1. Networks on a purpose By Indrani Chakraborty For VIII ICT 1Copyright reserved to Indrani @CVSL

2. What is a network? Two or more computer systems connected together so that they can share and exchange data Networks make better use of limited resources The definition is simple definition but the details are much more involved 2Copyright reserved to Indrani @CVSL

3. Why do we network? Sharing information –File sharing – data between computers Sharing resources Centralizing administration and support Better communication 3Copyright reserved to Indrani @CVSL

4. Traits of a good network Reliable - dependable Scalable – hardware and software can grow up or down as organization needs change Redundant – anticipates disaster – duplicate data and resource to minimize downtime and data loss Secure Good Speed 4Copyright reserved to Indrani @CVSL

5. Some advantages of a network are: Resources (Hardware and Software) can be shared. Allows more effective communication between users e.g. via e-mail. Networks are cheaper than “stand-alone PCs.” Information held on the network can be accessed by all users with authorised access. 5Copyright reserved to Indrani @CVSL

6. Some disadvantages of a network are: The set-up and maintenance costs can be expensive. A fault with the network server can cause difficulties with the organisation. Networks need security measures to restrict access to users. WANs are vulnerable to hackers and viruses. 6Copyright reserved to Indrani @CVSL

7. Networks A network is two or more computers connected together so they can communicate which each other. There are 2 main types of network… Computer 1 Computer 2 7Copyright reserved to Indrani @CVSL

8. LAN LAN stands for: LOCAL AREA NETWORK LANs are networks that are found where computers within a building need to communicate. They are Small and Local! 8Copyright reserved to Indrani @CVSL

9. What hardware do you need for a LAN network? File Server : Runs software, stores files. Terminals : Workstations that give network access. Print Server : Queues up all print jobs from users in network. Cables (wire/optic) : Sends data. 9Copyright reserved to Indrani @CVSL

10. WAN WAN stands for: WIDE AREA NETWORK WANs are networks that are found where computers in different areas or countries need to communicate. They are long range and not local! 10Copyright reserved to Indrani @CVSL

11. What extra hardware do you need for a WAN network ? Modems : To connect up to a telephone system (instead of cable). 11Copyright reserved to Indrani @CVSL

12. Transmission Media Transmission media are the ways in which parts of the networks are linked. Example –UTP (Unshielded twisted Pair) –Fiber Optics –Wireless Radio Wave –Infrared Device Copyright reserved to Indrani @CVSL 12

13. Hub A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When apacket arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packetsdevicesnetworksegmentsLANportspacket Copyright reserved to Indrani @CVSL 13

14. Switches Network switches appear nearly identical to network hubs, but a switch generally contains more intelligence (and a slightly higher price tag) than a hub. Unlike hubs, network switches are capable of inspecting data packets as they are received, determining the source and destination device of each packet, and forwarding them appropriately. By delivering messages only to the connected device intended, a network switch conserves network bandwidth and offers generally better performance than a hub.network hubspacketsnetwork bandwidth Copyright reserved to Indrani @CVSL 14

15. Server A server is powerful computer on a network which manages and control network resources. Copyright reserved to Indrani @CVSL 15

16. Router The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to Copyright reserved to Indrani @CVSL 16

17. MODEM A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from light emitting diodes to radio. The most familiar example is avoice band modem that turns the digital data of a personal computer into modulated electrical signals in the voice frequency range of a telephonechannel. These signals can be transmitted over telephone lines and demodulated by another modem at the receiver side to recover the digital data.analog carrier signaldigital informationsignallight emitting diodesradiovoice banddigital datapersonal computerelectrical signalsvoice frequencytelephonetelephone lines Copyright reserved to Indrani @CVSL 17

18. Bandwidth -is a measure how fast computer cork Copyright reserved to Indrani @CVSL 18

19. Network Management A network manager is usually appointed to ensure the smooth running of the network. His work includes –Configuration –Fault finding –Security Copyright reserved to Indrani @CVSL 19

20. Management Issues Training required for user There must network manager Use of license software Antivirus Backup Maintenance Copyright reserved to Indrani @CVSL 20