Installation guide

5-3
Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
OL-2238-03
Chapter 5 Troubleshooting the System
Managing Cable Modems on the HFC Network
Activating Cable Modem Authentication
The Cisco uBR7100 series CMTS can be configured to require all cable modems to return a known text
string to register with the CMTS and gain access to the network. The text string can be from 1 to 80
characters in length. To activate cable modem authentication, use the following command in cable
interface configuration mode.
Tip Be sure you enter the correct slot and port number in the cable interface configuration mode. Verify that
the cable modem is using BPI and that it is assigned to a QoS with privacy active. Verify that the cable
interface configuration file contains a matching key.
Verifying Cable Modem Authentication
To determine if cable modem authentication is activated or deactivated, enter the
more system:running-config command and look for the cable interface configuration information. If
cable modem authentication is deactivated, it appears in this output as
no cable secret-shared.
Activating Cable Modem Upstream Address Verification
Cable modem upstream address verification ensures that only cable modems that have received DHCP
leases through the Cisco uBR7100 series CMTS can access the HFC network. The Cisco uBR7100 series
CMTS discards all packets received from or for hosts that have not received DHCP-assigned addresses.
To activate cable modem upstream address verification, use the following cable interface configuration
command.
Verifying Cable Modem Upstream Address Verification
To determine if cable modem upstream verification is activated or deactivated, enter the
more system:running-config command and look for the
no cable source-verify notation in the
cable interface configuration information.
Command Purpose
CMTS01(config-if)# cable shared-secret [0|7]
authorization-key
CMTS01(config-if)# no cable shared-secret
Enable cable modem authentication:
• 0 specifies an unencrypted authentication key;
• 7 specifies an encrypted authentication key.
Disable cable modem authentication.
Command Purpose
CMTS01(config-if)# cable source-verify [dhcp]
CMTS01(config-if)# no cable source-verify
Activate cable modem upstream verification.
The dhcp option specifies that queries be sent
to verify unknown IP addresses in upstream
data packets.
Return to the default upstream verification
state.