What is a Network Interface Card (NIC) | Components, Types, & Working Explained

A network interface card (NIC) is a hardware component in electronic devices that connects them to a network. NICs are of various types, each having its limit of functionalities. This blog post will guide you about what a network interface card comprises, its working, functionalities, and common issues that impact its working.

What is a Network Interface Card?

A network interface card, sometimes called a network adapter or controller, is a hardware component. Typically, it is a PCB (printed circuit board) primarily found in computers and facilitates network connections.

Using network interface cards, devices connect to networks (wired, wireless, or LAN) via the Internet Protocol (IP). Continue reading this guide to learn more about the network interface cards, i.e., their functionality, types, components, and more.

What Are Network Interface Cards Used For?

Network interface cards are the primary source that connects devices to networks. This hardware transmits and receives data between a device and a network. NIC provides dedicated connectivity points to networks, which can be:

• Local Area Network (LAN)
• Wide Area Network (WAN)
• Public Internet

NICs are used for managing data flows. They help control traffic and maintain optimal network performance.

Key Components of a Network Interface Card

Network interface cards are of different types and designs. Whatever the type is, some components are included in all of them. Here are some of the key elements among them.

Controller/Processor

The controller or processor of an NIC is used to manage data flows between devices and networks. Their function is to:

• Process incoming and outgoing data.
• Perform error checking.
• Data formatting (primarily data packets as per network protocols).

MAC Address

The MAC (Media Access Control) Address is a unique identifier number assigned to each NIC. It helps recognize devices connected to a local network. Moreover, it also helps cards direct data packets to the correct destination within a network.

Transceiver

These components convert digital signals from devices into electrical or optical signals, facilitating network transmission. A transceiver provides a medium for two-way communication between the network and the NIC. It ensures that the data is both being sent and received efficiently.

Bus Interface

The bus interface in the NIC creates a connection between the motherboard and the card. It transfers data to and from processors. Bus interfaces are of different types, each varying in speed and architecture.

Memory (Buffer)

The buffer memory temporarily stores data on a network interface card (both incoming and outgoing). It helps in keeping the traffic flow smooth when activity is high.

Connector/Port

A connector or port is the component that creates a physical connection between the card and the network. This is the place where the network cable is plugged into the card.

In wired NICs, mostly RJ-45 type connectors are used, while antennas or internal connectors are used for signal transmission in wireless cards.

LED Indicators

These are the LED lights you will see on a network interface card. They usually are two in number and provide the visual status information such as speed, activity, and power.

Driver/Software Interface

To translate system commands into instructions, NIC cards need a driver. The software allows a device's OS (operating system) to communicate with the network interface card.

Profile Bracket

A profile bracket is used to place an NIC in a case. This case ensures that the NIC fits the expansion slot of the device properly. There are standard and low-profile brackets to match different case sizes.

Working of a Network Interface Card

Network interface cards operate at the physical and data link layers (usually layer 1 & 2) of the OSI (open system interconnection) model. Here is the sequence of how a network interface card works.

• The device sends data to the card via the system's bus.

• Upon receiving, NIC processes the data for transmission.

• NIC encapsulates the data into frames and assigns the MAC address to identify the source and destination devices.

• To manage the data flow, NIC temporarily stores the frame inside a memory buffer.

• A transceiver changes digital data into signals (electrical or optical).

• Signals travel to the network cable or antenna via the NIC port.

• Cards receive incoming data via the same port that transferred signals.

• The transceiver converts these signals back into digital data.

• NIC processes and formats the data for the device.

• The formatted data is passed through the device system memory via the bus.

Types of Network Interface Cards

Based on the connection type, bus interface, and the port type, network interface cards are categorized into different types. Some key among them are as follows.

1. Wired Cards

Wired network interface cards, aka Ethernet cards, involve physical cables connecting to a network. They are suitable for environments where high-speed connectivity is a necessity. The following are the types of wired network interface cards:

• Ethernet Cards: They build a connection with a network via Ethernet cables.

• Fiber Optic Cards: They involve fiber optic cables for connecting to networks and are used for making ultra-high-speed connections.

2. Wireless NICs

Wireless network interface cards (WNICs) do not involve physical cables like wired cards. They use antennas and radio waves to connect devices and networks. Examples of these cards include:

• Wi-Fi Cards: Use radio waves to create network connections for portable devices.

• Bluetooth Adapters: These are used for short-range network connections, often found in headphones, earpods, keyboards, etc.

• Cellular Network Cards: They refer to cellular modems and create cellular network connections by accessing mobile data in embedded systems and smartphones.

3. Bus Types

These types of NICs involve using different buses that create network connections between devices and networks. Common examples include:

• PCI (Peripheral Component Interconnect): These are older but still used by some systems. It is a standard for connecting peripherals to a system bus.

• PCIe (Peripheral Component Interconnect Express): This is a new and faster standard involving a serial communication protocol for creating network connections.

• USB (Universal Serial Bus): It is mainly used in external devices that lack internal slots. It uses a universal interface based on a serial bus system that connects devices and networks.

4. Speed Types

Each network interface card has its speed limit. Based on the brackets on speed, they are commonly divided into the following types (can be both wired and wireless):

• 10 Mbps: These provide 10 Megabits per second and are rarely used today.
• 100 Mbps: It uses the IEEE 802.3u standard and offers 100 Megabits per second, which is suitable for basic networking needs.
• 1 Gbps:  It uses the standard IEEE 802.3ab and offers 1 Gigabit (1000 Mb) speed per second. These are usually found in laptops and today’s desktop devices.

• > 10 Gbps: These NICs offer a speed of more than 10 Gigabits per second and use different standards. They are commonly used in data centers where high-speed networks are necessary.

Troubleshooting Common NIC Issues

Network interface cards are prone to many issues. Some of the common ones are discussed below, along with their solutions.

NIC Not Recognized by the System

Sometimes an NIC is not correctly recognized by systems and creates connectivity issues. This often happens when dealing with multiple NICs or using refurbished hardware. Sometimes, it happens due to drivers not being installed correctly.

For instance, if your NIC claims to be from the Intel company. But, upon performing a MAC Address Lookup, it shows a mismatched vendor name. This means you might be dealing with a damaged counterfeit adapter.

Solution:

There can be two solutions to the problem.

First is reinstalling the driver. As you now know, the manufacturer name simply downloads the relevant vendor driver from the internet and install it on your device.

If the issue persists, go for the second option, which is replacing the hardware (NIC).

Poor Network Performance

Another issue with NICs is poor network performance, which leads to slow internet speeds. There can be many reasons behind this issue, including:

• Outdated drivers
• Faulty Ethernet cable
• Network congestion
• Thermal throttling

Solution:

Consider updating drivers and try using the cable Cat 5e or Cat 6. Switch to a less congested Wi-Fi channel or band (5 GHz instead of 2.4 GHz). Make sure your NIC is not overheating. If so, try using the NIC in a different PCIe/USB slot (if possible.

Wrapping Up

The above guide includes all the information a beginner needs about network interface cards. Like what they are, how they work, their types, common issues, and how to resolve them. 

FAQs

How to test if the NIC is working properly?

You can test if the NIC is working correctly or not in various ways. Common ones include physical connection testing, running ping tests, and verifying the status of the operating system.

Can multiple NICs be connected to a device?

Yes, multiple network interface cards can be connected to a single device. But it depends on the slots available in the device.

How can I find the NIC manufacturer's name?

To find a NIC's manufacturer name, simply run its MAC address through our MAC address lookup tool. It will provide you with the necessary information, i.e., manufacturer name, address, etc.