Computer Network PDF - Course Material 2013

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This is the course material for the diploma students. it covers the basic topics of computer netwroking

This is the course material for the diploma students. it covers the basic topics of computer netwroking

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  • 1. Lecture #1 Introduction to Network Computer Network 1 2013 1. Define Network A computer network is defined as the interconnection of 2 or more independent computers and peripherals. 2. What are the uses of Network? – Resource Sharing – Reliability – Reduced Cost – Fast Communication 3. What are the types of Network? LAN (Local Area Network) WAN (Wide Area Network) MAN (Metropolitan Area Network) PAN (Personal Area Network) VPN (Virtual Private Network) CAN (Campus Area Network) GAN(Global Area Network) SAN (Storage Area Network) Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 2. Computer Network 1 2013 4. Mention the common name of the computers connected in a Network? Workstation / Nodes / Clients Server 5. Define Server The master computer is known as server 6. Define Client Computer attached to the master computer is known as client 7. Draw the diagram of Network Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 3. 8. What is NIC? Computer Network 1 2013 It is a device attached to each client and server. Helps to make connections within the network. Each NIU has a unique number identifying it called Node Address. NIU is also called Terminal Access Point (TAP). Each NIC is given a unique physical address called MAC address. 9. Give the Expansion of NIC, MAC and TAP NIC – Network Interface Card MAC – Machine Access Code TAP – Terminal Access Point 10. The computer on the network may be linked through ____________? Cables Telephone Lines Radio Waves Satellites Infrared Light Beams. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 4. Lecture #2 Network Components Computer Network 1 2013 1. What are the components needed for building a Network? Network Interface Card Repeaters Network Hub Network Bridge Network Switch Router 2. Define Repeaters A repeater is an electronic device that receives a low power signal and retransmits it at a higher power level Repeaters are required for cable runs longer than 100 meters. 3. Define Hub A hub contains multiple ports. When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 5. 4. Define Switch Computer Network 1 2013 A switch is a device that forwards and filters datagram's between ports Switches work at Physical, Data link, Network, or Transport Layers 5. Define Multilayer Switch A device that operates simultaneously at more than one layer is called a multilayer switch. 6. Define Router Router is a specialized network device used to interconnect different types of computer network that uses different protocols Routers work at the network layer 7. Define Bridge A network bridge connects two LANS having same protocol. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 6. 8. What are the available types of Bridge? Computer Network 1 2013 Local Bridge Remote Bridge Wireless Bridge 9. What is the use of Local Bridge? It is used to connect directly local area networks (LANs). 10. What is the use of Remote Bridge? It can be used to create a wide area network (WAN) link between LANs 11. What is the use of Wireless Bridge? It can be used to connect remote stations to LANs. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 7. Computer Network 1 2013 Lecture #3 Network Topology 1. Define Topology. The way in which the computers are interconnected together is known as TOPOLOGY 2. What are the types of Network Topology? 1. Physical Topology – How the cable are used 2. Logical Topology – How the messages travel 3. What are the types of Physical Topology? Bus / Linear - Both Physical and Logical Ring _ Both Physical and Logical Star - Physical Tree - Both Physical and Logical Mesh - Both Physical and Logical 4. Draw the diagram of Bus Topology? Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 8. 5. Draw the diagram of Ring Topology? Computer Network 1 2013 6. Draw the diagram of Star Topology? Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 9. 7. Draw the diagram of Mess Topology Computer Network 1 2013 7. Draw the diagram of Tree Topology Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 10. 8. Explain Bus Topology Computer Network 1 2013 9. Explain Ring Topology Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 4
  • 11. 10. Explain Star Topology Computer Network 1 2013 11. Explain Mess Topology Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 5
  • 12. Lecture #4 OSI Reference Model Computer Network 1 2013 1. What is the Expansion of OSI Open System Interconnection 2. What is OSI? An open system is a set of protocol that allows any two different systems to communicate regardless of their underlying architectures. It was designed by ISO-International Organization for Standardization in late1970s. It is a seven-layer model. 3. What are the types of layers in OSI? Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer Physical Layer The physical layer is responsible for transmitting bits from one node to the next Data Link layer The data link layer is responsible for transmitting frames from one node to the next Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 13. Network Layer Computer Network 1 2013 The network layer is responsible for the delivery of packets from the original source to the final destination Transport Layer The transport layer is responsible for delivery of a message from one process to another (process-to-process delivery) Session Layer The session layer is the network dialog controller. It establishes, maintains, and synchronizes the interaction between communicating systems Presentation Layer The presentation layer is concerned with the syntax and semantics of the information exchanged between two systems Application Layer The application layer enables the user to access the network. It provides user interfaces and support for services Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 14. Computer Network 1 2013 4. Draw the diagram of OSI Model Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 15. Lecture #5 Data Transmission Modes Computer Network 1 2013 Definition: Data transmission is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Communication channel is any physical media like cables etc. Transmission Modes: Data transmission has been categorized into two type’s namely Parallel and Serial Transmission. Serial transmission is further classified into Synchronous and Asynchronous Transmission. Parallel Transmission: 1. In parallel transmission of data, all the bits of a byte are transmitted simultaneously on separate wires. 2. This type requires multiple circuits for interconnecting the two devices. 3. It is practically possible only if two devices are close to each other. 4. This diagram represents parallel transmission of an 8-bit digital data. 5. This will require 8 wires for connecting two devices. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 16. Computer Network 1 2013 Advantages of Parallel transmission: 1. All the data bits will be transmitted simultaneously, so time required for transmission of N number of bits will be only one clock cycle. 2. Due to transmission in only one clock cycle, clock frequency can be kept low without affecting speed of operation. Disadvantages of Parallel transmission: 1. Transmission of N bits will require N number of wires. 2. With increase of users these wires will be too many to handle. Serial Transmission: 1. In serial transmission of data, all the bits of a byte are transmitted serially one after the other on same wire. 2. This type doesn’t require multiple circuits for interconnecting the two devices, indeed it just requires 1 wire to connect. 3. It is practically possible in all sorts of situations close or far. 4. This diagram represents serial transmission of an 8-bit digital data. 5. This will require only one wire for connecting two devices. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 17. Computer Network 1 2013 Advantages of serial transmission: 1. Only one wire is required. 2. Reduced cost due to less number of conductors. Disadvantages of serial transmission: 1. Speed of data transfer is low. 2. To increase speed of data transfer, clock frequency needs to be increased. Types of Serial Transmission: In data communication, Timing control of the reception of bits is important. There are two methods of timing control for reception of bits. Asynchronous Data Transfer 1. In asynchronous transmission, the transmitter transmits data bytes at any instant of time. 2. Only one byte is sent at a time. There is ideal time between two data bytes. 3. Transmitter and Receiver operate at different clock frequencies. 4. To help receiver ‘start’ and ‘stop’ bits are used along with data in middle. 5. Ideal time between byte is not constant. They are also known as gaps. 6. In asynchronous transmission timing of signal is not important. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 18. Computer Network 1 2013 Advantages of asynchronous transmission: 1. Synch between devices is not necessary. 2. It is cheap scheme. Disadvantages of synchronous transmission: 1. Use of ‘start’ and ‘stop’ bits and gaps between data makes transmission slow. 2. Timing error can take place. Synchronous Data Transmission 1. In synchronous transmission, data transmission is carried out under the control of a common master clock. 2. Bytes are transmitted as a block in a continuous stream of bits. 3. Transmitter and Receiver operate at synchronized clock frequencies. 4. No ‘start’ and ‘stop’ bits are used. 5. No need of ideal time between data bytes. 6. In synchronous transmission timing of signal is important. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 4
  • 19. Computer Network 1 2013 Advantages of asynchronous transmission: 1. Speed of data is much higher because of no ‘start’ and ‘stop’ bits and continuity. 2. Timing errors are reduced due to synch. Disadvantages of synchronous transmission: 1. Accuracy of data is entirely dependent on timing. 2. Transmitter and Receiver needs to be properly synchronized. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 5
  • 20. Lecture #6 Data Transmission Media Computer Network 1 2013 I. Introduction  On any network, the various entities must communicate through some form of media.  Just as humans can communicate through telephone wires or sound waves in the air, computers can communicate through cables, light, and radio waves.  Communication is possible only if information is encoded in a signal, and the signal is carried on a transmission the characteristics of the signal and of the medium both determine the quality of the communication medium.  There are two main groups of transmission media, namely the Guided Medium and the Wireless Medium / Unguided Medium.  For the guided medium, there is a physical path (such as a cable) for electromagnetic wave propagation.  For the wireless medium, however, the electromagnetic wave is transmitted through air, water, or vacuum. II. Characteristics  A good transmission medium should provide communication with good quality at long distance.  