3. LAN (Local Area Networks)
A LAN is a computer network that covers a small area (home, office,
building, campus)
o a few kilometers
LANs have higher data rates (10Mbps to 10Gbps) as compared to
WANs
LANs (usually) do not involve leased lines; cabling and equipments belong
to the LAN owner.
A LAN consists of
o Shared transmission medium
• now so valid today due to switched LANs
o regulations for orderly access to the medium
o set of hardware and software for the interfacing devices
4. WORKING OF LAN
LAN usually broadcast their message to all hosts on
that LAN.
This hosts shares a single transmission media.
This broadcast network can be a static or dynamic
method.
In this static method each host is given a fixed time
slides to send the information. This is the most popular
method used.
5. In the dynamic method a host can send a frame any time.
If the two hosts send a frame at the same time the two
frames could collide with each other.
Dynamic method can be further sub-divided in 2
categories:
1. Centralized
a. Carrier Sensing
b. Token Passing
2. Decentralized: Protocols are used to implement media
access control.
6. LAN Protocol Architecture
Corresponds to lower two layers of OSI model
o But mostly LANs do not follow OSI model
Current LANs are most likely to be based on Ethernet protocols developed
by IEEE 802 committee
IEEE 802 reference model
o Logical link control (LLC)
o Media access control (MAC)
o Physical
8. LAN Interconnection
Traditional LAN interconnection devices
Repeater – it operates at OSI layer 1 and transmits data bits over a physical
medium.
Bridge – it operates at OSI layer 2 and is commonly used to connect similar
LAN segments.
Switch – it operates at OSI layer 2 or layer 3 and is used to interconnect
multiple similar or dissimilar LANs.
Router – it operates at OSI layer 3. A router is used to interconnect individual
networks whose sizes vary from very small to very large. Routers may be
categorized into backbone router (or core router), border router and access
router depending on their role in the network.
11. Advantages
Long Distances Possible
10 Base-5 allows distances up to 500 meters (1650 feet). This
makes it very useful as a "backbone" technology for wiring
together multiple locations within a building without the use of
repeaters
Noise Immunity
Since 10 Base-5 uses a very heavily shielded cable, it can be used
in electrically noisy environments which can cause other network
types to fail.
Conceptually Simple
Since all devices on a 10 Base-5 network are simply chained
together on a common coaxial cable, it is a simple matter to plan
the routing of the cable
12. Disadvantages
Inflexible
10 Base-5 networks do not lend themselves well to installations
where the setup of the network will change much after the initial
installation. It can be very difficult to add or move a node once it
is connected to the coaxial cable.
Fault Intolerant
Since 10 Base-5 uses a common physical cable to interconnect all
the nodes, the failure of any part of the coaxial cable or any node
has the ability to cause the collapse of the entire network.
15. Bluetooth Birth
The Name –Bluetooth?
The name is
attributed to
Harald Bluetooth
was king of
Denmark around
the turn of the last
millennium.
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
16. What Is Bluetooth?
• Designed to be used to connect both mobile devices and
peripherals that currently require a wire.
• “USB without wires”
• Short range wireless radio
technology.
- operate range of 100
meters.
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
17. Who Started Bluetooth?
Ericsson Mobile Communication
• Bluetooth Special Interest Group (SIG)
-5 founding members
-Ericsson, Nokia, IBM, Intel & Toshiba
• Promoter’s Group
- 3COM, Lucent, Microsoft, Motorola
• Now over 1900 members
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
18. How Does It Work?
• Bluetooth is a standard
for tiny, radio frequency
chips that can be plugged
into your devices
• These chips were designed to
take all of the information that
your wires normally send, and
transmit it at a special
frequency to a receiver
Bluetooth chip.
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
19. Bluetooth @ Home
er
gita
lC ame
ra
NO WIRES
Computer
Scann
Di
Inkjet
Printer
xDSL
Access Point
Player
MP3
Home Audio System PDA Cordless Phone
Cell Phone Base Station
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
20. Bluetooth Products 1
• Bluetooth-enabled
PC Card
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
21. Bluetooth Products 2
• Bluetooth-enabled
PDA
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
22. Bluetooth Products 3
• Bluetooth-enabled
Cell Phone
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
23. Bluetooth Products 4
• Bluetooth-enabled
Head Set
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
24. Advantages (+)
• Wireless (No Cables)
• No Setup Needed
• Low Power Consumption (1 Milliwat)
• Industry Wide Support
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
25. Disadvantages (-)
• Short range (10 meters)
• Small throughput rates
- Data Rate 1.0 Mbps
• Mostly for personal use
(PANs)
• Fairly Expensive
Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555
30. INTRODUCTION
Data communications system
Alternates wired LAN
Transmits and receives data over the air
Minimize the need for wired connections
Become more popular in general-purpose
alternative of business customers.
Benefited several industries in productivity
and mobility
33. HOW IT WORKS
Use electromagnetic airwaves to
communicate information
Data imposed on radio carrier (radio wave)
RF electromagnetic wave can easily
pass through ordinary wall, it needs to
implement with heavy concrete or metal
screening.
34. WIRELESS TECHNOLOGY
Satellite-Based System
– Geosynchronous Earth Orbiting (GEO)
– Low Earth Orbiting (LEO)
Land-Based Network Access System
– Wireless WAN
– Wireless LAN
36. WIRELESS LAN
Wireless LAN Topology
– 2 main components
Access Points
Adapters
– Roaming
Wireless LAN Technology
– Types
– Standard
– Configuration
37. ACCESS POINTS
Connects to the wired network
single access point can support a small
group of users within a range of several
hundred feet
Wireless Clients Connected to LAN
via Access Point
39. INFRARED (IR)
TECHNOLOGY
Little used in commercial wireless LANs
Use very high frequencies
Inexpensive, but provide very limited
range (3ft)
Typically used for personal area
networks
Used only to implement fixed
subnetworks
43. Star Topology:
• The star network configuration is the most popular
physical topology
• In a star configuration, all computers or stations are
wired directly to a central location:
– Concentrator (a.k.a. hub)
– Multistation Access Unit (MAU)
• A data signal from any station goes directly to this
central device, which transmits the signal according
to the established network access method for the
type of network
46. Star topology advantages:
– A break in one cable does not affect all other
stations as it does in bus technologies
– Problems are easier to locate because symptoms
often point to one station
– The second-easiest topology to design and install
– Does not require manual termination
• Instead the media is terminated in the station at the
transceiver on the NIC and in the hub or MAU
47. Star topology disadvantages:
– Hubs, which are required for a star topology, are
more expensive than bus connectors
– A failure at the hub can affect the entire
configuration and all connected stations
– Uses more cable than bus topologies
