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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter 3 Configuring Cable Interface Features for the Cisco uBR10012 Router
Configuring the Upstream Cable Interface
Activating Upstream Forward Error Correction
The Cisco uBR10000 series CMTS uses forward error correction (FEC) to attempt to correct any
upstream data that might have been corrupted. When FEC is activated, all CMs on the network also
activate FEC.
Note
Although upstream FEC is an option, Cisco recommends that you use upstream FEC. FEC is
activated by default and should not be disabled.
To activate the upstream forward error correction and to enable FEC, use the following command in
cable interface configuration mode.
Router(config-if)#
cable upstream
usport
fec
Verifying Upstream FEC
To verify whether FEC is activated or deactivated, enter the
more system:running-config
command and
look for the cable interface configuration information. If FEC is enabled, an FEC entry appears in the
show running-config command
output. If FEC is disabled, no FEC entry appears in the output.
Perform these steps if you are having difficulty with verification:
Step 1
Ensure that the cable connections are not loose or disconnected.
Step 2
Ensure that the cable interface line card is firmly seated in its chassis slot.
Step 3
Ensure that the captive installation screws are tight.
Step 4
Verify that you have entered the correct slot and port numbers.
Step 5
Verify that you selected a valid frequency for your router.
Activating the Upstream Ports
Each upstream port must be activated to enable upstream data transmission from the CMs on the HFC
network to the Cisco uBR10000 series CMTS.
Note
The upstream cable interface does not operate until you either set a fixed upstream frequency or create
and configure a spectrum group. Refer to the
“Setting the Upstream Frequency” section on page 3-20
for
details.
To activate the upstream ports, use the following commands in global configuration mode.
Command
Purpose
Step 1
Router(config)#
interface cable
slot/port
Specifies a cable interface and enters cable interface
configuration mode.
Step 2
Router(config-if)#
no cable upstream
usport
shutdown
Enables upstream data traffic.