1 / 31

Chapter 3

Chapter 3. Fluency with Information Technology 4 th edition by Lawrence Snyder (slides by Deborah Woodall : woodall@mc.edu). Network Defined. computer network Two or more computer systems that can communicate with each other over some communications media.

keala
Download Presentation

Chapter 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 3 Fluency with Information Technology 4th edition by Lawrence Snyder (slides by Deborah Woodall : woodall@mc.edu)

  2. Network Defined computer network Two or more computer systems that can communicate with each other over some communications media. communications mediamay be classified as wired - telephone lines, coax, fiber optic wireless - microwave, satellite

  3. Far and Near • LAN – Local Area Network • WAN – Wide Area Network • The Internet – A global network of Wide Area Networks

  4. Classifying Communication Communication can be classified as either… • asynchronous – sending and receiving occur at separate times • synchronous – sending and receiving occur at the same time

  5. Classifying Communication Also Communication can be classified as either… • broadcast – one sender, many receivers • multicast – one sender, many selected receivers • point-to-point – one sender, one receiver

  6. Communication Classifications • In one way or another the Internet offers all of these forms of communication. • The Internet is truly a universal communications medium.

  7. The Client/Server Structure • Most encounters on the Internet reflect the client/server structure. • client: (e.g. your browser) requests a service (like a Web page) • server: (e.g. Web Server) provides a service (like sending a Web page)

  8. The Client/Server Structure • A client and a server have one or more BRIEF relationships. • An advantage: The server can handle many clients in a short period of time.

  9. IP Addresses • Every transmitted message on the Internet requires a destination address • IP address – the address of a computer connected to the Internet

  10. IP Addresses • Each IP address is a series of 4 numbers separated by dots, e.g. 234. 18. 45. 1 • Each of the 4 numbers takes up one byte of memory, so an IP address is a 4 byte address.

  11. IP Addresses The IP address from the previous slide would look like this when stored in RAM 234. 18. 45. 1 11101010 00010010 00101101 00000001

  12. IP Addresses • How many numbers will fit into one byte?

  13. IP Addresses • What would be the range of one of the numbers in an IP address?

  14. IP Addresses Why is each of the following an invalid IP address? 34.678.32.90 -89.53.244.32 34.23.67.89.145

  15. IP Addresses • And finally, how many IP addresses are possible using the current scheme? 232 >4.3 billion • There is an upgrade being planned for IPv4 called IPv6 – a 16 byte IP addressing scheme - e.g. 69DC:77AC:FF66:A1A2:BCDF:77AC:FF66:3459

  16. IP Addresses • Your PC has an IP address when connected to the Internet • temporary if connected by modem • permanent (or temporary) if connected to a LAN • Computers deal with numbers but humans don’t do very well remembering numbers.

  17. Domain Names • A domain is a related group of networked computers. • A domain name is a symbolic name for a 4-byte IP address, and thus a particular computer on the Internet.

  18. Domain Names • An example: www.mc.edu www is a specific computer in the mc domain of the edudomain • A domain name reveals a hierarchy.

  19. Domain Names

  20. Domain Names • Original top-level domains • .edu • .org • .net • .mil • .gov • .com • Newer top-level domains • .biz (businesses) • .info (information) • .museum (museums) • .name (individuals) • .pro (credentialed professionals) • country codes

  21. Domain Names The purpose of a top level domain name is to indicate • Function, or • Location

  22. The Domain Name System • We like www.jvim.com • Computers like 198.160.140.235 • Where does your browser get the IP Address for a domain name? DNS Servers

  23. TCP/IP • Once the address of the computer is found, how is the message actually sent over the Internet? TCP/IP • TCP/IP protocol specifies that the message is broken into pieces and each piece goes into a packet.

  24. TCP/IP • Each packet contains • A piece of the message being sent • The destination address for the packet • The source address of the packet • A collating number • Each packet is independent.

  25. Ethernet • How is a message sent over a LAN? Ethernet Protocol • Ethernet also uses packets. • Ethernet is a true broadcast medium.

  26. Connecting to the Internet How are computers connected to the Internet? • Connect to an Internet Service Provider (ISP) e.g. bellsouth.net, comcast.com, earthlink.net • 56K dial-up modem • DSL • Cable modem • Satellite • Cell phone • Connect through a campus or enterprise network.

  27. The World Wide Web • The WWW is not the same as the Internet. • The WWW is a subset of the Internet. • The WWW is made up of Web servers and their files (Web pages and associated files). • Web pages are NOT stored as bytes of pixel data but as a description of the page. • The WWW is organized hierarchically.

  28. http://www.mc.edu/campus/clubs/acm/members.html http:// • stands for Hypertext Transfer Protocol • tells the computer how to handle the file • indicates this is a Web page

  29. http://www.mc.edu/campus/clubs/acm/members.html www.mc.edu • the domain name • represents the IP address of the server (a computer) • specifies a hierarchy from specific to general (www is a computer in the mc domain of the edu domain) • not case sensitive

  30. http://www.mc.edu/campus/clubs/acm/members.html campus/clubs/acm/members.html • the path name telling which page and where it is on the server • specifies a hierarchy from general to specific (in the campus folder is a clubs folder containing an acm folder containing a Web page file called members.html) • may be case sensitive

  31. Wrap Up • mc.edu vs. www.mc.edu • http://www.mc.edu/faculty/woodall

More Related