Packet communication divides data into small units called "packets" for individual network transmission. Each packet carries destination information and is reassembled in correct order at the receiver, even if packets take different routes. All internet communication uses packet switching.
Unlike circuit switching that dedicates lines during calls, packet communication shares lines among users. No packets are sent during silence, avoiding bandwidth waste. This efficiency underpins VoIP and video call services.
Mobile plan terms like "flat-rate data" and "X GB data allowance" refer to packet communication volume. One packet is 128 bytes, with all data activities (web, email, video) metered in packet units.
Packet communication's weakness is congestion-induced delay and packet reordering, manifesting as "voice dropouts" in calls. Protocol-level delay compensation and jitter buffers now achieve practically acceptable VoIP quality. See VoIP basics.