Chapter 1

What is the Internet?

The Wired World of the Internet

Who runs the Internet? Collection of thousands of networks RFCs, users’ agreement about procedures &

standards for protocols ARPAnet, 1969 NSFnet, 1980s IAB, the Internet Activity Board W3C LANs, Ethernet Local Area Networks ISPs

The Wired World of the Internet

Connection channels:

- Leased Lines: telephone line, fiber optic cable with microwave links and satellite transmissions.

- Backbones: High-capacity lines – vBNS with 155 Mbps

Future Plan is “Internet2”

Information Travel

TCP breaks it to(Packets)

Computersent it to the ISP

SendingInformation

Hardware:1.Hubs2.Bridges3.Gateways4.Repeaters5.Routers

Information Travel

Mid-Level Networks:

1) LANs

2) WANs

TCP/IP, Winsock, MacTCP

Packets: pieces of Information Internet: packet-switched network

TCP (Transmission Control Protocol):Breaks down & reassembles

the packets

IP (Internet Protocol):Making sure the packets are sent to the

right destination

TCP/IP, Winsock, MacTCP

TCP/IP needs special software/ socket:- Winsock: PCs- MacTCP: Macintoshs A socket is necessary for full access to the

Internet Another protocols:- SLIP: Serial Line Internet Protocol- PPP: Point-to-Point Protocol

Addresses & Domains

IP: a series of 4 numbers

Ex. 126.52.128.72 DNS (Domain Name System) developed by

Sun Microsystems,1980s Easier way to keep track of addresses Domains: group of computers on the Net It helps in sending e-mails

Ex. bis303@hotmail.com

Web Connection

Web connection parts:- Desktop (client), ISP, Host (server) and

telecommunication Client needs:- PC, fast modem + telephone line, browser

and communication program

Browser Comm. Pro. ISPSending instructions Dials the modem

Retrieve pages or documents

Web Connection

InterNIC: handles domain names Host computers:- Handle multiple telecommunications- Have gigabytes of hard-disk- Have considerable RAM

Internet File Types

Files requirements:- Software (Plug-Ins)- Hardware- Downloading Internet files: 3 kinds- First is (ASCII)

American Standard Code for Information Interchange

Ex. PostScript files (.ps) + Acrobat reader (.pdf)

Internet File Types

- Second: (EBCDIC)

Extended Binary Coded Decimal Interchange Code This type is like (ASCII) but used on Mainframe

computers- Third is (Binary):- Bits: 0s – 1s

Ex: .Jpeg - .gif - .avi - .wav - .mpeg - Binary files are large, need hardware/ software,

and sometimes need to connect to the Net for streaming multimedia