Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
INTRODUCTION TO INTERNET      TECHNOLOGY                           1
History of the Internet and       World Wide Web   ARPANET      Implemented in late 1960’s by ARPA (Advanced       Resea...
History of the Internet and World                    Wide Web (Cont.)   ARPA’s goals      Allow multiple users to send a...
History of the Internet and World Wide                   Web (Cont.)   Transmission Control Protocol (TCP)        Name o...
History of the Internet and World Wide                  Web (Cont.)   Huge variety of networking hardware and software   ...
History of the Internet and World Wide                     Web (Cont.)   Internet traffic grew       Businesses spent he...
World Wide Web Consortium (W3C)   W3C Founded in 1994 by Tim Berners-Lee   Homepage at www.w3.org   Goals      Interne...
Internet Explorer 7 Features   Web browser        Software that allows the user to view certain types of Internet files ...
Internet Explorer 7 Features (Cont.)   AutoComplete        URLs from the history can be displayed in a drop-down list wh...
Search engines or Directories• Most people are primarily interested in tools  for finding information on the World Wide  W...
Search directories• Search directories are hierarchical databases with references to  websites.• The websites that are inc...
Search directories (Continued)• The first page normally gives you the most general categories  (like "Computers and Intern...
Search engines• Search engines are -- well -- "engines" or "robots" that crawl the  Web looking for new web pages.• These ...
A Communications Model                         14
The key elements of this model are:• Source - generates data to be transmitted• Transmitter - converts data into transmitt...
Communications TasksThe key tasks that must be performed in a data communications system.Transmission system utilization -...
Communications Tasks•   Flow control is required to assure that the source does not overwhelm the    destination by sendin...
Data Communications Model                            18
Networking• Growth of number & power of computers is  driving need for interconnection• Rapid integration of voice, data, ...
Wide Area Networks• Span a large geographical area• Rely in part on common carrier circuits• Alternative technologies used...
Circuit Switching• Uses a dedicated communications path  established for duration of conversation• Comprising a sequence o...
Packet Switching• Data sent out of sequence• Small chunks (packets) of data at a time• Each packet is passed through the n...
Frame Relay• Developed to take advantage of high data rates and  low error rates on modern WAN links.• Whereas the origina...
Asynchronous Transfer Mode• ATM uses fixed-length packets, called cells.• As with frame relay, ATM provides little overhea...
Local Area Networks• Smaller scope  – Building or small campus• Usually owned by same organization as  attached devices• D...
Metropolitan Area Networks•   MAN•   Middle ground between LAN and WAN•   Private or public network•   High speed•   Cover...
The Internet• Internet evolved from ARPANET  – first operational packet switching network  – applied to tactical radio & s...
Internet Elements                    28
Internet Architecture                        29
Example Configuration                        30
OSI Seven Layer Model• The Open Systems Interconnection Reference Model (OSI Reference Model  or OSI Model) is an abstract...
32
33
Layer 1:Physical Layer• Defines physical means of sending data over  network devices• Interfaces between network medium an...
Layer 2:Data Link Layer• Defines procedures for operating the  communication links• Frames packets• Detects and corrects p...
Layer 3:Network Layer• Determines how data are transferred  between network devices• Routes packets according to unique  n...
Layer 4:Transport Layer• Manages end-to-end message delivery in  network• Provides reliable and sequential packet  deliver...
Layer 5:Session Layer• Manages user sessions and dialogues• Controls establishment and termination of  logic links between...
Layer 6:Presentation Layer• Masks the differences of data formats  between dissimilar systems• Specifies architecture-inde...
Layer 7:Application Layer• Defines interface to user processes for  communication and data transfer in  network• Provides ...
Benefits of the OSI Model• By separating the network communications into logical smaller  pieces, the OSI model simplifies...
Upcoming SlideShare
Loading in …5
×

Introduction to internet technology

16,136 views

Published on

Click Here

http://www.eacademy4u.com/

Online Educational Website For You

Published in: Education, Technology
  • I REALY LIKE IT . MORE THAN IMPORTANT TO ME.
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Introduction to internet technology

