Hardware Components used in networking:-

LAN Card- A LAN card is a piece of computer hardware designed to allow computers to communicate over a network. It is a replacement of modem because modem works on 56 kbps speed whereas Lan card works on modulation/demodulation signals. It connects users to each other either by using cables or Wireless. It works on both layer 1 and layer 2 of OSI model.

NIC(Network Interface Card) is an another name of LAN Card.

Repeater- Repeater is an electronic device that receives signal and retransmit them at higher level so that signals can cover longer distance. Connection between various types of media is possible as coaxial cable,fibre optic etc. It operate on first layer of OSI model i.e. Physical Layer.

There is a disadvantage of repeater is that they cannot work on multiple networks.

Hub-  A Hub contains multiple ports which is used to connect devices in a star topology. When a packet arrives at one port, it is copied to all other ports of hub. In these days because it is replaced by Switch.  It has a single broadcast domain.

Hub is layer-1 device works on Physical layer of OSI model.

Types of hub:-

·        Active hub                                                                 

·        Passive Hub

 Switch- A switch is a device that is used for switching. It forward and filters OSI layer 2 datagrams between ports. Switch has numerous ports.  Switches can operate on one or more layer of OSI model including physical, data link, network or transport. A device which operate on more than one layer is known as Multilayer switch.

Types of switch:-

·        Manageable switch                                              

·        Unmanageable switch

Bridge- It is also a layer-2 device. It is used to connect multiple switches and it transfer data in the form of frames. It filters data traffic at a network boundary and reduce traffic on LAN by dividing it into segments. Bridges send broadcasts to all ports except the one which the broadcast was received.

Types:-

Local bridge

Remote bridge

Wireless bridge

Gateways- It is used to connect multiple protocols. gateways are also called protocol convertors, and they can operate on any network layer. A gateway is associated with both a router and a switch.

Routers- Routers are networking devices that forward data packets on a network. It is a WAN link device . It works on Layer-3 i.e. Network layer of OSI model or Internet layer of  TCP/IP model. Files are transfered in the form of packets. It is a manageable device. It creates internetwork by connecting two different networks.

Works on these points:

·        Route Advertisement

• Best Path Selection 

Firewall- It is a hardware or software based network security system that control incoming or outgoing traffic. A firewall establish a barrier or wall between trusted, secure and other networks.