1 circuit originates 
on an EC1, DS3, DS3E, DS3i-N-12, DS3XM-6, DS3XM-12, or OC-N card.