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PA-POS-2OC3 Two-Port Packet-over-SONET Port Adapter Installation and Configuration
OL-3028-06
Chapter 4 Configuring the PA-POS-2OC3
Customizing the Configuration
Configuring SONET Payload Scrambling
The default value for SONET payload scrambling is disabled. SONET payload scrambling applies a
self-synchronous scrambler (x^43+1) to the Synchronous Payload Envelope (SPE) of the OC-3 interface
to ensure sufficient bit-transition density.
Note
Both ends of the connection must use the same scrambling algorithm.
You enable SONET payload scrambling using the
pos scramble-atm
command. (This command has no
keywords or arguments.)
Step 1
To enable SONET payload scrambling, use the following command sequence:
Router(config)#
interface pos 3/0
Router(config-if)#
pos scramble-atm
Router(config-if)#
no shutdown
Router(config-if)#
end
Step 2
To verify that SONET payload scrambling is enabled on an interface, enter the
show startup-config
command. If scrambling is enabled, the following line is displayed in the configuration:
pos scramble-atm
Step 3
To disable SONET payload scrambling, use the
no pos scramble-atm
command.
Configuring APS
The
a
utomatic protection switching (APS) feature allows switchover of packet-over-SONET (POS)
circuits in the event of circuit failure and is often required when connecting SONET equipment to telco
equipment. APS refers to the mechanism of using a protect POS interface in the SONET network as the
backup for working POS interface. When the working interface fails, the protect interface quickly
assumes its traffic load.
The following example shows the configuration of APS on router A and router B. (See
.) In
this example, router A is configured with the working interface, and router B is configured with the
protect interface. If the working interface on router A becomes unavailable, the connection will
automatically switch over to the protect interface on router B.
Figure 4-1
Basic APS Configuration
Router A
E 0/0
POS 2/0/0
Working interface
SONET
network
equipment
Add Drop Multiplexer (ADM)
E 0/0
Router B
POS 3/0/0
Protect interface
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