CHAPTER
10-1
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
10
Circuits and Tunnels
This chapter explains Cisco ONS 15454 SDH high-order and l ow-order circuits; low-order, data
communication channel (DCC), and IP-encapsulated tunnels; a nd virtual concatenated (VCAT) circuits.
To provision circuits and tunnels, refer to the CiscoONS 15454 SDH Procedure Guide.
Chapter topics include:
10.1 Overview, page 10-1
10.2 Circuit Properties, page 10-2
10.3 Cross-Connect Card Bandwidth, page 10-9
10.4 DCC Tunnels, page 10-10
10.5 M ultiple Destinations for Unidirectional Circuits, page 10-12
10.6 Monitor Circuits, page 10-12
10.7 SNCP Circuits, page 10-12
10.8 MS-SPRing Protection Channel Access Circuits, page 10-14
10.9 Path Trace, page 10-15
10.10 Path Signal Label, C2 Byte, page 10-15
10.11 Automatic Circuit Routing, page 10-16
10.12 Manual Circuit Routing, page 10-18
10.13 Constraint-Based Circuit Routing, page 10-22
10.14 Virtual Concatenated Circuits, page 10-22
10.15 Merge Circuits, page 10-24
10.16 Reconfigure Circuits, page 10-25

10.1 Overview

You can create circuits across and within ONS 15454 SDH nodes and assign different attributes to
circuits. For example, you can:
Create one-way, two-way (bidirectional), or broadcast circuits. VC low-order path tunnels
(VC_LO_PATH_TUNNEL) are automatically set to bidirectional and do not use multiple drops.
Assign user-defined names to circuits.
Assign different circuit sizes.