Cisco ONS 15454 Series - Page 171

6-3
Cisco ONS 15454 Procedure Guide, R5.0
August 2005
Chapter 6 Create Circuits and VT Tunnels
Before You Begin
ONS 15454 circuits are either VT or STS circuits. Table 6-2 shows the circuit source and destination
options for VT circuits.
Table 6-1 ONS 15454 Circuit Options
Circuit Option Description
Source The circuit source is where the circuit enters the ONS 15454 network.
Destination The circuit destination is where the circuit exits an ONS 15454 network.
Automatic
circuit routing
Cisco Transport Controller (CTC) routes the circuit automatically on the shortest
available path based on routing parameters and bandwidth availability.
Manual circuit
routing
Manual routing allows you to choose a specific path, not just the shortest path chosen
by automatic routing. You can choose a specific synchronous transport signal (STS)
or virtual tributary (VT) for each circuit segment and create circuits from work orders
prepared by an operations support system (OSS) like the Telcordia Trunk Information
Record Keeping System (TIRKS).
VT tunnel VT tunnels allow VT1.5 circuits to pass through an ONS 15454 without utilizing
cross-connect card (XC, XCVT, XC10G) resources. VT circuits using VT tunnels use
cross-connect capacity only at the source and destination nodes. One VT tunnel can
carry 28 VT1.5 circuits.
VT aggregation
point
VT aggregation points (VAPs) allow VT circuits to be aggregated into an STS for
handoff to non-ONS 15454 networks or equipment, such as interoffice facilities
(IOFs), switches, or digital access cross-connect systems. VAPs reduce VT matrix
resource utilization at the node where the VT1.5s are aggregated onto the STS. This
node is called the STS grooming end. The STS grooming end requires an EC1, DS3,
DS3E, DS3i-N-12, DS3XM-6, DS3XM-12, or OC-N card. VT aggregation points can
be created on BLSR, 1+1, or unprotected nodes, but cannot be created on path
protection nodes.
Table 6-2 CTC Circuit Source and Destination Options for VT Circuits
Card Ports STSs VTs DS-1s
DS1-14, DS1N-14 — — — 14
DS3XM-6 6 — — 28 per port
DS3XM-12 12 — — 28 per port
DS3/EC1-48 48 — — 28 per port
EC1-12 12 — 28 per port —
OC3 IR 4/STM1 SH 1310 4 3 per port 28 per STS —
OC3 IR/STM1 SH 1310-8 8 3 per port 28 per STS —
OC12 IR/STM4 SH 1310
OC12 LR/STM4 LH 1310
OC12 LR/STM4 LH 1550
— 12 28 per STS —
OC12 IR/STM4 SH 1310-4 4 12 per port 28 per STS —
All OC-48 cards (does not include
the ML-Series card)
— 48 28 per STS —