Transcript Local-Area Networks

Local-Area Networks
Topology
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Defines the Structure of the Network
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Physical topology – actual layout of the wire
(media)
Logical topology – defines how the media is
accessed by the hosts
Physical Topology
LAN Devices in a Topology
Network Interface Cards (NICs)
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When Selecting a NIC, Consider the Following:
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Network architecture
Operating system
Media type
Data transfer speed
Available bus types
NICs
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Bus Architectures
 ISA (Industry
Standard Architecture)
 EISA (Extended ISA)
 PCI (Peripheral Component Interconnect)
 MCA (Micro Channel Architecture)
 PCMCIA (Personal Computer Memory Card
International Association)
NICs in the OSI Model
Media
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The basic function of media is to carry a flow
of information, in the form of bits.
Layer 1 components.
Repeaters: Layer 1
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.
Hubs: Layer 1
Hubs
• Regenerate and
repeat signals
• Used as
network
concentration
points
• Multiport
repeater
Bridges: Layer 2
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
Switches: Layer 2
LAN Switches
Combine the
connectivity of
a hub with the
traffic
regulation of a
bridge on each
port
Switches
Routers: Layer 3
Routers
• Two primary
purposes: path
selection, and
switching of
packets to the
best route
• Use logical
addresses
(network layer
addresses)
Network Cloud
Layer 1
through 7
device
Network Segments
Connected
by
networking
devices
Devices / Function / Layers
Data Flow Through LANs