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LAN Connectivity Devices

Connectivity Devices. Objectives:Basic LAN devicesThe Evolution of Network Devices:Network Devices that operate at each layer.Basics of Data Flow Through LANs (Encapsulation Process)How to Build a LAN. Local-Area Networks. Introduction:Understanding of:the OSI ModelWhat happens to the p

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LAN Connectivity Devices

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    1. Chapter 05 LAN Connectivity Devices

    2. Connectivity Devices Objectives: Basic LAN devices The Evolution of Network Devices: Network Devices that operate at each layer. Basics of Data Flow Through LANs (Encapsulation Process) How to Build a LAN

    3. Local-Area Networks Introduction: Understanding of: the OSI Model What happens to the packets as they travel through the layers. LANs Devices

    4. Network Devices As Organizations grow, so do their networks Growth in number of users Geographical Growth Network Devices : Are products used to expand or connect networks. Can control the amount of traffic on a network. Can speed up the flow of data over a network.

    5. Networking Devices Device: Equipment that connects directly to a network segment. End user devices or hosts Hosts are devices that connect directly to a network segment. It includes: Computers (Client / Servers), Printers, Scanners, etc. Network Devices: Include all devices that connect the end-user devices to allow them communicate.

    6. End-user devices or Hosts Allows users to share, create and obtain information Can exist without a network Are physically connected to the network media using a Network Interface Card.

    7. Network Interface Card (NIC) Physical link between machine & network Connection between machine & medium The NIC controls the host’s access to the medium. Translates parallel signals produced by the computer into serial format that is sent over the network. The MAC address is hard coded onto the NIC.

    8. Network Interface Card - NIC Transceiver: Send and receive signals Convert one type of signal (or connector) into another. Internal and / or External Layer 1 device. It looks only at bits and not at any address information or higher level protocols

    10. Network Interface Card

    11. From Parallel to Serial, and Vice Versa

    12. Selecting a Network Card Consider the following factors Network Architecture or LAN Technology: Ethernet, Token Ring, FDDI, etc. Type of Media: Thinnet or 10Base2, Thicknet or 10Base5, 10BaseT, Fiber Optic) Data Transfer Speed Type of System Bus: ISA, EISA, Microchanel, PCI, PCIMCA) Some NICs connect through SCSI bus Some NICs use USB Integrated on the Motherboard

    13. An Ethernet NIC

    14. Type of System Bus ISA (Industrial Standard Architecture) EISA (Enhanced ISA) MCA (Micro Channel Architecture) PCI (Peripheral Component Interconnect)

    15. Primary Bus Architectures

    16. Network Devices Provide transport for the data that needs to be transferred between end-user devices. Extend cable connections Concentrate connections Convert Data Formats Manage data transfer

    17. Connectivity Devices Each topology and network architecture has its limits. Beyond a point networks networks can not be expanded by simple adding more servers or cabling Connectivity devices are the basic building blocks of network expansion

    18. Connectivity Devices Are used to connect separate segments of the network or inter-network A segment is a portion of the network transmission media that is assigned a network address.

    19. Creating Larger Networks Physically expand the network Segment network to filter traffic Extend network to connect separate LANs Connect two separate computer environments

    20. Devices to Expand the Network Repeaters Bridges Switches Routers Gateway

    21. Network Connectivity Devices Repeaters Hubs Bridges Switches

    22. Internetwork Connectivity Devices Routers Gateways

    23. Repeaters A repeater can be used to increase the length of your network by eliminating the effect of attenuation on the signal. It connects two segments of the same network, overcoming the distance limitations of the transmission media. Some repeaters also serve as transmission media adapters, connecting two different types of media.

    24. Repeaters Repeaters can connect segments that have the same access method. (CSMA/CD, Token Passing, Polling, etc.) Disadvantages Repeaters do not filter data Its use is inappropriate when there is a heavy network traffic.

    25. Repeaters Figure 11-5

    26. Repeaters Figure11-6

    27. Hubs A hub is used as a central point of connection among media segments. Cables from network devices plug in to the ports on the hub. Hubs are referred as Concentrators or multi-port repeater Hubs receive signals from connected devices and transmit them to the other connected devices

    28. Hubs Regenerate and repeat signals Propagate signals through the network Can not filter network traffic Can not determine the best path Are used as network concentration points.

    29. Hubs

    30. Hubs

    31. Hubs

    32. Figure 6-3a Shared Media LAN Architecture

    33. Types of Hubs Passive Hubs Active Hubs Intelligent Hubs (Switches)

    34. Passive Hub It functions only as a connection point for the signals The signal pass through a passive hub without regeneration or amplification.

    35. Active Hub It regenerates or amplifies the signal before they are retransmitted. Drawback: The noise is also regenerated

    36. Bridges Layer 2 (Data Link Layer) device. Divide a network into segments and filter traffic. Each segment is a collision domain. Limit or filter traffic keeping local traffic local yet allow connectivity to other parts (segments) Make decision based on the MAC address list Connect different architectures and Forward packets between architectures: Ethernet & Token-Ring.

    37. Bridges

    38. Bridges Read network addresses at the MAC (Media Access Control) sub-layer Decide which segment address is on Decide whether or not to forward packet Drawback: Broadcast packages are passed across bridges.

