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Network Hardwareand Software
What is a network?          A network consists          of two or more          computers that are          linked in orde...
How are they linked?           Computers on a           network may be           linked through:            cables,      ...
The two basic types of  networks include:Local Area Networks   LAN(LAN)Wide Area Networks(WAN)                            ...
Local area networksLANs are confined to a relatively smallarea such as a school or a buildingLANs usually have one compute...
Wide Area Networks          WANs connect          larger areas, such          as whole states, or          even the world....
ProtocolA protocol is a set of     PROTOCOL =rules that governs the     SET OF RULES                              ABOUTcom...
The most common         protocols are:  Ethernet  Local Talk          Protocol = a formal  Token Ring          description...
Ethernet    Most widely used    Uses an access    method called    CSMA/CD (Carrier    Sense Multiple    Access/Collision ...
What does that mean?Each computer in thenetwork ‘listens’ to the   A bit like waiting forcable before sending       your y...
Ethernet (continued)Sometimes, two computersattempt to transmit at thesame instant. When thishappens, a collision occurs.E...
Ethernet (continued)Ethernet protocolallows for data to betransmitted overtwisted pair, coaxialor fiber optic cableat a sp...
Fast EthernetTo allow for fastertransmission, theEthernet protocol hasdeveloped a newstandard thatsupports 100 MbpsFast Et...
Gigabit EthernetThe Ethernetprotocol has alsodeveloped a new        One gigabit perstandard that allows    second = onetra...
Local TalkLocal Talk is a networkprotocol that wasdeveloped by Apple forMacintosh computersLocal Talk uses theCSMA/CA meth...
Token RingToken ringprotocol involves‘token-passing’.It is not as           A single electronic ‘token’popular as         ...
FDDIStands for FiberDistributed DataInterfaceIs used mainly toconnect two or moreLANs, often overlarge distancesCan operat...
ATMStands for AsynchronousTransfer ModeTransmit data at a speedof 155 Mbps and higherWorks by transmitting alldata in smal...
Where does TCP/IP fit    into all this???TCP/IP is the protocol that is used for thetransmission of information over the I...
Network HardwareNetwork hardwareincludes: Computers Peripherals Interface cards and Other equipment  needed to perform...
File serversA very fast computerwith a large amountof RAM and storagespace along with afast networkinterface cardThe netwo...
WorkstationsAll computersconnected to the fileserver on a networkare calledworkstations
Network interface cardsThe network interface card(NIC) provides the physicalconnection between thenetwork and the computer...
Ethernet cardsThe most commonNetwork Interface                       Co-axialCards are Ethernet     cablecardsThey contain...
Concentrators / Hubs A concentrator is a device that provides a central connection point for cables from workstations, ser...
SwitchesWhile hubs provide an easyway to scale up andshorten the distance thatthe packets must travel toget from one node ...
Switches (continued)A vital difference between a hub and a switch is that allthe nodes connected to a hub share the bandwi...
RepeatersA signal loses strength as it passesalong a cable, so it is often necessaryto boost the signal with a device call...
BridgesA bridge is a device that allows youto segment a large network into twosmaller, more efficient networks
RoutersA router translatesinformation from onenetwork to anotherThe router directs traffic toprevent “head-on”collisionsIf...
Routers (continued)
CablingNetwork cabling is themedium through whichinformation usuallymoves from onenetwork device toanotherThere are severa...
Unshielded Twisted Pair     (UTP) CableTwisted pair cablescome in two varieties:shielded andunshielded.Unshielded (UTP) is...
UTP (continued)UTP has four pairs of wires inside the jacketEach pair is twisted with a different number oftwists per inch...
UTP ConnectorThe standardconnector for UTPcabling is an RJ-45.It looks like atelephone styleconnection
Coaxial cableCoaxial cable has a single copper conductor at itscentre with a plastic layer between the centreconductor and...
Coaxial cable connectors The most common type of connector used with coaxial cables is the BNC connector
Fiber Optic CableFiber optic cabling consists of a center glasscore surrounded by several layers of protectivematerialsIt ...
Fiber Optic (continued)Fiber optic cable has the ability to transmitsignals over much longer distances thancoaxial or twis...
Wireless LANSWireless networks use high frequency radiosignals to communicate between theworkstations and the fileserver o...
Network Operating        SoftwareNetwork operatingsystems co-ordinate theactivities of multiplecomputers across anetworkTh...
Peer to peer network OSIn peer to peer network OS,there is no file server or centralmanagement source; allcomputers are co...
Client/Server network OSClient/server network OScentralise functions andapplications in one or morededicated file servers....
TopologyThe physical topology of a network refers tothe configuration of cables, computers andother peripherals.The main t...
Linear BusA linear bus topology consists of a main run ofcable with a terminator at each end. All serversworkstations and ...
StarA star network isdesigned with eachnode (file server,workstation,peripheral)connected directly toa central networkhub ...
