Editing Internetworking (section)

== Interconnection of networks ==
Internetworking, a combination of the components ''inter'' (between) and ''networking'', started as a way to connect disparate types of networking technology, but it became widespread through the developing need to connect two or more [[local area network]]s via some sort of [[wide area network]].

To build an internetwork, the following are needed:<ref name="CDKB2012">{{cite book|last1=Coulouris|first1=George|title=Distributed Systems: Concepts and Design|last2=Dollimore|first2=Jean|last3=Kindberg|first3=Tim|last4=Blair|first4=Gordon|date=2012|publisher=Addison-Wesley|isbn=978-0-13-214301-1}}</ref>{{rp|103}} A standardized scheme to [[Network address|address]] packets to any host on any participating network; a standardized [[Communication protocol|protocol]] defining format and handling of transmitted packets; components interconnecting the participating networks by [[routing]] packets to their destinations based on standardized addresses.

Another type of interconnection of networks often occurs within enterprises at the [[link layer]] of the networking model, i.e. at the hardware-centric layer below the level of the TCP/IP logical interfaces. Such interconnection is accomplished with [[network bridge]]s and [[network switch]]es. This is sometimes incorrectly termed internetworking, but the resulting system is simply a larger, single [[subnetwork]], and no internetworking [[Communications protocol|protocol]], such as [[Internet Protocol]], is required to traverse these devices. However, a single computer network may be converted into an internetwork by dividing the network into segments and logically dividing the segment traffic with routers and having an internetworking software layer that applications employ.

The Internet Protocol is designed to provide an [[Reliability (computer networking)|unreliable]] (not guaranteed) [[Packet switching|packet service]] across the network. The architecture avoids intermediate network elements maintaining any state of the network. Instead, this function is assigned to the endpoints of each communication session. To transfer data reliably, applications must utilize an appropriate [[transport layer]] protocol, such as [[Transmission Control Protocol]] (TCP), which provides a [[reliable stream]]. Some applications use a simpler, connection-less transport protocol, [[User Datagram Protocol]] (UDP), for tasks which do not require reliable delivery of data or that require real-time service, such as [[video streaming]]<ref name="Teare">
{{cite book
 |last=Teare 
 |first=Diane 
 |title=Designing Cisco Networks 
 |publisher=Cisco Press 
 |date=July 1999 
 |location=Indianapolis 
 |url=http://www.cisco.com/en/US/tech/tk1330/tsd_technology_support_technical_reference_chapter09186a0080759781.html 
 |archive-url=https://web.archive.org/web/20070207144013/http://cisco.com/en/US/tech/tk1330/tsd_technology_support_technical_reference_chapter09186a0080759781.html 
 |url-status=dead 
 |archive-date=2007-02-07 
}}</ref> or voice chat.