Chapter 05 LAN Connectivity Devices

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  • 04/12/10 01:08 PM
  • 04/12/10 01:08 PM
  • 04/12/10 01:08 PM
  • Chapter 05 LAN Connectivity Devices

    1. 1. Chapter 05 LAN Connectivity Devices 11
    2. 2. Connectivity Devices <ul><li>Objectives: </li></ul><ul><li>Basic LAN devices </li></ul><ul><li>The Evolution of Network Devices: </li></ul><ul><ul><li>Network Devices that operate at each layer. </li></ul></ul><ul><li>Basics of Data Flow Through LANs </li></ul><ul><li>(Encapsulation Process) </li></ul><ul><li>How to Build a LAN </li></ul>
    3. 3. Local-Area Networks <ul><li>Introduction: </li></ul><ul><li>Understanding of: </li></ul><ul><ul><li>the OSI Model </li></ul></ul><ul><ul><li>What happens to the packets as they travel through the layers. </li></ul></ul><ul><li>LANs Devices </li></ul>
    4. 4. Network Devices <ul><li>As Organizations grow, so do their networks </li></ul><ul><ul><li>Growth in number of users </li></ul></ul><ul><ul><li>Geographical Growth </li></ul></ul><ul><li>Network Devices : </li></ul><ul><ul><li>Are products used to expand or connect networks. </li></ul></ul><ul><ul><li>Can control the amount of traffic on a network. </li></ul></ul><ul><ul><li>Can speed up the flow of data over a network. </li></ul></ul>
    5. 5. Networking Devices <ul><li>Device: Equipment that connects directly to a network segment. </li></ul><ul><ul><li>End user devices or hosts </li></ul></ul><ul><ul><ul><li>Hosts are devices that connect directly to a network segment. It includes: Computers (Client / Servers), Printers, Scanners, etc. </li></ul></ul></ul><ul><ul><li>Network Devices: </li></ul></ul><ul><ul><ul><li>Include all devices that connect the end-user devices to allow them communicate. </li></ul></ul></ul>
    6. 6. End-user devices or Hosts <ul><li>Allows users to share, create and obtain information </li></ul><ul><li>Can exist without a network </li></ul><ul><li>Are physically connected to the network media using a Network Interface Card. </li></ul>
    7. 7. Network Interface Card (NIC) <ul><li>Physical link between machine & network </li></ul><ul><li>Connection between machine & medium </li></ul><ul><li>The NIC controls the host’s access to the medium. </li></ul><ul><li>Translates parallel signals produced by the computer into serial format that is sent over the network. </li></ul><ul><li>The MAC address is hard coded onto the NIC. </li></ul>
    8. 8. Network Interface Card - NIC <ul><li>Transceiver: </li></ul><ul><ul><li>Send and receive signals </li></ul></ul><ul><ul><li>Convert one type of signal (or connector) into another. </li></ul></ul><ul><ul><li>Internal and / or External </li></ul></ul><ul><ul><li>Layer 1 device. It looks only at bits and not at any address information or higher level protocols </li></ul></ul>
    9. 10. Network Interface Card
    10. 11. From Parallel to Serial, and Vice Versa
    11. 12. Selecting a Network Card <ul><li>Consider the following factors </li></ul><ul><ul><li>Network Architecture or LAN Technology: Ethernet, Token Ring, FDDI, etc. </li></ul></ul><ul><ul><li>Type of Media: Thinnet or 10Base2, Thicknet or 10Base5, 10BaseT, Fiber Optic) </li></ul></ul><ul><ul><li>Data Transfer Speed </li></ul></ul><ul><ul><li>Type of System Bus: </li></ul></ul><ul><ul><ul><li>ISA, EISA, Microchanel, PCI, PCIMCA) </li></ul></ul></ul><ul><ul><ul><li>Some NICs connect through SCSI bus </li></ul></ul></ul><ul><ul><ul><li>Some NICs use USB </li></ul></ul></ul><ul><ul><ul><li>Integrated on the Motherboard </li></ul></ul></ul>
    12. 13. An Ethernet NIC
    13. 14. Type of System Bus <ul><li>ISA (Industrial Standard Architecture) </li></ul><ul><li>EISA (Enhanced ISA) </li></ul><ul><li>MCA (Micro Channel Architecture) </li></ul><ul><li>PCI (Peripheral Component Interconnect) </li></ul>
    14. 15. Primary Bus Architectures
    15. 16. Network Devices <ul><li>Provide transport for the data that needs to be transferred between end-user devices. </li></ul><ul><li>Extend cable connections </li></ul><ul><li>Concentrate connections </li></ul><ul><li>Convert Data Formats </li></ul><ul><li>Manage data transfer </li></ul>
