What Is Downstream And Upstream (Uplink) Internet Bandwidth?

What Is Downstream And Uplink Internet Bandwidth? Differences Explained

When you buy a router or sign up to an internet service, you will likely want to know how much faster your network will be with your new products.

The best way to work this out is by looking at the amount of bandwidth available from your ISP. However when you see this, you will likely notice two numbers, one relating to downstream data and one to upstream data.

What are the differences between these two types of data flows? And how will they impact your network?

This article aims to answer both those questions.

What Is Internet Bandwidth?

Internet bandwidth is the speed at which you can receive data from the internet. Let’s say that your Internet Service Provider (ISP) provides you with speeds of 10 Mbps. This means that your network can theoretically receive 10 Megabits of data every second.

One thing to note is that these 10 megabits will have to be shared with everyone on your network. That means that is you have a lot of people using the internet on your network at the same time, your speeds could become much slower.

The good news is that at the start of 2017, the average speed of a US internet connection was 18.7 Mbps. According to Netflix, in order to stream an HD quality video, you only need around 5 Megabits per second.

This means that if you have an average speed connection three people could potentially stream HD video on your network without a problem (of course, Ultra HD is another question as it requires around 25 Mbps.)

There are other things that can affect the speeds you receive. For example, when a lot of people, such as your neighbors, use the internet at the same time (typically in the evening), the network can get congested and the bandwidth you receive from your ISP can reduce.

If you have a modern router, you may wonder why your internet speed is stuck at a certain number when you router claims to provide significantly higher speeds. Well, to put it simply, that is because routers advertise the total speeds that they can provide on their network.

This means that while transfers between computers on your network may work at a certain speed, your internet speed will always be stuck at what you receive from your ISP.

You should also remember that even if your router can handle far more than the speeds provided by your ISP, certain things can slow it down.

For example, having lots of people connected to your router, or having a weak signal can cause you problems that can slow down your internet connection.

As well as this, interference from other networks or physical objects can cause your network connection to become unreliable which can, in turn, slow down your internet connection.

A final thing to take into consideration is that it will be very rare for you to actually get the speeds advertised. These are the speeds you will theoretically get in the ideal environment. However, this “ideal environment” pretty much doesn’t exist meaning your upstream and downstream speeds will almost always be a little (or a lot) slower than advertised.

What Is Downstream And Upstream (Uplink)?

To put it simply, downstream and upstream bandwidth is the amount of bandwidth that is available coming into your network and the amount of bandwidth that is available when leaving your network.

Downstream Bandwidth

Downstream bandwidth is the amount of bandwidth available for data entering your network from your ISP. When you visit a webpage, stream a video, or download a file, most of these actions requires the use of your downstream bandwidth.

Not all of it however. Due to the nature of TCP, acknowledgements (known as ACKs) are mandatory for the downloading to take place. It is the nature of TCP Windowing. We won't go too much into this, as it's kind of beyond the scope of this article. We just want to mention it before someone else does in the comments, hehe.

Most of the time, you will have significantly more bandwidth on the downstream as this is generally used more often by consumers and therefore requires faster speeds.

Upstream Bandwidth

Upstream bandwidth is the amount of bandwidth available for data leaving your network. This can include things such as emails being sent, pictures being uploaded to social media, or information when playing games.

Upstream historically has been less important for normal users. However, with the massive rise in Cloud computing and online storage (think Google Drive, Dropbox etc), upstream (uplink) speeds have become more inportant.

Control Upstream And Downstream Bandwidth Using QoS

It is possible to adjust the amount of bandwidth dedicated to upstream and downstream on your network by using the QoS feature of your router.

QoS, or Quality of Service, is a way of adjusting how bandwidth is used on your network. While it is usually used for prioritizing certain devices or types of traffic (ie, video streams), it can also be used to adjust the amount of bandwidth available on the upstream or downstream.

Web Internet Traffic

This can help you ensure that none of your bandwidth is going to waste and allow you to set how much upstream or downstream is available on each application and/or device.

While QoS doesn't necessarily come with every router, if you want the benefits of QoS it is possible to install open source firmware that comes with QoS even if your router doesn't already have it. Not all routers support "flashing" open source firmware on your router, so check this out.

Open source firmware such as DD-WRT, Tomato, and OpenWRT all have the ability to give your existing router advanced QoS features if you are willing to install them.

Downstream Vs Upstream Internet Bandwidth

Hopefully, this article will have answered some of your questions about upstream and downstream bandwidth. To put it simply, upstream is the amount of bandwidth available when data is uploaded from your network to the internet, while downstream is other way around.

The amount of Bandwidth on the downstream is usually bigger than the amount available on the upstream due to the fact that data intensive activities like streaming usually take place on the downstream.

Both can affect your overall internet speed, so if you are having trouble, be sure to use something like QoS to help solve the problem!

Thanks for reading. If you have any questions, ask below...

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