Andmepaketid

Andmepaketid are data packets, the basic units of data transmitted over packet-switched computer networks. They enable efficient sharing of network resources by splitting a data stream into smaller, independently routed units that can take different paths to the destination.

A typical packet consists of a header and a payload. The header carries addressing (source and destination), sequencing, and control information, while the payload contains the actual user data. The size of a packet is constrained by the network's maximum transmission unit (MTU), commonly around 1500 bytes for Ethernet; the header itself uses part of that limit.

In the Internet protocol suite, data packets are created at the network layer by IP (IPv4 or IPv6). The transport layer protocols—TCP and UDP—send application data in segments or datagrams that become the payload of IP packets. IP is a best-effort protocol; it does not guarantee delivery, order, or avoidance of duplicates. TCP adds reliability through acknowledgments, retransmissions, and sequencing, while UDP provides a simpler, connectionless datagram service with lower overhead.

Routers forward packets toward their destination using the destination address. If a packet encounters a smaller MTU along the path, it may be fragmented and reassembled at the destination or at certain routers; modern networks often use path MTU discovery to avoid fragmentation. Packets may also carry or be subject to error- and control-messages, such as ICMP.

Beyond data transfer, packets are fundamental to concepts like packet-switching, routing, congestion control, and network security. They are distinct from frames (data-link layer) and segments or datagrams of different layers, but together enable end-to-end communication across networks.