Internet Development  What is the Internet anyway? Bryan Duggan
The Internet is short for: <ul><li>Inter connected  Net work </li></ul>
What is a network? <ul><li>From dictionary.com: </li></ul><ul><ul><li>An openwork fabric or structure in which cords, thre...
What is a network? <ul><li>From whatis.com </li></ul><ul><li>A network is a series of  points  or  nodes  connected by com...
What’s the Internet NOT? <ul><li>“ The web” </li></ul><ul><li>AOL </li></ul><ul><li>Email-reachable users </li></ul><ul><l...
What can it do? <ul><li>Email </li></ul><ul><li>WWW, Hypertext, RSS, browsers  </li></ul><ul><li>FTP, WebDav </li></ul><ul...
Where did it come from? <ul><li>Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first know...
How big is the Internet?
How big is the Internet? <ul><li>Traffic </li></ul>
Internet Software <ul><li>Clients </li></ul><ul><ul><li>A client is the requesting program or user in a client/server rela...
Browser <ul><li>An application program that provides a way to look at and interact with all the information on the World W...
 
Web Server <ul><li>Using the client/server model and the World Wide Web's Hypertext Transfer Protocol (HTTP), serves the f...
Other clients & servers? <ul><li>Mail server/client </li></ul><ul><ul><li>SendMail, Exchange, Lotus Domino </li></ul></ul>...
Peer to Peer <ul><li>Gnutella </li></ul><ul><li>Kazza </li></ul><ul><li>Bittorrent </li></ul><ul><li>Warez </li></ul><ul><...
Internet hardware <ul><li>Edge devices - Clients, servers, peers, PC’s servers, phones, PDA’s </li></ul><ul><li>Core devic...
Hub <ul><li>The central part of a wheel where the spokes come together.  </li></ul><ul><li>The term is familiar to frequen...
Switch <ul><li>A device that channels incoming data from any of multiple input ports to the specific output port that will...
Router <ul><li>A device or, in some cases, software in a computer, that determines the next network point to which a packe...
Combo devices <ul><li>Linksys Wireless-G ADSL Gateway WAG54G   </li></ul><ul><li>4-port 10/100 Ethernet  Switch </li></ul>...
Modem <ul><li>A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a c...
Network card <ul><li>A network interface card (NIC) is a computer circuit board or card that is installed in a computer so...
Wireless <ul><li>802.11 (a,b,g) </li></ul><ul><li>GPRS </li></ul><ul><li>3G </li></ul>
ISDN <ul><li>Standards for digital transmission over ordinary telephone copper wire as well as over other media.  </li></u...
ADSL <ul><li>Technology for transmitting digital information at a high bandwidth on existing phone lines to homes and busi...
Question? <ul><li>How can such a diverse range of hardware and software communicate? </li></ul><ul><li>You can replace all...
What’s a protocol? <ul><li>human protocols: </li></ul><ul><li>“ what’s the time?” </li></ul><ul><li>“ I have a question” <...
What’s a protocol? <ul><li>a human protocol and a computer network protocol: </li></ul>Q:  Other human protocol?  Hi Hi TC...
What do protocols look like? <ul><li>“ Binary” </li></ul><ul><ul><li>Fixed-length fields, like C-structures </li></ul></ul...
Connection-oriented service <ul><li>Goal:  data transfer between end sys. </li></ul><ul><li>handshaking:  setup (prepare f...
HTTP Protocol Parameters Request Query Results Response Web Server Web Browser Database (Optional) E.g. A user fills in a ...
SMTP Protocol <ul><li>Simple Mail Transfer Protocol </li></ul><ul><li>Protocol for sending Email </li></ul><ul><li>Origina...
Person Shop Wholesalers Co-op Farmer
Protocol Stacks
Internet Standardisation <ul><li>International Telecommunications Union (ITU) </li></ul><ul><ul><li>United Nations treaty ...
 
IETF <ul><li>Open membership </li></ul><ul><li>Meets three times a year, about 2,000+ people </li></ul><ul><li>Most work d...
RFC’s <ul><li>Network Working Group  Steve Crocker </li></ul><ul><li>Request for Comments: 1  UCLA </li></ul><ul><li>7 Apr...
What is Internet/Web development? <ul><li>Creating software that: </li></ul><ul><ul><li>Runs on Internet hardware </li></u...
