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

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 . . ?

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 . . ?

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 . .

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

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

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 . .

Pager Cordless telephone Satellite television Local area network

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 . .

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

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 . .

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 . .

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 . .

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

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?

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

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

Bus Topology

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

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

Star Topology

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

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

Ring Topology

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

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

Mesh Topology

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

Mesh Topology (Partial mesh)

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

Tree Topology

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

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

Open system interconnection (OSI) Model

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?

Functioning of OSI