Cable DHCP Proxy Enhancement

Cable DHCP Proxy Enhancement

With Phase Two, cable providers can use the Cable DHCP Proxy feature to obtain a public IP address, assign it to the loopback interface, and then have the cable modem interface get its IP address from the loopback interface. The Phase Two feature enhancement applies to the existing cable-modem dhcp-proxy interface configuration command for the uBR905 and uBR925 cable access routers.

For the router to configure the loopback interface automatically with the public IP address obtained from the DHCP server, the loopback interface must be created before issuing the cable-modem dhcp-proxy interface command.

The following example shows a loopback interface created first, and then the loopback interface being specified, so the router automatically assigns it with the public IP address:

Rtr1#config t
Rtr1(config)#interface loopback 0
Rtr1(config-if)#interface cable-modem 0
Rtr1(config-if)#cable-modem dhcp-proxy interface loopback0