Which two statements about the Diameter message direction on the Rf interface are true?
(Choose two.)
A.
Diameter Accounting-Request is initiated by S-GW/P-GW to CDF.
B.
Diameter Accounting-Answer is initiated by CDF to S-GW/P-GW.
C.
Diameter Accounting-Request is initiated by S-GW/P-GW to CGF.
D.
Diameter Accounting-Answer is initiated by CGF to S-GW/P-GW.
E.
Diameter Accounting-Request is initiated by S-GW/P-GW to the billing server.F. Diameter Accounting-Answer is initiated by the billing server to S-GW/P-GW.