RingA ring network isone where allworkstations andother devices areconnected in acontinuous loop.There is no centralserver
Tree or hybridA tree or hybridtopology combinescharacteristics oflinear bus and starand/or ringtopologies.It consists of g...
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Networks

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Networks

  1. 1. Network Hardwareand Software
  2. 2. What is a network? A network consists of two or more computers that are linked in order to:  share resources (such as printers and CD-ROMs),  exchange files, or  allow electronic communications
  3. 3. How are they linked? Computers on a network may be linked through:  cables,  telephone lines,  radio waves, satellites or  wireless technologies
  4. 4. The two basic types of networks include:Local Area Networks LAN(LAN)Wide Area Networks(WAN) WAN
  5. 5. Local area networksLANs are confined to a relatively smallarea such as a school or a buildingLANs usually have one computerdesignated as the file serverOther computers are connected to thenetwork by cables connecting networkinterface cards in each computer
  6. 6. Wide Area Networks WANs connect larger areas, such as whole states, or even the world. Transoceanic cables and satellites are used to connect WANs
  7. 7. ProtocolA protocol is a set of PROTOCOL =rules that governs the SET OF RULES ABOUTcommunications COMMUNICATIONbetween computers S BETWEEN NETWORKS!on a networkThese rules includeguidelines thatregulate the method ofaccess, types ofcabling and speed ofdata transfer
  8. 8. The most common protocols are: Ethernet Local Talk Protocol = a formal Token Ring description of a set of rules and conventions FDDI that govern how ATM devices on a network exchange informationDid you ever wonder what HTTP in web addresses wasabout? It stands for HyperText Transfer Protocol
  9. 9. Ethernet Most widely used Uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection
  10. 10. What does that mean?Each computer in thenetwork ‘listens’ to the A bit like waiting forcable before sending your younger sister toanything through the get off the telephonenetwork. If the network perhaps?is clear, the computerwill transmit.If another computer isalready transmitting onthe cable, the computerwill wait and try againwhen the line is clear
  11. 11. Ethernet (continued)Sometimes, two computersattempt to transmit at thesame instant. When thishappens, a collision occurs.Each computer then backs offand waits a random amount oftime before attempting toretransmit.It is normal to havecollisions using this method, CSMA/CD =Carrierbut the delays caused by Sense Multiplecollisions and transmissions is Access /Collisionsmall, and does not effect Detectionspeed of transmission on thenetwork
  12. 12. Ethernet (continued)Ethernet protocolallows for data to betransmitted overtwisted pair, coaxialor fiber optic cableat a speed of 10Mbps(more on that later)
  13. 13. Fast EthernetTo allow for fastertransmission, theEthernet protocol hasdeveloped a newstandard thatsupports 100 MbpsFast Ethernetrequires the use ofmore expensiveequipment andnetwork cards
  14. 14. Gigabit EthernetThe Ethernetprotocol has alsodeveloped a new One gigabit perstandard that allows second = onetransmission of 1 thousandGbps (gigabit per megabits persecond) second
  15. 15. Local TalkLocal Talk is a networkprotocol that wasdeveloped by Apple forMacintosh computersLocal Talk uses theCSMA/CA method(Carrier Sense MultipleAccess with CollisionAvoidance) which works ina similar way toCSMA/CDIt is a lot slower thanEthernet (only 230 Kbps)
  16. 16. Token RingToken ringprotocol involves‘token-passing’.It is not as A single electronic ‘token’popular as moves around the ring from one computer to the next. If aEthernet protocol computer wishes to transit and receives an empty token, it attaches data to the token which then proceeds around the ring until it comes to the computer the data is meant for.
  17. 17. FDDIStands for FiberDistributed DataInterfaceIs used mainly toconnect two or moreLANs, often overlarge distancesCan operate overfiber optic cable at100 Mbps
  18. 18. ATMStands for AsynchronousTransfer ModeTransmit data at a speedof 155 Mbps and higherWorks by transmitting alldata in small packets offixed size (other protocolstransfer variable sizepackets)Like FDDI , is most oftenused to connect two ormore LANs
  19. 19. Where does TCP/IP fit into all this???TCP/IP is the protocol that is used for thetransmission of information over the InternetIP (Internet Protocol) - the main delivery systemfor information over the InternetTCP (Transport Control Protocol) - used tobreak apart and rebuild information that travelsover the Internet
  20. 20. Network HardwareNetwork hardwareincludes: Computers Peripherals Interface cards and Other equipment needed to perform data processing and communications within the network
  21. 21. File serversA very fast computerwith a large amountof RAM and storagespace along with afast networkinterface cardThe networkoperating systemsoftware resides onthis computer
  22. 22. WorkstationsAll computersconnected to the fileserver on a networkare calledworkstations
  23. 23. Network interface cardsThe network interface card(NIC) provides the physicalconnection between thenetwork and the computerworkstation.Most NICs are internal withthe card fitting into anexpansion slot in thecomputer.Three common networkinterface connections areEthernet cards, Local Talkconnectors and TokenRing cards
  24. 24. Ethernet cardsThe most commonNetwork Interface Co-axialCards are Ethernet cablecardsThey containconnections foreither coaxial ortwisted pair cables, Twisted pair cableor both
  25. 25. Concentrators / Hubs A concentrator is a device that provides a central connection point for cables from workstations, servers and peripherals Hubs are multi-slot concentrators
  26. 26. SwitchesWhile hubs provide an easyway to scale up andshorten the distance thatthe packets must travel toget from one node toanother, they do not breakup the actual network intodiscrete segments. That iswhere switches come in.
