问题：

[多选] Which two statements are true about Voice over IP （VoIP） packet delivery in a digital infrastructure？ （）

A .  Packets can arrive out of order.
B .  Packets must take the same path to the destination.
C .  Once packets are received at the destination router， the router performs sampling to ensure the quality of the voice traffic.
D .  Packets can experience varying delays across the network.
E .  Packets containing voice samples are sequentially numbered by default， allowing for reordering upon arrival at the terminal router along the path.