    16. 17. Connectivity Devices <ul><li>Each topology and network architecture has its limits. </li></ul><ul><li>Beyond a point networks networks can not be expanded by simple adding more servers or cabling </li></ul><ul><li>Connectivity devices are the basic building blocks of network expansion </li></ul>
    17. 18. Connectivity Devices <ul><li>Are used to connect separate segments of the network or inter-network </li></ul><ul><li>A segment is a portion of the network transmission media that is assigned a network address. </li></ul>
    18. 19. Creating Larger Networks <ul><li>Physically expand the network </li></ul><ul><li>Segment network to filter traffic </li></ul><ul><li>Extend network to connect separate LANs </li></ul><ul><li>Connect two separate computer environments </li></ul>11
    19. 20. Devices to Expand the Network <ul><li>Repeaters </li></ul><ul><li>Bridges </li></ul><ul><li>Switches </li></ul><ul><li>Routers </li></ul><ul><li>Gateway </li></ul>11
    20. 21. Network Connectivity Devices <ul><li>Repeaters </li></ul><ul><li>Hubs </li></ul><ul><li>Bridges </li></ul><ul><li>Switches </li></ul>
    21. 22. Internetwork Connectivity Devices <ul><li>Routers </li></ul><ul><li>Gateways </li></ul>
    22. 23. Repeaters <ul><li>A repeater can be used to increase the length of your network by eliminating the effect of attenuation on the signal. </li></ul><ul><li>It connects two segments of the same network, overcoming the distance limitations of the transmission media. </li></ul><ul><li>Some repeaters also serve as transmission media adapters, connecting two different types of media. </li></ul>
    23. 24. Repeaters <ul><li>Repeaters can connect segments that have the same access method. (CSMA/CD, Token Passing, Polling, etc.) </li></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Repeaters do not filter data </li></ul></ul><ul><ul><li>Its use is inappropriate when there is a heavy network traffic. </li></ul></ul>
    24. 25. Repeaters Figure 11-5 11
    25. 26. Repeaters Figure11-6 11
    26. 27. Hubs <ul><li>A hub is used as a central point of connection among media segments. </li></ul><ul><li>Cables from network devices plug in to the ports on the hub. </li></ul><ul><li>Hubs are referred as Concentrators or multi-port repeater </li></ul><ul><li>Hubs receive signals from connected devices and transmit them to the other connected devices </li></ul>
    27. 28. Hubs <ul><li>Regenerate and repeat signals </li></ul><ul><li>Propagate signals through the network </li></ul><ul><li>Can not filter network traffic </li></ul><ul><li>Can not determine the best path </li></ul><ul><li>Are used as network concentration points. </li></ul>
    28. 29. Hubs
    29. 30. Hubs
    30. 31. Hubs
    31. 32. Figure 6-3a Shared Media LAN Architecture
    32. 33. Types of Hubs <ul><li>Passive Hubs </li></ul><ul><li>Active Hubs </li></ul><ul><li>Intelligent Hubs (Switches) </li></ul>
    33. 34. Passive Hub <ul><li>It functions only as a connection point for the signals </li></ul><ul><li>The signal pass through a passive hub without regeneration or amplification. </li></ul>
    34. 35. Active Hub <ul><li>It regenerates or amplifies the signal before they are retransmitted. </li></ul><ul><li>Drawback: </li></ul><ul><ul><li>The noise is also regenerated </li></ul></ul>
    35. 36. Bridges <ul><li>Layer 2 (Data Link Layer) device. </li></ul><ul><li>Divide a network into segments and filter traffic. Each </li></ul><ul><li>segment is a collision domain. </li></ul><ul><li>Limit or filter traffic keeping local traffic local yet allow </li></ul><ul><li>connectivity to other parts (segments) </li></ul><ul><li>Make decision based on the MAC address list </li></ul><ul><li>Connect different architectures and Forward packets </li></ul><ul><li>between architectures: Ethernet & Token-Ring. </li></ul>11
    36. 37. Bridges
    37. 38. Bridges <ul><li>Read network addresses at the MAC </li></ul><ul><li>(Media Access Control) sub-layer </li></ul><ul><li>Decide which segment address is on </li></ul><ul><li>Decide whether or not to forward packet </li></ul><ul><li>Drawback: </li></ul><ul><ul><li>Broadcast packages are passed across bridges. </li></ul></ul>11
    38. 39. Bridges 11
    39. 40. Switches <ul><li>A high speed multiport bridge </li></ul><ul><li>Replacing repeaters & hubs in UTP </li></ul><ul><li>Switches maintains a switching table </li></ul><ul><li>Dedicated bandwidth to each port, making data </li></ul><ul><li>transmission more efficient. </li></ul><ul><li>Each port can use full 10/100/1000 Mbps. </li></ul>11
