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1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
Ways to connect a LAN
Using IP and MAC addresses
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
Ways to connect a LAN
Using IP and MAC addresses
Cambridge Technicals IT
1 Fundamentals of IT
2
2
Types of Network
Types of LAN
WAN
LAN
Client/Server
Peer to Peer
Bus
4
Ways to connect LAN
Ring
Mesh
Star
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
Ways to connect a LAN
Using IP and MAC addresses
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
There are two basic ways to
organise a local area network…
Client/server
‘centralised’
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Peer to Peer
‘decentralised’
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN Client/server
Client
Server
‘centralised’
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN Client/server
Advantages
• Security – Can be
managed by server e.g.
control access to files
• Back-ups – Can be
done for data on all
clients by server
• Upgrades - As demand
grows, can improve
server
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Disadvantages
• Cost – Must buy server
and pay extra for high
performance hardware
• Cabling – Extra needed
to connect each client
• Staff – Need technicians
to set-up & run server
• Dependence – If server
crashes, then whole
network fails
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN Peer to Peer
‘Workstations’
Peer = equals
‘decentralised’
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1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN Peer to Peer
Advantages
• Decentralised – Keeps
running even if one
workstation crashes
• Low cost – No need to
buy a central server
and employ IT staff
• Sharing - Workstations
can store & share files
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Disadvantages
• Security – No central
logon control & users
can delete ‘shared’ files
• Recovery – No central
backups so data can
be lost
• Upgrades – Each
machine must be
upgraded separately
1 Fundamentals of IT
3.3
Types of LAN Comparison
Peer to Peer
• Good for smaller networks, such as for
a business with around 10 employees
• Good for sharing files, where security is
not a major concern
Client/Server
• Good for larger networks, where cost of
server is worth the extra performance
• Good for central control, such as
managing logons or access to files
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
Ways to connect a LAN
Using IP and MAC addresses
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Ways to Connect a LAN
• Means how devices are actually
connected on a network
• Four options!
• Key factors for choice include
cost and scale
• Know basic types plus
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1 Fundamentals of IT
3.3 Networking Characteristics
‘Classic’ LAN Topologies
Bus
Ring
Mesh
Star
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1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Bus
Terminator
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‘Backbone’
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Bus
Terminator
‘Backbone’
Data Collision
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Data sent simultaneously from
different computers but cable
can’t carry but signals at once
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Bus
Advantages
• Installation - simpler
and cheaper since
needs less cabling
• Reliable – if one
workstation fails, rest
of network still works
• Expansion – easy to
add extra workstations
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Disadvantages
• Backbone – If main cable
fails, network fails
• Performance - As more
workstations connected,
more data collisions
slows performance
• Security – Very weak as
all workstations receive
all data
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Ring
Take turns
Devices take
turns to
transmit
data
One Direction
All data
travels
same way
to reduce
collisions
Closed ‘loop’
of cabling
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1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Ring
Advantages
• Transfer speed – Good
because no ‘collisions’
since data only flows in
one direction
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Disadvantages
• Ring route – data
must travel through all
workstations to reach
destination machine
• Broken links – If one
workstation fails, then
network affected
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Mesh
Individual links
Each device
connected
to all others
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1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Mesh
Individual links
Each
device
connected
to all others
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Wireless mesh
Give all
benefits
and
saves
cabling
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Mesh
Advantages
• Wireless – works well
with no cable
• Reliable – if one
workstation fails, rest
of network still works
• Direct links – No need
for routing since all
workstations linked
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Disadvantages
• Cable – Set-up is costly
if actually ‘wired’
• Maintenance – Hard
because so many links
• Expansion - tricky since
‘old’ workstations also
need new connections
adding
1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Star
Central links
Central control
? Switch
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1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Star
File Server
Local Area Network (LAN)
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1 Fundamentals of IT
3.3 Networking Characteristics
LAN Topologies Star
Advantages
• Reliable – if a cable
or device fails, rest of
network is fine
• Expansion – Adding
extra machines won’t
disrupt others
• Control – Can
monitor network
using central hardware
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Disadvantages
• Cost – Need to buy
central hardware, such
as switch
• Dependence - if central
hardware fails, then
network fails!
1 Fundamentals of IT
3.3 Networking Characteristics
Types of LAN
Ways to connect a LAN
Using IP and MAC addresses
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing
Internet Public
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LAN
Private
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing
Internet Public
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LAN
Private
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing Internet Public
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1 Fundamentals of IT
3.3 Networking Characteristics
Addressing Internet Public
0100
1000
DNS Server
185.67.45.176
Data Centre
We humans
use web addresses or URLs
A
But that gets translated into an IP address
It’sCambridge
done Technicals
behindIT the scenes by DNS servers
B
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing Inside a Packet
Footer
‘Payload’
Header
Destination
IP address
Actual data
Sender
IP address
e.g. few hundred bytes
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1 Fundamentals of IT
3.3 Networking Characteristics
Summary
Internet Public
• The ‘public’ internet
uses IP addresses
• We use URLs that are
converted into IP
addresses by DNS
• Packets then labelled
with IP address for
sender & destination
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1 Fundamentals of IT
3.3 Networking Characteristics
Addressing
Internet Public
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LAN
Private
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing LAN Private
• ‘Private’ LANs
also need a
unique ID or
address for each
device
• This is called a
MAC address…
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1 Fundamentals of IT
3.3 Networking Characteristics
Addressing LAN Private
File Server
Local Area Network (LAN)
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing LAN Private
MAC address and NIC
The MAC address is ‘burned in’
permanently to every device
Devices usually have a Network
Interface Card (NIC)
So switches use MAC addresses to
send packets to right device
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing
Mac Address
All your wireless gadgets also have
a MAC address as a unique ‘ID’
That’s done via chipset, not a NIC
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Addressing Summary
‘Public’ Internet
• Uses IP addresses as unique IDs as
labels for packets to show destination
• We use URLs as web address but they’re
translated to IP addresses by DNS servers
‘Private’ LANs
• Use MAC addresses that are burned into
all devices & work on wired/wireless links
• Switches & routers can use MAC address
to send data packets to the correct device
Cambridge Technicals IT
1 Fundamentals of IT
3.3 Networking Characteristics
Cambridge Technicals IT