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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

Verifying the Downstream Helper Address

To verify the downstream helper address setting, enter the show running-config command and look for
cable helper-address in the cable interface configuration information:
Router# show running-config
Building configuration...
Current configuration:
!
interface cable5/0/0
ip address 10.254.254.254 255.0.0.0
no ip directed-broadcast
cable helper-address 192.168.1.1
no keepalive
Perform these steps if you are having difficulty with verification:
Step1 Check the cables, upconverters, RF levels, and frequencies if the cableinterfaces do not find a
downstream signal.
Step2 Check the cables, RF levels, and upstream frequencies, and enter a no shut command if the
cableinterfaces find a downstream signal, but not an upstream signal.
Step3 Check the provisioning servers.
•Ping the DHCP server using the source IP address option—the primary IPaddress of a cable
interface.
•Check IP routing if the cableinterfaces acquire an RF upstream and downstream lock, but do not
stay up.
Step4 Check DHCP options and the IP address of the Time-of-Day (ToD) server:
•Ping the ToD server using the source IP address option.
•Check IP routing.
•Verify that the TFTP filename is correct.
•Verify that the TFTP file is in the correct directory on the TFTP server.
•Ensure that the TFTP file has read privileges.
•Ping the TFTP server using the source IP address option, and check IP routing if the cableinterfaces
acquire an RF and a DHCP, but fail on ToD or TFTP.
Setting the Downstream Interleave Depth
Set the interleave depth for the downstream port on the Cisco cable interface line card. A higher
interleave depth provides more protection from bursts of noise on the HFC network; however, it
increases downstream latency.
Note The valid values are 8, 16, 32 (default), 64, and 128.
To set the downstream interleave depth in milliseconds, use the following command in cable interface
configuration mode:
Router(config-if)# cable downstream interleave-depth {8|16|32 |64|128}