I can’t take credit for the config example below, it was one of my awesome engineers..
The snippet below shows the config required to configure a Cisco 800 series router for FTTC while maintaining the DSL config (partcularly useful if you are planning to migrate to FTTC via the self install option and don’t wish to make a site visit) This config was built on a Cisco 867VAE.
This assumes you are using a Cisco 867VAE, a VPI/VCI of 0/38 and have the latest DSL firmware, you you are unsure and do not wish to mess with your router firmware then ignore the first 4 lines of config.
It goes without saying, I take no responsibility for any loss of config, or if you render yourself/others without connectivity. Always backup your config and take care to note changes etc..
controller VDSL 0 firmware filename flash:adslphy_A35d_B35d.bin modem ukfeature sra ! interface ATM0 description ++++ DSL/VDSL Interface +++++ no ip address ip flow ingress load-interval 30 no atm ilmi-keepalive pvc 0/38 encapsulation aal5mux ppp dialer dialer pool-member 1 ! ! interface Ethernet0 mtu 1512 no ip address ! interface Ethernet0.101 encapsulation dot1Q 101 pppoe-client dial-pool-number 1 pppoe-client ppp-max-payload 1500 !