1 / 26

The Basics of Computer Networks & Internet

The Basics of Computer Networks & Internet. 1. Computer Skills and Programming Concepts I (UEC01). Introduction. Data Communication. The act of transmitting data from one computer to another. Components of Data Communication System.

marged
Download Presentation

The Basics of Computer Networks & Internet

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. The Basics of Computer Networks & Internet 1 Computer Skills and Programming Concepts I (UEC01)

  2. Introduction • Data Communication The act of transmitting data from one computer to another. • Components of Data Communication System A data communication system is made up of five components : 1- Message : The data to be transmitted, It can consists of text, numbers, pictures, sound, or any combination of these. 2- Sender : The device that sends the data message, it can be a computer, workstation, video camera, and son on. 3- Receiver : The device that receives the message. 4- Medium : The physical path by which a message travels from sender to receiver. 5- Protocol : The set of rules that govern data communication. 2 Computer Skills and Programming Concepts I (UEC01)

  3. Introduction • Types of Communication • Synchronous Communication • Both the sender and the receiver are active at the same time • Example : A telephone conversation • Asynchronous Communication • The sending and receiving occur at different times • Example : Email • Broadcast Communication • A single sender and many receivers • Example : Radio and Television • Point-to-point Communication • The opposite of broadcasting • Example : A telephone conversation 3 Computer Skills and Programming Concepts I (UEC01)

  4. Introduction • Computer Networks A network is a computer system that uses communications equipment to connect two or more computers and their resources. • Why Network • Sharing of data and recourses (Software or/and Hardware) • Remote access. • To Support distributed applications (e.g. WWW, FTP……) 4 Computer Skills and Programming Concepts I (UEC01)

  5. Introduction • Network Applications Some of the network applications in different fields are : • Marketing and Sales • Financial services • Manufacturing • Electronic messaging • Information services • Electronic data interchange (EDI) • Teleconferencing • Cellular telephone • Cable television 5 Computer Skills and Programming Concepts I (UEC01)

  6. Transmission Media • The physical path between sender and receiver in a data communication system • Types of Transmission Media • Wired Media • Twisted-pair Cable • Coaxial Cable • Fiber-optic Cable • Wireless Media • Terrestrial Microwave • Satellite Communication • Cellular Telephony 6 Computer Skills and Programming Concepts I (UEC01)

  7. Network Topology • It defines the physical or logical arrangement of links in a network. • There are five basic topologies : Mesh Topology Ring Topology Bus Topology Hybrid Topology Star Topology 7 Computer Skills and Programming Concepts I (UEC01)

  8. Transmission Mode • It defines the direction of signal flow between two linked devices. • There are three types of transmission modes : • Simplex • It allows transmissions in one direction only. • e.g. TV broadcasting – Arrival/departure screens at airport • Half-Duplex • It allows transmissions in either direction, but only one way at a time. • e.g. Police radio • Full-Duplex • It allows transmissions in both directions at once. • e.g. Telephone 8 Computer Skills and Programming Concepts I (UEC01)

  9. Categories of Networks • Local Area Networks (LANs) • A data Communication system within a building, plant, or campus, or between nearby buildings. • LANs are designed to allow resources (S.W., H.W., or data) to be shared between personal computers. • A given LAN uses only one type of transmission media. • LAN topologies are bus, ring, and star. 9 Computer Skills and Programming Concepts I (UEC01)

  10. Categories of Networks • Metropolitan Area Networks (MANs) • A data Communication system covering an area with the size of a town or city • It may be a single network such as a cable television network • It may a network of LANs, a company use a MAN to connect the LANs in all of its offices throughout a city 10 Computer Skills and Programming Concepts I (UEC01)

  11. Categories of Networks • Wide Area Networks (WANs) A data Communication system spanning states, countries, or the whole world. 11 Computer Skills and Programming Concepts I (UEC01)

  12. WAN LAN LAN LAN LAN MAN MAN R R R R R R R R Internetworks • When two or more networks are connected, they become an internetwork • Individual networks are joined into internetwork by using internetworking devices (routers and gateways) 12 Computer Skills and Programming Concepts I (UEC01)

