CHAPTER 5 CABLE ACCESS TO MPLS VPN INTEGRATIONCABLE DOCSIS 1

3/0.3.

Both non-VPN and VPN cable access routers receive IP addresses from the same DHCP server. The VPN

hosts obtains IP addresses from a DHCP server within the VPN. The non-VPN hosts obtain IP addresses

from a server reachable from the global routing table.

The sharing of routes between the management VPN and user VPN allows the user VPN cable access

routers to obtain and renew their IP addresses. The non-VPN hosts need additional routing configuration

commands to obtain and renew their IP addresses.

Since the DHCP request from the non-VPN user cable access router enters the network on a non-VPN

interface and the DHCP server is connected to the management VPN, the global routing table requires a

route to the DHCP server. The easiest way to achieve this is to configure a static route on the router

connected to the DHCP server, and redistribute the static route into the global routing table. The DHCP

server's router interface is in the management VPN, which must have a route back to the user’s subnet.

A simple way to achieve this is to place a static route within the management VPN pointing at a P router’s

interface. The P router uses the global routing table to reach the user’s subnet.

The keyword global should be used with the static route. For example, if the DHCP server were

connected to a router that is remote to the VHG/PE, the static route could be “ip route vrf vpn1