The Internet is a global system of interconnected computer networks that uses TCP/IP protocols to serve billions of users worldwide. It is a network of networks made up of private, public, academic, business, and government networks linked together across different technologies. The Internet provides a wide range of information resources and services like the World Wide Web and email infrastructure. Mobile devices allow users to access the Internet almost anywhere through wireless connections, within limitations of small screens. While often used interchangeably, the Internet and World Wide Web are not synonymous - the Web is a set of interlinked documents accessed through HTTP, but the Internet contains hundreds of communication protocols.

1. lecture 23 Internet
The Internetis a global systemof interconnected computernetworks thatuse the standard Internet
protocol suite (TCP/IP) toserve billionsof usersworldwide.Itisa networkof networks thatconsistsof
millionsof private,public,academic, business,andgovernmentnetworks,of local toglobal scope,that
are linkedbyabroad array of electronic,wirelessandoptical networkingtechnologies.The Internet
carriesan extensiverange of informationresourcesandservices,suchasthe inter-
linkedhypertextdocumentsof the WorldWide Web (WWW) andthe infrastructure tosupportemail.
The Internetallowsgreaterflexibilityinworkinghoursandlocation,especiallywiththe spreadof
unmeteredhigh-speedconnections.The Internetcanbe accessedalmostanywhere bynumerous
means,includingthrough mobileInternetdevices.Mobile phones, datacards, handheldgame
consoles andcellularrouters allow userstoconnectto the Internet wirelessly.Withinthe limitations
imposedbysmall screensandotherlimitedfacilitiesof suchpocket-sizeddevices,the servicesof the
Internet,includingemail andthe web,maybe available.Serviceprovidersmayrestrictthe services
offeredandmobile datachargesmaybe significantlyhigherthanotheraccessmethods.
Many people use the terms InternetandWorld Wide Web, or justthe Web, interchangeably,butthe
twoterms are not synonymous.The WorldWide Web isa global setof documents,imagesandother
resources,logicallyinterrelatedby hyperlinks andreferencedwith UniformResource Identifiers (URIs).
URIs symbolicallyidentifyservices, servers,andotherdatabases,andthe documentsandresourcesthat
theycan provide. HypertextTransferProtocol (HTTP) isthe mainaccessprotocol of the World Wide
Web,but itis onlyone of the hundredsof communicationprotocolsusedonthe Internet. Web
servicesalsouse HTTPto allowsoftware systemstocommunicate inordertoshare andexchange
businesslogicanddata.