Normally when we deploy FTTC to a client in an MPLS VPN we use the Cisco 887 and bypass the BT installed VDSL modem. On this occasion the client is already fully kitted out with Cisco 877 routers and is not minded to replace them all straight away so we need to check out the config needed. In short we need to stop using the ATM interface and hook up an ethernet interface into the VDSL modem supplied by BT.
Stage 1 – Disable the ATM port
int ATM0 shutdown
Stage 2 – Create the new vlan and and assign to a switch port
vlan 100 name FFTC_VLAN int E3 switchport access vlan 100
Stage 3 – Create the BVI and enable PPPoE
interface Vlan100 description *** FTTC *** no ip address pppoe enable group local pppoe-client dial-pool-number 1
Stage 4 – Enable VPDN
vpdn enable vpdn-group 1
Stage 5 – Set up the dialer interface
interface Dialer0 mtu 1492 ip address negotiated ip virtual-reassembly encapsulation ppp dialer pool 1 ppp chap hostname XXXXXXX ppp chap password XXXXXXX
Stage 6 – Add a default route
ip route 0.0.0.0 0.0.0.0 Dialer0
Thats the lot, it should all work now – Good Luck!