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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 12 Configuring LRE
Configuring LRE Ports
Make sure that all the CPEs in the production network are running the same LRE binary version.
Use the show controllers lre cpe version privileged EXEC command to display the binary version
on all CPE device interfaces.
Caution Changing the noise model while the switch is functioning in a network can disrupt the network
operation.
Beginning in privileged EXEC mode, follow these steps to configure upstream power back-off on a
Catalyst 2950ST-24 LRE 997 switch:
To return the switch to its default setting, use the no lre upbo {noise-model | offset value} global
configuration command.
Configuring CPE Toggle
The CPE toggle feature is enabled by default. It cannot be disabled on a link from a Cisco 575 LRE or
Cisco 576 LRE 997 CPE to a remote Ethernet device (such as PC).
You can disable CPE toggle on a Cisco 585 LRE CPE link. Then the CPE Ethernet link does not
transition to the up state when the LRE link comes up.
Beginning in privileged EXEC mode, follow these steps to disable CPE toggle on a Cisco 585 LRE CPE
link:
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 lre upbo {noise-model | offset value}Enter the noise level or the offset value. Supported noise-model
values are etsi-a, etsi-b, etsi-c, etsi-d and etsi-f.
The offset value is calculated with reference to –140. For
example, if you require a reference PSD of –95 dbm/Hz, you need
to enter the offset of 45 (–95 – [–140] = 45). The supported value
range is 300 to 800.
Note The LRE CPE power spectral density (PSD) offset value
is in 10*dB (for example, 450 means 45 dB).
Step 3 end Return to privileged EXEC mode.
Step 4 show controllers lre status psd
show controllers lre cpe version
Verify the change.
Displays the LRE binary version running on the CPE.
Step 5 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the LRE port to be configured, and enter interface
configuration mode.
Step 3 no cpe toggle [port port-id]Disable CPE toggle on a CPE Ethernet link.
(Optional) Specify the CPE port on which CPE toggle is disabled.