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What is the internet Lecture

  1. 1. Internet Development What is the Internet anyway? Bryan Duggan
  2. 2. The Internet is short for: <ul><li>Inter connected Net work </li></ul>
  3. 3. What is a network? <ul><li>From dictionary.com: </li></ul><ul><ul><li>An openwork fabric or structure in which cords, threads, or wires cross at regular intervals. </li></ul></ul><ul><ul><li>Something resembling an openwork fabric or structure in form or concept, especially: </li></ul></ul><ul><ul><ul><li>A system of lines or channels that cross or interconnect: a network of railroads. </li></ul></ul></ul><ul><ul><ul><li>A complex, interconnected group or system: an espionage network. </li></ul></ul></ul><ul><ul><ul><li>An extended group of people with similar interests or concerns who interact and remain in informal contact for mutual assistance or support. </li></ul></ul></ul>
  4. 4. What is a network? <ul><li>From whatis.com </li></ul><ul><li>A network is a series of points or nodes connected by communication paths. Networks can interconnect with other networks and contain subnetworks. </li></ul><ul><li>Topology – Star, bus, ring </li></ul><ul><li>Spatial distance as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). </li></ul><ul><li>Type of data transmission technology in use on it (for example, a TCP/IP or Systems Network Architecture network); </li></ul><ul><li>Whether it carries voice, data, or both kinds of signals </li></ul><ul><li>Who can use the network (public or private); </li></ul><ul><li>Nature of its connections (dial-up or switched, dedicated or nonswitched, or virtual connections); </li></ul><ul><li>By the types of physical links (for example, optical fiber, coaxial cable, and Unshielded Twisted Pair). </li></ul>
  5. 5. What’s the Internet NOT? <ul><li>“ The web” </li></ul><ul><li>AOL </li></ul><ul><li>Email-reachable users </li></ul><ul><li>Private networks </li></ul>
  6. 6. What can it do? <ul><li>Email </li></ul><ul><li>WWW, Hypertext, RSS, browsers </li></ul><ul><li>FTP, WebDav </li></ul><ul><li>Voice access (VXML, SALT) </li></ul><ul><li>Mobile phones (WAP) </li></ul><ul><li>IM, IRC </li></ul><ul><li>Online gaming </li></ul><ul><li>Video conferencing </li></ul><ul><li>Remote backups </li></ul><ul><li>Remote login/admin gotomypc.com </li></ul><ul><li>Streaming video & audio </li></ul>
  7. 7. Where did it come from? <ul><li>Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the ARPANET. </li></ul><ul><li>Original aim was to create a network that would allow users of a research computer at one university to be able to &quot;talk to&quot; research computers at other universities. </li></ul><ul><li>A side benefit of ARPANet's design was that, because messages could be routed or rerouted in more than one direction, the network could continue to function even if parts of it were destroyed in the event of a military attack or other disaster. </li></ul>
  8. 8. How big is the Internet?
  9. 9. How big is the Internet? <ul><li>Traffic </li></ul>
  10. 10. Internet Software <ul><li>Clients </li></ul><ul><ul><li>A client is the requesting program or user in a client/server relationship. </li></ul></ul><ul><li>Servers </li></ul><ul><ul><li>A program that awaits and fulfills requests from client programs in the same or other computers. </li></ul></ul><ul><li>Peers </li></ul><ul><ul><li>A program may function as a client with requests for services from other programs and also as a server of requests from other programs. </li></ul></ul>
  11. 11. Browser <ul><li>An application program that provides a way to look at and interact with all the information on the World Wide Web. </li></ul><ul><ul><li>Mosaic 1993 </li></ul></ul><ul><ul><li>Opera </li></ul></ul><ul><ul><li>Mozilla </li></ul></ul><ul><ul><li>Firefox </li></ul></ul><ul><ul><li>AOL </li></ul></ul><ul><ul><li>And if you have no other choice then Internet Explorer </li></ul></ul>
  12. 13. Web Server <ul><li>Using the client/server model and the World Wide Web's Hypertext Transfer Protocol (HTTP), serves the files that form Web pages to Web users (whose computers contain HTTP clients that forward their requests). </li></ul><ul><li>Every computer on the Internet that contains a Web site must have a Web server program. </li></ul><ul><li>Apache </li></ul><ul><li>Tomcat </li></ul><ul><li>IIS </li></ul>
  13. 14. Other clients & servers? <ul><li>Mail server/client </li></ul><ul><ul><li>SendMail, Exchange, Lotus Domino </li></ul></ul><ul><ul><li>Opera, Outlook, Mozilla </li></ul></ul><ul><li>FTP Server/Client </li></ul>
