COM 205 Multimedia Applications St. Joseph’s College Fall 2004 2/28/2019

The Internet and How It Works Chapter 12 The Internet and How It Works 2/28/2019

HISTORY A. ARPANET 1. The Internet was created in 1969 by the Advanced Research Projects Agency (ARPA). a) ARPA was part of the U.S. Department of Defense. b) The ARPANET grew as it networked universities, military sites, and government agencies. 2. In 1985, National Science Foundation (NSF) used ARPANET to connect supercomputers and computer science centers. a) Management of the ARPANET officially passed to the NSF in 1989. 3. Commercial use of the Internet began in 1992.

Internetworking Networking basics 1. Two or more computers connected to each other make a network. 2. A local network is called a local area network (LAN). 3. Distant LANs can be connected via phone lines or another medium to form a wide area network (WAN). 4. LANs, WANs, and individual computers can also connect to the Internet through a server. a) A server is permanently connected to the Internet through a high-bandwidth physical connection

Internetworking TCP/IP is the protocol used for communicating on the Internet TCP is Transmission Control Protocol IP is the Internet Protocol In 1983 the Domain Name System (DNS) was established to assign names to computers which were linked to the Internet.

Internet Addresses 1. Address syntax a) Internet addresses use the following syntax: [protocol]://[domain name]/[path]/[file name] ( http://www.sjcny.edu) for example b) The server directory path and file name are often left off. c) The protocol usually does not need to be typed. d) The protocol is also often hidden, such as (1) mailto (2) news

Internet Addresses 2. Top-level domains (TLDs) a) The current Domain Name System (DNS) was developed in 1983. b) TLDs were established for various categories. c) The TLD is part of the domain name, such as (1) .com (2) .net (3) .gov (4) .mil (5) . edu (6) Two-letter country codes

Domain Name System ( DNS) In 1998 (ICANN) Internet Corporation for Assigned Names and Numbers was set up to oversee the DNS. In 2000, ICANN approved seven new TLDs: aero info pro biz museum coop name

Domain Name System ( DNS) Other names are under discussion and may be added in the future: web arts shop firm nom rec

IP Addresses and Data Packets A The Internet transmits data using the Transmission Control Protocol (TCP). (1) Data is broken up into packets. B The Internet Protocol (IP) transmits the packets. (1) Packets can travel along various paths and are reassembled at the receiving end. (2) Destinations are identified by numeric IP addresses such as: 140.174.162.10 (3) Domain name servers look up these addresses.

Connections 1. To connect to the Internet, a computer or network needs a) A data connection to a server (1) The data connection can be wireless or a land line. (2) You usually need an account with the server. (3) Most people access a server through an Internet service provider (ISP). b) TCP/IP software (1) Your operating system may need to be configured to connect to the server and use TCP/IP software.

Connections c) Internet software includes (1) E-mail programs (2) Web browsers (3) FTP software (4) News readers d) ISP ( Internet Service Providers) software PPP - (Point to Point) for dialing up TCP/IP for sending and receiving POP (Point of Presence) - local telephone number

Bandwidth Bottleneck 1. Bandwidth is how much data, you can send from one computer to another in a given unit of time ( See p. 337) 2. The bandwidth bottleneck a) Bandwidth is measured in bits per second (bps). b) Available bandwidth greatly affects how a person can use the Internet. c) Users with slow connections will have a difficult time using multimedia over the Internet.

Bandwidth Bottleneck d) To accommodate low bandwidth users (1) Compress data when possible. (2) Take advantage of the browser’s cache. (3) Design for download efficiency- don’t overdo animation, colors, etc. (4) Design alternate sites for low- and high-bandwidth users. (5) Consider using streaming technology.

Internet Services 1. Services include http, ftp, telnet, Usenet, SMTP, IRC, and others. a) Some services, such as Gopher, are not commonly used. 2. Multipurpose Internet Mail Extensions (MIME)-types a) Files used online must conform to Internet protocols. b) Data types are identified using MIME-types. c) File types must be recognized by servers to be used on the Internet.

The World Wide Web and HTML A. Web history 1. Tim Berners-Lee of CERN (the European Particle Physics Laboratory) developed the Web’s hypertext system in 1989. a) The Hypertext Transfer Protocol (HTTP) was designed as a means for sharing documents over the Internet. b) The Hypertext Markup Language (HTML) is the markup language of the Web. c) Cross-platform compatibility was a design goal.

HTTP The Hypertext Transfer Protocol ( HTTP) provided rules for a simple transaction: 1. Establishing a connection 2. Requesting that a document be sent 3. Sending a document 4. Closing the connection

HTML The HTTP protocol also required a simple document format called HTML (Hypertext Markup Language) for presenting text and graphics The HTML document can contain hotlinks which a user can click to jump to another location

Dynamic Web pages and XML 1. Advanced tools can be used to make a Web page dynamic. a) Dynamic technologies include (1) Cold Fusion (CFM) (2) Hypertext Preprocessor (PHP) (3) Active Server Pages (ASP) (4) Java Script and Java Applets b) Dynamic pages work in conjunction with database applications to look up data.

(XML) eXtensible Markup Language a) XML goes beyond HTML and is the next step in developing web pages. b) This markup language allows developers to define their own styles and elements. c) It allows you to create your own tags to describe what the data means d) Whether or not XML is the future of Web design is still somewhat questionable. Check www.xml.org and www.xml.com

Multimedia on the WEB Developers need to understand how to create and edit elements of multimedia and also how to deliver it for HTML browsers The number of new users of the web will create a greater need for high quality, compelling content, and reasonably quick presentations

Project Idea Visit these web sites http://www.navy.com/ http://www.sigov.si/ http://www.w3.org/MarkUp/Guide/Style.html For each address, answer the following questions: What is the title of the Web page? Briefly describe the content of the Web page. What is unique about the URL?