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CH03_NET+ by shitingting

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Chapter 3

NETWORK
CONNECTION
HARDWARE
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NETWORK INTERFACE ADAPTER

   Provides the link between a computer and the
    network
   Requires a device driver to perform both data-link
    and physical layer functions
   Plugs into a bus slot or universal serial bus (USB)
    port on a computer
   Also referred to as a network interface card (NIC)
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A NETWORK INTERFACE ADAPTER
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TRANSMISSION FUNCTIONS

 Network interface adapters perform the following
  functions during data transmission:
   Data transfer, buffering, and encapsulation
   Media Access Control (MAC)
   Parallel/ serial conversion
   Signal encoding and amplification
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NETWORK INTERFACE ADAPTER FEATURES

 Multiple duplex modes and autonegotiation of
  modes
 Processor offloading features
   Bus mastering
   Checksum processing
   Transmission Control Protocol (TCP) segmentation
   IP Security (IPSec) processing
 Network management
 Wake on LAN
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HALF-DUPLEX AND FULL-DUPLEX MODES
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SELECTION CRITERIA

 When selecting network interface adapters, you must
  consider the following:
    The data-link layer protocol being implemented and the specific
     standard
    The transmission speed requirements for the local area network
     (LAN)
    The specific cabling and connector types that will be used
    Each computer’s bus architecture and resource availability
    Network interface driver availability
    The operating system type
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INSTALLING A NETWORK INTERFACE
ADAPTER IN A COMPUTER        NIC Installation
To install a network interface adapter:
1. Physically insert the network interface adapter
  card into the slot.
2. Configure the card to use the appropriate hardware
  resources.
3. Install the card’s device driver.
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A NETWORK INTERFACE ADAPTER IN A
COMPUTER
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CONFIGURING A NETWORK INTERFACE
ADAPTER
 Network interface adapters that do not support plug
  and play (PnP) must be manually configured for
  some or all of the following hardware resources:
   Interrupt request (IRQ)
   I/O
   Memory address
   Direct memory access (DMA) channel
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NETWORK INTERFACE ADAPTER DEVICE
DRIVERS
 Network interfaces require a device driver to provide
  the link between the computer and the interface.
 Operating systems ship with device drivers for
  common interfaces.
 Operating systems that support PnP detect and
  configure the interface automatically.
 You can get drivers from the manufacturer’s Web
  site.
 The driver configuration must match the interface’s
  resource settings.
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TROUBLESHOOTING A NETWORK INTERFACE
ADAPTER
 To troubleshoot the suspect network interface
  adapter, open the computer case and do the
  following:
   Verify that the interface is seated properly in the bus
    slot.
   Remove the card, clean the slot, and then reseat the
    card in the same slot or try another slot.
   Test a different interface (known to be functional) in
    the same slot and in a different slot
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PHYSICAL, DATA-LINK, AND NETWORK LAYER
HARDWARE
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HUBS, REPEATERS, AND CONCENTRATORS

 Hubs, repeaters, and concentrators are all physical
  layer devices that
    Amplify and repeat signals
    Extend the distance of a network
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THICK ETHERNET REPEATERS

 Thick Ethernet repeaters extend the distance of a
  bus network.
 The maximum segment length is 500 meters.
 The maximum network distance is 2500 meters.
 You must observe the 5-4-3 rule.
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THIN ETHERNET REPEATERS

 Thin Ethernet repeaters extend the distance of a bus
  network.
 The maximum segment length is 185 meters.
 The maximum network distance is 925 meters.
 You must observe the 5-4-3 rule.
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AN ETHERNET REPEATER
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10BASE-T AND 100BASE-X HUBS

 10Base-T and 100Base-TX/100Base-T4 standards define
  Ethernet networks that function at 10 Mbps and 100 Mbps,
  using baseband signaling over twisted-pair wire.
 10Base-T
    Maximum distance limitation for each connection: 100 meters,
     including workstation-to-hub and hub-to-hub connections
    Can have up to four hubs connected to form a hierarchical star
    Includes an internal crossover circuit
    Uses an uplink port to form a hierarchical star
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10BASE-T AND 100BASE-X HUBS (CONT.)