  14. 15. Peer to Peer <ul><li>Gnutella </li></ul><ul><li>Kazza </li></ul><ul><li>Bittorrent </li></ul><ul><li>Warez </li></ul><ul><li>eDonkey </li></ul>
  15. 16. Internet hardware <ul><li>Edge devices - Clients, servers, peers, PC’s servers, phones, PDA’s </li></ul><ul><li>Core devices – Hubs, switches, routers, gateways </li></ul><ul><li>Access devices – analogue modems, 802.11 base stations, ISDN modems, network cards, cable modems, DSL modem </li></ul><ul><li>Connection devices – POTS, wireless, fibre, CAT5 </li></ul>
  16. 17. Hub <ul><li>The central part of a wheel where the spokes come together. </li></ul><ul><li>The term is familiar to frequent fliers who travel through airport &quot;hubs&quot; to make connecting flights from one point to another. </li></ul><ul><li>In data communications, a hub is a place of convergence where data arrives from one or more directions and is forwarded out in one or more other directions </li></ul>
  17. 18. Switch <ul><li>A device that channels incoming data from any of multiple input ports to the specific output port that will take the data toward its intended destination. </li></ul>
  18. 19. Router <ul><li>A device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. </li></ul><ul><li>The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to. </li></ul><ul><li>May create or maintain a table of the available routes and their conditions and use this information along with distance and cost algorithms to determine the best route for a given packet </li></ul>
  19. 20. Combo devices <ul><li>Linksys Wireless-G ADSL Gateway WAG54G </li></ul><ul><li>4-port 10/100 Ethernet Switch </li></ul><ul><li>Wireless-G (802.11g) Access Point </li></ul><ul><li>also compatible with Wireless-B (802.11b) </li></ul><ul><li>Firewall to keep Internet intruders and attackers out </li></ul><ul><li>Internet Access Time Limits and Key Word Blocking </li></ul>
  20. 21. Modem <ul><li>A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device </li></ul>
  21. 22. Network card <ul><li>A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network. </li></ul><ul><li>A dedicated full time connection </li></ul><ul><li>Wired or wireless </li></ul>
  22. 23. Wireless <ul><li>802.11 (a,b,g) </li></ul><ul><li>GPRS </li></ul><ul><li>3G </li></ul>
  23. 24. ISDN <ul><li>Standards for digital transmission over ordinary telephone copper wire as well as over other media. </li></ul><ul><li>Home and business users who install an ISDN adapter (in place of a telephone modem) receive Web pages at up to 128 Kbps compared with the maximum 56 Kbps rate of a modem connection. </li></ul><ul><li>Being replaced by ADSL where availible </li></ul>
  24. 25. ADSL <ul><li>Technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses. </li></ul><ul><li>Unlike regular dialup phone service, ADSL provides continously-available, &quot;always on&quot; connection. </li></ul><ul><li>ADSL is asymmetric in that it uses most of the channel to transmit downstream to the user and only a small part to receive information from the user. ADSL simultaneously accommodates analog (voice) information on the same line. </li></ul><ul><li>ADSL is generally offered at downstream data rates from 512 Kbps to about 6 Mbps. </li></ul>
  25. 26. Question? <ul><li>How can such a diverse range of hardware and software communicate? </li></ul><ul><li>You can replace all the hardware with new hardware and replace all the software with new software, but its still the Internet! </li></ul><ul><li>How come? </li></ul><ul><ul><li>Standard Protocols </li></ul></ul>
  26. 27. What’s a protocol? <ul><li>human protocols: </li></ul><ul><li>“ what’s the time?” </li></ul><ul><li>“ I have a question” </li></ul><ul><li>introductions </li></ul><ul><li>… specific msgs sent </li></ul><ul><li>… specific actions taken when msgs received, or other events </li></ul><ul><li>network protocols: </li></ul><ul><li>machines rather than humans </li></ul><ul><li>all communication activity in Internet governed by protocols </li></ul>protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt
  27. 28. What’s a protocol? <ul><li>a human protocol and a computer network protocol: </li></ul>Q: Other human protocol? Hi Hi TCP connection req. Got the time? 2:00 TCP connection reply. Get http://gaia.cs.umass.edu/index.htm <file> time
  28. 29. What do protocols look like? <ul><li>“ Binary” </li></ul><ul><ul><li>Fixed-length fields, like C-structures </li></ul></ul><ul><ul><li>Type-length-value (TLV) </li></ul></ul><ul><li>“ Text” </li></ul><ul><ul><li>ftp: PUT foo </li></ul></ul><ul><ul><li>GET index.html HTTP/1.1 </li></ul></ul><ul><ul><li>Content-Length: 100 </li></ul></ul>
