Internet and Networking Terms Bob Bradley The University of Tennessee at Martin
The Internet • The global collection of connected networks that use TCP/IP protocols. • The Internet was created from research done by the U.S. Department of Defense Advanced Research Projects Agency (ARPA) in the late 1960s – early 1970s. • The Internet became a commercial success in the 1990s. • No one group or country owns or “runs” the Internet, because it is a collection of networks.
Growth of the Internet • The Internet has experienced exponential growth over two decades. It has been doubling in size every nine to twelve months. (only recently has this growth rate started to slow) • In 2001, there were over 100 Million computers attached to the Internet. • In 2002, there were over 160 Million computer and nearly 800 Million Internet users. • In 2003, the number is approaching 200 Million computers. • Click here to see the real-time Internet growth charts http://www.netsizer.com/ (may not work) • See Internet growth at: http://www.isc.org/ds/
World Wide Web • The hypermedia system used on the Internet in which a page of information can contain text, images, audio or video clips, and references to other pages. • The main protocol of the Web is HTTP and the main information format is HTML. • Information on the web is identified by a URL. • Invented by Dr. Tim Berners-Lee who donated his work to the world for free!!!! • http://www.w3.org/People/Berners-Lee/Overview.html
URL (Uniform Resource Locator) • A syntactic form used to identify a page of information on the World Wide Web. • Example: http://www.utm.edu/~bbradleyConsists of a protocol :// hostname / page name • URLs are universal and unique. The URL to a page can be used to identify and access it from anywhere in the world on the Internet. • Can be on T-Shirts, on bill-boards, in magazines.
TCP/IP • Transmission Control Protocol / Internet Protocol • The protocol suite used in the Internet. • Allows all the computers on the internet to communicate with each other. • The common language of the Internet • A computer must be able to “speak” TCP/IP before it can talk on the Internet.
Protocol • A design that specifies the details of how computers interact, including the format of messages they exchange and how errors are handled.
Protocol Suite • A set of protocols that work together to provide a seamless communication system. Each protocol handles a subset of all possible details. The Internet uses the TCP/IP protocol suite. • Includes: HTTP, SMTP, POP, IMAP, FTP.
RFC (Requests For Comments) • Most of the Internet standards and protocols are fully described in documents called RFCs. • See http://www.rfc-editor.org/ • The Requests for Comments (RFC) document series is a set of technical and organizational notes about the Internet. • Memos in the RFC series discuss many aspects of computer networking, including protocols, procedures, programs, and concepts, as well as meeting notes, opinions, and sometimes humor.
Example RFCs • The following protocols are described by the indicated RFC documents: • SMTP (RFC 821) • POP (RFC 1725) • IMAP (RFC 1730) • DNS (RFC 1034, RFC 1035)
IETF & IESG • The official specification documents of the Internet Protocol suite that are defined by the Internet Engineering Task Force (IETF) and the Internet Engineering Steering Group (IESG ) are recorded and published as standards track RFCs. As a result, the RFC publication process plays an important role in the Internet standards process. RFCs must first be published as Internet Drafts.
IP Address • A 32-bit address assigned to a computer that uses the TCP/IP protocols. The sender must know the IP address of the destination computer before sending a packet. • This is like a phone number for the computer. • A program on one computer communicates with a program on another computer, by connecting to its IP address. • The 32-bit address is usually represented as four 8-bit decimal numbers separated by periods. • Example: www.utm.edu’s IP address is 220.127.116.11
IPv4 (Internet Protocol Version 4) • The version of IP currently used in the Internet. • IPv4 uses 32-bit addresses
Dotted Decimal Notation • The syntactic notation used to express a 32-bit IPv4 address. • Each octet is written in decimal with a period separating octets. • Example: • Mars.utm.edu’s IP address is 18.104.22.168 • www.utm.edu’s IP address is 22.214.171.124 • www.yahoo.com’s IP addresses are 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206
IP Numbers • Four groups of 8 bit numbers. • Each 8 bit range has 256 possibilities: • 00000000 = 0 • 11111111 = 255 • Therefore IP’s range from • 0.0.0.0 to 255.255.255.255 • There are about 4 billion possible addresses. • However, there are several reserved ranges.
DNS (Domain Name System) • The automated system used to translate computer names into equivalent IP addresses. • A DNS server responds to a query by looking up the name and returning the address. • DNS is a global distributed database. • Central authority for top level domain names. • Local authority for your own names. • If you tell your web browser to connect to www.utm.edu, the web browser will use the DNS system to convert the host name (www.utm.edu) into an IP address (220.127.116.11)
Packet • A small, self-contained parcel of data sent across a computer network. • Each packet contains a header that identifies the sender and recipient, and a payload area that contains the data being sent. • All messages sent on a network such as the Internet are broken into small chucks called packets.
Packets • For example, if I download a web page, my web browser sends a message in a packet like this to the web server: • When the web server receives this request, it will send the web page back to my computer by breaking it down into smaller parts and sending each part in a packet: To From Payload / Data 18.104.22.168:80 10.11.1.115 GET /index.html Header To From Payload / Data Part 1 of web page 10.11.1.115 22.214.171.124 Packet 1 Part 2 of web page 10.11.1.115 126.96.36.199 Packet 2
E-Mail Protocols • SMTP – Simple Mail Transfer Protocol • Used to transfer e-mail from one computer to another across the Internet. • SMTP is part of the TCP/IP protocol suite. • POP3 – Post Office Protocol • A simple protocol used by a email client program to download mail from a server. • IMAP - Internet Message Access Protocol • A more complicated protocol used by some email clients to download and manage email
Web Protocol and Language • HTTP – Hyper Text Transfer Protocol • The simple protocol used to transfer a World Wide Web page from one computer to another. • A web client opens up a connection to a web server and sends GET PAGENAME and then the web server sends back the page text (usually HTML) over the connection. • HTML – Hyper Text Markup Language • The source form used for documents on the World Wide Web. HTML embeds commands that determine formatting along with the text to be displayed (e.g., to move to a new line or indent text).
LAN (Local Area Network) • A network that uses technology designed to span a small geographic area. For example, an Ethernet is a LAN technology suitable for use in a single building. • LAN’s can be “bridged” together to allow multiple buildings to be on the same LAN, but a LAN cannot span for much more than a few thousand feet. • The University of Tennessee at Martin has a LAN that connects all of the computers on its campus. • LAN’s have lower propagation delay than WANs.
LAN Computers A LAN can consist of computers in the same room or building that are hooked together using a Hub/Switch type device. Hub
LAN Computers Computers Hub Hub A LAN can also allow Computers on different floors or even different buildings to be bridged together. Hub
LAN Computers Computers File Server Printer Hub Hub A LAN can allow computers to share resources such as printers, disks or Internet connections. Internet Gateway Internet Hub
WAN (Wide Area Network) • A network that uses technology designed to span a large geographic area. For example, a satellite network is a WAN because a satellite can relay communication across an entire continent. WANs have higher propagation delay than LANs. • The University of Tennessee System has a state wide WAN network connection it’s campuses.
UT WAN Martin
UT WAN : State Internet Links Up North Martin Kansas City Atlanta
UT WAN : State Internet Links Up North Martin Kansas City Internet II Internet II Atlanta
Reference • Slides created by Bob Bradley, The University of Tennessee at Martin • Most of these terms were taken from the Glossary of Networking Terms and Abbreviations in the back of the book Computer Networks and Internets with Internet Applications Third Edition, Douglas E. Comer • Comments and notes added by Bob Bradley, The University of Tennessee at Martin