What is Network Devices ? Explain different types of Network Devices ?

Network Devices :-                                                                                             
All those devices which is used to create a network are called as Network Device .
Network Devices are used to increase the size of a network , network devices are called as Internetworking Devices or Connecting Devices . e.g. router , hub , switch , amplifier , etc .

Types Of Network Devices :-                                                                             

1. HUB
2. Repeater
3. Modem
4. Switch
5. Router
6. NIC
7. Multiplexer
8. DSL
9. Amplifier
10. Gateway

1.HUB :-                                                                                                                  
HUB is a network device , which is used to increase the number of computers in a network . HUB is used to increase th size of a network . With the help of HUB multiple ports are made available in a network through which we connect multiple devices in a network .

Types of HUB :-                                                                                                     
There are three types of HUB :-
1.Active HUB
2.Passive HUB
3.Intelligence HUB

1.Active HUB :-
It regenerate as well as amplify signals . This hub need electricity to work . they maximize network media distances and also follow the same rules as repeater .

2.Passive HUB :-
Passive HUB neither regenerate nor amplifies signal . This simply distribute the signal coming from previous ports . This HUB do not require electricity to work .

3.Intelligence HUB :-
This HUB is also known as manageable HUB . This HUB allow to configure ports individually . It works like active hub and has remote management capabilities .

Advantages of HUB :-                                                                                            

• It helps to increase the size of a network .
• There is no impact in the performance of network from HUB .
• HUB supports various types of network media .

Disadvantages of HUB :-                                                                                       

• HUB cannot filter network traffic .
• HUB cannot divide network in segment .
• HUB cannot connect different type of network architecture .
• HUB cannot reduce network traffic .

2.Repeater / What is repeater in network device :-                                            

It is a network device which is used to regenerate signal . If transmission of data is for long distance then at some point the signal becomes weak so at that point there is a use of repeater which regenerate the signal and transmit it , due to which data is transmitted successfully .

Wireless Repeaters are capable enough to enhance the signal in the remote areas where signal can travel but becomes weak at some point .

Repeater is an intellegent device which regenerate signals as well as it removes noise and resolves error in a network . 

Repeater works on the Physical Layer of OSI Model . As many repeaters are used in a network the signal will be more strong and it will allow to transmit data for a long distance .

Now a days , repeater is inbuilt with SWITCH and HUB and it can work as both HUB and SWITCH.

Advantages of Repeater :-                                                                                       

• Signals can be transmitted to long distance with the help of repeater by regenerating the signal .
• There is no impact on the performance if we use repeater in a network 
• The cost of Repeater is not very expensive . So , using repeater in a network is not very expensive .
• Repeater can work by connecting it with different media like Co-axial cable , twisted pair cable , fiber optic cable .

Disadvantages of Repeater :-                                                                                   

• Repeater cannot filter traffic in a network .
• Repeater can work in only one type of protocol .
• Repeater can work only with digital signal, it cannot work with analog signal .
• Two different LAN ( Local Area Network ) cannot be connected by using Repeater . Repeater can connect different segment of single LAN ( Local Area Network ) .

3.MODEM / What is modem :-                                                                               

Full Form of MODEM is Modulator and Demodulator . Data sent through computer is Digital Signal , however data sent via phone or telephone is Analog Signal . So , Modem is used to convert analog signal to digital signal and digital signal to analog signal .

Function of Modem  :-                                                                                             

Modem is used to convert analog signal to digital signal and the process is called as Demodulation and digital signal to analog signal and the process is called Modulation .

Importance Of Modem :-                                                                                         

It is an important network device which is used to transmit digital signal to analog and analog to digital signal . In other word it allows computer to receive signal from phone line or cable connection . 

Use of Modem :-                                                                                                        
This device helps to connect to the internet and to modulate and demodulate signals .

4.SWITCH:-                                                                                                              
In a small network , Switch allow to share resources by connecting together with all the devices including computer , printer and server . This allow devices to share information and talk with each other . Building a small business network is impossible without SWITCH .

How does Switch in a network work ?

• Network switch create network , network switches allow devices in a network to communicate .
• Network Switch work on the 2nd layer of OSI Model i.e. DATA LINK LAYER

5.ROUTER:-                                                                                                             

Router is a network device which connects multiple switches , and thir respecting networks to create an even larger network . To build a small business network , one or more router will be needed . router also allows multiple user to access internet .

which layer of OSI model does router works ?

Router works on the 3rd layer of OSI model i.e. Network Layer .

Types of Router :-                                                                                                       

There are five types of Router which are as follows :-

1.Wifi Router

2.Bridge router

3.Core Router

4.Edge Router

5.Virtual Router 

1.Wifi Router :- Wireless router provide WI-FI access to smartphones , computers , laptops and all the other devices with WI-FI network capabilities .

2.Bridge Router :- Bridge Router is also called as Brouter in short form . It is a type of router which work as both bridge and router .

3.Core Router :- It is a type of router that routes data within a network , but not within a networks .

4.Edge Router :- this router act as an entry point into the core of the network .

5.Virtual Router :- It is a backup router which is used in VRRP setup .

6.NIC:- ( Network Interface Card )                                                                         

Full form of NIC is Network Interface Card .It is a network device which is also called as Ethernet Card or Netowork Adapter

Use of NIC :-

NIC is used to connect to a network . NIC controls a wired and wireless connection of a computer to exchange information with other computers and internet also .

Importance of NIC :- 

If you want to connect to a Local Data Network or to the internet then NIC is must needed . The NIC translates the computer signal to electric signal which helps to transmit data through ethernet to a network .

Advantages of NIC card :-                                                                                     

1. Speed :- It provides a fast internet connection speed can be upto 1 gigabyte i.e 1 Gbps .
2. Reliability and security :- It provides a reliable internet connection that should not vary if the performance or availability of the network is functioning properly .

Disadvantages of NIC card :-                                                                                

1. Portability :- NICs are not portable as that of wireless cards . when you are connected with a network in your location with an ethernet connection and you want to move your computer to other area then you will need to disconnect the ethernet connection from the old location and connect your computer with the connection in the new location .
2. Convinience :- It is not as convinient as wireless card . e.g. no longer hotel rooms are providing ethernet connection for the guest in the room . In place of that , they are providing internet to the guest via wireless network .

7.Multiplexer :-                                                                                                      
It is a network device which take multiple input and only forward the selected input into a single line . This device is used to increase the amount of data that can be transmitted over a network . A network multiplexer is used  with a variety of dignal types like digital , analog , video and optical . they support different transport mechanism e.g wired and wireless .

Multiplexing :- It is a method by which multiple analog , digital signal are combined into one signal over a shared medium .

8.DSL :-                                                                                                                          

full form of DSL is Digital Subscriber Line . It is a network device which is used to transmit digital data over telephone lines . It is a very high speed connection that uses the same wire as that of phone line .

OR

DSL is a service which uses phoneline to provide or data access for both resedential purpose as well as commercial purpose .

NOTE :- A DSL service is out dated sevice now a days .

9.Amplifier :-                                                                                                         

As the name suggest amplifier is a network device which is used to increase the amplitude or strength of , if the previous found signal is weak .

10.Gateway :-                                                                                                        

Gateway is a network device which act as a gate between two network . It joins two network so that the devices in the network can communicate with the devices on another network .

without gateway it is not possible to connect to the internet , communicate and send data back and forth .