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Chapter 10 Basic Networking.pdf

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  2. Outcome of this chapter  Basics of data communication and the components needed for it  The client server model  Different network topologies  Different network types  Physical mediums that connect computers  Different transmission lines 2
  3. Computer Network  A computer network consists of a collection of computers, printers and other equipment that is connected together so that they can communicate with each other. 3 Figure : A simple computer network
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  5. Data Communication  Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.  For data communications to occur, the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs). 5
  6. Components of Data Communication 1. Message 2. Sender 3. Receiver 4. Medium or Communication Channel 5. Encoder and Decoder 6. Protocol 6
  7. Message  The message is the information or data that is to be communicated.  It may consist of text, numbers, pictures, sounds, videos or any combination of these. 7 Components of Data Communication
  8.  Sender • A device that is used for sending messages (or data) is called sender. • It is also called transmitter or source. • The sender can be a computer, telephone, or a video camera etc. • Usually, a computer is used as sender in data communication system.  Receiver • A device that is used for receiving messages is called receiver. • It is also known as sink. • The receiver can be a computer, telephone set, printer, or a fax machine etc. • Usually, a computer is also used as receiver in data communication system. 8 Components of Data Communication
  9.  Medium  The path through which data is transmitted (or sent) from one location to another is called transmission medium.  It is also called communication channel.  It may be a wire, or fiber optic cable, or telephone line etc.  If the sender and receiver are within a building, a wire is used as the medium.  If they are located at different locations, the medium may be telephone line, fiber optics, and microwave or satellite system. 9 Components of Data Communication
  10. Protocol:  A protocol is a set of rules that govern data communications.  It represents an agreement between the communicating devices.  Without a protocol, two devices may be connected but not communicating, just as a person speaking French cannot be understood by a person who speaks only Japanese. 10 Components of Data Communication
  11.  Encoder and Decoder: In communication systems, computers are used for senders and receivers. A computer works with digital signals. The communication channels usually use analog signals. The encoder and decoder are used in communication systems to convert signals from one from to another.  Encoder: The encoder is an electronic device. It receives data from sender in the form of digital signals. It converts digital signals into a form that can be transmitted through transmission medium.  Decoder: The decoder is an electronic device. It receives data from transmission medium. It converts encoded signals (i.e. analog signals) into digital form. 11 Components of Data Communication
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  13. Understanding Client server interaction There are two main types of computers on a network: server and client. Server Computer: A server is a network computer that contains resources that are shared with other computers within the network. A computer that is being served with these resources is a client. What Servers Do:  Data server stores and serves database information to client computers.  Application server holds a web-based application and its data. It processes requests from users of the application and sends results to the client computers.  Web server stores and serves web pages over the Internet.  File server stores and shares data files and programs among users on a network.  Email server stores and moves mail across local networks and over the Internet. 13
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  15. Computer Network Types  Personal Area Network (PAN):  A Personal Area Network or simply PAN, is smallest network which is very personal to a user.  This may include Bluetooth enabled devices or infra-red enabled devices.  PAN has connectivity range up to 10 meters.  PAN may include wireless computer keyboard and mouse, Bluetooth enabled headphones, wireless printers and TV remotes for example. 15
  16.  Local Area Network (LAN):  A computer network spanned inside a building and operated under single administrative system is generally termed as Local Area Network.  Usually, Local Area Network covers an organization’s offices, schools, college/universities etc.  Resources like Printers, File Servers, Scanners and internet is easy sharable among computers. 16 Computer Network Types
  17.  Metropolitan Area Network (MAN):  A metropolitan area network (MAN) is computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.  A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. 17 Computer Network Types
  18.  Wide Area Network (WAN):  A wide area network (WAN) is a geographically dispersed telecommunications network.  The term distinguishes a broader telecommunication structure from a local area network (LAN). 18 Computer Network Types
  19. Network Topologies  A Network Topology is the way computer systems or network equipment connected to each other.  Point-to-point: Point-to-point networks contains exactly two hosts (computer or switches or routers or servers) connected back to back using a single piece of cable. 19
