Class 12 Computer Network | Network Devices

Network Devices

Network Interface Cards (Ethernet Card)

A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. NIC or LAN Card or Network Interface Unit(NIU) enables a computer to connect with a network using a port. It allows users to connect to each other either by using cables or wirelessly. WLANS Cards are also used for connecting PCs with wireless network.


Switch is a device that is used to segment networks into different subnetworks called subnets or LAN segments. It is responsible for filtering and forwarding the message between LAN segments. A switch is an intelligent hub. It looks exactly like a hub but the difference between two is that a switch sends the information selectively to the intended computer while hub transmits the data to all the computers or nodes connected to it.

computer networks : switch


Routers are devices that forward data packets from the source machine to the destination machine using shortest path. It is device used to separate different LAN segments in a network. It works like a bridge but can handle different protocols. If the destination is unknown to the router it send the traffic to another router which knows the destination.

computer networks : router


A hub is a connecting device which connects multiple computers together to form a Local Area Network(LAN). A hub contains multiple ports into which cables from multiple computer’s NICs are inserted. Whenever a computer has to send some information to some other computer the information is sent by the NIC to hub. Hub then retransmits this information to other computers attached to it. The computers for which information is intended receives and accepts it and other computers just reject it.


Wireless Access Point

This device allows a wireless connection to a wired network using the Wi-Fi standard. A wifi card is either an internal or external local area network adapter with built-in wireless radio and antenna. It is used in desktop computer to establish internet connection. They are also called as wireless fidelity cards.