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Regarding e-mails

Regarding e-mails. If not your UW e-mail address, be sure to include your name (or even your UW netID ) in the message Sign your e-mails with your name (and preferably in English) Also e-mail your TA to ensure we reply promptly. Office Hours. Now posted on the website

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Regarding e-mails

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  1. Regarding e-mails • If not your UW e-mail address, be sure to include your name (or even your UW netID) in the message • Sign your e-mails with your name (and preferably in English) • Also e-mail your TA to ensure we reply promptly Katherine Deibel, Fluency in Information Technology

  2. Office Hours • Now posted on the website • You can attend any TA’s office hours • My hours are • after class on Fridays • by appointment • when I’m in my office with the door open Katherine Deibel, Fluency in Information Technology

  3. INFO100 and CSE100 Fluency with Information Technology Connecting with Networks Katherine Deibel Katherine Deibel Katherine Deibel, Fluency in Information Technology

  4. Networks... • Computers are useful alone, but are better when connected (networked) • Access more information and software than is stored locally • Help users to communicate, exchange information…changing ideas about social interaction • Perform other services—printing, Web, email, texting, mobile, etc. Katherine Deibel, Fluency in Information Technology

  5. Network Structure • Different networks depending on distance between computers: • Local area network (LAN) • Small area: room or building • Either wired or wireless • Wide area networks (WAN) • Large area: more than 1 km • Fiber-optic, copper transmission lines, satellite Katherine Deibel, Fluency in Information Technology

  6. Basic Types of Networks Katherine Deibel, Fluency in Information Technology

  7. Protocols • To communicate computers need to know how to set up the data to be sent and interpret the data received • Example protocols • EtherNet—for physical connection in a LAN • TCP/IP: transmission control protocol / internet protocol (Internet) • HTTP: hypertext transfer protocol (Web) Katherine Deibel, Fluency in Information Technology

  8. LAN in the Lab • EtherNet is a popular LAN protocol • Recall, it’s a “party” protocol Connection to campus network infrastructure Typical MGH or OUGL Lab PC PC PC PC PC PC Ether Net Cable Katherine Deibel, Fluency in Information Technology

  9. Campus & The World • The campus subnetworks interconnect computers of the UW domain which connects to Internet via a gateway washington.edu Internet MGH Homer Dante Student Gateway CS All communication by TCP/IP Katherine Deibel, Fluency in Information Technology

  10. What is TCP/IP • Transfer Control Protocol / Internet Protocol • The primary protocol for data transmission on the Internet • Video: Warriors of the Net • http://www.youtube.com/watch?v=PBWhzz_Gn10 • Linked to on the Calendar page Katherine Deibel, Fluency in Information Technology

  11. History of the Internet • Again, a video: History of the Internethttp://vimeo.com/2696386 • The basic story: • Computer systems at multiple locations • Desire to share data and eliminate duplicate work • Two major design challenges Katherine Deibel, Fluency in Information Technology

  12. Design Goals for the Internet • Diversity of systems in place Site B: Morse Code Not feasible to rebuild every site with the same type of connectivity Site A: Pig Latin Site C: Uses carrier pigeons Katherine Deibel, Fluency in Information Technology

  13. Design Goals for the Internet • Diversity of systems in placeSolution: Accept the diversity Site B: Morse Code Site A: Pig Latin Site C: Uses carrier pigeons Katherine Deibel, Fluency in Information Technology

  14. Internet Protocol • Within a local network, any protocol is allowed • To send messages outside a local network, it must be converted into the IP protocol Katherine Deibel, Fluency in Information Technology

  15. Internet Protocol Network A convert Pig Latin into IP Packets and sends out on Internet A Pig Latin B Morse Code IP IP IP IP Network B converts IP into Morse Code Katherine Deibel, Fluency in Information Technology

  16. Hourglass Analogy Reptiles Turtle Cobra Crocodile DNA Echidna Squirrel Mole Mammals Katherine Deibel, Fluency in Information Technology

