Editing Internet Protocol (section)

==Function==
[[File:UDP encapsulation.svg|thumb|260px|Encapsulation of application data carried by [[User Datagram Protocol|UDP]] to a link protocol frame]]
The Internet Protocol is responsible for addressing [[host interface]]s, encapsulating data into datagrams (including [[IP fragmentation|fragmentation and reassembly]]) and routing datagrams from a source host interface to a destination host interface across one or more IP networks.'''<ref>{{citation |url=http://www.tcpipguide.com/free/t_IPFunctions.htm |title=The TCP/IP Guide |author=Charles M. Kozierok |access-date=2017-07-22 |archive-date=2019-06-20 |archive-url=https://web.archive.org/web/20190620010402/http://www.tcpipguide.com/free/t_IPFunctions.htm |url-status=live }}</ref>''' For these purposes, the Internet Protocol defines the format of packets and provides an addressing system.

Each datagram has two components: a [[Header (computing)|header]] and a [[Payload (computing)|payload]]. The [[IP header]] includes a source IP address, a destination IP address, and other metadata needed to route and deliver the datagram. The payload is the data that is transported. This method of nesting the data payload in a packet with a header is called encapsulation.

IP addressing entails the assignment of IP addresses and associated parameters to host interfaces. The address space is divided into [[subnet]]s, involving the designation of network prefixes. IP routing is performed by all hosts, as well as [[Router (computing)|routers]], whose main function is to transport packets across network boundaries. Routers communicate with one another via specially designed [[routing protocol]]s, either [[interior gateway protocol]]s or [[exterior gateway protocol]]s, as needed for the topology of the network.<ref>{{Cite web|title=IP Technologies and Migration — EITC|url=http://www.eitc.org/research-opportunities/future-internet-and-optical-quantum-communications/internet-networks-and-tcp-ip/ip-technologies-and-migration|access-date=2020-12-04|website=www.eitc.org|archive-date=2021-01-05|archive-url=https://web.archive.org/web/20210105023938/http://www.eitc.org/research-opportunities/future-internet-and-optical-quantum-communications/internet-networks-and-tcp-ip/ip-technologies-and-migration|url-status=dead}}</ref>