W 10 introduction to network


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  • The connectivity of two or more than two devices through some transmission medium and share the information to each other.
  • The computer which use but do not provide network resources.. OR
  • Network in small geographical Area (Room, Building or a Campus) is called LAN (Local Area Network)
  • Network in a City is call MAN (Metropolitan Area Network)
  • W 10 introduction to network

    1. 1. Week-10 <ul><li>Introduction to Computer Networks </li></ul><ul><ul><li>Application of Computer Network </li></ul></ul><ul><ul><li>Host, Terminal, Client Server Network, Peer to Peer Network </li></ul></ul><ul><li>Networking Devices (NIC (Physical Address), Modem, Hub, Switch & Router) </li></ul><ul><li>Categories of Network </li></ul><ul><li>Network Topology (Bus, Star, Ring and Mesh Topology) </li></ul><ul><li>Bandwidth, Broadband & Baseband Communication </li></ul><ul><li>Transmission Modes (Simplex, Half Duplex, & Full Duplex) </li></ul>
    2. 2. Network <ul><li>A network is a set of devices (often referred to as nodes) connected by communication links. </li></ul><ul><li>A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. </li></ul><ul><li>A group of computers and other devices joint together through some transmission medium is called Computer Network. </li></ul>
    3. 3. The concept of connected computers sharing resources is called Networking. Computer network that is part of network can share the following, Data, Messages, Graphics, Printers, Modem, Fax machine & other Hardware resources. Why Computer Network? To share information or receive a service via a network, or group of members able to communicate with each other.
    4. 4. Applications of Networks <ul><li>Resource Sharing </li></ul><ul><ul><li>Hardware (computing resources, disks, printers) </li></ul></ul><ul><ul><li>Software (application software) </li></ul></ul><ul><li>Information Sharing </li></ul><ul><ul><li>Easy accessibility from anywhere (files, databases) </li></ul></ul><ul><ul><li>Search Capability (WWW) </li></ul></ul><ul><li>Communication </li></ul><ul><ul><li>Email </li></ul></ul><ul><ul><li>Message broadcast </li></ul></ul>
    5. 5. What do you find on a network? <ul><li>The following types of nodes may be found on a data communications system. </li></ul><ul><li>Host: - A central computer which stores data and executes programs for terminals. </li></ul><ul><li>It is usually associated with minicomputers or mainframes. </li></ul><ul><li>It requires a multi-tasking, multi-user operating system such as Unix. </li></ul><ul><li>Terminal: - A computing device which is composed of a video screen and a keyboard. It allows a user to communicate with a host by typing in information or commands. </li></ul><ul><li>The host communicates with the terminal by updating the CRT (video). </li></ul><ul><li>Terminals cannot execute programs. </li></ul>
    6. 6. <ul><li>Client </li></ul><ul><li>A computer which takes advantage of the services provided by servers on the network. </li></ul><ul><li>Client also called Front End computer. </li></ul><ul><li>Server </li></ul><ul><li>The computer which used and provide services & resources is called Server. </li></ul><ul><li>Server is also called Back End computer. </li></ul>What do you find on a Network? (Cont’d) A Network with two Clients and one Server.
    7. 7. <ul><li>Client Server Network </li></ul><ul><li>Server based network also called client-server network, containing Client & the server that support them. </li></ul><ul><li>The Web is known as a client-server system. Your computer is the client; the remote computers that store electronic files are the servers. Examples include file, print or communication servers. </li></ul>What do you find on a Network? (Cont’d)      
    8. 8. <ul><li>Peer-to-Peer Network: - Peer-to-Peer or simply peer means the computer which has both qualities as server as well as client. </li></ul><ul><li>It means which both use & provide network resources. </li></ul><ul><li>Peer network which have no servers & use the network to share resources among independent peers. </li></ul><ul><li>Users simply share disk space & resources, such as printers & faxes. </li></ul>What do you find on a Network? (Cont’d) In a peer-to-peer system there are no fixed clients and servers.
    9. 9. Network Interface Card <ul><li>A computer is connected to the network cabling with a network interface card, (also called a &quot;NIC&quot;, &quot;nick&quot;, or network adapter. </li></ul><ul><li>Faster computers, like high-speed Pentiums, Dual Core, and Core 2 Duo or Core 2 Quad, often have 32-bit, 64-bit or PCI slots. </li></ul><ul><li>These PCs require 32-bit NICs to achieve the fastest networking speeds possible for speed-critical applications like desktop video, multimedia, publishing, and databases. </li></ul>
    10. 10. <ul><li>Physical address : - It is also known as link address. </li></ul><ul><li>The physical addresses have authority over the network (LAN & WAN). </li></ul><ul><li>Ethernet uses a 48-bit (6-byte) physical address written as 12 hexadecimal digits; every byte (2 hexadecimal digits) is separated by a colon. </li></ul><ul><li>The first 6 Hexa-decimal digits of a Mac address contain a manufacturer, identification (vender code) also known as the organizationally unique identifier (OUT). The last 6 digit are given by each vender and often the represents the interface serial no. </li></ul><ul><li>On most LAN interface card the MAC address is burned into ROM. It is only used for LAN communication. </li></ul>Network Interface Card (Cont’d) 07:01:02:01:2C:4B A 6-byte (12 hexadecimal digits) physical address.