  1. 1. INTRODUCTION TO INTERNET TECHNOLOGY 1
  2. 2. History of the Internet and World Wide Web ARPANET  Implemented in late 1960’s by ARPA (Advanced Research Projects Agency of DOD)  Networked computer systems of a dozen universities and institutions with 56KB communications lines  Grandparent of today’s Internet  Intended to allow computers to be shared  Became clear that key benefit was allowing fast communication between researchers – electronic- mail (email) 2
  3. 3. History of the Internet and World Wide Web (Cont.) ARPA’s goals  Allow multiple users to send and receive info at same time  Network operated packet switching technique  Digital data sent in small packages called packets  Packets contained data, address info, error-control info and sequencing info  Greatly reduced transmission costs of dedicated communications lines  Network designed to be operated without centralized control  If portion of network fails, remaining portions still able to route packets 3
  4. 4. History of the Internet and World Wide Web (Cont.) Transmission Control Protocol (TCP)  Name of protocols for communicating over ARPAnet.  Ensured that messages were properly routed and that they arrived intact. Organizations implemented own networks  Used both for intra-organization and communication. 4
  5. 5. History of the Internet and World Wide Web (Cont.) Huge variety of networking hardware and software appeared  ARPA achieved inter-communication between all platforms with development of the IP  Internetworking Protocol  Current architecture of Internet  Combined set of protocols called TCP/IP The Internet  Limited to universities and research institutions  Military became big user  Next, government decided to access Internet for commercial purposes 5
  6. 6. History of the Internet and World Wide Web (Cont.) Internet traffic grew  Businesses spent heavily to improve Internet  Better service their clients  Fierce competition among communications carriers and hardware and software suppliers  Resulted in massive bandwidth increase and plummeting costs  Tim Berners-Lee invents Hyper Text Markup Language (HTML)  Also writes communication protocols to form the backbone new information system = World Wide Web  Hypertext Transfer Protocol (HTTP)—a communications protocol used to send information over the web  Web use exploded with availability in 1993 of the Mosaic browser  Marc Andreessen founds Netscape  Company many credit with initiating the explosive Internet of late 1990s. 6
  7. 7. World Wide Web Consortium (W3C) W3C Founded in 1994 by Tim Berners-Lee Homepage at www.w3.org Goals  Internet universally accessible  Standardization  W3C Recommendations: Technologies standardized by W3C include the Extensible Hyper Text Markup Language (XHTML), Cascading Style Sheets (CSS), Hyper Text Markup Language (HTML—now considered a “legacy” technology) and the Extensible Markup Language (XML). not an actual software product, but a document that specifies a technology’s role, syntax rules and so forth. 7
  8. 8. Internet Explorer 7 Features Web browser  Software that allows the user to view certain types of Internet files in an interactive environment  URL (Uniform Resource Locator)  Each web page on the Internet has unique URL  Usually begin with http-:// or https:// Hyperlinks  Visual elements on web pages that when clicked, load a specified web document  Images and text  Can reference other web pages, e-mail addresses, files and more  Download files Tabbed Browsing  Allows the user to browse multiple pages without many windows  Page Organization Using the History Feature  List of previously visited URLs in chronological order 8
  9. 9. Internet Explorer 7 Features (Cont.) AutoComplete  URLs from the history can be displayed in a drop-down list when a user types a URL into the Address bar Off-Line Browsing  Web pages can be saved directly to the computer’s hard drive for off- line browsing  Not connected to the Internet Downloads  Files from the Internet may be copied to a computer’s hard drive  Applications  Plug-ins  Extensions Viewing Source Code  Understand how the programmer created the page  Learn how to develop your own pages 9
  10. 10. Search engines or Directories• Most people are primarily interested in tools for finding information on the World Wide Web.• Originally there were two kinds of search services on the Web: Directories Engines 10
  11. 11. Search directories• Search directories are hierarchical databases with references to websites.• The websites that are included are hand picked by living human beings and classified according to the rules of that particular search service.• Yahoo is the mother of all search directories. However, in order to search the directory you must go to their special directory page.• Their regular search results are not fetched from the directory, but from their search engine. 11
  12. 12. Search directories (Continued)• The first page normally gives you the most general categories (like "Computers and Internet" or "Education").• Click your way down the hierarchy to the right category, select the website you find the most interesting and start reading.• If you use the search form when exploring a directory, remember that you are not searching the text of the actual web pages of a particular site.• Instead you are searching the text contained in the site title and the description of the site.• These are composed by the directory editors, and are often based on suggestions from the site owners themselves. 12
  13. 13. Search engines• Search engines are -- well -- "engines" or "robots" that crawl the Web looking for new web pages.• These robots read the web pages and put the text (or parts of the text) into a large database or index that you may access.• None of them cover the whole Net, but some of them are quite large.• The major players in this field are Google, Yahoo! Search (which is not the same as the Yahoo! Directory), Live Search and Ask.• Search engines should be your first choice when you know exactly what you are looking for.• They also cover a much larger part of the Web than the directories. 13
  14. 14. A Communications Model 14
  15. 15. The key elements of this model are:• Source - generates data to be transmitted• Transmitter - converts data into transmittable signals• Transmission System - carries data from source to destination• Receiver - converts received signal into data• Destination - takes incoming data 15
  16. 16. Communications TasksThe key tasks that must be performed in a data communications system.Transmission system utilization - need to make efficient use oftransmission facilities typically shared among a number of communicatingdevicesA device must interface with the transmission system once an interface isestablished, signal generation is required for communicationThere must be synchronization between transmitter and receiver, todetermine when a signal begins to arrive and when it ends there is avariety of requirements for communication between two parties that mightbe collected under the term exchange managementError detection and correction are required in circumstances where 16errors cannot be tolerated
