A method and apparatus for handling mobility between a non-third
generation partnership project (3GPP) radio access technology (RAT) and a
3GPP RAT includes utilizing services provided by the non-3GPP RAT. A need
to utilize services provided by the 3GPP RAT is determined and a 3GPP
non-access stratum (NAS) state is entered. 3GPP messages are tunneled to
the 3GPP EPC network over the non-3GPP access RAT and a transition is
made from the non-3GPP RAT to the 3GPP RAT. A 3GPP NAS state transition
is made and a transition to a second 3GPP NAS state occurs.