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The Internet : a world wide combination of WANs and LANs involving millions of machines

The Internet : a world wide combination of WANs and LANs involving millions of machines. U.S. Department of Defense research initiative drive was partially military… secure connections between major military sites (MILNET) …partially economic

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The Internet : a world wide combination of WANs and LANs involving millions of machines

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  1. The Internet: a world wide combination of WANs and LANs involving millions of machines • U.S. Department of Defense research initiative • drive was partially military… • secure connections between major military sites (MILNET) • …partially economic • get most economical use out of scarce computer resources • December 1969: startup of 4-node ‘ARPANET’ • 1980s: evolved into ‘The Internet’ • consisting of thousands of hosts and millions of users • 1990: ARPANET replaced by NSFnet • NSFnet still major internet backbone in the USA

  2. Connecting to the Internet • Many home and small business users connect to the Internet via high-speed broadband Internet service Discovering Computers 2012: Chapter 2 Page 76

  3. Evolution of the Internet • Each organization is responsible only for maintaining its own network • The World Wide Web Consortium (W3C) oversees research and sets guidelines and standards • Internet2 • A not-for-profit research • To develop and test advanced network technologies require that will benefit Internet users in the short-term future • connect more than 200 universities and 115 companies via a high-speed private network

  4. Internet Protocol Address (IP Address) • An IP addressis a number that uniquely identifies each computer or device connected to the Internet • A domain nameis the text version of an IP address • Top-level domain (TLD) • A DNS servertranslates the domain name into its associated IP address 74.125.230.210

  5. http://en.utrace.de/?query=www.psu.ac.th • http://www.whois.net/ • http://whatismyipaddress.com/

  6. Internet Architecture Internet Corporation for Assigned Names and Numbers • Domain names must be registered (at ICANN) • so everybody knows where each domain resides • Hierarchical structure of networks of networks… • Internet service provider (ISP) provides Internet access for you

  7. The Internet: Addressing • Machines in the Internet have unique addresses: • IP-address (32 bits (4 groups)) consisting of two parts • Domain name: ‘network address’ (given by ICANN) • Machine name: ‘host address’ (given by network operator) • In dotted decimal form, example: 74.125.95.103 • As registered domain name: google.co.th • Top-Level Domain (TLD): domain’s classification • In each domain list of IP-addresses is maintained • publicly accessible through name server 010000011

  8. List of Internet top-level domains • Generic top-level domains • USA top-level domains • Country code top-level • domains • Internationalized country • code top-level domains

  9. However: • 1980s: e-mail • 1990s: web-browsing • 2000s: search engines • 2010s: Grid computing? The Internet: Killer Applications • The internet originally intended for: • remote login & file transfer (does work) • distributed computing (still a promise only)

  10. The World Wide Web • Software infrastructure on top of the Internet • Developed at CERN High-Energy Physics laboratories in Geneva, Switzerland (1991) • Hypertext (HTML): • ‘mouse-clickable’ access to files on other computers • Requires special software: • web browser (client) • web server

  11. The World Wide Web • The World Wide Web, or Web, consists of a worldwide collection of electronic documents (Web pages) • A Web siteis a collection of related Web pages and associated items • A Web serveris a computer that delivers requested Web pages to your computer • Web 2.0refers to Web sites that provide a means for users to interact

  12. The World Wide Web • A Web browser, or browser, allows users to access Web pages and Web 2.0 programs

  13. To find documents on the World Wide Web HyperText Transfer Protocol: HTTP)คือโพรโทคอลในระดับชั้นโปรแกรมประยุกต์เพื่อการแจกจ่ายและการทำงานร่วมกันกับสารสนเทศของสื่อผสม ใช้สำหรับการรับทรัพยากรที่เชื่อมโยงกับภายนอก ซึ่งนำไปสู่การจัดตั้งเวิลด์ไวด์เว็บ  • Each document has unique address: • URL (uniform resource locator) Web page name domain name path protocol

  14. Homework (What is it?) FTP (File Transfer Protocol) เป็นโปรโตคอลมาตรฐานในอินเตอร์เน็ต ซึ่งเป็นวิธีที่ง่ายที่สุดในการแลกเปลี่ยนไฟล์ ระหว่างคอมพิวเตอร์บนอินเตอร์เน็ต Hypertext Transfer Protocol (HTTP) ที่ใช้ในการส่งเว็บเพ็จและไฟล์ที่เกี่ยวข้อง Simple Mail Transfer Protocol (SMPT) ที่ใช้ส่งผ่าน e-mail POP3 (Post Office Protocol version 3) IMAP (Internet Mail Access Protocol) MIME (Multipurpose Internet Mail Extensions) • VoIP (Voice over Internet Protocol)

  15. HTML – HyperText Markup Language HTML is the main markup language for web pages. HTML elements are the basic building-blocks of webpages.

  16. XML – Extensible Markup Language • XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. 

  17. jass.xml Linking to jw.css style sheet jass.xml document formatted with jw.css style sheet jw.css the cascading style sheet stored in the jw.css file

  18. How messages are transferred over the Internet. • This transfer process requires • the cooperation of all the computers in the system, and • software for controlling this process (resides on every computer in the Internet).

  19. Networking Software • Provide the infrastructure required for transferring messages from one machine to another. • In the Internet, this message-passing activity is accomplished by means of a hierarchy of software units, which perform tasks analogous to those that would be performed if you were to send a gift in a package from the South to a friend on the North.

  20. Gift Package-Shipping Example • You are not concerned with the details of the shipping company, and the • shipping company is not concerned with the internal operations of the airline.) You are not concerned with the details of the shipping company, and the shipping company is not concerned with the internal operations of the airline.

  21. The Internet Software Layers

  22. Network Protocols • Define details of all network activities, a.o.: • encoding of messages • addressing of messages • splitting and merging of (large) messages • deciding who has the right to send messages, etc… • In other words, protocols ensure that messages: • arrive at the right place • in the right order • without errors • and are understood by the receiver as well

  23. Following a Message Through the Internet

  24. Network Protocol Summary • Interaction between four software layers • Application: • deals with messages and addressing • Transport: • deals with message ↔ packets conversion • Network: • deals with ‘hopping’ packets through the internet • Link: • deals with the transmission of packets as bit streams

  25. Multiple Implementations: TCP versus UDP

  26. Towards ‘The Grid’ • The Internet: • a network with static compute and data resources in which information flows from the producer to the consumer (and sometimes back). • user personally decides what data to access and what servers to use • The Grid: • dynamic computing utility over a distributed set of compute and data resources • automatic resource detection, automatic error recovery, automatic performance optimization, etc…

  27. The Grid: Large Scale Problem Solving • Utilize (a) large number or (b) very high-end, specialized resources over large distances Identifying brain disorders California: earthquake simulations Telescope data analysis Finding E.T.???

  28. Cloud Computing Cloud computing is Internet- ("cloud-") based development and use of computer technology ("computing"). • Cloud computing is about hardware-based services (involving computing, network and storage capacities), where: • Services are provided on-demand; customers can pay for them as they go, without the need to invest into a datacenter. • Hardware management is abstracted from the customers. • Infrastructure capacities are elastic and can easily scale up and down.

  29. Web 2.0 • The term "Web 2.0" is commonly associated with web applications that facilitate interactive information sharing, interoperability, user-centered design and collaboration on the World Wide Web. • Examples of Web 2.0 include • web-based communities - hosted services • web applications - social-networking sites • video-sharing sites - wikis • blogs - mashups • folksonomies

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