For voice communication, quality of communication is determined by the voice quality.  For data communication, however, the quality of communication is mainly determined by the effective data rate of communication. III. Factors Affecting Data Communication of a Medium  Communication bandwidth of the medium  Interference  The transmission impairments  The bandwidth of a medium determines the signal frequencies that can be carried in the medium. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 21. IV. Reasons for Transmission Impairence  Attenuation  Distortion during signal propagation  Computer Network 1 2013 Noises V. Design Factors for Transmission Media Bandwidth: All other factors remaining constant, the greater the band-width of a signal, the higher the data rate that can be achieved. Transmission impairments: Limit the distance a signal can travel. Interference: Competing signals in overlapping frequency bands can distort or wipe out a signal. Number of receivers: Each attachment introduces some attenuation and distortion, limiting distance and/or data rate. TYPES OF TRANSMISSION MEDIA 1. Guided Media : Use a conductor such as a wire or a fiber optic cable to move the signal from sender to receiver. 2. Wireless or Unguided Media: Use radio waves of different frequencies and do not need a wire or cable conductor to transmit signals. Guided Transmission Media Guided media includes everything that ‘guides’ the transmission. That usually takes the form of some sort of a wire. Usually copper, but can also be an optical fiber Transmission capacity depends on the distance and on whether the medium is point-to-point or multipoint Examples: Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 22. o Twisted Pair Wires Computer Network 1 2013 o Coaxial Cables o Fiber Optical Cable A. Twisted Pair Wires A transmission medium consisting of pairs of twisted copper wires arranged in a regular spiral pattern to minimize the electromagnetic interference between adjacent pairs Often used at customer facilities and also over distances to carry voice as well as data communications Low frequency transmission medium We can transmit 1 Mbps over short distances (less than 100m). They are mainly used to transmit analog signals, but they can be used for digital signals. Twisted Pair Advantages Inexpensive and readily available Flexible and light weight Easy to work with and install Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 3
  • 23. Twisted Pair Disadvantages Susceptibility to interference and noise Computer Network 1 2013 Attenuation problem  For analog, repeaters needed every 5-6km  For digital, repeaters needed every 2-3km Relatively low bandwidth (3000Hz) Applications They are used in telephone lines to provide voice and data channels. Local area networks, such as 10 Base-T and 100 Base-T also use twisted-pair cables. B. Coaxial Cable (or Coax) In its simplest form, coaxial consists of a core made of solid copper surrounded by insulation, a braided metal shielding, and an outer cover. A transmission medium consisting of thickly insulated copper wire, which can transmit a large volume of data than twisted wire. Coax Advantages Higher bandwidth  400 to 600Mhz  up to 10,800 voice conversations Much less susceptible to interference than twisted pair Coax Disadvantages High attenuation rate makes it expensive over long distance Bulky Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 4
  • 24. Computer Network 1 2013 Applications  It is used in cable TV networks  It is used in traditional Ethernet LANs. C. Fiber Optic Cable Relatively new transmission medium used by telephone companies in place of long-distance trunk lines Also used by private companies in implementing local data communications networks Require a light source with injection laser diode (ILD) or light-emitting diodes (LED) Optical fiber consists of a glass core, surrounded by a glass cladding with slightly lower refractive index. In most networks fiber-optic cable is used as the high-speed backbone, and twisted wire and coaxial cable are used to connect the backbone to individual devices. Fiber Optic Advantages Greater capacity (bandwidth of up to 2 Gbps). Smaller size and lighter weight. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 5
  • 25. Lower attenuation. Computer Network 1 2013 immunity to environmental interference. highly secure due to tap difficulty and lack of signal radiation. Fiber Optic Disadvantages expensive over short distance requires highly skilled installers adding additional nodes is difficult Applications The fiber optic cable is often found in backbone networks because its bandwidth is cost effective. Used in TV companies. LAN such as 100 Base-FX Network Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 6
  • 26. Computer Network 1 2013 Wireless (Unguided Media) Transmission Transmission and reception are achieved by means of an antenna Directional  Transmitting antenna puts out focused beam  Transmitter and receiver must be aligned Omni directional  Signal spreads out in all directions  Can be received by many antennas Wireless Examples Terrestrial Microwave Satellite Microwave Broadcast Radio Infrared A. Microwaves Electromagnetic waves having frequency between 1 and 300 GHz are called as Micro waves. Micro waves are unidirectional. Microwave propagation is line of sight. Very high frequency Micro waves cannot penetrate walls. The microwave band is relatively wide, almost 299 GHz Terrestrial Microwave Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 7
