What is NIC (Network Interface Card)? How NIC works?

In this article, we will discuss What is NIC (Network Interface Card)?, How NIC works? and Components of NIC. So let’s discuss.

What is Network Interface Card?

NIC means network interface card is a hardware component, install in computer devices, used to connect a computer or other device to the network. So to create a network, NIC has a very important role.

It is also known as a network adapter, network interface controller, or LAN adapter.

It is the most necessary hardware component for a network connection, install in computers, servers, printers, or any other devices that allow a device to connect with other devices on a network.

It is a very basic network hardware component, which provides a network interface, without it a computer cannot be connected to any device on the network.

Any device which wants to connect to the network must contain a NIC card, even switches and routers also consist network interface cards in order to connect to the networks.

NIC installed in one computer is used to communicate with other NICs which installs on another computer.

For example:

If I have a computer and I want to connect to a network. So to connect my computer with other computers or to connect with the internet, I need a NIC card installed in my computer, which provides my computer a unique MAC address, which helps to connect to the network.

Another Example, If I have a company where have 100’s of computers and I want to create a local network in my company then I need NIC card on every computer or laptop so all computers can connect with each other. So NIC card provides us a network interface.

Every NIC card contains a unique MAC address that can never change because the address is assigned at the factory where NIC is manufactured.

What is the MAC address?

MAC address is a physical address that is assigned by the manufacturer on a network interface card (NIC), use to uniquely identify a device on a network.
It is called a physical address because it is physically assigned to a device called network interface controller (NIC).
It is a 48-bit address, consist of six sets of two characters in hexadecimal numbers, every set contains 8 bits address, separated by a colon: 2A:1B:55:23:5A:B3.


Functions of Network Interface Card (NIC)

The main functions of a Network Interface Card (NIC) include:

  1. NIC provides physical connectivity between a device and a network. A wired NIC typically uses an Ethernet cable to connect to the network, while a wireless NIC uses radio waves to connect wirelessly.
  2. It is responsible for transmitting and receiving data between the device and other devices on the network.
  3. It converts the data into a form that can be sent over the network, and then back into a format that the device can understand.
  4. NICs have error detection and correction capabilities to ensure that data is transmitted accurately and reliably.
  5. NIC manages network traffic by prioritizing certain types of data or limiting data transmission to prevent congestion on the network.
  6. Provides network security features such as encryption or authentication to protect the network from unauthorized access or data breaches.


How NIC Works?

It is a physical card or chip, which contains MAC addresses, helps to identify the device on the network.

NIC works on the physical layer and the data-link layer. Actually, NIC collects the data from the computer and sends it to the transmission Channel. It acts as a middleman between your computer and the data network. It is responsible to exchange the computer’s data with a network. Any incoming data that comes from the network medium is received by the NIC.

How NIC transmits the data?

  • For outgoing data, first, the network protocol transfers a packet to the buffer which presents on the NIC card.
  • Then the source and destination MAC address are attached as the frame header and calculate the CRC.
  • CRC (Cyclic Redundancy Code) is a numerical value, is a powerful type of checksum, which has the purpose of detecting errors.
  • Lastly, NIC transmits frames onto the medium as bit signals.

How NIC receive the data?

  • Bit signals travel along with the medium and are received by NIC, then the received bits are formatted into a frame.
  • First, CRC (a type of checksum) is calculated and compared to CRC in the frame trailer.
  • If they don’t match that means the frame is damaged or changed, and frame is discarded.
  • If CRC is okay, then the destination MAC address is checked.
  • Once the MAC address is checked and verified, the frame header and trailer are removed and the packet comes out from the frame, which is sent to the network protocol for further processing.

You should also read: How Switch Works, How Router Works, How Modem Works.


Types of NIC

Network Interface Card NIC

Types of NIC can be categorized into

  • Internal NIC vs External NIC
  • Wired NIC vs Wireless NIC vs USB NIC

Wired vs Wireless vs USB NIC

Wired NIC

A wired NIC connects to the network using a physical cable, such as an Ethernet cable. It is a common and widely used type of NIC in desktop computers, servers, and other devices that require high-speed and reliable network connectivity.

