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When you connect a computer to a network, there’s more happening than simply plugging in a cable or connecting to Wi-Fi. Your device needs a way to communicate with the network, and the network needs a way to move those signals between devices.

Two important pieces of this process are the network interface card (NIC) and the network device that connects multiple computers together, such as an Ethernet hub.

What Is Network Media?

For devices to communicate, information has to travel from one device to another across some type of network media.

There are three basic ways we can send these signals:

• Electrical signals through a conductor such as copper cable
• Light signals through fiber optics
• Radio signals through the air

Regardless of the method, the goal is the same: transfer information between devices.

Computers work with 1s and 0s, so those bits have to be represented as signals that can travel across the chosen media. With copper, for example, an electrical signal can represent a 1 while the absence of a signal can represent a 0. Radio communication uses more complex methods to represent those same bits.

Fiber optics takes a different approach by sending information using light.

The Role of the Network Interface Card

Your network interface card, or NIC, provides the interface between your computer and the network.

Computers work with digital information, but the network media doesn’t necessarily communicate in the same form. A NIC helps translate the computer’s 1s and 0s into signals that can travel across the network media and then converts incoming signals back into information the computer can understand.

The term “network interface card” comes from the days when networking functionality was commonly provided by a separate expansion card installed into a computer.

Today, the NIC is often built directly into the motherboard or system.

A computer may have multiple network interfaces. For example, a laptop might have:

• Ethernet
• Wi-Fi
• Bluetooth
• Other network interfaces

In Windows, you can view these interfaces through Network Connections. You can also see information about an active connection, including its connection status, speed, and other details.

MAC Addresses and IP Addresses

When looking at a network interface’s details, you’ll encounter different types of addresses.

One of these is the MAC address, also called the physical address or burned-in address. The network interface has a MAC address associated with it.

You’ll also see an IP address, which is used for network communication at the IP level.

These addresses serve different purposes, and understanding the difference between MAC addresses and IP addresses becomes increasingly important as you learn more about networking.

Connecting Multiple Devices

Once devices have network interfaces, we need something that allows those devices to communicate with each other.

One example is an Ethernet hub.

A hub provides multiple ports where devices can connect using Ethernet cables. When a device sends a signal into the hub, the hub takes that signal and broadcasts it out through the other ports.

For example, if one computer sends a message into Port 1, the hub sends that signal out through the other connected ports. The other devices receive the signal and determine whether the communication is intended for them.

This is one of the fundamental ideas behind Ethernet communication.

Hubs vs. Modern Switches

It’s important to note that Ethernet hubs aren’t commonly used in modern networks. Switches are generally used instead.

However, understanding hubs provides a useful way to learn how Ethernet communication works. Hubs were part of the earlier development of Ethernet, and their simple behavior makes the underlying concept easier to visualize.

A hub essentially says: “I received a signal here, so I’ll send it everywhere else.”

A switch is more intelligent about how it handles traffic and can make forwarding decisions rather than simply broadcasting everything to every port.

Putting It All Together

The process of networking devices starts with the ability to physically or wirelessly transmit information.

Your computer’s NIC provides the interface between the device and the network media. That media might use electrical signals, light, or radio waves to carry information.

From there, networking equipment such as hubs or switches provides a way for multiple devices to communicate.

Understanding these foundational concepts makes it easier to understand everything that comes later in networking. Before you can learn about routing, subnetting, IP addressing, or more advanced networking concepts, it’s important to understand the basic question:

How does information actually get from one device to another?

Building that foundation is an important step toward developing the networking skills you’ll use throughout an IT career.

If you’re ready to strengthen your networking fundamentals, check out the free networking starter experience to practice these core concepts and build your confidence with computer networking.