Installation guide

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Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
OL-2238-03
Chapter 3 Configuring the Cisco Cable Interface
Setting Optional IP Parameters
• “Activating IP Broadcast Echo” section on page 3-39
Note The default values for the commands used in these configuration steps are adequate in most cases to
configure the Cisco uBR7100 series CMTS.
Activating IP Multicast Echo
The Cisco uBR7100 series CMTS echos IP multicast packets by default. To activate IP multicast echo if
it has been previously disabled, use the following command in cable interface configuration mode.
To disable IP multicast echo, enter the no cable ip-multicast-echo command in cable interface
configuration mode.
Verifying IP Multicast Echo
To determine if IP multicast echo is activated or deactivated, enter the more system:running-config
command and look for the cable interface configuration information. If IP multicast echo is activated,
there is no notation in the output, because this is the default setting. If IP multicast echo is deactivated,
a notation appears in the output:
CMTS01# more system:running-config
Building configuration...
Current configuration:
!
interface Cable1/0
ip address 1.1.1.1 255.255.255.0
no keepalive
no cable ip-multicast-echo
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable upstream 0 frequency 15008000
no cable upstream 0 shutdown
Tip If you are having difficulty with verification, make sure that you have entered the correct slot and port
numbers when you entered cable interface configuration mode.
Activating IP Broadcast Echo
By default, the Cisco uBR7100 series CMTS does not echo IP broadcast packets. To activate IP
broadcast echo, use the following command in cable interface configuration mode.
Command Purpose
CMTS01(config-if)# cable ip-multicast-echo
Enable IP multicast echo. This is the default.
Command Purpose
CMTS01(config-if)# cable ip-broadcast-echo
Enable IP broadcast echo.