Cisco Systems uBR7200 manual Activating Cable Modem Upstream Address Verification, MC-587

Configuring Headend Broadband Access Router Features

Managing Cable Modems on the HFC Network

Command	Purpose
CMTS01(config-if)# cable shared-secret[0 7]	Enables cable modem authentication. The number 0
authentication-key	specifies that an unencrypted authentication key
	follows; the number 7 specifies that an encrypted
	authentication key follows.

Verifying Cable Modem Authentication

To verify whether cable modem authentication has been activated or deactivated, enter the more system:running-configcommand and look for the cable interface configuration information. If cable modem authentication has been activated, it does not appear in this output. If cable modem authentication has been deactivated, it appears in this output as no cable secret-sharedas shown in this command output excerpt:

CMTS01# more system:running-config

Building configuration...

Current configuration:

!

interface Cable6/0

ip address 1.1.1.1 255.255.255.0 no keepalive

no cable secret-shared

cable insertion-interval 150000 cable downstream annex B

cable downstream modulation 64qam cable downstream interleave-depth 32 cable downstream symbol-rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec

cable upstream 0 scrambler no cable upstream 0 shutdown

Troubleshooting Tips

To troubleshoot the configuration, perform the following tasks:

•Make sure you entered the correct slot and port numbers when you entered 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 modem configuration file contains a matching key.

Note The DOCSIS configuration file editor cannot reread the key from a completed file because it would violate the security design.

Activating Cable Modem Upstream Address Verification

Cable modem upstream address verification ensures that only known cable modems that have received DHCP leases through the Cisco uBR7200 series can access the HFC network. The Cisco uBR7200 series will discard all packets received for or from hosts that have not received DHCP-assigned addresses.

Cisco IOS Multiservice Applications Configuration Guide

MC-587