In this slide I explain What is Data Communication and Networks and its Applications And also explain Physical Topology, Types of Physical Topologies, Categories of Networks that is LAN, WAN, MAN and coverage of Networks etc.
2. DataCommunication
Exchange of data between two or more
devices using some transmission
medium.
Another explanation could be:
Electronic transmission of information
that has been encoded digitally (as for
storage and processing by computers)
3. Components of Data
Communication System
Message (text,image, numbers, audio, video)
Sender(computer, workstation, telephone,
camera etc.)
Receiver
Transmission Medium(twisted-pair,optical
fiber, coaxial cable, radiowaves)
Protocol(set of rules that govern data
communication)
9. PhysicalTopology
It refers to the way how the network is
laid out physically.
Geometric representation of the
relationship of all the links and linking
devices
10. Advantage and
Disadvantages
Increased speed, Reduced cost, Improved security,
centralized software management, Electronic mail
High cost of installation, requires time for
administration, failure of server, cable faults
12. Mesh topology
In mesh topology, every device in the network is
physically connected to every other device in the
network.
In mesh topology every device has a dedicated
point-to-point link to every other device.
The term dedicated means that the link carries
traffic only between two devices it connects.
14. Advantages
The use of dedicated links guarantees that each
connection can carry its own data load.
Failure of single computer does not bring down
the entire network
Security and privacy over the dedicated link
Easy diagnosis
Disadvantages
Installation and configuration is difficult
Cabling cost is more
The hardware required to connect each link
15. Star topology
All the cables connects from the computer to the
central location called HUB.
Broadcast star network
Resends message to all the connected computers
Switched star network
Sends data to a destination computer
16. Working of star topology
The sending computers send
the data to hub. The hub
sends data to the receiving
computer. Each computer in
star network communicates
with a central hub.
18. Advantages
Easy to install and wire.
No disruptions to the network when connecting or
removing devices.
Easy to detect faults and to remove parts.
Single computer failure does not broke down the whole
network.
Disadvantages
If the central hub fails , the whole network fails to
operate.
The cabling cost is more.
It require a large length of cable to connect
computers.
19. Bus Topology:
A bus topology is
a topology for a Local
Area Network (LAN) in which
all the nodes are connected to
a single cable. The cable to
which the nodes connect is
called a "backbone".
20. Bus Topology
Signal travels along the backbone
Nodes are connected to the bus cable by
drop lines and taps.
Drop line is a connection running between
the device and the main cable
In this topology, at any instant, only one
computer acts as master and it is allowed to
transmit(broadcast). Other devices are
supposed to listen
23. Advantages
It is simple and easy to use.
It require a small length of cable to connect
computers.
It is less expensive.
It is easy to extend a bus.
Disadvantages
It is difficult to troubleshoot.
It only supports small number of computers.
The network slow down if the numbers of
computers is increases.
Bus topology is not great for large networks.
Terminators are required for both ends of the main
cable.
24. Ring Topology
In ring topology, each computer is connected to
the next computer with the last one connected to
the first. Thus, a ring of computers is formed.
In ring topology each node connects exactly two
other nodes
Signal is passed along the ring in one direction,
from device to device until , until it reaches the
destination.
Each device is attached or incorporates or
repeater.
25. Working of ring topology:
Every computer connected to next computer
in a ring.
Each computer receives message from the
previous computer and transmits it to the next
computer. The message
Flows in one direction. The message is passed
around the ring
Until it reaches the correct destination
computer.
28. Ring Topology
Advantages
1 It is relatively less expensive than a star topology network.
2. In a Ring topology, every computer has an equal access to
the network.
3. Performs better than a bus topology under heavy network
load
4. Ring is relatively easy to install and reconfigure
Disadvantages
1 Failure of one computer in the ring can affect the whole
network.
2. It is difficult to find faults in a ring network topology.
3. Adding or removing computers will also affect the whole
network since every computer is connected with previous
and next computer.
29. Categories of Networks
Network Category depends on its size
Primary categories are:
PAN: within a room
LAN: Covers area < 2miles
WAN: Can be worldwide
MAN: Between LAN & WAN, span 30-100 miles
30. Local Area Network (LAN)
Privately owned
Links devices in the same office,
building, or campus
Simple LAN: 2 PCs & 1 printer in home
or office
Size is limited to a few kilometers
Allow resources to be shared
(hardware, software, or data)
31. Local Area Network (LAN)
An isolated LAN connecting 12 computers to a hub in a closet
32. Local Area Network (LAN)
LAN is distinguished by:
Size (# users of OS, or licensing restrictions)
Transmission medium (only one type)
Topology (bus, ring, star)
Data Rates (speed):
Early: 4 to 16 Mbps
Today: 100 to 1000 Mbps
38. Metropolitan Area Networks
(MAN)
Size between LAN and WAN
Inside a town or a city
Example: the part of the telephone
company network that can provide a
high-speed DSL to the customer or
cable TV network
39. MetropolitanArea
Network(MAN)
Designed to extend over the entire city.
It may be asingle network asacable TV
network OR
It may be means of connecting anumber of
LANs into alargernetwork
The main reason fordistinguishing MANs asa
special category is that astandard has been
adopted for them. It is DQDB(Distributed
Queue Dual Bus) or IEEE802.6.
40. Network coverage
Local Area Networks:
Used for small networks (school, home, office)
Examples and configurations:
Wireless LAN or Switched LAN
ATM LAN, Frame Ethernet LAN
Peer-2-PEER: connecting several computers together (<10)
Client/Server: The serves shares its resources between different
clients
Metropolitan Area Network
Backbone network connecting all LANs
Can cover a city or the entire country
Wide Area Network
Typically between cities and countries
Technology:
Circuit Switch, Packet Switch, Frame Relay, ATM
Examples:
Internet P2P: Networks with the same network software can be
connected together (Napster)