A network technology that breaks up a message into small packets for transmission. Unlike circuit switching, which requires the establishment of a dedicated point-to-point connection, each packet in a packet-switched network contains a destination address. Thus, all packets in a single message do not have to travel the same path. As traffic conditions change, they can be dynamically routed via different paths in the network, and they can even arrive out of order. The destination computer reassembles the packets into their proper sequence. Network protocols such as IP and IPX were designed for packet-based networks.
Data, Voice and Video
Packet switching has always excelled at handling messages of different lengths, as well as different priorities, providing quality of service (QoS) attributes were included. However, packet switching was designed for data. Today, using the IP protocol, packet networks are becoming the norm for voice and video as well (see IP on Everything).
X.25, Frame Relay and ATM
The first international standard for wide area packet switching networks was X.25, which was defined when all circuits were analog and very susceptible to noise. Subsequent technologies, such as frame relay, were designed for today's almost-error-free digital lines.
ATM uses a cell-switching technology that provides the bandwidth-sharing efficiency of packet switching with the guaranteed bandwidth of circuit switching. See frame relay and ATM. Contrast with circuit switching.
IP-based packet switching is expected to be the next generation transport for everything, including voice and video. For voice conversations especially, analog and digital-based circuit switching waste as much as 75% of the bandwidth due to one person listening and pauses in speech.
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