  27. 27. Switches (continued)A vital difference between a hub and a switch is that allthe nodes connected to a hub share the bandwidthamong themselves, while a device connected to a switchport has the full bandwidth all to itself.Think of a switch as a ‘clever’ hub
  28. 28. RepeatersA signal loses strength as it passesalong a cable, so it is often necessaryto boost the signal with a device calleda repeaterA repeater might be a separate device,or might be part of a concentrator
  29. 29. BridgesA bridge is a device that allows youto segment a large network into twosmaller, more efficient networks
  30. 30. RoutersA router translatesinformation from onenetwork to anotherThe router directs traffic toprevent “head-on”collisionsIf you have a LAN that youwant to connect to theInternet, you will need arouter to serve as thetranslator betweeninformation on your LANand the Internet
  31. 31. Routers (continued)
  32. 32. CablingNetwork cabling is themedium through whichinformation usuallymoves from onenetwork device toanotherThere are severaldifferent types of cablecommonly used inLANSSome networks use avariety of cable typeswithin the one network
  33. 33. Unshielded Twisted Pair (UTP) CableTwisted pair cablescome in two varieties:shielded andunshielded.Unshielded (UTP) isthe most popularShielded twisted pair isused only inenvironments wherethere may be electricalinterference
  34. 34. UTP (continued)UTP has four pairs of wires inside the jacketEach pair is twisted with a different number oftwists per inch to help eliminate interferencefrom adjacent pairs
  35. 35. UTP ConnectorThe standardconnector for UTPcabling is an RJ-45.It looks like atelephone styleconnection
  36. 36. Coaxial cableCoaxial cable has a single copper conductor at itscentre with a plastic layer between the centreconductor and the braided metal shieldAlthough coaxial cabling is difficult to install, it ishighly resistant to signal interference
  37. 37. Coaxial cable connectors The most common type of connector used with coaxial cables is the BNC connector
  38. 38. Fiber Optic CableFiber optic cabling consists of a center glasscore surrounded by several layers of protectivematerialsIt transmits light rather than electronic signalsIt is the standard for connecting networksbetween buildings, due to its immunity to theeffects of moisture and light
  39. 39. Fiber Optic (continued)Fiber optic cable has the ability to transmitsignals over much longer distances thancoaxial or twisted pairIt can also carry information at vastly greaterspeedsFiber optic cable is more difficult to install thanother cabling
  40. 40. Wireless LANSWireless networks use high frequency radiosignals to communicate between theworkstations and the fileserver or hubs.Disadvantages of wireless networks are: they are expensive (relatively), provide poor security, are susceptible to interference and are slower than cabled networks
  41. 41. Network Operating SoftwareNetwork operatingsystems co-ordinate theactivities of multiplecomputers across anetworkThe two major types ofnetwork OS are: Peer-to-peer Client/server
  42. 42. Peer to peer network OSIn peer to peer network OS,there is no file server or centralmanagement source; allcomputers are considered equalPeer to peer networks aredesign primarily for small tomedium LANSAppleShare and Windows forWorkgroups are examples ofprograms that can function aspeer to peer
  43. 43. Client/Server network OSClient/server network OScentralise functions andapplications in one or morededicated file servers.The file server providesaccess to resources andprovides securityNovelle Netware andWindows NT Server areexamples of client/servernetwork operating systems
  44. 44. TopologyThe physical topology of a network refers tothe configuration of cables, computers andother peripherals.The main types of network topologies are: Linear Bus Star Ring Tree or Hybrid
  45. 45. Linear BusA linear bus topology consists of a main run ofcable with a terminator at each end. All serversworkstations and peripherals are connected tothe linear cable
  46. 46. StarA star network isdesigned with eachnode (file server,workstation,peripheral)connected directly toa central networkhub or server
  47. 47. RingA ring network isone where allworkstations andother devices areconnected in acontinuous loop.There is no centralserver
  48. 48. Tree or hybridA tree or hybridtopology combinescharacteristics oflinear bus and starand/or ringtopologies.It consists of groupsof star-configuredworkstationsconnected to alinear bus backbonecable

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