IPPakete

IPPakete, or IP packets, are the basic units of data that travel through networks using the Internet Protocol. An IP packet consists of a header and a payload. The header carries addressing and control information used by routers to forward the packet to its destination, while the payload carries the encapsulated transport-layer data or other user information.

Two main versions of IP are in common use: IPv4 and IPv6. IPv4 packets have a variable-length header with fields such as version, header length, total length, identification, flags, fragment offset, time to live, protocol, header checksum, and 32‑bit source and destination addresses. IPv6 packets use a fixed 40‑byte header with fields including version, traffic class, flow label, payload length, next header, hop limit, and 128‑bit addresses, plus optional extension headers for additional information.

Processing: A host creates an IP packet by encapsulating a transport-layer segment (such as TCP or UDP) inside the IP header. The packet is then carried over a link-layer frame and routed by network devices toward its destination. If a network path has a smaller maximum transmission unit, fragmentation may occur; fragments may be reassembled at the endpoint. IP provides best‑effort, connectionless service; reliability and ordering are typically provided by higher-layer protocols rather than IP itself.

Usage and security: IP packets enable global routing on the Internet and support unicast, multicast, and, depending on version and options, other delivery models. Security considerations include validation of addresses to prevent spoofing and the use of mechanisms like IPsec to provide confidentiality and integrity when required.