An Introduction to the Internet

1. An Introduction to the Internet INLS 80, Summer I, 1999 Ilana Kingsley Notes based on previous INLS80 classes from Kristen Chaffin & Dr. Greg Newby

2. What is the Internet? • An internet is a set of computer networks that are connected to each other • The Internet is a world-wide set of networks that interoperate using TCP/IP protocols • Think of “communication software” or “standards” when you see “protocol” • more on TCP/IP and other protocols later… • A loosely controlled anarchy

3. History of the Internet • From a DARPA research project… • To an NSF-sponsored research project... • To a full "production" global infrastructure

4. Internet Timeline • Hobbes' Internet Timeline v4.1 • Internet Society's Listings

5. History of Internet • In the 1960’s the Defense Advanced Research Projects Agency (DARPA) wanted to develop a network that would connect geographically diverse, heterogenous computers. • 1969 -- 4 sites are connected in the original ARPAnet demonstration • To expand this network, standards were necessary. • 1974 --First TCP/IP protocols • By 1983, the use of TCP/IP had been mandated by the Secretary of Defense

6. History of Internet • 1980 --ARPAnet becomes backbone for Internet • 1986 --NSF takes over and NSFNET becomes the backbone. • 1992 --WWW emerges • 1994 --NSF ceases funding and commercial industry moves in • 1998 --WWW is ubiquitous in the United States and other countries

7. TCP/IP • Transmission Control Protocol/Internet Protocol • Provides reliable, in-order, end-to-end transmission of data. • All Internet applications use TCP/IP

8. IP (Internet Protocol) • A set of rules for communicating • The IP specifies the host and destination Internet address ("IP address") and describes the content of each packet. • The IP is in the midst of an upgrade for better handing of multimedia, quality of service (QoS), and better security. [Internet2]

9. A possible piece of the Internet

10. Networking “Structure” The Layered approach • Applications:Web Clients, PC Apps, … • Services Naming: Mail, File Transfer • Conventions: Protocols, Standards • Physical: Wire, Routers, Hosts

11. Who Creates Standards? • Internet Society (ISOC) • To promote evolution and growth of Internet • Internet Architecture Board (IAB) • Technical oversight and coordination • Internet Engineering Task Force (IETF) • IETF develops Internet standards - internet protocols • Called RFCs (Request for Comments) • Internet Research Task Force (IRTF) • To promote research of importance to the evolution of the future Internet

12. Internet Applications Include • Telnet • FTP [File Transfer Protocol] • E-mail • Gopher, Veronica, Archie, Jughead- [old] • Usenet Newsgroups • IRC (Inter-Relay Chat) • MUDs (Multi-User Dimensions) • MOOs (Mud-Object Oriented) • WWW (World Wide Web)

13. Internet Applications • Different applications use different protocols, in addition to TCP/IP [http; ftp; telnet] • Most are based on client-server model

14. Important Concepts • host - a computer that is connected to the Internet • has an IP address that uniquely identifies it • Example: 152.2.81.100 • has a domain • domain - a grouping of networked computers • Example: unc.edu • client - asks for a service • server - provides a service

15. Important Concepts • Adresses vs. Names • DNS is Domain Name Service • the DNS server stores name/address pairs which are used for ‘host lookups’ • Domain Names are registered with ICANN (formerly by IANA) • Domain Names registration services in the .com, .net, and .org domains are provided by Network Solutions, Inc (formerly InterNic). • Until this year InterNic was a “monopoly”. ICANN is running a testbed of five registrars of the new competitive Shared Registry System for the .com, .net, and .org domains. SeeISOC.

16. Client/Server/Protocol Relationship • Client Initiates a Connection • Server Waits & Responds to Incoming Connections