  13. Internet • Internally, Internet is an Interconnection of independent physical networks • Individual networks are linked together by Router • Internet uses Transmission Control Protocol / Internet Protocol (TCP/IP) to send information from host to host • Under TCP/IP, an Internet operates like a single network connecting many computer of any size and type Hosts 13 Computer Skills and Programming Concepts I (UEC01)

  14. Internet • Hosts • Any computer attached to the internet is a host • Mail servers are hosts • Web servers are hosts • Desktop and notebook PCs are hosts too 14 Computer Skills and Programming Concepts I (UEC01)

  15. Routers Route Internet • Routers • Connect the Internet’s individual networks • Routers cooperate to give a point-to-point connection between sender and receiver 15 Computer Skills and Programming Concepts I (UEC01)

  16. Internet • IP Address • Network deliver messages based on network addresses • Each host connected to the Internet is given a unique address called IP address • IP address is a series of four numbers separated by dots (Dotted Decimal Notation) • For example: 128.47.17.47 163.18.47.145 128.47.17.47 16 Computer Skills and Programming Concepts I (UEC01)

  17. Internet • Classes of IP Address • Example : Class B Network 17 Computer Skills and Programming Concepts I (UEC01)

  18. Internet • Subnet Mask • It used by the router to determine which part of the IP address is the network address and which part is the host address • It done by ANDing the bits in the subnet mask with the IP address • The following are the Default subnet mask 18 Computer Skills and Programming Concepts I (UEC01)

  19. Internet • Host Name • Internet uses human-readable symbolic names for computers • Easy to remember than dotted decimal notation • It is not official address • Example : WWW.IBM.COM HANY.BAU.EDU.LB • Domain Name System (DNS) • It translates the Host name into the IP address • DNS Server • A computer that keeps a list of host names and the corresponding IP addresses 19 Computer Skills and Programming Concepts I (UEC01)

  20. Internet • Connecting a computer to the Internet • How are computers actually connected to the Internet? • Today there are two basic methods: • By an Internet Service Provider (ISP) • By a campus or enterprise network 20 Computer Skills and Programming Concepts I (UEC01)

  21. ISP Carrier Access Line Internet • Connections by ISP (Using Dial-Up) • Users Plug their computer into the telephone system • The computer’s modem can dial up the ISP and establish a connection • The modems enable the home computer to talk to the ISP’s Computer so that they can send or receive information • The ISP’s computer is connected to the internet, so it relays information for its customers Internet 21 Computer Skills and Programming Concepts I (UEC01)

  22. ISP Carrier Access Line Internet • Connections by ISP (Using DSL) • Using Digital Subscriber Line the computer’s modem establish a dedicated connection to the ISP • Four quick facts about DSL : • DSL is fast • DSL does not tie up your phone line • DSL is always on • DSL is reliable Internet 22 Computer Skills and Programming Concepts I (UEC01)

  23. Organization’s LAN Gateway Internet • Enterprise Network Connections • Organization’s computers are connected in a LAN (Intranet) • The Intranet supports communications within the organization • Also the Intranet connects to the Internet by a gateway • Information from a distant Web computer is sent across the Internet, through the gateway to the organization’s Intranet, and across the LAN to the user’s computer Internet 23 Computer Skills and Programming Concepts I (UEC01)

  24. Internet Services • Electronic Mail (E-mail) • A widely used network service • A system for sending messages or files to one or more recipients • Its process based on mailbox addresses rather than a direct host-to-host exchange. • Every user on the network has a private mailbox. • E-mail address user name@domain name Ahmed@pua.edu.eg 24 Computer Skills and Programming Concepts I (UEC01)

  25. Internet Services • World Wide Web (WWW) • A repository of information spread all over the world and linked together. • Searching - Navigation - Retrieval- Shopping 25 Computer Skills and Programming Concepts I (UEC01)

  26. :// :// / / Method Host Path Internet Services • World Wide Web (WWW) • Browser • is the interface software used to explore the Net • Uniform Resource Locator (URL) • A standard for specifying any kind of information on the internet. • URL requires a method, a host computer and a pathname to locate information on the WWW http :// www.ibm.com /en/us/default.aspx 26 Computer Skills and Programming Concepts I (UEC01)

More Related