Local-Area Networks

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Local-Area Networks
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Topology

• Defines the Structure of the Network
• Physical topology actual layout of the wire
  (media)
• Logical topology defines how the media is
  accessed by the hosts

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Physical Topology
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LAN Devices in a Topology
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Network Interface Cards (NICs)

• When Selecting a NIC, Consider the Following
• Network architecture
• Operating system
• Media type
• Data transfer speed
• Available bus types

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NICs

• Bus Architectures
• ISA (Industry Standard Architecture)
• EISA (Extended ISA)
• PCI (Peripheral Component Interconnect)
• MCA (Micro Channel Architecture)
• PCMCIA (Personal Computer Memory Card
  International Association)

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NICs in the OSI Model
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Media

• The basic function of media is to carry a flow of
  information, in the form of bits.
• Layer 1 components.

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Repeaters Layer 1
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Repeaters
A repeater solves the problem of too many nodes
and not enough cable cleans, amplifies, and
resends a signal that is weakened by long cable
length.
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Hubs Layer 1
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Hubs

• Regenerate and repeat signals
• Used as network concentration points
• Multiport repeater

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Bridges Layer 2
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Bridges
Bridges filter traffic by looking at MAC
addresses.
Designed to create two or more LAN segments, each
of which is a separate collision domain
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Switches Layer 2
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LAN Switches
Combine the connectivity of a hub with the
traffic regulation of a bridge on each port
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Switches
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Routers Layer 3
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Routers

• Two primary purposes path selection, and
  switching of packets to the best route
• Use logical addresses (network layer addresses)

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Network Cloud
Layer 1 through 7 device
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Network Segments
Connected by networking devices
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Devices / Function / Layers
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Data Flow Through LANs