 100Base-TX and 100Base-T4
   There are two types of hubs: Class I and Class II.
   The maximum distance for each node connection is
    100 meters.
   Class II hub-to-hub connections can be no more than
    5 meters long.
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                                                    Play Video
HUB CONNECTIONS
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10BASE-T HUB
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BRIDGES AND SWITCHES

 Are data-link layer devices that use destination
  addresses to forward frames
 Are protocol independent
 Do not filter broadcast packets
 Do not define separate networks
 Two forwarding modes in switches: cut-through and
  store-and-forward
 One forwarding mode in bridges: store-and-forward
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                                                          Hubs & Switches
CUT-THROUGH SWITCHING

 The cut-through method is the fastest way to
  forward frames.
   Looks at only the first 6 bytes (destination MAC
    address) before forwarding
   Does not perform cyclical redundancy check (CRC) on
    the frame contents
   Does not define separate collision domains
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STORE-AND-FORWARD SWITCHING

 Store-and-forward switching is slower but more
  reliable than the cut-through method of forwarding
  frames.
 Store-and-forward switching pulls in the entire
  frame and performs a CRC check on the frame
  contents.
 Each port defines a separate collision domain.
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TRANSPARENT BRIDGING AND SWITCHING

Perform three basic functions:
 Flood
    Frames with unidentified destination addresses are transmitted
     out all ports except the one they were received through.
 Learn
    Switches use the source addresses within frames to learn which
     devices use specific ports, and then they use this information to
     build their internal address tables.
 Forward
    Frames are selectively forwarded to a port using known
     destination addresses stored in the MAC address table.
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FLOODING AND LEARNING
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FORWARDING
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OTHER BRIDGING TECHNOLOGIES

 Source route bridging
    Source route bridging is used in Token Ring networks.
    The source host determines the path through the network, not
     the bridge.
    Bridges add path information when frames are forwarded and
     use this information to continue to forward frames between
     source and destination hosts.
 Translation bridging
    Translation bridging is used to connect dissimilar data-link
     architectures.
 Remote bridge
    A remote bridge connects two segments across a wide area
     network (WAN) link.
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OTHER DATA-LINK LAYER TECHNOLOGIES

 Spanning tree protocol
   Used to avoid bridging loops
   Ensures a single active path to all segments within a
    LAN
 Virtual LANs (VLANs)
   Are logical LANs defined on switches
 Layer 3 switches
   Have built-in routing capabilities
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SPANNING TREE
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VLANS
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                                                     Bridges & Routers
ROUTERS

Routers are network layer devices that connect LANs.
 Connect similar or different data-link layer LANs
 Must understand and support the network layer protocol and
  addressing
 Perform fragmentation
 Strip the data-link header and footer off received frames
 Add a new data-link header and footer before transmitting
  frames
 Use routing protocols to build routing tables and forward
  frames
 Define separate broadcast domains
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A SIMPLE ROUTED NETWORK
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A ROUTED INTERNETWORK
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GATEWAYS

 Can include the functions of all seven layers of the
  OSI model
 Connect dissimilar systems and protocols
 Perform translation and conversion services
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SUMMARY
   Network interface adapters provide the physical link between computers
    and the network.
   Hubs are physical layer devices that amplify and repeat signals out all
    ports except the one they were received through.
   Bridges and switches are data-link layer devices that use destination
    addresses to forward frames.
   Spanning tree is used by bridges and switches to avoid loops.
   VLANs are logical LANs used to group computers within a switched
    network.
   Routers are network layer devices that forward datagrams between
    LANs.
   Gateways translate and convert protocols between dissimilar systems.

								
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