Specifications

Configuration Tasks
16
Cisco IOS Release 12.0(3)T
Customizing the Cable Modem Interface
Different geographical regions and different cable plants use different frequency bands. The
Cisco uBR904 cable modem uses a built-in default frequency scanning feature to address this issue.
After the cable modem finds a successful downstream frequency channel, it saves the channel and
power setting to NVRAM. The cable modem recalls this value the next time it needs to synchronize
its frequency or register with the cable service provider’s CMTS.
However, you can customize the cable modem’s interface configuration if you need to deviate from
the default setting that ships with the modem. For example, you might need to specify a different
compliant mode, modify the saved downstream channel setting and upstream power value, or enable
a faster downstream search algorithm.
Note Most cable network scenarios will not require you to use these commands.
To customize the cable modem interface, perform the following tasks, starting in global
configuration mode:
Note For more information on the use and effects of the commands in Step 3 and Step 4 above,
refer to the command reference pages for those commands.
Step Command Purpose
1
uBR904(config)#interface cable-modem 0
Specify cable modem interface 0.
2
uBR904(config-if)#cable-modem
compliant bridge
Enable DOCSIS-compliant bridging.
3
uBR904(config-if)#cable-modem
downstream saved channel
ds-frequency
us-power
Modify the saved downstream channel setting and
upstream power value. If you do this, you must specify
an exact downstream frequency and a power value.
1
1. Use the no cable-modem downstream saved channel ds-frequency us-power command to remove a saved frequency and power
setting from NVRAM.
4
uBR904(config-if)#cable-modem
fast-search
Enable a faster downstream search algorithm.