FluencyFluency

Chapter 3Chapter 3

The Basics of NetworkingThe Basics of Networking

What is the Internet?What is the Internet?

►The totality of all wires, fibers, The totality of all wires, fibers, switches, routers, satellite links, and switches, routers, satellite links, and other hardware for transporting other hardware for transporting information between addressed information between addressed computers.computers.

►What’s your address?What’s your address?

How have computers changed How have computers changed our lives?our lives?

►For the better?For the better?

►For the worse?For the worse?

►What effect has it had on the influence What effect has it had on the influence of the English language?of the English language?

Communication CategoriesCommunication Categories

►SynchronousSynchronous►AsynchronousAsynchronous►BroadcastBroadcast►MulticastMulticast►Point-to-pointPoint-to-point

So what category So what category does the Internet fit into?does the Internet fit into?

Computer addressesComputer addresses

►Each computer connected to the Each computer connected to the Internet is given a unique Internet is given a unique IPIP (Internet (Internet Protocol) addressProtocol) address

► IP address – currently series of IP address – currently series of 4 4 numbersnumbers separated by dots: e.g. separated by dots: e.g. 213.43.1.156213.43.1.156

►Each # can be in range of 0-255Each # can be in range of 0-255► Internet protocol moving to Version 6 Internet protocol moving to Version 6

((IPv6IPv6) with a 16-byte address system.) with a 16-byte address system.

Domain NamesDomain Names

► A more human-friendly way of addressing A more human-friendly way of addressing computers based on a computers based on a hierarchyhierarchy of domains. of domains.

►DomainDomain – related group of networked – related group of networked computerscomputers

► markel.faculty.msmc.edumarkel.faculty.msmc.edu► Domain Name System (Domain Name System (DNSDNS) translates the ) translates the

domain name into its 4-number IP addressdomain name into its 4-number IP address►DNS serverDNS server – a computer that keeps a list of – a computer that keeps a list of

the symbolic names and the corresponding IP the symbolic names and the corresponding IP addressesaddresses

Top Level DomainsTop Level Domains

► .com.com► .org.org► .mil.mil► .net.net► .gov.gov► .edu.edu

In addition there’s a 2-letter In addition there’s a 2-letter country codecountry code: : .uk, .au, .fr etc. that identifies countries.uk, .au, .fr etc. that identifies countries

TCP/IPTCP/IPTransmission Control Transmission Control

Protocol/Internet ProtocolProtocol/Internet Protocol

►TCPTCP – breaks a transmission up into – breaks a transmission up into small fixed-size packetssmall fixed-size packets

►Each packet contains the following:Each packet contains the following: Data being sentData being sent Destination IP addressDestination IP address Sequence #Sequence #

► IPIP - re-orders the packets at the - re-orders the packets at the destination to assemble the informationdestination to assemble the information

Characteristics of TCP/IPCharacteristics of TCP/IP

►Packets are Packets are independentindependent►Packets are transmitted over the Packets are transmitted over the

Internet using Internet using whatever routewhatever route is is availableavailable

►Transmissions often rely on Transmissions often rely on multiple multiple technologiestechnologies to move the packets to move the packets through the Internet:through the Internet: Telephone linesTelephone lines Fiber opticsFiber optics Dedicated linesDedicated lines

NetworksNetworks

►WANWAN – wide-area networks: networks – wide-area networks: networks designed to send information between designed to send information between two locations not directly connected.two locations not directly connected. Packets take several “hops” before Packets take several “hops” before

deliverydelivery

►LANLAN – local-area network. Computers – local-area network. Computers are directly cabled or “channeled” are directly cabled or “channeled” together. Most LANs use together. Most LANs use EthernetEthernet technology.technology.

Connecting to the InternetConnecting to the Internet

► ISPISP – Internet Service Provider – Internet Service Provider Examples?Examples? Connection method:Connection method:

► ModemModem► DSL (digital subscriber line)DSL (digital subscriber line)

► Network connectionsNetwork connections LANs connect to the Internet via a LANs connect to the Internet via a gatewaygateway. .

Information from a remote Web computer is sent Information from a remote Web computer is sent across the Internet, through the gateway to the across the Internet, through the gateway to the organization’s intranet, and across the LAN to the organization’s intranet, and across the LAN to the user’s computer.user’s computer.

The World Wide WebThe World Wide Web

► Web serversWeb servers – computers programmed – computers programmed to send files to browsers running on to send files to browsers running on other computers connected to the other computers connected to the Internet.Internet.

►Subset of the InternetSubset of the Internet►Each web page has a unique address Each web page has a unique address

called a Universal Resource Locator or called a Universal Resource Locator or URLURL

►Built on a Built on a client-serverclient-server relationship relationship

The URLThe URL

The URL consists of three parts:The URL consists of three parts:► Protocol: http:// - stands for Hypertext Protocol: http:// - stands for Hypertext

Transfer PtococolTransfer Ptococol► Server computer’s nameServer computer’s name► Pathname of the particular pagePathname of the particular page

http://domain.address/pathnamehttp://domain.address/pathname

http://faculty.msmc.edu/markel/cit1100/outline.htmlhttp://faculty.msmc.edu/markel/cit1100/outline.html

Structure of emails and URLsStructure of emails and URLs

►Email: Email: receiver@domain.addressreceiver@domain.address The receiver can have dots, dashes, and The receiver can have dots, dashes, and

underscores. underscores.

►URL: URL: http://domain.address/pathnamehttp://domain.address/pathname The domain address has one or more The domain address has one or more

dots, no @, no slashes.dots, no @, no slashes.

Spaces are not allowed in email or URLs.Spaces are not allowed in email or URLs.

Describing a Web Page

• Web pages stored as a description of how they should appear

• Description file is called the source file• Written in HTML (hypertext markup

language)• Markup languages describe document

layout• Hypertext – breaks linear sequence of text

through links: non-linear and dynamic

Directory OrganizationDirectory Organization

index.html

cit1050 cit1100 csc1200 mst1010

outline.html

grading.html assignments

Assignment1.html

root root pagepagefolderfolder

foldefolderr

patpathh

Th . . .th . . . that’s all, folks!