The internet address

• hunterl@cs.montana.edu
• vicepresident@whitehouse.gov
• lateshow@cbs.com

• The userid is on the left side of the @
• The host/network is on the right side of the @ sign
• domain hierarchy
• identifies the type of organization that server or client is associated with host computer names
• com - commercial enterprises
• edu - educational instutions
• net - networking organizations
• gov - government

• USEnet - newsgroups mailing lists
• TelNet - log on to other computers
• FTP - file transfer protocol
• Gopher - search for data across the world
• Wais - wide area information search
• IRC - internet relay chat
• Telephony - combining telephone technology with computer technology
• WWW - world wide web
• E-mail - very popular stuff

ALL OF THESE THINGS MAKE UP THE INTERNET

Server

• Can be anything from a PC to a supercomputer
• Supplies computing services
• stores information or data
• Databases
• Files
• Graphics
• Full motion video
• Sounds

Client

• Can also be anything from a PC to a supercomputer
• Typically a PC or a Workstation
• Requests the information or data
• Uses computing services offered by server

Every computer location on the Internet as a numeric address, my web server http://www.cs.montana.edu, translates to the numerical address 153.90.192.1. This numerial address is know as the IP address.

    My web address

Domain name = www.cs.montana.edu/~hunterl
IP address = 153.90.192.1/~hunterl

• Type in the IP address instead of the domain name and you will get the same result.

• Your computer sends a request with the domain name.
• The request goes to a Domain Name System (DNS) Server that looks up the domain name you typed in a huge table that resides on the DNS Server. The table has domain names linked with IP addresses, so the domain name you've requested is translated into an IP address.
• After the IP address is found your request is resubmitted with the IP address.
• The Internet usese the IP address as a routing scheme, each layer of numbers means something to the computers searching for your request.
• When you type in a domain name and hit enter all the steps above are handled, and then your request must travel to wherever the server you are looking for is located. Then that server must pack up your request and ship that request back to you. There is a lot going on, but it happens within micro-seconds.

How data travels

• When you make your request for a Web page the computer builds the request for you. It then will divide your requests into small chunks called packets.
• Something small like a single request might be one packet, but something like a Web page with a lot of graphics might be divided into several packets.
• Dividing the data into packets allows the computers to move the data faster.
• Each packet contains part of the data being sent and a header that has the destination, origination point, how many packets the data was divided into, and a few other admin type things.
• Once the data is divided into packets and sent across the Internet, the packets might not take the same route to the destination. If you are in Montana, and the data is being sent from Georgia, there is a chance that one packet might go through Texas, and another through Chicago.
• At the destination the packets are reorganized and then the data is displayed.

TCP/IP

• TCP/IP is a protocol on how the computers communicate and move the packets across the network.
• Transmission control protocol/Internet protocol
• Protocols are a set of rules and procedures, the computer must have rules and procedures to communicate. It's like talking in English, if you are talking in English you are communicating with the English protocol. Computers communicate with the TCP/IP protocol.
• We will discuss the different protocols in the Networks lectures later in the semester.

• Search engines

Make sure you know the difference between the two types of search engines I mention in the Internet tutorial that is linked on the main cs150 web page. Yahoo is one type, and Altavista is the other type. The search engine part of the tutorial will be on the test.
 
• Yahoo
• Use + to narrow your search (ex. +montana+universities)
• Infoseek
• Lycos
• Use + with Lycos also, also - will work to exclude words

•     Graphics (pictures) must be saved in a certain format.
•    GIF and JPG (JPEG) are the two most common formats on the Web.
• Animation is a series of images show in consective order to create the illusion of movement.
• The most popular example of animation are animated GIFS. All the animations on my homepages are animated GIFS. If you have a series of pictures you want to animate together you can use animation software such as Animagic and create your own animations. Animagic is free from www.downloads.com.
• Audio - Sounds, music, narration, use your ears not your eyes. Most sound on Web pages is a bad idea, sounds have to download completely before you playing and sound files can be very big for just a small sound.
• Because of this Streaming Audio was created. See RealAudio below.
• Video - Video is the biggest file size as far as multimedia is concerned. Videos make up many images that are just swapped out one after another, and videos usually have sound also. The combination of many images, plus sound make the files very large and time consuming to download over the Internet.
• Another reason Streaming Video was produced.
• Virtual Reality -  3D images that you can explore and manipulate interactively. The Internet technology on this subject is very volatile, not one application process has taken over. VRML was the most prevelant, but in the last year it has faded. I am a VRML programmer, I have many 3D worlds on my web pages if you have the correct plugin to view them. (see Cosmo Player below).

• CGI - Common gateway Interface
• Java Applets
• Javascript
• VRML
• Streaming Audio/Video
• Shockwave/Shockrave
• Secured Data Encryption
• MP3