Specifications

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Cisco ONS 15530 Planning Guide

OL-7708-01

Chapter 2 Protection Schemes and Network Topologies

Supported Topologies

Figure 2-20 shows the behavior of bidirectional path switching when a loss of signal occurs. For the

example network, bidirectional path switching operates as follows:

• Node 2 sends the channel signal over both the active and standby paths.

• Node 1 receives both signals and selects the signal on the active path.

• Node 1 detects a loss of signal light on its active path and switches over to the standby path.

• Node 1 sends an APS switchover message to node 2 on the protection path.

• Node 2 switches from the active path to the standby path.

Both node 1 and node 2 communicate on the same path.

Figure 2-20 Bidirectional Path Switching Overview

Cisco ONS 15530

Cisco ONS 15540

Active path

Standby path

Node 1

Node 2

Node 3

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Switchover