    40. 41. Switches
    41. 42. Switches
    42. 43. Switches
    43. 44. Figure 6-4 Implementation Scenarios for Switched LAN Architectures
    44. 45. Figure 6-4a Implementation Scenarios for Switched LAN Architectures: Stand-Alone Workgroup
    45. 46. Switches <ul><li>Selection Issues: </li></ul><ul><li>Need for 10 Mbps, 100 Mbps, or 1 Gbps on media. </li></ul><ul><li>Need for trunking and internet-switch links </li></ul><ul><li>Workgroup segmentation (VLAns) </li></ul><ul><li>Port Density needs: 12, 16, 24 ports. </li></ul><ul><li>Different User Interfaces. </li></ul>
    46. 47. Type of Switches <ul><li>Store and Forward Switches </li></ul><ul><li>Cut Through Switches </li></ul><ul><li>Symetric Switches </li></ul><ul><li>Asymetric Swicthes </li></ul>
    47. 48. Routers <ul><li>Layer 3 (Network Layer) device </li></ul><ul><li>Connect networks with multiple paths between network segments (subnets) </li></ul><ul><li>Make decisions based on the network address. </li></ul><ul><li>Network segment – Network address </li></ul><ul><li>Connect different layer 2 technologies (ethernet, Token Ring, FDDI, etc.) </li></ul><ul><li>Have become the backbone for the Internet, running the IP protocol. </li></ul>
    48. 49. Routers <ul><li>Its purpose is to: </li></ul><ul><ul><li>examine incoming messages (layer 3 data), </li></ul></ul><ul><ul><li>choose the best path for them through the network, and </li></ul></ul><ul><ul><li>switch them to the proper outgoing port. </li></ul></ul><ul><li>They don’t allow bad data or broadcast storm to be passed on the network </li></ul><ul><li>They can connect networks using the same protocol but different network architecture. </li></ul>
    49. 50. Routers Figure 11-7 11
    50. 51. Routers vs Bridges
    51. 52. Segmentation <ul><li>Collision Domains </li></ul><ul><li>Broadcast Domains </li></ul><ul><li>Segmentation with Bridges </li></ul><ul><li>Segmentation with Switches </li></ul><ul><li>Segmentation with Routers </li></ul>
    52. 54. Phase 1: The Traditional Routed Network Traditional LAN routers that segment the network will not be able to keep up with the performance as network communications demands grow.
    53. 55. Phase 2: Switched Networks <ul><li>The standard switched network provides a fast, simple and cost-effective alternative, but …. </li></ul><ul><li>are becoming harder to control and ……. </li></ul><ul><li>vulnerable to broadcast storms and redundant traffic. </li></ul>
    54. 57. Phase 3: The Layer 3 Solution <ul><li>By integrating router functionality into the silicon within a switch, Layer 3 Switching offers high-speed LAN routing in affordable solution. </li></ul>
    55. 58.                                                                                                                                                                                                   
    56. 59.                                                                                                                                                                                                           
    57. 60. Clouds <ul><li>Its symbol suggests another network or perhaps the entire Internet. </li></ul><ul><li>It represents a collection of devices that operate at all levels of the OSI model. </li></ul>
    58. 61. Network Segments <ul><li>Different definitions </li></ul><ul><li>Its correct definition depend on the situation in which is used. </li></ul><ul><li>A segment identifies the Layer 1 media that is the common path for data transmission. </li></ul><ul><ul><li>There is a maximum length for each media transmission (Coaxial, UTP, Fiber Optic) </li></ul></ul><ul><li>A definition used by Cisco: </li></ul><ul><ul><li>A segment is a collision domain. </li></ul></ul><ul><li>Other definition: </li></ul><ul><ul><li>A segment is the Packet Data Unit at the transport layer. </li></ul></ul>
