Packet switching allows delivery of variable bit rate data streams, realized as sequences of short messages in fixed format, i., packets, that are transmitted over a telecommunications network. The header directs the packet to its destination, where the payload is. Each packet carries addressing information, travels hop-by-hop through routers, competes for shared resources, and may even take a different path than its siblings. This model is probabilistic rather than. Packet-switched network compared with a circuit-switched network In a packet-switched network, data is broken up into smaller units (“packets”) to be transferred, while circuit-switched networks transmit data as one unit. Adam Volle is a freelance writer and editor based in Atlanta, Georgia.