  • 27. Used for long-distance telephone service. Computer Network 1 2013 Uses radio frequency spectrum, from 2 to 40 Ghz. Parabolic dish transmitter, mounted high. Used by common carriers as well as private networks. Requires unobstructed line of sight between source and receiver. Curvature of the earth requires stations (repeaters) ~30 miles apart. B. Satellite Microwave A microwave relay station in space Can relay signals over long distances Geostationary satellites  Remain above the equator at a height of 22,300 miles (geosynchronous orbit)  Travel around the earth in exactly the time the earth takes to rotate Applications They are used in Cellular phones. They are used in satellite networks. They are used in wireless LANs. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 8
  • 28. C. Radio Radio waves particularly those waves that Computer Network 1 2013 propagate in the sky mode , can travel long distances .This makes Radio waves a good candidate for long distance broadcasting such as AM Radio Radio is a general term often used to encompass frequencies in the range 3 kHz to 300 GHz. Mobile telephony occupies several frequency bands just under 1 GHz. Radio waves are Omni directional. Application The omnidirectional characteristics of Radio waves make them useful for multicasting, in which there is one sender but many receivers. AM and FM Radio, television, maritime radio, cordless phone, and paging are examples of multicasting. D. Infrared Infrared waves, with frequencies from 300GHz-400THz can be used for short range communication. When we use our Infrared control, we do not interfere with use of the remote by our neighbors. We cannot use Infrared waves outside a building because the sun rays Contain Infrared waves that can interfere with communication. Uses transmitters/receivers (transceivers) that modulate no coherent infrared light. Transceivers must be within line of sight of each other (directly or via reflection). Unlike microwaves, infrared does not penetrate wallshaving high frequencies. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 9
  • 29. Application Computer Network 1 2013 The infrared band almost 400 THz has an excellent potential for data transmission. Such a wide bandwidth can be used to transmit digital data with a very high data rate. Infrared waves are used in communication between devices such as Keyboard, PCs and Printers. Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 10
  • 30. Lecture #7 Data Encryption Computer Network 1 2013 I. Definition Encryption is the process of transforming information (referred to as Plaintext) using an algorithm (called Cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a Key. The result of the process is encrypted information (in cryptography, referred to as cipher text). Decryption is the process to make the encrypted information readable again Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 31. Computer Network 1 2013 II. Process diagram of Encryption Plain Text Key Cyber Text Process diagram of Decryption Cyber Text Key Plain Text III. Types of Encryption 1. Manual Encryption 2. Transparent Encryption 3. Symmetric Encryption 4. Asymmetric Encryption IV. Methods of Encryption 1. Stream Encryption - Plain text encrypted character by character 2. Block Cyber Encryption - Plain text encrypted block by block V. Uses of Encryption 1. Protect information on your computer 2. Protect information over network transmission 3. Wireless Phones 4. E-Mail Programs 5. Digital Signature 6. Confidentiality of medical, personal and bank transaction records Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 2
  • 32. Lecture #8 Internet Service Providers Computer Network 1 2013 1. Define ISP A specialized company that connects customers with PCs and browsers to the Internet The ISP gives you a software package, a user name and password, and an access phone number to connect to the Internet for the payment. 2. What are the types of Service Providers? Internet Service Provider (ISP) Application Service Provider (ASP) Business Service Provider (BSP) Wholesale Service Provider (WSP) Wireless Application Service provider (WASP 3. What are the types of Web Hosting Services? 1. Dial-Up Access 2. Developer’s Hosting 3. Industrial Strength Hosting 4. What are the 3 major target markets of ISP? 1. Residential 2. Commercial 3. Public 5. What is meant by DNS (Domain Name Service)? A repository where the domain name for each ISP is stored 6. What are the services provided by ISP? WWW Server FTP Internet Relay Chat (IRC) News Server HTTP Proxy Service Broadband Connection Local Loop Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1
  • 33. Lecture #9Packet Switching Computer Network 1 2013 1. Define Packet Switching • Packet Switching refers to technologies in which messages are divided into packets before they are sent. • Each packet is then transmitted individually and can even follow different routes to its destination • Once all the packets forming a message arrive at the destination, they are recompiled into their original form 2. What are the types in Packet Switching? TCP/IP X.25 Frame Relay 3. Draw the diagram of TCP/IP 4. Define X.25 • X.25 is an open standard WAN technology for packet-switching networks. • It is one of the earliest international standards for packet switching. • It defines layers 1, 2, and 3 in the OSI Reference Model 5. Define Frame Relay • Frame Relay is a packet-switching protocol for connecting devices on a WAN. • It operates at layer two or the Data Link layer in the OSI model. • It is used in applications such as LAN interconnection, public and private wide area networks and gradually replacing X.25 Prepared By Mrs.Vasanthi Muniasamy M.Sc., M.Phil Rank: Asst. Prof., CCG, KKU Page 1