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Ch. 3 FIT5, CIS 110 13F

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The document discusses the basics of networking, including synchronous vs asynchronous communication, the client-server structure of most internet applications, and IP addressing. Key points are that the internet uses asynchronous, point-to-point communication over a packet switched network, most applications follow a stateless client-server model where clients connect briefly to servers to request and receive information, and each device on the internet has a unique IP address.

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Chapter 3 The Basics of Networking Friday, October 18, 13
General Communication Synchronous communication: (eg) wired telephone network => circuit-switched network Asynchronous communication: (eg) email; the internet => packet-switched network Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Internets Communication Properties point-to-point, asynchronous communication fast enough to mimic synchronous communication (e.g., VOIP) Multicasting is possible (chat rooms, radio, tv) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Internet Schematic Diagram Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Client/Server Structure Most Internet applications are client/server interaction click a hyperlink: your computer connects to server page returned => connection ends Next connection is brand new => Stateless protocol No memory of prior connection Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Basic Client/Server Interaction Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Many Brief Relationships server can handle many clients at a time server is busy only for as long as it takes to perform your request Google: 5,134,000,000 searches/day (2012) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Client/Server Relationships Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Internet Protocol (IP) Address Each computer on the Internet has a unique IP address four numbers separated by dots: 128.223.223.85 => dotted quad each number is 0255 (one byte / 8bits each) => octet Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
IP Addresses Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
IPv4 Address Exhaustion each of the four numbers is in the range 0255 requires one byte (8 bits) of memory => octet IP address is 4x8= 32 bits long => IP addresses in short supply. Why? 2^32 = 4.3 billion, a finite number (ask Google the exact value) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
IPv6: 128 bit addresses IPv6 addresses will have 16, 8-bit, fields 2^128 = 10^38 10^28 times as many addresses as IPv4 new switching hardware/software is required to handle IPv6 Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Domain Names symbolic names (human-readable) vs. IP addresses based on hierarchy of domains domain: related group of networked computers (eg) pages.uoregon.edu Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Domain Names Domain name hiearchy reads right-to-left ix.cs.uoregon.edu top-level domain: edu subdomain uoregon next subdomain cs server is ix Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
The .edu Domain Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
DNS Servers Domain Name System (DNS): translates domain names into IP address Every Internet host knows the IP address of its nearest DNS name server How the DNS Works (youtube, 00:02:25) http://bit.ly/ab4s50 Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
DNS Servers your computer asks a DNS name server to translate a name to an IP address If the address is not stored on the DNS name server), the server asks an authoritative name server 13 root name servers keep the complete list of all authoritative name servers Tagged A..M here: www.root-servers.org Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
DNS Root Servers 13 root name servers (A..M) scattered around the world Plus 243 mirror sites => DNS is the worlds largest distributed database Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
TCP/IP TCP/IP Postcard Analogy The Internet is like sending a novel to your publisher using postcards Packet Switching Flash Demo Packet Layer in OSI Network Model Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
TCP/IP packets routed around failed nodes ensures delivery of entire message large scale, built-in redundancy crucial to reliability packet switching => rapid store-&-forward design node receives a packet, stores it determines best route to destination sends it to next node Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
TCP/IP: The Language of the Internet analogy: postcards = IP packets travel different routes / arrive out of order can be lost IP: stamps packet w/address & packet number TCP: re-arranges, requests retransmission network can optimize packet paths, but.. prone to chaos Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Ethernet Ethernet uses a physical channel wire, cable, or optical fiber media layer / physical layer Key point: Each packet seen by all computers on the local network => store-&-forward design Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Ethernet Analogy Party Protocol How an Ethernet network works: two people start speaking at same time => collision Collision Resolution policy wait random amt of time try again Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Ethernet Analogy How an Ethernet network works: Party Protocol two people start speaking at same time => collision Collision Resolution wait random amt of time try again Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Figure 3.9. Media Layer Robert Metalfes original drawing of the Ethernet-computers tap onto the wire labeled The Ether 際際滷 3Friday, October 18, 13
The World Wide Web (http) client/server protocol requests: URL (/slideshow/fit5-ch-27345186/27345186/a.k.a. URI) client & server both speak HTTP Jeopardy Category: Application Layer Q: The World Wide Web A: What is, an Internet Application? Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
File Systems: How to Organize your Folders Folders on the server are called Directories Directory Hierarchy folders can contain folders as well as files => the file system, or directory hierarchy Think of any hierarchy as a tree folders are branches files are the leaves root directory is at the top of the hierachy Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
File System Pathnames Files are identified by the path from the root diretory to the file: (eg) /fluency/part1/chapter3/file-structure/ directory-hierarchy/figure-3-13.pdf Note: do not use spaces or special characters in a Unix pathname Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Pathnames & URIs Part of a web page files pathname is used in the URI: URL: pages.uoregon.edu/susanq/110/ Unix pathname on server: /home7/susanq/public_html/110/ URL: pages.uoregon.edu/susanq/110/p2/index.html Unix pathname on server: /home7/susanq/public_html/110/p2/index.html Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Web Directories: The Default Document When a URL ends in a slash: => browser automatically looks in that folder for a file called index.html or default.html => default document => supresses directory listing in browser Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Organize your Folders Why have a hierarchy? organize your thinking & work directories/folders cost nothing work on the server and your computer => highly recommended Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
Ch. 3: Assessment Learning Outcomes - Know the following Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13

