3. Network Types(Geographical Coverage)
I) LAN(Local Area Network)
Small network, short distance
A Room, a floor, a building
Limited by no. of computers & distance covered.
Has very high speed mainly due to proximity of computer
and network devices.
Connection speeds can be 10Mbps or 100Mbps or
1000Mpbs also.
4. LAN cont’d…
Tend to use certain connectivity technologies, primarily
Ethernet and Token Ring.
Components are Layer 2(switches and bridges) and
Layer 1 devices like hubs and repeaters.
LANs tend to have fewer problems associated with
them, as there is smaller number of systems to deal with.
Typically owned, controlled, and managed by a single
person or organization.
LAN covers 100 meters.
Example: Network inside student computer room, or
Network inside your home
5. 5
II.MAN(Metropolitan Area Network)
Metropolitan area network (MAN) is similar to a local area
network (LAN) but spans an entire city or campus.
MANs are formed by connecting multiple LANs.
Thus, MANs are larger than LANs but smaller than wide
area networks (WAN).
MAN network has lower speed compared to LAN.
MAN connection speeds can be 10Mbps or 100Mbps.
Example: A network among campuses of Arba Minch
university.
6. III. WAN(Wide Area Network)
Have no geographical boundaries(it covers towns, states and
countries).
WAN speed varies based on geographical location of the
servers.
WANs (like the Internet) are not owned by any one organization
but rather exist under collective or distributed ownership and
management over long distances.
Components are Layers 3 devices like Routers, Multi-layer
Switches and Technology specific devices like ATM or Frame-
relay Switches , etc.
7. WANs tend to be less fault tolerant as they consist of large
number of systems.
WANs have a lower data transfer rate as compared to LANs.
Less speed (150 mbps).
WANs tend to use technologies like ATM, Frame Relay and
X.25 for connectivity over longer distances.
Example: Internet is a good example of a WAN
8. 8
Network Types (Based on Architecture)
1. Peer to Peer (P2P) network
They are more commonly implemented where less than
ten computers are involved and where strict security is not
necessary.
No hierarchy among computers all are equal
No administrator responsible for the network
Peer-to-peer network is also called workgroup.
9.
10. 10
2. Client-Server network
These are more suitable for larger networks.
A central computer(server) acts as the storage location for
files and applications shared on the network.
Usually the server is a higher than average performance
computer.
It controls the network access of the other computers
(client).
11.
12.
13. Network Types( Based on Topology)
Topology refers to the layout of connected devices on a
network.
The network topology defines the way in which
computers, printers, and other devices are connected.
A network topology describes the layout of the wire and
devices as well as the paths used by data transmissions.
14. A network has both a physical and a logical topology.
Physical topology shows the physical arrangement of a
network, which refers to the actual physical layout of the
devices and media.
Logical topology refers to the paths that signals travel
from one point on the network to another.
15. 1. Bus topology
All networked nodes are interconnected, peer to peer, using a
single, open-ended cable.
Both ends of the bus must be terminated with a terminating
resistor(Terminator) to prevent signal bounce.
A single cable called a trunk (backbone, segment) is used.
It is passive topology in which only one computer can send
messages at a time.
This topology is rarely used and would only be suitable for a
home office or small business with only a few hosts.
16.
17. 1) Easy to implement and extend
2) Well suited for temporary and
small networks that must be
set up in a hurry
3) Typically the least cheapest
topology to implement
4) Failure of one station does not
affect others
1) Difficult to administer/troubleshoot
2) Limited cable length and number of
stations
3) A cable break can disable the entire
network
4) Maintenance costs may be higher in
the long run
5) Performance degrades as additional
computers are added
Disadvantages of Bus topology
Advantages of Bus topology
18. 2. Star topology
Each computer has a cable connected to a single point.
Each networked device in star topology can access the media
independently.
Have become the dominant topology type in contemporary LANs.
19. 1) Compared to Bus topology it gives
far much better performance
2) Easy to connect new nodes or
devices
3) Centralized management. It helps
in monitoring the network
4) Failure of one node or link doesn’t
affect the rest of network
1) If central device fails whole
network goes down
2) The use of hub, a router or a
switch as central device
increases the overall cost of the
network
3) Performance and as well
number of nodes which can be
added in such topology is
depended on capacity of central
device.
Advantages of star topology Disadvantages of star topology
20. Star/Tree topology
Larger networks use the extended star topology also
called tree topology.
When used with network devices that filter frames or
packets, like bridges, switches, and routers, this topology
significantly reduces the traffic on the wires by sending
packets only to the wires of the destination host.
21. 3. Ring topology
All nodes are connected to one another in the form of
closed loop.
Each networked workstation had two connections: one to
each of its nearest neighbors.
Point to point connection with only two devices.
Signal is passed in one direction only, moves until it
reaches to its destination.
22. Token Passing
Sending and receiving of data takes place by the help
of TOKEN.
Token contains a piece of information along with data
which is sent by the source computer.
This token then passes to next node, which checks if
the signal is intended to it.
Only the computer who gets the token can send the
data.
23. 1) Performance is better than that
of Bus topology
2) No need for network server to
control the connectivity between
workstations
3) Additional components do not
affect the performance of network.
