Lecture Number One

History of the internet and a bit about how it works

The Ancestors

ARPANET

NSFNET

ARPANET Advanced Research Projects Agency

The original “backbone of the internet”

Purpose: to create a decentralized computer network so government could keep working in case of nuclear attack

More about ARPANET

- started in California in ?

- originally linked three universities (Stanford, UCLA,UCSB) and SRI

- Designed for max of 256 computers

1976: ? ; 1984: ?

NSFNET National Science Foundation Network

Purpose: to connect scientific researchers and engineers

More about NSFNET

- started by the feds in ?

- originally, access limited to official agencies

The relationship between ARPANET and NSFNET

- ARPANET the original “backbone” of the internet

- With NSFNET, two “backbones”

- By 1988 more than ? linked computers

How the Internet is run today

- NSFNET replaced ARPANET as backbone in ?

- Internet transferred to nonprofit corporation ? years later

How does the internet work?

Overall Internet MechanicsAll machines on the web are either servers or

clients

Servers ________ information, clients_________ it.

Servers have numbered ports, one for each service provided (like web access, ftp, etc)

Clients connect to the port that offers the needed service

Whenever you are on the net you’re part of a network

At home…

May have DSL or use a MODEM to connect to an ISP

DSL= ? (talk & surf at the same time!)

MODEM= ?ISP= ?

And at work…

Orgs have POP servers (point of presence)

where local users access the company’s networks

Networks connect to each other through NAPs

(network access points)

Protocols: How networks communicate

Protocol, defined

Internet Protocols

TCP/IP

WWW

TCP/ IP

Stands for ____________________________

Developed in the 70s for ARPANET

Formalized in 1982

TCP/IP Sends Informationfrom one IP address to another

- - Transmission broken into 1.5K ?

sent from router to router

- - a router is ?

- - receiving computer reassembles according

to instructions bundled with the ?

IP Addresses

- Every machine on the net has a unique address made up of 4 numbers, 0-255, separated by periods

-looked at in binary each number is an octet- the

first is always the net, the last the host

Do you have your own IP Address?

Yes, if you have cable or DSL (digital subscriber line)

No, if you dial up– when you do, you’re given the ISP address for that session which corresponds to the MODEM that connects you

We tend to use Domain Names rather than IP Addresses

- At first, you had to know IP addresses

- DNs were created at the University of Wisconsin to map text to IP addresses automatically

What are Domain Names

- Descriptive words associated with a specific _________________

- advantage that when machines replaced don’t have to learn new IP address

- not case-sensitive - must be purchased (IP addresses are free)

Domain names made up of

First level domains (like .edu)

Second level domains (like ufl)

First level domains can’t have duplicates

But second can- spca.com not equal spca.org

Examples of first level domain Names

.com / .org ( not necessarily nonprofit, just don’t pay dividends)

.edu / .net

.mil/ .gov

.mx / .nl /.ch / .ca/ .uk etc.

Examples of Full Domain names

A travel agency http://www.side-step.com/ My son's music

http://www.att.com/

Domain names are contained within URLs

URL Stands for________________

protocol:location/document

http://www.cise.ufl.edu/~rjd/workshop06photo.html

http://www.schaferhund.com/pregnancy.htm

Some DN Considerations

Cyber squatters

Buy misspellings just in case

http://www.howstuffworks.com/

http://www.howstuffowrks.com/

Examples of multiple purchases

http://www.bn.com/http://www.barnesandnoble.com/http://www.barnesandnoble.com/

Some Places To Get a Domain Name

GodaddyRegisterFly planetdomain

WWW

World Wide Web

protocols we use every day

finalized in _______

Some Uses of WWW Protocols

To log into remote computers (?)

To transfer web pages (?) To transfer files (?)

To send email (?)