    39. Bridges

    40. Switches A high speed multiport bridge Replacing repeaters & hubs in UTP Switches maintains a switching table Dedicated bandwidth to each port, making data transmission more efficient. Each port can use full 10/100/1000 Mbps.

    41. Switches

    42. Switches

    43. Switches

    44. Figure 6-4 Implementation Scenarios for Switched LAN Architectures

    45. Figure 6-4a Implementation Scenarios for Switched LAN Architectures: Stand-Alone Workgroup

    46. Switches Selection Issues: Need for 10 Mbps, 100 Mbps, or 1 Gbps on media. Need for trunking and internet-switch links Workgroup segmentation (VLAns) Port Density needs: 12, 16, 24 ports. Different User Interfaces.

    47. Type of Switches Store and Forward Switches Cut Through Switches Symetric Switches Asymetric Swicthes

    48. Routers Layer 3 (Network Layer) device Connect networks with multiple paths between network segments (subnets) Make decisions based on the network address. Network segment – Network address Connect different layer 2 technologies (ethernet, Token Ring, FDDI, etc.) Have become the backbone for the Internet, running the IP protocol.

    49. Routers Its purpose is to: examine incoming messages (layer 3 data), choose the best path for them through the network, and switch them to the proper outgoing port. They don’t allow bad data or broadcast storm to be passed on the network They can connect networks using the same protocol but different network architecture.

    50. Routers Figure 11-7

    51. Routers vs Bridges

    52. Segmentation Collision Domains Broadcast Domains Segmentation with Bridges Segmentation with Switches Segmentation with Routers

    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.

    55. Phase 2: Switched Networks The standard switched network provides a fast, simple and cost-effective alternative, but …. are becoming harder to control and ……. vulnerable to broadcast storms and redundant traffic.

    57. Phase 3: The Layer 3 Solution By integrating router functionality into the silicon within a switch, Layer 3 Switching offers high-speed LAN routing in affordable solution.

    60. Clouds Its symbol suggests another network or perhaps the entire Internet. It represents a collection of devices that operate at all levels of the OSI model.

    61. Network Segments Different definitions Its correct definition depend on the situation in which is used. A segment identifies the Layer 1 media that is the common path for data transmission. There is a maximum length for each media transmission (Coaxial, UTP, Fiber Optic) A definition used by Cisco: A segment is a collision domain. Other definition: A segment is the Packet Data Unit at the transport layer.

    62. Evolution of Network Devices 1940’s – Huge computers – Electromechanical devices. 1947 – The invention of semiconductor – Smaller and more reliable computers 1950’s – Mainframes – Punched-card programs – Large institutions Late of 1950’s – Integrated Circuit was invented – Millions of transistors on one small piece of semiconductor. 1960’s Mainframes with terminals – Commonplace 1960s and 1970s – Smaller computers – middle range computers – came into existence. 1978 – Apple computer introduced – Personal Computer 1981 – IBM – Introduced the open-architecture personal computer

    63. Encapsulation Process Top three layers prepare data for transmission by creating a common format for transmission Transport layer – Segments, Sequence Number Network layer – Encapsulates the segment creating a data packet or datagram adding headers about source and destination network. Data Link encapsulates datgrams into frames and transmit bits to physical layer media Physical layer media - signals

    64. Network Devices Physical Layer Devices (Work with bits) Passive: Plugs, connectors, jacks, patch panels, physical media. Active: Repeaters and hubs Transceivers Connector adapters: RJ45- AUI port Media converters: RJ-45 – ST Optical) Data Link Layer Devices: NIC, Bridges, Switches Network Layer Devices: Layer 1: Bits from the media to the router interface Layer 2: Frames Switched from one Interface to another Layer 3: Routing decisions

    65. Summary LAN devices: Routers, Switches and Hubs Evolution of networking devices Basics of Data Flow Basics related to build networks.

    66. Voice, DSL, Cable Modem, and Optical Devices Demand of new devices due to integration of voice and data networks Fast Data Transmission Network Backbones Voice Gateways Handling converged packetized voice and data traffic. Convert information from one protocol stack to another.

    67. Digital Subscriber Line Access Multiplexer (DSLAM) Used at ISP central office for concentrating DSL modem connections from hundreds of homes. Cable Modem Termination System (CMTS) Used at cable operator’s headend or central location to concentrate connections from many cable subscribers. Optical Platforms For sending and receiving data over fiber-optic cable, providing high-speed connections

    68. Security Devices Increased Internet and extranet connections More telecommuters Mobile users Security Devices: Firewalls: Software or Hardware Only valid traffic can enter or leave the network AAA Servers Authentication, Authorization, and Accounting Servers VPN Concentrators Remote access and site-to site VPN capablities

    69. Wireless Devices Wireless NICs Provide wireless connectivity PCMCIA and PCI cards to provide Wireless Access Points It is a wireless LAN tranceiver Acts as a hub or as a bridge Multiple Access Points – Roaming Functionality Wireless Bridges Provide long-range connectivity – 25 miles Line of sight wireless

    70. Wireless LAN Topology

    71. Wireless Bridges Extended LAN (ELAN)

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