CBSE Class 11 & 12 Computer Science and Informatics Practices Python Materials, Video Lecture

Computer Network Devices


Computer Network Devices

Introduction -

Specialized hardware is required to carry out various roles in a network e.g. Establishing connections, controlling network traffic, and many more.
Network Devices

NIC (Network Interface card) -

It is a device attached to each workstation and server. Helps to make connections within the network.
Each NIC has a unique number identifying it called node address/MAC address (Media Access Control) /Physical Address.
  1. Ethernet Card
  2. WiFi Card

RJ - 45 -:

  • RJ-45 stands for Registered Jack-45.
  • RJ-45 is an eight-wire connector, which is commonly used to connect computers on LAN especially Ethernet.

MODEM (Modulator - Demodulator) -:

  • The modem is an abbreviation for Modulator – Demodulator. 
  • The modulator converts information from digital mode to analog mode at the transmitting end and the demodulator converts the same from analog to digital at receiving end.


  • It is a device that accepts the weak signals and amplifies the signals for further transmission.
  • Different types of wires have different transmission distances, hence repeater should be used according to the types of wire.
  • Generally, we consider that most wires require a repeater after a 100m distance.

HUB - :

  • Hub is an electronic device that connects several nodes to form a network and redirect the received information to all the nodes in a broadcast mode. It is called a non-intelligent device. 
  • It is mostly used in Star or Ring topology and works on MAC addresses. 


Active hub:- electrically amplify the signal.
Passive hub:- do not amplify the data.


  • In telecommunication networks, a bridge is a product that connects a local area network (LAN) to another local area network that uses the same protocol.
  • The bridge acts on MAC/Physical Address.
  • A bridge examines each message on a LAN, "passing" those known to be within the same LAN, and forwarding those known to be on the other interconnected LAN (or LANs).


  • It is an intelligent device that connects several nodes to form a network and redirect the received information only to the intended node(s).
  • A switch is also called Intelligent HUB.
  • Switch stores the MAC address table of all the connected nodes, which helps it to send the data to the desired node.


The router works on IP address.
Routers normally connect LANs and WANs together.
It has a dynamically updating routing table (stores IP Addressed) based on which they make decisions on routing the data packets.


  • Gateway is a device that connects dissimilar networks.
  • Establishes an intelligent connection between a local network and external networks with completely different structures.
  • Gateway is the ISP(Internet Service Provider) that connects the user to the internet. The gateway can also act as Firewall, API Gateways, etc.

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