What are two reasons for packet loss on a VoIP connection？（）

A.Each subinterface has its own hardware queue and can experience congestion just like its main interface
B.Hardware queuing is only used if the software queues are experiencing congestion.
C.Hardware queues and software queues are not used concurrently.
D.The hardware queuing system always uses the FIFO queuing mechanism.

A.RTP multiplexing is used to keep multiple phone conversations separate
B.RTP provides end-to-end delivery services for voice traffic.
C.UDP is used to ensure a reliable transmission from sender to receiver.
D.RTP is used to provide resource reservation for the voice stream.
E.UDP provides multiplexing of multiple phone conversations.