Internet Protocols n241.tplt The Changing Role of Computers How are they used?
-powerful calculators
-word processors
-game platform
-communication tool
-etc. Computer Prior to World War II, it was a human being who undertook complex mathematical calculations Early machines were used to calculate artillery firing tables and code breaking Today, computers still are used to do calculations, but the more frequent use if for communication Computer Communication Evolution In 1943, Thomas Watson, then chairman of IBM, is reported to have said: "In the whole world there is a market for maybe 5 computers." During Mr. Watson's time, this might have been true - computers filled large rooms
-they were expensive to build and maintain
-they were difficult to program Mainframe Computer A massive computer that could be used by many people at the same time Each person had their own keyboard and monitor The advantage of this was the computer was used as a communication medium The Personal Computer The microprocessor was developed in the 1970's which initiated the personal computer Image changed from a huge room full of a computer to what you see on your desktop "Paperless office" was touted a potential benefit of computers - but paper remained the method of communication Enter the LAN Local Area Network - combination of programs and hardware that connected a series of personal computers so the computers could communicate electronically LAN's were useful within an organization, but made transferring information outside the LAN a problem Not all computers store information the same way The Internet Got its start at the heart of the Cold War (1960's) Research in computing was funded by the US military The military wanted a communications network that could tie several geographical locations together, but one that would not be affected if one location was blown up by the opposing side TCP/IP
(Transfer Control Protocol/Internet Protocol) This took messages, broke them into packets and sent each packet separately to its destination If the path was blocked, the packets could find another route When the packets reached the destination, the packets were automatically re-joined ARPANET
(Advanced Research Projects Agency Network) The network using TCP/IP to tie together the military computers Was later modified to include scientific and educational capabilities NSF
(National Science Foundation) Control of ARPANET was absorbed by NSF which changed the name to NSFNET Commerce was strictly forbidden on the NSFNET "Internet" Became popular during the 1992 US Presidential campaign The charter of NSFNET was changed to encourage personal and commercial use NSFNET (which is a US institution) joined forces with other large networks to for the Internet InterNIC - a consortium of private entities has what little control there is of the Internet The Internet Global in scope Is not owned or controlled by anybody IAB - Internet Architecture Board helps to establish mutually agreed standards for Internet protocols The Internet is NOT Centrally owned A single entity "Den of Iniquity" A hive of viruses waiting to attach your computer Not just for teenagers What IS the Internet? A vast information source Relatively universal Dynamic - ever changing The Problem How do we take advantage of the vast resource? How can we find the specific information we want? What types of problems can we solve by using the World Wide Web? Tools World Wide Web
- formats for storing, retrieving and transferring information on the Internet are called PROTOCOLS Each major protocol could be considered a tool, but we will concentrate on the World Wide Web The WWW protocol is different from other protocols WWW Protocols Uses a model based on pages Designed to use hypertext Allows exploration without the user having to worry about which computer he will be accessing Is easy to use Very easy to create pages Designed to share information Browsers as Tools Browsers use similar features that make navigation easier:
-Location box
-Navigation buttons
-Menus
-On-line help Commands within browsers are tools (previous page, home page, search, directory, etc.) Protocols Are a series of agreements about how information will be shared and communicated between machines and networks Protocols are NOT the same as programs TCP/IP Transfer Control Protocol/Internet Protocol is the underlying protocol of the Internet today Telnet One of the earliest protocols Allows the user to access a remote computer Is an inexpensive protocol to implement and utilize, but uses plain text, no graphics FTP (File Transfer Protocol) Designed to aid in copying information between computers through the Internet Mail and News Protocols Protocols designed to transfer text from computer to computer SMNP POP HTTP (HyperText Transfer Protocol) The World Wide Web is based on this protocol Integrates many of the other protocols Is designed with Hypertext in mind Encourages hypertext multimedia DNS (Domain Name Server) System IP numbers - addresses Domain names - the "Name" for the IP numbers

Domain	Type of Orginization
.edu	Educational institution
.com	Commercial or business
.gov	Government organization
.org	Non-profit organization

Subdomains Large Organizations Organizations apply to InterNIC for a particular subdomain name UserIDs Often called login or userid
-usually based on the user's name, often abbreviated and lower case letters Passwords An important consideration of the Internet is security Passwords are a way to "lock" your computer Protect your password
-change it regularly
-consider combining words and numbers
-don't use something simple that some can guess
-don't use words in English, people can hook up spell checkers How does this all work? Consider the tree structure
-the smallest unit on the Internet is the individual user
-LAN (Local Area Network) a network of computers within a department or floor of an organization connected together for ease of communication
-WAN (Wide Area Network) LANs tied together within an organization LANs and Routers Routers are designed to direct traffic between the LAN and the Internet Routers take the information you give it and uses TCP/IP to send the packet to other routers The packets are "routed" to the 'Information Super-highway' to the Internet Backbone Packets are transferred to other routers via the IP addresses until they find the correct destination The Client-Server Approach Drive-thru restaurant example
-You are the client ordering from the server (restaurant) The restaurant (server) waits for requests from clients (you at the drive-thru window), processes them and gives the results to the clients Levels of Connectivity Direct connection Dial-in connection Slip-PPP connection Commercial service providers Proprietary Networks
-Compuserve, Prodigy, America Online ISP (Internet Service Providers) Email Uses the mail/news protocol Communication tool Email etiquette Talk and Chat Allows a connected person to interact directly with another connected person by typing simultaneously and seeing the message Mailing Lists Mailing lists are simple - contains an email address
-Listserv
-Majordomo Sign up using email to join the list
-when sending a message to the list, all members of the list receive the message