    11. 11. <ul><li>Example: </li></ul><ul><li>In Figure, a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link (bus topology LAN). As the figure shows, the computer with physical address 10 is the sender, and the computer with physical address 87 is the receiver. </li></ul>Network Interface Card (Cont’d)
    12. 12. <ul><li>MODEM short for modulator/demodulator. </li></ul><ul><li>The modem is necessary because the phone network transmits audio, not data bits. </li></ul><ul><li>The modem is for compatibility with existing equipment. </li></ul><ul><li>Modulation is a prescribed method of encoding digital (or analog) signals onto a waveform (the carrier signal). </li></ul><ul><li>Once encoded, the original signal may be recovered by an inverse process called demodulation. </li></ul>MODEM
    13. 13. HUB <ul><li>HUB is a common connection point for devices in a network. </li></ul><ul><li>The benefits of HUB used in a network is that if a cable break on a network, the break cable node will only affected and not affect on the rest of network. </li></ul><ul><li>HUB internally uses BUS topology. </li></ul><ul><li>Network can be easily expanded using Hubs. </li></ul><ul><li>Active Hub : - A HUB that regenerate and retransmit signals are called Active Hub. </li></ul><ul><li>Active HUB is also called multi-port repeater. </li></ul><ul><li>Active HUB requires electrical Power to run. </li></ul><ul><li>Passive HUB : - A HUB that do not regenerate and do not retransmit signals are called Passive HUB. </li></ul><ul><li>Passive HUB do not require electrical power to run. </li></ul>
    14. 14. Connector RJ-45 <ul><li>The standard connector for twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector. </li></ul><ul><li>Cable used as a medium to carry the signal. </li></ul><ul><li>Coaxial Cable </li></ul><ul><li>Twisted-Pair Cable </li></ul><ul><li>Fiber-optic Cable </li></ul>
    15. 15. <ul><li>Today when we speak, we are generally referring the primary categories LAN, MAN and WAN. </li></ul><ul><li>The category into which a network falls is determined by </li></ul><ul><li>Technology, </li></ul><ul><li>its Size, </li></ul><ul><li>Standard Port & Media. </li></ul>Categories of Networks
    16. 16. <ul><li>A Local Area Network can connect many types of computing devices together such as microcomputers, minicomputers and switches. </li></ul><ul><li>A LAN is usually privately owned links the devices in a single office, building, or campus. </li></ul><ul><li>Depending on the need of organization and the type of technology used. </li></ul><ul><li>A LAN can be as simple as two PCs and a printer in someone’s home office, or it extend throughout a company and include voice, sound, and video peripherals. Currently LAN size is limited to a few kilometers. Ethernet, token ring </li></ul>Local Area Network
    17. 17. <ul><li>It has two main components Hardware & Software. </li></ul><ul><li>Network hardware includes NIC, Hub, Switch, Medium, Connectors (RJ-45). </li></ul><ul><li>Network software includes, Protocols (TCP/IP), Network services. </li></ul><ul><li>It usually uses cable (coaxial, twisted pair or fiber) but may use radio waves, infrared or micro waves. </li></ul><ul><li>It is used by a single organization. </li></ul>Local Area Network (Cont’d)
    18. 18. <ul><li>A high speed (100Mbps) network which spans city distances. or </li></ul><ul><li>It may be a single network such as a cable television network, or </li></ul><ul><li>It may be a means of connecting a number of LANs into a larger network, so that resources may be shared LAN-to-LAN as well as device-to-device. FDDI, ATM </li></ul><ul><li>Many telephone companies provided a popular MAN service called Switched Multi-megabit Data Service (SMDS). It is a service for handling high-speed communication for metropolitan area network. </li></ul>A metropolitan area network based on cable TV. Metropolitan Area Network
    19. 19. <ul><li>WAN : - The network between different cities, countries or in the world using WAN standard port & routing technology is called WAN. </li></ul><ul><li>A WAN is a network that covers a large geographical area using communication channel that combines many types of media such as telephone lines, cables & radio waves. </li></ul><ul><li>The Internet is the worlds largest WAN. </li></ul><ul><li>They use data lines which belong to a third party service provider such as the telephone company. </li></ul><ul><li>They require special interfaces to the data lines such as synchronous modems & routers. </li></ul><ul><li>Routing technology is a crucial component of a WAN. Routers decide how a packet should be sent in order that it arrives at its intended destination. </li></ul>Wide Area Network
    20. 20. Line Configuration Line Configuration defines the attachment of communication Devices to a link. OR It concerned with the connection of devices to the media.
