Configuring Headend Broadband Access Router Features
Configuring and Activating Frequency Agility
MC-573
Cisco IOS Multiservice Applications Configuration Guide
To adjust the frequency hop threshold percentage or the minimum period between frequency hops, use
the following commands in global configuration mode:
The current implementation is known as blind frequency hop because there is no “look-ahead”
mechanism. In this case, the search time is 0 seconds and the switching time is 20 ms.
To specify that a particular spectrum group is a shared RF spectrum group, use the following command
in global configuration mode:
Verifying Spectrum Group Characteristics
To verify spectrum group characteristics and whether or not a spectrum group is shared, enter the show
cable spectrum-group command:
CMTS01# show cable spectrum-group
22:07:46: %SYS-5-CONFIG_I: Configured from console by console
Group Frequency Upstream Weekly Scheduled Power Shared
No. Band Port Availability Level Spectrum
(Mhz) From Time: To Time: (dBmV)
1 5.000-15.000 0 Yes
1 12.000 0 Yes
1 22.000 7 Yes
2 29.000 6 No
2 26.000 0 No
3 35.000-41.000 0 No
3 16.000-19.000 5 No
5* 5.000-10.000 Thu 21:50:00 Thu 21:45:00 0 Yes
Troubleshooting Tips
To troubleshoot the configuration, perform the following tasks:
• Make sure you entered a valid spectrum group number and type.
• Make sure you are in global cable configuration mode.
Command Purpose
Step 1
CMTS01(config)# cable spectrum-group groupnum hop
threshold percent
Sets the percentage of all cable modems losing
keepalive messages (going offline) that will cause a
frequency hop.
Step 2
CMTS01(config)# cable spectrum-group groupnum hop
period seconds
Sets the minimum time between frequency hops in
seconds. Valid values are from 1 to 3600 seconds.
Command Purpose
CMTS01(config)# cable spectrum-group groupnum shared
Specifies a given spectrum group as “shared” and tells the
Cisco uBR7200 series that you want to be sure that upstream
frequencies assigned to upstream interfaces are not assigned
to additional upstream interfaces.