4) Each computer has equal access to
resources
1) Each packet of data must pass through
all the computers between source and
destination, slower than star topology
2) If one workstation or port goes down,
the entire network gets affected
3) Network is highly dependent on the
wire which connects different
components
4) Expensive and difficult to install
Advantages of Ring topology Disadvantages of Ring topology
24. Here every device has a point to point link to every other device.
It is used in WANs to interconnect LANs and for mission critical
networks like those used by banks and financial institutions.
Advantage: Eliminates traffic problem, Robust/fault tolerant,
privacy/security of message.
Disadvantage: More cabling required, more I/O ports needed, hard
to install and expensive.
4. Mesh topology
25.
26. Mesh topology…
One node must be connected with n-1 nodes.
A fully connected mesh can have n(n − 1)/2 channels to link n
devices.
Example: A network is to use a fully interconnected mesh topology
to connect 10 nodes together. How many links are required?
Solution: Number of nodes, n = 10
Links = n(n-1)/2 = 10(10-1)/2 = 10x9/2 = 90/2 = 45 links needed
29. Transmission Media
The transmission medium is the physical path or wireless between
transmitter and receiver.
So, the characteristics and quality of a data transmission are
determined both by the characteristics of the medium and the
characteristics of the signal
Channel capacity
It is the maximum rate at which data can be transmitted over a
given communication path, or channel, under given conditions.
30. In data communication data are encoded in a form of energy
and sent across the transmission medium.
Forms of Energy: links can be categorized by the type of energy
used for transmission:
Electrical Energy is used on wires.
Radio Frequency Transmission is used for wireless.
Light is used for optical fiber cables.
33. Twisted Pair (TP) Wires are classified in to two parts:
I. Shielded twisted pair(STP)
II. Unshielded twisted pair(UTP)
It is the most commonly-used transmission medium.
1. Twisted Pair (TP) Wires
34. Advantages of TP
Cheap or less expensive for short distance
Easy to install &work with
It can be used for both analog and digital transmission
Disadvantages of TP
Signals cannot travel for long distance without repeaters
High error rate if distance is longer than 100m
Since it is very thin, it breaks easily
35. I. Unshielded Twisted Pair(UTP)
Is commonly used for local area networks (LANs).
Connect using RJ-45 connectors.
Data rates for LANs 10 Mbps to 100 Mbps.
Ordinary telephone wire (RJ-11)
Cheapest and easiest to install
Suffers from external EM interference
37. Metal braid or sheathing that reduces interference
More expensive than UTP cables
Each pair of metals shield with metal foil or braided foil
Foil shields:- consists aluminum foil
Braided shield:-consists copper braided
II. Shielded Twisted Pair (STP)
38. STP: cables are similar to UTP cables, except there is a metal foil
or braided-metal-mesh cover that encases each pair of insulated
wires.
39. 2. Coaxial cable
Similar to cable TV wire
Used for cable television, LANs, telephony
One wire runs through cable
Shielded from interference
High attenuation rate makes it expensive over long distance
Much less susceptible to interference than twisted pair
41. Types of coaxial cables
10 Base-2 – ThinNet
It uses a lighter and thinner coaxial cable
It is a less expensive technology.
It allows distances up to 185 meters.
10 Base-5 – ThickNet
It can be used in electrically noisy environments which can cause
other network types to fail.
10 Base-5 allows distances up to 500 meters.
42. 3. Fiber Optic Cable
Fiber optic cables are made of thinnest strands of glass that enable
the transmission of information as light.
It carries signals as a light pulses.
Has extremely high capacity.
Works better under harsh environments.
43. Fiber Optic Cable Structure
Core : very small, the size of a single hair where the light particles
travels through this part.
Cladding(glass/plastic): it keeps light particles inside the core.
Plastic jacket: it is the protective outer jacket.
plastic jacket glass or plastic
cladding
fiber core
46. Unguided Transmission Media/ Wireless Media
Data is transmitted through the air
LANs use radio waves
WANs use microwave signals
Easy to setup
Difficult to secure
47. Radio
Wireless transmission of electrical waves over air
Each device has a radio transceiver with a specific frequency
Includes:
AM and FM radios, Cellular phones
Wireless LANs (IEEE 802.11) and Bluetooth
Microwaves and Satellites
Infrared
“invisible” light waves (frequency is below red light)
Requires line of sight; generally subject to interference from
heavy rain, smog, and fog
Used in remote control units (e.g. TV)
48. Satellite Communications
Satellites are special form of microwaves communication that moves
around large objects.
Earth stations communicate by sending signals to the satellite on an
uplink.
The satellite then repeats those signals on a downlink
It is useful for TV distribution, long-distance telephone transmission
and many more.
50. Types of Satellite
There are different satellites based on how height
above from earth such as:
1. Low Earth Orbit (LEO)
Occupy region of space from 111 miles (180km)
to 1243 miles(2000km) above the earth.
2.Medium Earth Orbit (MEO)
It is a satellite that parks in between the low and
high flyers
3.Geosynchronous Orbit (GEO)
It altitude 22,223 miles (36000km) above the
earth
