Bandwidth - it affects the entire network (wired or wireless)

Not having enough available bandwidth can cause speed problems for all or almost all devices (remember the theme - Slow Speeds (all devices)). This section will explain in a bit more detail how you can quickly analyze a customer's bandwidth usage and needs.

What is bandwidth?

Bandwidth is the amount of data that can be transferred in a specific amount of time. It is commonly showed in Mbps (megabits per second) or Gbps (gigabits per second), where 1 Gbps is 1000Mbps.

In other terms, Bandwidth is the available speed per second available inside a customer's home. And in ideal conditions the amount of bandwidth available will be close to the customer's internet plan speed as purchased from their ISP.

You can think of bandwidth as the "pie" of available speed for the whole network. Here's an example for a 100Mbps plan:

The full pie

If I pay for 100Mbps and my internet is being delivered properly, I will have about 100Mbps inside my home network for my devices to use.

There is only so much pie, or bandwidth, to go around on my network!

The pie before any of my devices have taken their slice

Adding a device

Bandwidth is a finite resource, like in a pie it has to be shared. I can't eat the same piece of pie as you just like two devices can't use the same "part" of bandwidth.

For example, if I stream 4k video to my TV it could use 25Mbps. That means that leaves only 75Mbps for my other devices.

If one device uses 25Mbps, only 75Mbps remains for everything and everyone else in my home to use!

Pie-Fi

The other thing to note is that the advertised bandwidth of an internet package is a wired connection (using an Ethernet cable to the router). If a customer has their devices on WiFi the starting bandwidth is commonly reduced by 20%.

This means a 100Mbps plan is usually only 80Mbps in reality, even before you add any devices as almost everything works over WiFi these days.

Who even has an Ethernet cable these days?

Bandwidth math

This means it can be pretty simple to put together how much bandwidth a customer has available or needs with some simple addition and subtraction! As the remaining bandwidth in a home gets close to zero, speed problems will occur as devices fight each other for bandwidth.

80% of total bandwidth - Bandwidth being used for devices = Bandwidth remaining

So for example, on a 50Mbps plan if I am using mostly WiFi devices and streaming 2 HD videos (5Mbps each) it will look like:

(50Mbps*0.8) - (5Mbps*2), or
40Mbps - 10Mbps = 30Mbps for all my other devices

One thing to note is that if I ran a Speedtest at this moment, the Speedtest would tell me I have 30Mbps!

That's right, Speedtest apps like Speedtest.net measure how much bandwidth is not being used so every device on the network doing any activity will make the result lower. This means if a customer is complaining about slow speeds (or buffering video, video quality, etc.), often the culprit is just that most of their bandwidth is being used at the moment, they need to turn off some devices.

RouteThis can tell you how much bandwidth is being used on the network and if this is a dangerously high level that may contribute to speed problems!

Common bandwidth use

To quickly figure out if a customer may be using too much bandwidth for their plan, here is a short reference on common amounts of bandwidth used by various apps and devices. Remember, typically consumer internet packages have an upload bandwidth maximum that is 10x less than download bandwidth:

1. HD Video Streaming - 1080p Video typically needs 5Mbps download speed

2. HD Video Broadcasting - 5Mbps is typically used on a customer's upload bandwidth but download bandwidth is not affected

3. Ultra HD or 4K Streaming - Netflix recommends 25Mbps for 4K streaming (plus a 4K device and subscription!)

4. Game updates or system updates - These usually use all remaining bandwidth and can slow networks down completely!

5. Online Gaming (such as Fortnite on XBox, Playstation, PC, etc.) - Minimum is 1Mbps down and up but it is safer to aim for 5Mbps in case the player is "hosting" a game.

6. Video Calls - Some platforms require 5Mbps per participant for HD video to be received. 5Mbps up will be needed to send back HD video

7. Streaming Audio - 1Mbps down for stable audio streams. Most platforms like Google Home or Alexa do not require this to increase if you have multiple speakers

With this information it is quick to estimate how much bandwidth a customer is using or how much they may need on their internet package to support what they want to do. You can see that it's quite hard to use 100Mbps unless you have 20 TVs!