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Cisco ONS 15600 SDH Reference Manual, Release 9.0
78-18400-01
Chapter 7 Circuits and Tunnels
7.18.2 Manual Low-order Circuit Creation
Once the tunnel or end-to-end circuit exists, additional low-order circuits can be routed until all of the
bandwidth is used. The tunnel source and destination are the low-order circuit source and destination,
and when created results in the creation of high-order pass-through circuits on each node in the path. For
any of the listed topology combinations except SNCP to SNCP, one tunnel is required; an
SNCP-to-SNCP topology requires two tunnels.
7.18.2 Manual Low-order Circuit Creation
When you must route low-order traffic from an ONS 15454 SDH SNCP across an ONS 15600 SDH hub
to a line-protected domain, CTC cannot automatically create the end-to-end low-order circuit. The
configuration requires three TL1-like circuits. You must create all three circuits separately:
1. Low-order open-ended circuit on the ONS 15454 SDH SNCP
2. STS open-ended circuit on the ONS 15600 SDH hub node
3. Low-order two-way circuit on the ONS 15454 SDH line-protected node
The three TL1-like circuits must physically align for CTC to automatically merge the circuits.
is an example of an ONS 15600 SDH node bridging an ONS 15454 SDH SNCP and an
ONS 15454 SDH line-protected domain. In
, the following circuits are present:
•
An open-ended low-order circuit exists on Node 1. Slot 1 is the source, and Slots 2 and 3 are the
destinations.
•
An open-ended high-order circuit exists on Node 2 (the hub ONS 15600 SDH node). Slot 1 and
Slot 2 are the sources, and Slot 3 is the destination.
•
A two-way low-order circuit exists on Node 3 between Slot 1 and Slot 2.
Figure 7-14
Low-order Traffic Routing over an ONS 15600 SDH Hub Node
For information on creating an open-ended circuit on the ONS 15600 SDH to bridge protection domains,
refer to the “Turn Up Network” chapter in the
Cisco ONS 15600 SDH Procedure Guide
.
ONS 15454 SDH
Node 1
ONS 15600 SDH
Node 2
ONS 15454 SDH
Node 3
159714
Trunk or
drop card
Low-order
SNCP
cross-connect
High-order
SNCP
cross-connect
Low-order
Two-way
cross-connect
SNCP paths
1+1/MS-SPRing
Trunk or
drop card