interfaces {
   at-4/3/0 {
      description "Interface ATM";
      clocking external;
      encapsulation atm-pvc;
      sonet-options {
         payload-scrambler;
      }
      atm-options {
         vpi 63 {
            maximum-vcs 4090;
         } 
      }
      unit 0 {
         encapsulation atm-snap;
         vci 63.300;
         family inet6 {
            address 2001:688:1F80:ABCD::2/64;
         }
      }
   }
}