Bandwidth and throughput are confusing terms mainly because their definitions are very similar, but not the same.
The fine line between what differentiates them makes it easy to mix them up. Which can be a crucial mistake if your goal is to increase network performance.
Let’s see what each of these terms really means and how they depend on one another.
What Is Bandwidth?
Bandwidth tells you how much data your network could theoretically handle.
It is the maximum transfer capacity available for you to use. It is usually measured in bits (bps), megabits (Mbps), or gigabits (Gbps) per second .
So, what does this mean? Let’s take a look at a simple example.
The broadband “speed” your internet service provider advertises is actually the bandwidth they are giving you for your network.
If you sign up for a 300 Mbps plan, that is the maximum amount of data your network will be able to handle at any given time.
Let’s say sometime later you decide to keep the same router and devices, but you upgrade to a 500 Mbps plan.
Sure, you’ll notice websites load faster, and downloads are much quicker. But this just means that your network is now able to handle more data in the same amount of time.
This gives the impression of a faster connection, but the speed at which said data is traveling is still the same.
What Is Throughput?
Throughput tells you how much data your network did handle at a particular time. It is the real-time measurement of how much data traveled through your network for a specific task.
You will find that throughput is frequently measured in bits per second, but some people might prefer to use data per second.
You might notice that even though your internet service provider gives you a, let’s say, 500 Mbps connection, a speed test says you barely reach 100 Mbps.
This is the difference between bandwidth (the 500 Mbps your ISP provided) and throughput (the 100 Mbps real-life speed you get).
How Are Bandwidth & Throughput Different?
Think of bandwidth as a pipe and throughput as the water going through it. If the pipe is new and clean, water will fill the pipe as much as possible and come out the other end fast.
But if the pipe is full of blockages and debris, the amount of water coming out of the other end will be much slower . And if the pipe has some cracks, you could even lose some of the water while it goes through it.
The same applies to your network.
There are factors along the way your data travels that slow it down, like latency and congestion. And cracks that lose some of the data in the way, known as packet loss.
So, while water could travel faster if the pipe were clean (bandwidth), it does the best it can at that particular moment (throughput).
The goal here is to “clean” the pipe as much as we can, so your throughput is always as close to your bandwidth as possible.
Let’s take a look at all these different things that crowd our data “pipes”.
Latency is the amount of time it takes for data to go from one point to another .
For our purpose, it is how long it takes for your computer to reach a remote server (to access a website, for example).
Data travels pretty quickly, at 2/3rds of the speed of light, to be exact. But other factors affect it along the way.
Depending on what you’re trying to reach, your request might go through dozens of routers along the way.
Each of them will slow the data down a little bit while it receives it and figures out where to send it next.
As you can imagine, this means latency can never be eliminated entirely. And that distance is one of its most significant factors.
How congested your network is directly affects your throughput. Since bandwidth is fixed (to the amount your ISP provides), sending more data than it can handle will create congestion.
This time, let’s think of bandwidth as a single-lane road and throughput as cars. If there is only one car every 3 minutes, traffic will always flow freely.
But if 100 cars are trying to use this road simultaneously, traffic will become a problem. It will take longer for that last car to reach its destination.
To avoid congestion, we could either send less data at the same time (decrease the number of cars). Or create more space for data to travel in (add lanes to the road).
Remember the cracks on our pipe? If some of the water never reaches the other side, we’ll need to send more water. Meaning it will take more time than initially planned to send the original amount we intended.
Units of data, also known as “packets”, are sometimes lost along the way. When this happens, packets need to be retransmitted, and the information exchange takes longer. Thus, reducing your throughput.
Common causes of packet loss are network congestion or problems with your network hardware. Old or dated routers, switches, and firewalls are common culprits of packet loss.
What Increases Speed, Then?
Unfortunately, there is no simple, straight answer.
The first factor to look at is bandwidth. No matter what actions you take or how clean your network is, your speed will always be limited by your bandwidth.
If you want to run at 1 Gbps but your bandwidth is only 500 Mbps, no amount of troubleshooting or advanced network devices will get you there. Increasing your bandwidth is your only option.
As for improving throughput, here are some things you can do:
- Check that your router and modem are capable of handling the desired speeds.
- Check that your network cables are capable of your desired transfer rate.
- Frequently review how many devices are using your network and how.
- Monitor your network for congestion. If there is no way to avoid it, upgrade your hardware or bandwidth.
- Keep your devices and software up to date.
- If you use a VPN, choose a server closer to you to avoid increasing latency.
It’s almost impossible to improve your network performance if you don’t know the difference between bandwidth and throughput.
Throughput is clearly the better performance indicator here. But you need to pay special attention to how close it gets to your maximum bandwidth.
If you’re unsure about how much bandwidth you need in today’s world, check out this article.
And if you think old hardware might be the cause of your problems, it might be time to replace your router.