  17. 17. Communications Tasks• Flow control is required to assure that the source does not overwhelm the destination by sending data faster than they can be processed and absorbed• Addressing and routing, so a source system can indicate the identity of the intended destination, and can choose a specific route through this network• Recovery allows an interrupted transaction to resume activity at the point of interruption or to condition prior to the beginning of the exchange• Message formatting has to do with an agreement between two parties as to the form of the data to be exchanged or transmitted• Frequently need to provide some measure of security in a data communications system• Network management capabilities are needed to configure the system, monitor its status, react to failures and overloads, and plan intelligently for future growth 17
  18. 18. Data Communications Model 18
  19. 19. Networking• Growth of number & power of computers is driving need for interconnection• Rapid integration of voice, data, image & video technologies• Two broad categories of communications networks: – Local Area Network (LAN) – Wide Area Network (WAN) 19
  20. 20. Wide Area Networks• Span a large geographical area• Rely in part on common carrier circuits• Alternative technologies used include: – circuit switching – packet switching – frame relay – Asynchronous Transfer Mode (ATM) 20
  21. 21. Circuit Switching• Uses a dedicated communications path established for duration of conversation• Comprising a sequence of physical links• with a dedicated logical channel• eg. telephone network 21
  22. 22. Packet Switching• Data sent out of sequence• Small chunks (packets) of data at a time• Each packet is passed through the network from node to node along some path leading from source to destination.• At each node, the entire packet is received, stored briefly, and then transmitted to the next node.• Packet-switching networks are commonly used for terminal-to-computer and computer-to-computer communications. 22
  23. 23. Frame Relay• Developed to take advantage of high data rates and low error rates on modern WAN links.• Whereas the original packet-switching networks were designed with a data rate to the end user of about 64 kbps, frame relay networks are designed to operate efficiently at user data rates of up to 2 Mbps.• The key to achieving these high data rates is to strip out most of the overhead involved with error control. 23
  24. 24. Asynchronous Transfer Mode• ATM uses fixed-length packets, called cells.• As with frame relay, ATM provides little overhead for error control, depending on the inherent reliability of the transmission system and on higher layers of logic in the end systems to catch and correct errors.• By using a fixed packet length, the processing overhead is reduced even further for ATM compared to frame relay.• The result is that ATM is designed to work in the range of 10s and 100s of Mbps, and in the Gbps range.• ATM allows the definition of multiple virtual channels with data rates that are dynamically defined at the time the virtual channel is created. 24
  25. 25. Local Area Networks• Smaller scope – Building or small campus• Usually owned by same organization as attached devices• Data rates much higher• Switched LANs, eg Ethernet• Wireless LANs 25
  26. 26. Metropolitan Area Networks• MAN• Middle ground between LAN and WAN• Private or public network• High speed• Covers a larger area 26
  27. 27. The Internet• Internet evolved from ARPANET – first operational packet switching network – applied to tactical radio & satellite nets also – had a need for interoperability – led to standardized TCP/IP protocols 27
  28. 28. Internet Elements 28
  29. 29. Internet Architecture 29
  30. 30. Example Configuration 30
  31. 31. OSI Seven Layer Model• The Open Systems Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design.• It was developed as part of the Open Systems Interconnection (OSI) initiative.• In its most basic form, it divides network architecture into seven layers which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data-Link, and Physical Layers.• It is therefore often referred to as the OSI Seven Layer Model.• A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it.• For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of the path. 31
  32. 32. 32
  33. 33. 33
  34. 34. Layer 1:Physical Layer• Defines physical means of sending data over network devices• Interfaces between network medium and devices• Defines optical, electrical and mechanical characteristics 34
  35. 35. Layer 2:Data Link Layer• Defines procedures for operating the communication links• Frames packets• Detects and corrects packets transmit errors 35
  36. 36. Layer 3:Network Layer• Determines how data are transferred between network devices• Routes packets according to unique network device addresses• Provides flow and congestion control to prevent network resource depletion 36
  37. 37. Layer 4:Transport Layer• Manages end-to-end message delivery in network• Provides reliable and sequential packet delivery through error recovery and flow control mechanisms• Provides connectionless oriented packet delivery 37
  38. 38. Layer 5:Session Layer• Manages user sessions and dialogues• Controls establishment and termination of logic links between users• Reports upper layer errors 38
  39. 39. Layer 6:Presentation Layer• Masks the differences of data formats between dissimilar systems• Specifies architecture-independent data transfer format• Encodes and decodes data; Encrypts and decrypts data; Compresses and decompresses data 39
  40. 40. Layer 7:Application Layer• Defines interface to user processes for communication and data transfer in network• Provides standardized services such as virtual terminal, file and job transfer and operations 40
  41. 41. Benefits of the OSI Model• By separating the network communications into logical smaller pieces, the OSI model simplifies how network protocols are designed.• The OSI model was designed to ensure different types of equipment (such as network adapters, hubs, and routers) would all be compatible even if built by different manufacturers.• A product from one network equipment vendor that implements OSI Layer 2 functionality, for example, will be much more likely to interoperate with another vendors OSI Layer 3 product because both vendors are following the same model.• The OSI model also makes network designs more extensible as new protocols and other network services are generally easier to add to a layered architecture than to a monolithic one. 41

×