Looking for a Tutor Near You?

Post Learning Requirement » x
Ask a Question
x

Choose Country Code

x

Direction

x

Ask a Question

x

Hire a Tutor

Computer Networking

Published in: Computer Science
73,919 Views

Computer Networking- An Introduction.

Rohit K / Kolkata

3 years of teaching experience

Qualification: B.Tech/B.E. (WEST BENGAL UNIVERSITY OF TECHNOLOGY - 2017)

Teaches: Chemistry, Computer Science, IT & Computer Subjects, Mathematics, All Subjects, Physics

Contact this Tutor
  1. CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 1 BASIC CONCEPTS OF NETWORK
  2. DEFINTION & APPLICATIONS DEFINTION: A computer network is defined as the interconnection of two or more computers, It is done to enable the computers to communicate and share available resources, APPLICATIONS: Sharing of resources such as printers Sharing of expensive software's and database Communication from one computer to another computer Exchange of data and information among users via network Sharing of information over geographically wide areas,
  3. THE USE OF COMPUTER NETWORK Business Applications t' online buying Home Applications mail, chat Mobile Users wireless: laptops, PDA, mobile, in plane Social Issues
  4. THE USE OF COMPUTER NETWORK o$haring information Do you prefer these? Or this? data communication
  5. THE USE OF COMPUTER NETWORK o$haring hardware or software E.g. print document 'Centralize administration and support e E.g. Internet-based, $0 everyone can access the same administrative or support application from their PCs Modem Modem
  6. COMPONENTS OF COMPUTER NETWORK Two or more computers Cables as links between the computers A network interfacing card(NIC) on each computer Switches Software called operating system(O$)
  7. NETWORK BENEFITS The network provided to the users can be divided into two categories: Sharing Connectivity
  8. SHARING RESOURCES Types of resources are: 1, Hardware: A network allows users to share many hardware devices such as printers , modems, fax machines, CD ROM, players, etc, Software: sharing software resources reduces the cost of software installation, saves space on hard disk,
  9. OTHER BENEFITS OF COMPUTER NETWORK Increased speed Reduced cost Improved security Centralized software managements Electronic mail Flexible access
  10. DI$DAVATAGE$ OF NETWORKS High cost of installation Requires time for administration Failure of server Cable faults
  11. CLASSIFICATION OF AREA BY THEIR GEOGRAPHY NETWORK PAN LAN WAN MAN CAN
  12. LOCAL AREA NETWORK(LAN) LAN is a network which is designed to operate over a small physical area such as an office, factory or a group of buildings, LAN's are easy to design and troubleshoot Exchange of information and sharing of resources becomes easy because of LAN, In LAN all machines are connected to a single cable, Different types of topologies such as star, tree, bus, ring, etc Can be used It is usually a privately owned network,
  13. WIDE AREA NETWORK(WAN) When network spans over a large distance or when the computers to be connected to each other are at widely separated locations a local area network cannot be used, A wide area network(WAN) is installed, The communication between different users of WAN is established using leased telephone lines, satellite links and similar channels, It is cheaper and more efficient to use the phone network for the link, Most WAN networks are used to transfer large blocks of data between its users,
  14. PERSONAL AREA NETWORK(PAN) A personal area network is a computer network organized around an individual person, It generally consists of a mobile computer, a cell phone or personal digital assistant, PAN enables the communication among these devices, It can also be used for communication among personal devices themselves for connecting to a digital level network and internet, The PAN$ can be constructed using wireless or cables,
  15. CAMPUS AREA NETWORK(CAN) The campus area network is made up of an interconnection of LAN with limited geographical area, Network equipments such as switches, routers and the transmission media i,e, optical fibre etc are almost entirely owned by the campus owner,
  16. METROPOLITAN AREA NETWORK(MAN) o It is in between LAN & WAN technology that covers the entire city, o It uses similar technology as LAN, o It can be a single network such as cable TV network, or a measure of connecting a number of LAN's o a large network $0 that resources can be shared LAN to LAN as well as device to device,
  17. LAN CAN Internet Campus LAN PAN Laptop with WI-AN ('Nireless LAN) Wireless Access Point WAN LAN MAN LAN ALAN LAN WAN LAN ALAN LAN BLAN pc ALAN
  18. DISTINGUISH BETWEEN PARAMETERS Ownership of network Geographical area covered Design and maintenance Communication medium Bandwidth Data rates(speed) LAN Private Small Easy Coaxial cable Low High WAN Private or public Very large Not easy PSTN or satellite links High Low MAN Private or public Moderate Not easy Coaxial cables, P$TN, optical fibre, cables, wireless moderate moderate
  19. NETWORK CLASSIFICATION BY THEIR COMPONENT ROLE LOCAL AREA NETWORK PEER TO PEER NETWORK CLIENT SERVER NETWORK
  20. PEER TO PEER NETWORK In peer to peer network each computer is responsible for making its own resources available to other computers on the network, Each computer is responsible for setting up and maintaining its own security for these resources, Also each computer is responsible for accessing the required network resources from peer to peer relationships, Peer to peer network is useful for a small network containing less than 10 computers on a single LAN , In peer to peer network each computer can function as both client and server, Peer to peer networks do not have a central control system, There are no servers in peer networks, Peer networks are amplified into home group,
