多项选择题

A.物理层/ATM/AAL5/IP/TCP/GTP-U/Iu-UP
B.物理层/ATM/AAL5/IP/UDP/GTP-U/Iu-UP
C.物理层/ATM/AAL2/IP/TCP/GTP-U/Iu-UP
D.物理层/ATM/AAL2/IP/UDP/GTP-U/Iu-UP