Wired NICs can provide high-speed network connections with low latency, making them suitable for applications that require large data transfers, real-time communications, and online gaming. They are also typically more reliable than wireless NICs, as they are not subject to interference or signal loss.

Wireless NIC

A wireless NIC connects to the network using Wi-Fi technology. Wireless NICs offer mobility and flexibility, making them suitable for portable devices such as laptops, smartphones, and tablets. They can provide network connectivity in areas where physical connections are not available or practical, such as in public spaces or outdoor areas.

Wireless NICs can transmit data over short to medium distances, and their speed and reliability depend on the quality of the wireless signal.

However, wireless NICs may have limitations in terms of speed and reliability, particularly when the device is far from the wireless access point or is subject to interference from other wireless signals or objects. This can result in slower data transfer speeds and connection dropouts.


A USB NIC is a NIC that connects to the device via a USB port. It allows a device to connect to a network using a standard USB port, which is typically found on most computers and laptops.

USB NICs are relatively easy to install and use, making them a popular choice for people who need to quickly and easily add network connectivity to a device. They are also relatively inexpensive, making them an affordable option for those on a budget.

However, USB NICs may have limitations in terms of speed and reliability compared to internal or external NICs that connect directly to the motherboard or network. This is because the USB port is typically slower than the other types of ports, such as PCI or PCIe, used by internal or external NICs.


Internal vs External NIC

Internal NIC

An internal NIC, also known as an integrated NIC or onboard NIC, is a type of Network Interface Card (NIC) that is built into a computer or other device. It is typically connected to the motherboard via a PCI or PCIe slot and provides a wired network connection to the device.

Internal NICs can be either wired or wireless, and they are designed to be part of the device’s hardware. They are usually included with most desktop computers and some laptops, and they are often pre-installed and configured in the device’s firmware.

One advantage of an internal NIC is that it provides a stable and reliable network connection, as it is physically integrated into the device and does not require an external connection. Internal NICs are also typically faster than USB NICs and may support more advanced networking protocols and features.

Advantages of Internal NIC:

  • It provides a stable and reliable network connection, as it is physically integrated into the device and does not require an external connection.
  • Internal NICs are faster than USB NICs and may support more advanced networking protocols and features.
  • Consumes less power than USB NICs.
  • An internal network interface card is built into the device so it does not require any additional setup or installation.

Disadvantages of Internal NIC:

  • Lacks flexibility and is permanently installed in the device.
  • Not portable and may not be suitable for devices that need to connect to multiple networks.
  • Can be difficult to repair or replace without professional help.
  • Can be more expensive than USB NICs or wireless network adapters.

External NIC

An external NIC is a separate device that connects to the device via a USB or Thunderbolt port. External NICs are commonly found in laptops and mobile devices, providing a flexible and portable solution for network connectivity.

External NICs can be either wired or wireless, and they come in various forms, such as USB network adapters, Thunderbolt network adapters, and PC Card network adapters. They are typically easy to install and configure, and they do not require any internal hardware modifications to the device.

Advantages of External NIC:

  • External NICs can be easily added or removed from devices, making them suitable for use with multiple devices and networks.
  • Easy to install and use.
  • Can be easily replaced or upgraded.
  • Suitable for mobile devices and laptops.

Disadvantages of External NIC:

  • May require additional hardware or cables.
  • Not as fast or reliable as internal NICs.
  • May require more power or affect battery life.


Frequently Asked Questions

What are the other names of NIC?

Network interface controller, Ethernet card, LAN Card, network adaptor, network adaptor card, Ethernet controller, physical network interface card, connection card, etc. all the name refers to NIC, So no matter what names the NIC has, they all refer to the circuit board, that gives the functionality any computer device to be connected to the network.

What are the components of NIC?

Controller: It is a processor, which is the core part of the NIC. Every data transmission from the computer to the network is done by the processor.
External Memory: It works like a buffer or RAM, used to store the data temporarily for the processor.
LED indicators: It’s a simple LED light that helps to identify the working status of a NIC card.
MAC address: It is a unique address, which is attached to the frame. It gives a unique identity to the computer also called physical network address.
NIC ports: NIC ports are used to connect with an Ethernet cable directly. Normally NIC has only one port, but they also come in more than one port.


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