    21. 21. Network Topology The network topology is the shape or the physical connectivity Of the network.
    22. 22. <ul><li>A bus topology is a multipoint. One long cable acts as a backbone to </li></ul><ul><li>link to the entire device in a network. </li></ul><ul><li>In this topology all the computers are connected in a series to one </li></ul><ul><li>cable. </li></ul><ul><li>Nodes are connected to the bus cable by drop-line and tap. </li></ul><ul><li>A drop-line is a connection running b/w the device and main cable. </li></ul><ul><li>A tap is a connector that either splices into the main cable to </li></ul><ul><li>create a contact with the metallic core. </li></ul>Bus Topology
    23. 23. <ul><li>In star topology, each device has a dedicated point-to-point link </li></ul><ul><li>only to the central controller, usually called HUB. </li></ul><ul><li>In star topology communication with a central HUB that resend </li></ul><ul><li>the message either to all the computers </li></ul><ul><li>(in a broadcast star network) or only to the destination computer </li></ul><ul><li>(in a switch star network). </li></ul><ul><li>The devices are not directly linked to one another. The controller </li></ul><ul><li>acts as an exchange, if one device want to send data to another, </li></ul><ul><li>it send the data to the controller, which than relays the data to </li></ul><ul><li>the other connected device. </li></ul>Star Topology
    24. 24. <ul><li>In ring topology, each device has a dedicated point-to-point </li></ul><ul><li>connection with only to the two devices on either side of it. </li></ul><ul><li>A signal is passed along the ring in one direction, from device to </li></ul><ul><li>device, until it reaches its destination. </li></ul><ul><li>Each device in the ring incorporates the repeater, when a device receives a signal intended for another device; its repeater generates the bit and passes them along. </li></ul>Ring Topology
    25. 25. <ul><li>In mesh topology, every device has a dedicated point-to-point </li></ul><ul><li>link to every other device. </li></ul><ul><li>The term dedicated means that link carries traffic only b/w two </li></ul><ul><li>devices it connects. </li></ul><ul><li>So we need n (n-1) physical link, however, if physical link allow </li></ul><ul><li>communication in both direction (duplex mode), we can divide the no; of links by 2. </li></ul><ul><li>In other words we can say that in mesh topology we need n (n-1)/2 duplex mode links. </li></ul>Mesh Topology
    26. 26. Bandwidth, Baseband & Broadband Transmission <ul><li>Bandwidth refers to the way of allocating the capacity of transmission media. </li></ul><ul><li>The total media capacity or bandwidth can be divided into channels. </li></ul><ul><li>A channel is simply a portion of the bandwidth that can be used for transmitting data. </li></ul><ul><li>The two ways of allocating the capacity of bounded transmission media are the following. </li></ul><ul><li>Base band transmission </li></ul><ul><li>These transmissions use the entire media bandwidth for a single channel. Base band is commonly used for digital signaling. It can also be used for analog signals. Most LANs use base band signaling. </li></ul>
    27. 27. <ul><li>Broadband transmission : - These transmissions provide the ability to divide the entire media bandwidth into multiple channels. </li></ul><ul><li>Since each channel can carry a different analog signals, broad band network support multiple simultaneous conversion over a single transmission medium. </li></ul>Baseband & Broadband Transmission (Cont’d)
    28. 28. Data Transmission Modes <ul><li>There are three modes of communication. </li></ul><ul><ul><li>Simplex </li></ul></ul><ul><ul><ul><li>In simplex transmission mode, communication can take place in only one direction. </li></ul></ul></ul><ul><ul><ul><li>It means the sender will always send & the receiver will always receive. </li></ul></ul></ul><ul><ul><ul><li>An example is TV waves, we can watch different channels on TV but there is no need to send any type of signals from TV. Another example is line printer. </li></ul></ul></ul><ul><ul><li>Half-Duplex </li></ul></ul><ul><ul><ul><li>A half-duplex system can transmit data in both direction, but only in one direction at a time. </li></ul></ul></ul><ul><ul><ul><li>It means that at a time one computer can only send or receive, when one device completes a transmission, this device must “turn over” the medium to the other device so that this second device has turn to transmit. e.g. wireless </li></ul></ul></ul>
    29. 29. <ul><ul><li>Full-Duplex </li></ul></ul><ul><ul><ul><li>This mode allows a device to send & receive data simultaneously is called duplex or full-duplex mode. </li></ul></ul></ul><ul><ul><ul><li>This mode provides two ways to simultaneously data transfer by providing each device with a separate communication channel. Voice telephone is full-duplex devices and either party to a conversation can talk at any time. </li></ul></ul></ul>Data Transmission Modes (Cont’d)
    30. 30. Data Transmission Modes (Cont’d)