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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter3 Configuring Cable Interface Features for the CiscouBR10012Router
Configuring the Downstream Cable Interface
Activating Downstream Cable Address Resolution Protocol Requests
This configuration is required. Address Resolution Protocol (ARP) is an Internet protocol used to map
IP addresses to MAC addresses on computers and other equipment installed in a network. You must
activate ARP requests on the cable interface so that the CiscouBR10000series CMTS can perform IP
address resolution on the downstream path.
Note The default values for the commands used in this configuration step are adequate in most cases to
configure the CiscouBR10000series CMTS.
To activate ARP requests, use the following command in cable interface configuration mode.

Verifying ARP Requests

To verify that cable ARP is activated, enter the more system:running-config command and look for the
cable interface configuration information. If ARP is activated, it does not appear in this output. If ARP
is deactivated, it appears in the output as no cable arp.
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 arp
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable downstream symbol-rate 5056941
cable upstream 0 frequency 15008000
no cable upstream 0 shutdown
Tip If you are having difficulty with verification, verify that you entered the correct port and cable
interface line card slot number when you activated ARP and when you entered the
show interface cable command.
Command Purpose
Router(config-if)# cable arp Enable ARP. This is the default.