Configuring Headend Broadband Access Router Features
Configuring and Activating Frequency Agility
Frequency Management Policy
Upstream port frequency should be set to a fixed value during system installation and testing. This value is chosen from the allocation plan for the RF domain for the RF plant segment connected to the upstream.
Note Having fixed frequency settings is recommended during early deployment at least until amplifier cascade adjustments or plant repair becomes infrequent for the nodes connected to the upstream port. When multiple upstream ports are combined to provide increased bandwidth, care should be taken to prevent overlapping frequency bands.
When the system has reached sufficient stability, the RF domain topology can be entered into the Cisco IOS configuration file to enable RF spectrum management. This management
Spectrum management or frequency agility is configured and activated using spectrum groups. A spectrum group is a frequency hop table that can be used by upstream ports to implement a
Note When each upstream port has its own RF domain, the group is called a nonshared spectrum group. When multiple upstream ports share the same RF domain, the group is called a shared spectrum group.
Note The cable interface will not operate until you either create and configure a spectrum group or set a fixed upstream frequency. From the interface configuration prompt, an interface is assigned membership in a spectrum group. From the interface point of view, the spectrum group also represents the set of upstreams connected to the same group of fiber nodes. The spectrum manager is able to determine if upstream frequencies need to be managed together.
In general, when defining your spectrum use the following guidelines:
•Avoid frequencies with known ingress problems such as amateur radio bands or
•Avoid hostile spectrum below 20 MHz.
•Allow extra bands for frequency hopping.
•Place upstream ports in the same combiner group in a shared spectrum group.
•Use the receive power level setting to perform slight equalization adjustments.
Frequency agility is configured and activated using spectrum groups that are controlled by the spectrum manager. You can create from 1 to 32 spectrum groups for each Cisco uBR7200 series cable modem card upstream port.
To configure and activate frequency agility, perform the tasks in the following sections:
•Determining the Upstream Ports Assigned to a Combiner Group
•Creating Spectrum Groups
•Configuring and Activating Spectrum Groups
Cisco IOS Multiservice Applications Configuration Guide
