Transcript Network Components

Two Network Types Defined by
DISTANCE
LAN
WAN
NETWORKS
LAN
LOCAL AREA NETWORK
LAN
Ethernet
A particular type of LAN
Network Components (LAN)
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Workstations
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microcomputers
minicomputers
workstations
mainframes
terminals
supercomputers
Servers (optional)
Media
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Interfaces
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Gateways
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circuit boards
network adapter
NIC – network
interface card
connect dissimilar parts of
a network
Bridges
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connect similar parts of a
network
Media - cables
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Twisted pair
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inexpensive
least reliable
easiest to install
what is used in telephone lines
slow
Media - cables
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Coaxial
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more reliable
what is used in cable TV
harder to install
faster
Media - cables
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Fiber optic
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works with light waves (lasers)
most reliable
most expensive
fastest
most difficult to work with
becoming the media of choice
TOPOLOGIES
Physical design of a network
Three LAN topologies:
 BUS
 STAR
 RING
Bus
Single cable
Easy to install
No server
Ring
Single connected cable
Break does not destroy all the connections
Usually does not have a server
Star
Individual cables
Easiest to trouble shoot
Has a server
Network Protocols
rules for communicating
Specifies type of topology
handshake
synchronous/asynchronous transmission
how data will be packaged
3 Protocol Classifications

Polling
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CSMA/CD

Token ring
Polling
 Goes to each workstation in turn
 Assures that all work stations will access
 Problem if there are many workstations
CSMA/CD
 Carrier sense multiple access with
collision detection
 Workstations try to seize the network
when they want to access
 Problem if two workstations want to
access at the same time
Token Ring
 Token - electronic device
 Token circulates around network
 Token is either free or has a message
 If it has a message, goes to the receiver
and back to sender before continuing
Network Software
Operating system of the
network
Resides on server
Controls file transfers
Controls hardware sharing
Controls uploading/downloading of files
May include:
– electronic mail
– performance analyzation software
– security software
– diagnostic routines
LAN
Ethernet
Most widely used type of LAN
Characteristics
• Coax cable
– High volume of
transmission for short
distances
Characteristics
• Special hardware
– Transceiver – connects
nodes to network
– Interface – performs
data conversions from a
byte to a series of bits
– Repeater – strengthens
and retimes the signals
Characteristics
• Uses CSMA/CD
– Controller – determines
when to activate
communications
between nodes