...
set interfaces st0 unit 0 family inet mtu 1480
set interfaces st0 unit 0 family inet address x.x.x.x/30
...
VDSL: PPPoE
set interfaces pt-1/0/0 mtu 1530
set interfaces pt-1/0/0 vdsl-options vdsl-profile 17a
set interfaces pt-1/0/0 unit 0 encapsulation ppp-over-ether
set interfaces pt-1/0/0 unit 0 vlan-id 10
set interfaces pp0 unit 0 ppp-options pap default-password "<<VDSL Password>>"
set interfaces pp0 unit 0 ppp-options pap local-name <<VDSL Username>>
set interfaces pp0 unit 0 ppp-options pap local-password "<<VDSL Password>>"
set interfaces pp0 unit 0 ppp-options pap passive
set interfaces pp0 unit 0 pppoe-options underlying-interface pt-1/0/0.0
set interfaces pp0 unit 0 pppoe-options idle-timeout 0
set interfaces pp0 unit 0 pppoe-options auto-reconnect 2
set interfaces pp0 unit 0 pppoe-options client
set interfaces pp0 unit 0 family inet negotiate-address
set interfaces vlan unit 0 family inet address <<internal IP range>>/24
set routing-options static route 0.0.0.0/0 next-hop pp0.0
set routing-options generate route 0.0.0.0/0
...