I'm making a node with two interfaces, and the second one is UMTS, I've changed the procedure add-interface in ns-mobilenode.tcl: set t $nifs_ ;# counter set numif [$ns set numifs] for {set i 0} {$i 0} { set opt(channel) Channel/WirelessChannel set opt(pmodel) Propagation/UmtsTdd set opt(lltype) LL/RLC set opt(mactype) Mac/UmtsTdd/MS set opt(qtype) Queue/MQ set opt(..