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Ch. 3 FIT5, CIS 110 13F

  • 1. Chapter 3 The Basics of Networking Friday, October 18, 13
  • 2. General Communication Synchronous communication: (eg) wired telephone network => circuit-switched network Asynchronous communication: (eg) email; the internet => packet-switched network Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 3. Internets Communication Properties point-to-point, asynchronous communication fast enough to mimic synchronous communication (e.g., VOIP) Multicasting is possible (chat rooms, radio, tv) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 4. Internet Schematic Diagram Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 5. Client/Server Structure Most Internet applications are client/server interaction click a hyperlink: your computer connects to server page returned => connection ends Next connection is brand new => Stateless protocol No memory of prior connection Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 6. Basic Client/Server Interaction Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 7. Many Brief Relationships server can handle many clients at a time server is busy only for as long as it takes to perform your request Google: 5,134,000,000 searches/day (2012) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 8. Client/Server Relationships Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 9. Internet Protocol (IP) Address Each computer on the Internet has a unique IP address four numbers separated by dots: 128.223.223.85 => dotted quad each number is 0255 (one byte / 8bits each) => octet Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 10. IP Addresses Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 11. IPv4 Address Exhaustion each of the four numbers is in the range 0255 requires one byte (8 bits) of memory => octet IP address is 4x8= 32 bits long => IP addresses in short supply. Why? 2^32 = 4.3 billion, a finite number (ask Google the exact value) Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 12. IPv6: 128 bit addresses IPv6 addresses will have 16, 8-bit, fields 2^128 = 10^38 10^28 times as many addresses as IPv4 new switching hardware/software is required to handle IPv6 Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 13. Domain Names symbolic names (human-readable) vs. IP addresses based on hierarchy of domains domain: related group of networked computers (eg) pages.uoregon.edu Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 14. Domain Names Domain name hiearchy reads right-to-left ix.cs.uoregon.edu top-level domain: edu subdomain uoregon next subdomain cs server is ix Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 15. The .edu Domain Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 16. DNS Servers Domain Name System (DNS): translates domain names into IP address Every Internet host knows the IP address of its nearest DNS name server How the DNS Works (youtube, 00:02:25) http://bit.ly/ab4s50 Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 17. DNS Servers your computer asks a DNS name server to translate a name to an IP address If the address is not stored on the DNS name server), the server asks an authoritative name server 13 root name servers keep the complete list of all authoritative name servers Tagged A..M here: www.root-servers.org Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 18. DNS Root Servers 13 root name servers (A..M) scattered around the world Plus 243 mirror sites => DNS is the worlds largest distributed database Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 19. TCP/IP TCP/IP Postcard Analogy The Internet is like sending a novel to your publisher using postcards Packet Switching Flash Demo Packet Layer in OSI Network Model Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 20. TCP/IP packets routed around failed nodes ensures delivery of entire message large scale, built-in redundancy crucial to reliability packet switching => rapid store-&-forward design node receives a packet, stores it determines best route to destination sends it to next node Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 21. TCP/IP: The Language of the Internet analogy: postcards = IP packets travel different routes / arrive out of order can be lost IP: stamps packet w/address & packet number TCP: re-arranges, requests retransmission network can optimize packet paths, but.. prone to chaos Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 22. Ethernet Ethernet uses a physical channel wire, cable, or optical fiber media layer / physical layer Key point: Each packet seen by all computers on the local network => store-&-forward design Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 23. Ethernet Analogy Party Protocol How an Ethernet network works: two people start speaking at same time => collision Collision Resolution policy wait random amt of time try again Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 24. Ethernet Analogy How an Ethernet network works: Party Protocol two people start speaking at same time => collision Collision Resolution wait random amt of time try again Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 25. Figure 3.9. Media Layer Robert Metalfes original drawing of the Ethernet-computers tap onto the wire labeled The Ether 際際滷 3Friday, October 18, 13
  • 26. The World Wide Web (http) client/server protocol requests: URL (/slideshow/fit5-ch-27345186/27345186/a.k.a. URI) client & server both speak HTTP Jeopardy Category: Application Layer Q: The World Wide Web A: What is, an Internet Application? Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 27. File Systems: How to Organize your Folders Folders on the server are called Directories Directory Hierarchy folders can contain folders as well as files => the file system, or directory hierarchy Think of any hierarchy as a tree folders are branches files are the leaves root directory is at the top of the hierachy Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 28. Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 29. File System Pathnames Files are identified by the path from the root diretory to the file: (eg) /fluency/part1/chapter3/file-structure/ directory-hierarchy/figure-3-13.pdf Note: do not use spaces or special characters in a Unix pathname Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 30. Pathnames & URIs Part of a web page files pathname is used in the URI: URL: pages.uoregon.edu/susanq/110/ Unix pathname on server: /home7/susanq/public_html/110/ URL: pages.uoregon.edu/susanq/110/p2/index.html Unix pathname on server: /home7/susanq/public_html/110/p2/index.html Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 31. Web Directories: The Default Document When a URL ends in a slash: => browser automatically looks in that folder for a file called index.html or default.html => default document => supresses directory listing in browser Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 32. Organize your Folders Why have a hierarchy? organize your thinking & work directories/folders cost nothing work on the server and your computer => highly recommended Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13
  • 33. Ch. 3: Assessment Learning Outcomes - Know the following Copyright 息 2013 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Friday, October 18, 13