  21. ADVANTAGES & DISADVANTAGES OF PEER TO PEER NETWORK Advantages: Use less expensive computer hardware Easy to administer No NO$ required More built in redundancy Easy setup & low cost Disadvantages: Not very secure No central point of storage or file archiving Additional load on computer because of resource sharing Hard to maintain version control
  22. Server-based P2P-network
  23. CLIENT/SERVER NETWORK In client-server network relationships, certain computers act as server and other act as clients, A server is simply a computer, that available the network resources and provides service to other computers when they request it, A client is the computer running a program that requests the service from a server, Local area network(LAN) is based on client server network relationship, A client-server network is one n which all available network resources such as files, directories, applications and shared devices, are centrally managed and hosted and then are accessed by client, Client serve network are defined by the presence of servers on a network that provide security and administration of the network,
  24. ADVANTAGES AND DISADVANTAGES OF CLIENT-SERVER NETWORK Advantages: Very secure Better performance Centralized backup very reliable Disadvantages: requires professional administration More hardware- intensive More software intensive Expensive dedicated software
  25. TYPES OF SERVERS File server SERVERS Application Print server server Message sever Database server
  26. TYPES OF SERVERS File server: These servers provide the services for storing, retrieving and moving the data, A user can read, write, exchange and manage the files with the help of file servers, Printer server: The printer server is used for controlling and managing printing on the network, It also offers the fax service to the network users, Application server: The expensive software and additional computing power can be shared by the computers in a network with he help of application servers, Message server: It is used to co-ordinate the interaction between users, documents and applications, The data can be used in the for of audio, video, binary, text or graphics, Database server: It is a type of application server, It allows the uses to access the centralised strong database,
  27. TRANMI$$ION MEDIA Two main categories: 1' Guided wires, cables 'l Unguided wireless transmission, e.g. radio, microwave, infrared, sound, sonar We will concentrate on guided media here: l' Twisted-Pair cables: Unshielded Twisted-Pair (UTP) cables Shielded Twisted-Pair (STP) cables '1 Coaxial cables t' Fiber-optic cables
  28. TRANMI$$ION MEDIA Twisted-Pair Cables If the pair of wires are not twisted, electromagnetic noises from, e.g., motors, will affect the closer wire more than the further one, thereby causing errors Noise source Sender 4 3 4 3 o 4 3 he total effect i 4 -14 Receiver 14 3
  29. TRANMI$$ION MEDIA Unshielded Twisted-Pair (UTP) Typically wrapped inside a plastic cover (for mechanical protection) A sample UTP cable with 5 unshielded twisted pairs of wires Twisted pairs (5 pairs) Insulator Metal Plastic cover
  30. TRANMI$$ION MEDIA Shielded Twisted-Pair (STP) STP cables are similar to UTP cables, except there is a metal foil or braided-metal-mesh cover that encases each pair of insulated wires Plastic cover Metal shield Insulation Copper
  31. TRANMI$$ION MEDIA Coaxial Cables , carry signals of higher In general, coaxial cables, or coax freq (100KHz-500MHz) than UTP cables Outer metallic wrapping serves both as a shield against noise and as the second conductor that completes the circuit Plastic cover Insulator Outer conductor Inner conductor (shield)
  32. TRANMI$$ION MEDIA Fiber-Optic Cables Light travels at ms-I in free space and is the fastest possible speed in the Universe Light slows down in denser media, e,g, glass Refraction occurs at interface, with light bending away from the normal when it enters a less dense medium Critica angle Beyond the critical angle total internal reflection
  33. TRANMI$$ION MEDIA Fiber-Optic Cables An optical fiber consists of a core (denser material) and a cladding (less dense material) Simplest one is a multimode step-index optical fiber Multimode = multiple paths, whereas step-index = refractive index follows a step-function profile (i,e, an abrupt change of refractive index between the core and the cladding) Light bounces back and forth along the core Common light sources: LED$ and lasers
  34. TOPOLOGY e How $0 many computers are connected together? Bus Topology Star Topology Hub Ring Topology
  35. TOPOLOGY , Bus Topology e Simple and low-cost A single cable called a trunk (backbone, segment) Only one computer can send messages at a time Passive topology - computer only listen for, not regenerate data Star Topology Each computer has a cable connected to a single point More cabling, hence higher cost All signals transmission through the hub; if down, entire network down Depending on the intelligence of hub, two or more computers may send message at the same time
  36. TOPOLOGY Ring Topology Every computer serves as a repeater to boost signals Typical way to send data: Token passing e only the computer who gets the token can send data Disadvantages Difficult to add computers More expensive If one computer fails, whole network fails