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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter3 Configuring Cable Interface Features for the CiscouBR10012Router
Configuring Optional Cable Interface Features
Setting Optional Broadcast and Cable IP Multicast Echo
You can set additional IP parameters to enable downstream echoing of upstream data. This section
contains two procedures to configure these optional IP parameters:
Setting IP Multicast Echo section on page28
Setting IP Broadcast Echo section on page29
Note The default values for the commands used in these configuration steps are adequate in most cases to
configure the CiscouBR10012router.

Setting IP Multicast Echo

The CiscouBR10012router echoes 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 whether IP multicast echo is activated or deactivated, enter the
moresystem: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:
Router# more system:running-config
Building configuration...
Current configuration:
!
interface cable5/0/0
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 entered the correct slot and port
numbers when you entered cable interface configuration mode.
Command Purpose
Router(config-if)# cable ip-multicast-echo Enables IP multicast echo. This is the default.