  20.  Bus Topology :  All devices are connected to this shared line.  It is one of the simple forms of networking where a failure of a device does not affect the others. But failure of the shared communication line make all other devices fail.  Both ends of the shared channel have line terminator. 20 Network Topologies
  21.  Star topology:  All hosts in star topology are connected to a central device, known as Hub device, using a point-to-point connection.  Star topology is not expensive as to connect one more host, only one cable is required and configuration is simple. 21 Network Topologies
  22.  Ring topology:  In ring topology, each host machine connects to exactly two other machines, creating a circular network structure.  When one host tries to communicate or send message to a host which is not adjacent to it, the data travels through all intermediate hosts.  Failure of any host results in failure of the whole ring. 22 Network Topologies
  23.  Mesh topology:  In this type of topology, a host is connected to one or two or more than two hosts.  Full Mesh: All hosts have a point-to- point connection to every other host in the network. Thus for every new host n(n-1)/2 cables (connection) are required. It provides the most reliable network structure among all network topologies.  Partially Mesh: Not all hosts have point-to-point connection to every other host. Hosts connect to each other in some arbitrarily fashion. This topology exists where we need to provide reliability to some host whereas others are not as such necessary. 23 Network Topologies
  24. Internet, Intranet, Extranet  The Internet: A means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. When two computers are connected over the Internet, they can send and receive all kinds of information.  Intranet: An intranet is a computer network that uses Internet Protocol technology to share information, operational systems, or computing services within an organization.  Extranet: An extranet is a private network that uses Internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses. 24
  25. Network media and connector  Transmission Medium : A transmission medium can be broadly defined as anything that can carry information from a source to a destination.  Magnetic Media:  One of the most convenient ways to transfer data from one computer to another, even before the birth of networking, was to save it on some storage media and transfer physical from one station to another.  Though it may seem odd in today’s world of high speed Internet, but when the size of data to transfer is huge, Magnetic media comes into play. 25
  26.  Twisted Pair Cable: A twisted pair cable is made of two plastic insulated copper wires twisted together to form a single media. Out of these two wires only one carries actual signal and another is used for ground reference. The twists between wires are helpful in reducing noise (electro-magnetic interference) and crosstalk. There are two types of twisted pair cables available:  Shielded Twisted Pair (STP) Cable  Unshielded Twisted Pair (UTP) Cable  STP cables comes with twisted wire pair covered in metal foil. This makes it more indifferent to noise and crosstalk.  UTP has seven categories, each suitable for specific use. In computer networks, Cat-5, Cat-5e and Cat-6 cables are mostly used. UTP cables are connected by RJ45 connectors. 26 Network media and connector
  27. Coaxial Cable:  Coaxial cables have two wires of copper. The core wire lies in center and is made of solid conductor.  Core is enclosed in an insulating sheath. Over the sheath the second wire is wrapped around and that too in turn encased by insulator sheath. This all is covered by plastic cover.  Because of its structure coax cables are capable of carrying high frequency signals than that of twisted pair cables.  The wrapped structure provides it a good shield against noise and cross talk.  Coaxial cables provide high bandwidth rates of up to 450 mbps. 27 Network media and connector
  28. Fiber Optics:  Fiber Optic works on the properties of light.  When light ray hits at critical angle it tends to refracts at 90 degree. This property has been used in fiber optic.  The core of fiber optic cable is made of high quality glass or plastic.  From one end of it light is emitted, it travels through it and at the other end light detector detects light stream and converts it to electric data form.  Fiber Optic provides the highest mode of speed.  It comes in two modes; one is single mode fiber and second is multimode fiber.  Single mode fiber can carries single ray of light whereas multimode is capable of carrying multiple beams of light. 28 Network media and connector
  29.  Wireless:  Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.  Wireless operations permit services, such as long-range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls etc.) 29 Network media and connector
  30. Wireless Technology 30
  31. Transmission Modes  Simplex:  A simplex connection is a connection in which the data flows in only one direction, from the transmitter to the receiver.  This type of connection is useful if the data do not need to flow in both directions (for example, from your computer to the printer or from the mouse to your computer). 31
  32.  Half-Duplex :  A half-duplex connection (sometimes called an alternating connection or semi-duplex) is a connection in which the data flows in one direction or the other, but not both at the same time. 32 Transmission Modes
  33.  Full-Duplex :  A full-duplex connection is a connection in which the data flow in both directions simultaneously.  Each end of the line can thus transmit and receive at the same time. 33 Transmission Modes
  34. Thank You 34
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