  29. 30. Connection-oriented service <ul><li>Goal: data transfer between end sys. </li></ul><ul><li>handshaking: setup (prepare for) data transfer ahead of time </li></ul><ul><ul><li>Hello, hello back human protocol </li></ul></ul><ul><ul><li>set up “state” in two communicating hosts </li></ul></ul><ul><li>TCP - Transmission Control Protocol </li></ul><ul><ul><li>Internet’s connection-oriented service </li></ul></ul><ul><li>TCP service [RFC 793] </li></ul><ul><li>reliable, in-order byte-stream data transfer </li></ul><ul><ul><li>loss: acknowledgements and retransmissions </li></ul></ul><ul><li>flow control: </li></ul><ul><ul><li>sender won’t overwhelm receiver </li></ul></ul><ul><li>congestion control: </li></ul><ul><ul><li>senders “slow down sending rate” when network congested </li></ul></ul>
  30. 31. HTTP Protocol Parameters Request Query Results Response Web Server Web Browser Database (Optional) E.g. A user fills in a form, which gets submitted to a web server Port Numbers (16 bit numbers) identify the service RFC’s: 1945 2068 2616 http://www.ietf.org/rfc/rfc1945.txt?number=1945
  31. 32. SMTP Protocol <ul><li>Simple Mail Transfer Protocol </li></ul><ul><li>Protocol for sending Email </li></ul><ul><li>Originally designed for a secure network </li></ul>Mail Client Mail Server Mail Server Mail Server Issues? Security & Non-repudiation RFC’s: 821 974 1869 2821 http://www.ietf.org/rfc/rfc0821.txt?number=821
  32. 33. Person Shop Wholesalers Co-op Farmer
  33. 34. Protocol Stacks
  34. 35. Internet Standardisation <ul><li>International Telecommunications Union (ITU) </li></ul><ul><ul><li>United Nations treaty organization </li></ul></ul><ul><ul><li>Modem standards (V.90) </li></ul></ul><ul><ul><li>Traditional telephone services, fax </li></ul></ul><ul><li>Internet Engineering Task Force (IETF) </li></ul><ul><ul><li>Core: Internet Protocol, transport (TCP) </li></ul></ul><ul><ul><li>Applications: email, HTTP, ftp, NFS </li></ul></ul><ul><ul><li>Not: HTML, APIs </li></ul></ul><ul><li>W3C </li></ul><ul><ul><li>HTML, XML, XSL, … </li></ul></ul><ul><li>IEEE </li></ul><ul><ul><li>WiFi </li></ul></ul>
  35. 37. IETF <ul><li>Open membership </li></ul><ul><li>Meets three times a year, about 2,000+ people </li></ul><ul><li>Most work done on mailing lists (see www.ietf.org) </li></ul><ul><li>Working groups produce technology </li></ul><ul><li>No formal voting at WG level, but review by “area directors” </li></ul><ul><li>Emphasis on interoperability and deployment </li></ul><ul><li>Internet drafts -> Proposed Standard (RFC) </li></ul><ul><li>See www.normos.org for RFC directory </li></ul>
  36. 38. RFC’s <ul><li>Network Working Group Steve Crocker </li></ul><ul><li>Request for Comments: 1 UCLA </li></ul><ul><li>7 April 1969 </li></ul><ul><li>Title: Host Software </li></ul><ul><li>Author: Steve Crocker </li></ul><ul><li>Installation: UCLA </li></ul><ul><li>Date: 7 April 1969 </li></ul><ul><li>Network Working Group Request for Comment: 1 </li></ul><ul><li>… </li></ul><ul><li>… </li></ul><ul><li>Introduction </li></ul><ul><li>The software for the ARPA Network exists partly in the IMPs and </li></ul><ul><li>partly in the respective HOSTs. BB&N has specified the software of </li></ul><ul><li>the IMPs and it is the responsibility of the HOST groups to agree on </li></ul><ul><li>HOST software. </li></ul><ul><li>During the summer of 1968, representatives from the initial four </li></ul><ul><li>sites met several times to discuss the HOST software and initial </li></ul><ul><li>experiments on the network. There emerged from these meetings a </li></ul><ul><li>working group of three, Steve Carr from Utah, Jeff Rulifson from SRI, </li></ul><ul><li>and Steve Crocker of UCLA, who met during the fall and winter. The </li></ul><ul><li>most recent meeting was in the last week of March in Utah. Also </li></ul><ul><li>present was Bill Duvall of SRI who has recently started working with </li></ul><ul><li>Jeff Rulifson. </li></ul><ul><li>Somewhat independently, Gerard DeLoche of UCLA has been working on </li></ul><ul><li>the HOST-IMP interface. </li></ul><ul><li>I present here some of the tentative agreements reached and some of </li></ul><ul><li>the open questions encountered. Very little of what is here is firm </li></ul><ul><li>and reactions are expected. </li></ul>http://www.ietf.org/rfc.html
  37. 39. What is Internet/Web development? <ul><li>Creating software that: </li></ul><ul><ul><li>Runs on Internet hardware </li></ul></ul><ul><ul><li>Runs on Internet software </li></ul></ul><ul><ul><li>Uses Internet protocols </li></ul></ul>

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