The Internet Protocol (IP) is the principal network-layer protocol of the Internet protocol suite, responsible for addressing hosts and routing packets of data from a source to a destination across interconnected networks. It defines a best-effort, connectionless delivery service in which each datagram is forwarded independently using hierarchical addresses. IP provides the universal addressing and packet format on which higher-layer transport and application protocols depend.
Overview
- The Internet Protocol is the thin waist of the Internet architecture: a single, simple addressing and forwarding service over which an enormous diversity of link technologies below and applications above interoperate. Its connectionless, best-effort model pushes reliability and ordering to the transport layer, keeping the network core stateless and scalable.
Mechanisms
- Hierarchical addressing assigns each interface an IP address that encodes network and host parts for scalable routing.
- Datagram forwarding moves each packet hop by hop based on its destination address and routers’ forwarding tables.
- Fragmentation and reassembly adapt datagrams to the maximum transmission unit of each underlying link.
- IPv4 and IPv6 define the two deployed address formats, with IPv6 vastly expanding the address space.
Applications
- Universal addressing and packet delivery for all Internet communication.
- Foundation for transport protocols such as TCP and UDP.
- Interconnection of heterogeneous link-layer networks into a single internetwork.