Relinquish control of your Bell Fibe router.

If you want to configure your router as I did,  here is a sample Vyatta/VyOS configuration:

ethernet eth0 {
    duplex auto
    description SAGECOM Router WAN
    vif 35 {
        pppoe 0 {
            mtu 1492
            password <your-bell-password>
            user-id <your-bell-username>
        }
    }
}

# vyos
# add this line into /opt/vyatta/etc/config/scripts/vyatta-postconfig-bootup.script 
iptables -t mangle -I POSTROUTING 1 -p tcp -o pppoe0 --tcp-flags SYN SYN -j TCPMSS --set-mss 1452 

# edgerouter 
set firewall options mss-clamp interface-type pppoe
set firewall options mss-clamp mss 1412

In no time your PPPOE will be up and running. You'll be in full control of your internet connection.