  17. Hourglass Analogy ISPs AOL Comcast ClearWire IP connects them all UBC University Networks UW UM Katherine Deibel, Fluency in Information Technology

  18. Hourglass Analogy ? ? ? ? Talk with your neighbor for a minute and come up with other examples of hourglass analogies. ? ? ? ? ? Katherine Deibel, Fluency in Information Technology

  19. Design Goals for the Internet • Diversity of systems in place • Maintain communication in times of disasters, breakdowns, etc. Katherine Deibel, Fluency in Information Technology

  20. Design Goals for the Internet • Diversity of systems in place • Maintain communication in times of disasters, breakdowns, etc.Solution: Postcard analogy Katherine Deibel, Fluency in Information Technology

  21. Postcard Analogy • Break messages into parts • Send each message separately • Delivery: • Each card moves forward to a server that knows how to get to the destination • Cards can take multiple paths • Cards arrive out of order Katherine Deibel, Fluency in Information Technology

  22. Tracing these Virtual Routes tracert 128.227.205.2 You can find such “trace route” sites through Google Katherine Deibel, Fluency in Information Technology

  23. Naming Computers—Take 1 • People give computers domain names • Hierarchical scheme • Domains begin with a “dot” and get “larger” going right • .edu All educational computers, a TLD • .washington.edu All computers at UW • dante.washington.edu A UW computer • .ischool.washington.edu iSchool computers • .cs.washington.edu CSE computers • june.cs.washington.edu A CSE computer Katherine Deibel, Fluency in Information Technology

  24. Naming Computers—Take 2 • Computers are named by IP address, four numbers in the range 0-255 • cse.washington.edu: 128.95.1.4 • ischool.washington.edu: 128.208.100.150 • Remembering IP addresses would be brutal for humans, so we use domains • Computers find the IP address for a domain name from the Domain Name System—an IP address-book computer Katherine Deibel, Fluency in Information Technology

  25. Top-Level Domains (TLDs) • .edu .com .mil .gov .org .net domains are “top level domains” for the US • Recently, new TLD names added • Each country has a top level domain name: • .ca (Canada) • .es (Spain) • .de (Germany) • .au (Australia) • .at (Austria) • .us (US) Katherine Deibel, Fluency in Information Technology

  26. Logical vs Physical • View the Internet in two ways: • Humans see a hierarchy of domains relating computers—logical network • Computers see groups of four number IP addresses—physical network • Both are ideal for the “user's” needs • The Domain Name System (DNS) relates the logical network to the physical network by translating domains to IP addresses Katherine Deibel, Fluency in Information Technology

  27. Internet vs World Wide Web • Many people misuse the terms “Internet” and “World Wide Web” • Let’s get them right Internet: All of the wires, fibers, switches, routers etc. connecting named computers World Wide Web: That part of the Internet that stores and serves Web pages—web servers, client computers Katherine Deibel, Fluency in Information Technology

  28. internet or Internet? • The terms "internet" and "Internet" refer to different things • "Internet" is the complete collection of internetworked computers • "internet" refers to any collection of networked computers • Most of the time, you probably mean the "Internet" Katherine Deibel, Fluency in Information Technology

  29. Summary • Networking is changing the world • Internet: named computers using TCP/IP • WWW: servers providing Web pages • Principles • Logical network of domain names • Physical network of IP addresses • Protocols rule: LAN, TCP/IP, http... • Domain Name System connects the two • Client/Server, fleeting relationship on WWW Katherine Deibel, Fluency in Information Technology

  30. What we did not cover • Net neutrality • SOPA • Digital divide • Government control of Internet access • Web 2.0 • VPNs • Wireless pirating • Etc. These topics could be interesting fodder for GoPost discussions Katherine Deibel, Fluency in Information Technology

  31. For Wednesday • Check the calendar for due dates • Read Chapters 5 & 6 • Continue GoPosting Katherine Deibel, Fluency in Information Technology

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