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.

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.

Types:

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.

REPEATER - 

• 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. 

Types:

Active hub:- electrically amplify the signal.

Passive hub:- do not amplify the data.

BRIDGE - :

• 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).

SWITCH - :

• 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.

ROUTER - :

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 - :

• 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.