C H A P T E R
8-1
Cisco ONS 15600 SDH Reference Manual, Release 9.0
78-18400-01
8
SDH Topologies and Upgrades
This chapter explains Cisco ONS 15600 SDH topologies and upgrades. To provision topologies, refer to
the
Cisco ONS 15600 SDH Procedure Guide
.
Chapter topics include:
•
•
8.2 Point-to-Point and Linear ADM Configurations, page 8-1
•
8.3 Multiplex-Section Shared Protection Rings, page 8-2
•
8.4 Subnetwork Connection Protection Rings, page 8-7
•
8.5 Dual-Ring Interconnect, page 8-9
•
8.6 Subtending Rings, page 8-17
•
8.7 Extended Subnetwork Connection Protection Networks, page 8-19
•
8.8 In-Service Topology Upgrades, page 8-21
•
8.9 Overlay Ring Circuits, page 8-23
8.1 Overview
The ONS 15600 SDH usually operates as a hub node in networks that include ONS 15454 SDHs. Single
nodes are installed at geographic locations where several ONS SDH topologies converge. A single
ONS 15600 SDH node might be a part of several ONS SDH rings/networks.
To avoid errors during network configuration, Cisco recommends that you draw the complete ONS SDH
network topology on paper (or electronically) before you begin the physical implementation. A sketch
ensures that you have adequate slots, cards, and fibers to complete the topology.
8.2 Point-to-Point and Linear ADM Configurations
You can configure ONS 15600 SDHs as a line of add/drop multiplexers (ADMs) by configuring one
STM-N port as the working path and a second port as the protect path. Unlike rings, point-to-point (two
node configurations) and linear (three node configurations) ADMs require that the STM-N ports at each
node be in 1+1 protection to ensure that a break to the working line automatically routes traffic to the
protect line.