Internet Protocol: Difference between revisions

{{Short description|Communication protocol that allows connections between networks}}

{{IPstack}}

The '''Internet Protocol''' ('''IP''') is the [[network layer]] [[communications protocol]] in the [[Internet protocol suite]] for relaying [[datagram]]s across network boundaries. Its [[routing]] function enables [[internetworking]], and essentially establishes the [[Internet]].

IP was the [[connectionless]] datagram service in the original ''[[Transmission Control Program]]'' introduced by [[Vint Cerf]] and [[Bob Kahn]] in 1974, which was complemented by a [[connection-oriented]] service that became the basis for the [[Transmission Control Protocol]] (TCP). The Internet protocol suite is therefore often referred to as ''TCP/IP''.

== Version history ==

In May 1974, the [[Institute of Electrical and Electronics Engineers]] (IEEE) published a paper entitled "A Protocol for Packet Network Intercommunication".<ref>{{Cite journal|last1=Cerf|first1=V.|last2=Kahn|first2=R.|date=1974|title=A Protocol for Packet Network Intercommunication|url=https://www.cs.princeton.edu/courses/archive/fall06/cos561/papers/cerf74.pdf|journal=IEEE Transactions on Communications|volume=22|issue=5|pages=637–648|doi=10.1109/TCOM.1974.1092259|issn=1558-0857|quote=The authors wish to thank a number of colleagues for helpful comments during early discussions of international network protocols, especially R. Metcalfe, R. Scantlebury, D. Walden, and H. Zimmerman; D. Davies and L. Pouzin who constructively commented on the fragmentation and accounting issues; and S. Crocker who commented on the creation and destruction of associations.|access-date=2020-04-06|archive-date=2017-01-06|archive-url=https://web.archive.org/web/20170106204542/http://www.cs.princeton.edu/courses/archive/fall06/cos561/papers/cerf74.pdf|url-status=live}}</ref> The paper's authors, [[Vint Cerf]] and [[Bob Kahn]], described an [[internetworking]] protocol for sharing resources using [[packet switching]] among [[network node]]s. A central control component of this model was the Transmission Control Program that incorporated both connection-oriented links and datagram services between hosts. The monolithic Transmission Control Program was later divided into a modular architecture consisting of the [[Transmission Control Protocol]] and [[User Datagram Protocol]] at the [[transport layer]] and the Internet Protocol at the [[internet layer]]. The model became known as the ''Department of Defense (DoD) Internet Model'' and ''[[Internet protocol suite]]'', and informally as ''TCP/IP''.

===IP version numbers===

==Reliability==

As a consequence of this design, the Internet Protocol only provides [[best-effort delivery]] and its service is characterized as [[Reliability (computer networking)|unreliable]]. In network architectural parlance, it is a [[connectionless protocol]], in contrast to [[connection-oriented communication]]. Various fault conditions may occur, such as [[data corruption]], [[packet loss]] and duplication. Because routing is dynamic, meaning every packet is treated independently, and because the network maintains no state based on the path of prior packets, different packets may be routed to the same destination via different paths, resulting in [[out-of-order delivery]] to the receiver.

==Link capacity and capability==

* [[Next-generation network]]

* [[New IP]] (proposal)

==References==