1. Wireless technology Network topology OSI - Model
Network Concepts
Wireless technology
Network topology
OSI - Model

2. A network is a group of two or more computer systems linked together
A group of interconnected computers and peripherals
They are connected through data connection systems
( Peripherals = any external devices )
EX :- Printer, Mouse, Keyboard etc
What is Network . . ?

3. N/w allows Sharing of H/w & S/w resources, among various users working on different computers
Resources can be Data files, application S/w or H/w devices like scanner and printer
Why Network . . ?

4. Advantages of N/w . . Computer N/w has bought Information sharing
Connectivity
Efficiency => ( high productivity with minimum effort & expense )
Communication
Storage media
Cost effective
Redundancy => ( state of no longer useful or needed )
Reliability => ( trustworthy & performing well )
Advantages of N/w . .

5. Wireless technology . . Radio, Infrared, Bluetooth, hotspot
Also wireless adaptors which like Ethernet adaptor

6. The 1st wireless transmitters went on air in the early 20th century using radiotelegraphy, later modulation made it possible to transmit voice & music via wireless,
the medium came to be called “ RADIO “
( 47 )
Knowledge booster

7. Common wireless N/w’s we use daily . .
Cellular phones &Pagers
Global positioning systems ( GPS )
Cordless telephone sets ( wire less )
Satellite television
Wireless LAN
Common wireless N/w’s we use daily . .

8. Pager Cordless telephone Satellite television Local area network

9. Wireless can be divided into . .
Fixed wireless :- In homes & offices devices connected to particular equipment connected to internet via modem
Mobile Wireless :- Wireless devices ( Drones ), moving vehicles, personal communication services
Wireless can be divided into . .

10. Portable wireless :- Battery powered wireless devices, handheld mobiles & PCS units
IR wireless :- IR ( infrared ) devices which van convey data to a certain limited range

11. Bluetooth . . Electronic gadget Allows us to share info
Allows to connect with another Bluetooth device only
Commonly used in TV/Video, remote, keyboard, mouse, phones & head phones
Bluetooth . .

12. WiFi . . Very popular wireless n/w
Uses radio waves technology & provides high speed internet
Even mobile phones having this technology
One can connect to many devices & share printer, scanner, internet access
WiFi . .

13. Advantages of Wi-Fi . . Share your internet
Share resources between Pc”s
Access your files via a NAS drive
( N/w attached drive )
Printing & Scanning
Remote control of your entertainment system
Listen to music
Stream video ( without interruption )
Play Video games
Advantages of Wi-Fi . .

14. Questions What is Bluetooth? Explain Wi-Fi and its advantages?
What is wireless technology?
Questions

15. What is the purpose of a network?
The fundamental purpose of computer networks is to communication between two or more different systems to share information or data resources
What is the purpose of a network?

16. Arrangement of computers connected in a LAN network id called Topology
Topology determines the shape and the communication path between various computer networks
There are various types of Topologies
Network Topology

17. Types of topology Bus Topology Star Topology Ring Topology
Mesh Topology
Tree Topology
Types of topology

18. Bus Topology

19. In this bus network topology, every workstation is connected to a main cable called BUS.
Therefore, each workstation is directly connected to every other workstation in the network
When the node wants to connects with the other nodes in the network, it simply sends a message to the common bus.
( NODE = Connected system in the network)
Bus Topology

20. Advantages & Disadvantages of Bus Topology
Usually requires less cabling (cable)
Very simple to configure and install
Failure of one computer does not effect on other computers in the network
DISADVANTAGES
The failure of backbone results in breakdown of entire network
Bus Topology is difficult to reconstruct in case of fault
Advantages & Disadvantages of Bus Topology

21. Star Topology

22. In Star Topology, All the computers are connected to a central computer or a server, known as HUB
Every workstation is directly connected to other through central computer
When node wants to send message to other nodes, it first sends the message to HUB, which forwards the message to the intended node.
Star Topology

23. Advantages & Disadvantages of Star Topology
It allows easy error detection and correction
The failure of one computer does not affect on other computers in the network
Easy to install
Disadvantages
If the hub fails it leads to overall network crash
It requires more amount of cables to connect the nodes
Expensive due to the cost of hub
Advantages & Disadvantages of Star Topology

24. Ring Topology

25. In Ring topology, the workstations are connected in the form of ring with help of twisted pair cable,
Adjacent pair of workstations are directly connected (Adjacent = Adjoining or next)
Other workstations are indirectly connected
The data passing through one or more intermediate nodes
The node passes the message, first passes the message to its consecutive node in the network
Ring topology

26. Advantages & Disadvantages of Ring topology
Each node has equal access to other nodes in the network
If the new node is added it, dose not degrade the performance of network
It is easy to configure (arrange or putting together) and install
Disadvantages
It is expensive to construct the ring topology
Failure of one node in the ring topology effectives the other nodes in the ring
Advantages & Disadvantages of Ring topology

27. Mesh Topology

28. In Mesh topology, employs either of two two schemes, called full mesh or partial Mesh.
Full mesh:- In full mesh topology, each workstation is directly connected to each of the others.
Partial mesh:- Some workstations are connected to all others, and some are connected to only to those other nodes with which they exchange the most data.
A mesh can take several possible paths to reach a destination.
Mesh Topology

29. Mesh Topology (Partial mesh)

30. Advantages & Disadvantages of Mesh topology
Message delivery is more reliable (good quality and trustable)
Network congestion (rush of traffic) is minimum due to large number of links
Disadvantages
It is expensive to implement
It is difficult to configure & Install
Advantages & Disadvantages of Mesh topology

31. Tree Topology

32. Two or more star topologies are connected is nothing but tree topology
Central computers of the start networks are connected to a main bus,
Thus, a tree network is a bus network of star networks
Tree Topology

33. Advantages & Disadvantages of tree Topology
It is more effective as it uses multiple networks
It contains the best and efficient (max productivity with min effort) features of the combined topologies
Disadvantages
More complex (consisting of many different and connected parts) than the other topologies
Very difficult to install and configure (arrange or putting together)
Advantages & Disadvantages of tree Topology

34. Open system interconnection (OSI) Model

35. OSI model is the only reference for to tell how applications communicate over a network
So it is also called as OSI reference model
It divides the communication path into seven layers
They are Physical layer, Data layer, Network layer, Transport layer, Session layer, Presentation layer, Application layer
What is OSI?

36. Functioning of OSI