In which three network technologies is traffic shaping used to prevent and manage congestion？（）

A.a class can be identified as a single application， multiple applications with similar service needs，or be based on the source or destination IP address
B.a drawback of the DiffServ field in the MAC header to mark frames into behavior aggregates （BAs）
C.DiffServ uses the DiffServ field in the MAC header to mark frames into behavior
D.the DiffServ field occupies the same eight bits of the MAC header that were previously used for the ToS field
E.the first six high-order bits of the DiffServ field are used to identify the Resource Reservation Protocol （RSVP） value
F.the primary goal of DiffServ is scalability

A.FECN
B.LLQ
C.WRED
D.LFI
E.CRTP
F.CBWFQ

A.Cisco CallManager
B.Cisco CallManger Express （CME）
C.Cisco CallManager Gateway （CMG）
D.Cisco CallManager Voice Gateway （CMVG）
E.Media Gateway Control Protocol （MGCP）