    59. 62. Evolution of Network Devices <ul><li>1940’s – Huge computers – Electromechanical devices. </li></ul><ul><li>1947 – The invention of semiconductor – Smaller and more reliable computers </li></ul><ul><li>1950’s – Mainframes – Punched-card programs – Large institutions </li></ul><ul><li>Late of 1950’s – Integrated Circuit was invented – Millions of transistors on one small piece of semiconductor. </li></ul><ul><li>1960’s Mainframes with terminals – Commonplace </li></ul><ul><li>1960s and 1970s – Smaller computers – middle range computers – came into existence. </li></ul><ul><li>1978 – Apple computer introduced – Personal Computer </li></ul><ul><li>1981 – IBM – Introduced the open-architecture personal computer </li></ul>
    60. 63. Encapsulation Process <ul><li>Top three layers prepare data for transmission by creating a common format for transmission </li></ul><ul><li>Transport layer – Segments, Sequence Number </li></ul><ul><li>Network layer – Encapsulates the segment creating a data packet or datagram adding headers about source and destination network. </li></ul><ul><li>Data Link encapsulates datgrams into frames and transmit bits to physical layer media </li></ul><ul><li>Physical layer media - signals </li></ul>
    61. 64. Network Devices <ul><li>Physical Layer Devices (Work with bits) </li></ul><ul><ul><li>Passive: Plugs, connectors, jacks, patch panels, physical media. </li></ul></ul><ul><ul><li>Active: </li></ul></ul><ul><ul><ul><li>Repeaters and hubs </li></ul></ul></ul><ul><ul><ul><li>Transceivers </li></ul></ul></ul><ul><ul><ul><ul><li>Connector adapters: RJ45- AUI port </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Media converters: RJ-45 – ST Optical) </li></ul></ul></ul></ul><ul><li>Data Link Layer Devices: NIC, Bridges, Switches </li></ul><ul><li>Network Layer Devices: </li></ul><ul><ul><li>Layer 1: Bits from the media to the router interface </li></ul></ul><ul><ul><li>Layer 2: Frames Switched from one Interface to another </li></ul></ul><ul><ul><li>Layer 3: Routing decisions </li></ul></ul>
    62. 65. Summary <ul><li>LAN devices: Routers, Switches and Hubs </li></ul><ul><li>Evolution of networking devices </li></ul><ul><li>Basics of Data Flow </li></ul><ul><li>Basics related to build networks. </li></ul>
    63. 66. Voice, DSL, Cable Modem, and Optical Devices <ul><li>Demand of new devices due to integration of voice and data networks </li></ul><ul><ul><li>Fast Data Transmission </li></ul></ul><ul><ul><li>Network Backbones </li></ul></ul><ul><li>Voice Gateways </li></ul><ul><ul><li>Handling converged packetized voice and data traffic. </li></ul></ul><ul><ul><li>Convert information from one protocol stack to another. </li></ul></ul>
    64. 67. <ul><li>Digital Subscriber Line Access Multiplexer (DSLAM) </li></ul><ul><ul><li>Used at ISP central office for concentrating DSL modem connections from hundreds of homes. </li></ul></ul><ul><li>Cable Modem Termination System (CMTS) </li></ul><ul><ul><li>Used at cable operator’s headend or central location to concentrate connections from many cable subscribers. </li></ul></ul><ul><li>Optical Platforms </li></ul><ul><ul><li>For sending and receiving data over fiber-optic cable, providing high-speed connections </li></ul></ul>
    65. 68. Security Devices <ul><li>Increased Internet and extranet connections </li></ul><ul><li>More telecommuters </li></ul><ul><li>Mobile users </li></ul><ul><li>Security Devices: </li></ul><ul><ul><li>Firewalls: </li></ul></ul><ul><ul><ul><li>Software or Hardware </li></ul></ul></ul><ul><ul><ul><li>Only valid traffic can enter or leave the network </li></ul></ul></ul><ul><ul><li>AAA Servers </li></ul></ul><ul><ul><ul><li>Authentication, Authorization, and Accounting Servers </li></ul></ul></ul><ul><ul><li>VPN Concentrators </li></ul></ul><ul><ul><ul><li>Remote access and site-to site VPN capablities </li></ul></ul></ul>
    66. 69. Wireless Devices <ul><li>Wireless NICs </li></ul><ul><ul><li>Provide wireless connectivity </li></ul></ul><ul><ul><li>PCMCIA and PCI cards to provide </li></ul></ul><ul><li>Wireless Access Points </li></ul><ul><ul><li>It is a wireless LAN tranceiver </li></ul></ul><ul><ul><li>Acts as a hub or as a bridge </li></ul></ul><ul><ul><li>Multiple Access Points – Roaming Functionality </li></ul></ul><ul><li>Wireless Bridges </li></ul><ul><ul><li>Provide long-range connectivity – 25 miles </li></ul></ul><ul><ul><li>Line of sight wireless </li></ul></ul>
    67. 70. Wireless LAN Topology
    68. 71. Wireless Bridges Extended LAN (ELAN)

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