Battle for bandwidth: The hidden truth

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Bandwidth:  what only a few decades ago was a scarce resource; today seems to have no limit. In fact phone and cable companies trip over themselves trying to capture new customers with alluring promises of super fast fibre optic internet, using speeds that could only be dreamt about just a few years ago. At speeds close to a Gigabit per second, Fibre Internet delivers much faster downloads than broadband cable or ADSL. But is “more always better”? Is it worth the price? What is the hidden truth behind bandwidth offers? Understanding some basic principles about how Fibre to the Home Networks (FTTH) work can help you to navigate the sea of available offers to make better decisions when choosing services.

Starting from the basics, what is bandwidth? By definition, bandwidth is the amount of data you can successfully send from one location to another within a fixed about of time, this data transfer is measured in bits per second (bps). With the increase in mobile phone use, 4K Ultra HD streaming TV, Netflix, Amazon, and You Tube, our bandwidth consumption, or the amount of data that we consume has grown exponentially.

At home, what you probably care about most is the quality of the services you have subscribed to (i.e. High Speed Internet, Voice over IP and IPTV). For quality, fibre optic delivers much faster and reliable connection. Yet not all fibre is created equal. When facing figures like (50/100/300/600Mps), what do you actually need? Each represents a very different Bandwidth consumption profile that contributes to the overall Bandwidth subscribed. To decide, it helps to better understand the amount of bandwidth you consume.

Let’s see what happens to your bandwidth when you place a phone call, watch your favourite IP TV channel or series on Netflix, or browse through Internet.  I used a GPON protocol analyser over a “real” subscriber line to demonstrate what actually happens.

What happens when you make a phone call?

Voice communications are more concerned with continuity than bandwidth. As you see in the graphs below, while the call takes place, there is a symmetric bandwidth consumption of 90 Kbps.  Symmetric, meaning the same amount of data is downloaded and uploaded at the same time.

What happens when you watch TV?

TV channels are provided to all subscribers connected within the same Fibre to the Home network, if you live in a city block, this can usually be up to a maximum of 32. They are provided through a Multicast stream (including only the channels that are watched by at least one user). There are different qualities supported, Standard Definition-SD (4-6Mbps), High Definition-HD (8-12Mbps) or 4KTV (16-30Mbps). As an example, the BW graphs below show a stream of 48Mbps (4*HD channels being watched simultaneously) and another 70Mbps going up to 88Mbps when one user switched from HD to a 4K TV channel (5*HD channels + 1*4K channel).

The best thing about this approach is that bandwidth is shared among all subscribers so it does not compute against your individual Bandwidth consumption (which is what happens with xDSL).

But something very interesting happens when you “zap” TV channels or channel surf. In order to avoid the perception that this process is slow (compared to the speed of a traditional TV), operators have a trick up their sleeve, they send the content of the new channel over the same channel used for Video-on-Demand during 10 seconds (approximately) until content is available in the Multicast IPTV stream. And YES, these 10Mbps are consumed using your downstream total available Bandwidth. Graphs below show the behaviour by zapping through different TV channels continuously.

On demand TV series and films

As part of your subscription, you may also have access to a limited number of TV series and movies. But how are they delivered to you?

In this case the video is sent to you through your individual connection and 10Mbps of your Downstream Bandwidth is used. Also a bit of upstream bandwidth is used (some peaks at 90Kbps maximum). Interestingly, the first 30 seconds are related to a commercial that is included before the film starts.

At this point it is easy to see that while enjoying Video and Voice Services only a few Mbps of your total Subscriber’s Bandwidth have been used.

Let’s recap:

1. - A Maximum of 10Mbps of Downstream Bandwidth is consumed, and only while we are switching channels or enjoying a Video on Demand TV Series/Film.

2. - The complete Upstream Bandwidth is completely untouched (only 200kpbs in some cases).

Therefore, if your subscription profile is 100Mps symmetric, you still have 90Mbps Downstream and 99Mbps Upstream for High Speed Internet.

Do you really need such high speed? Let’s analyse some more common services provided through the Internet: OTT services (Netflix, HBO), YouTube, Vimeo, TWITCH, a live streaming platform, playing video games and downloading.

Over the top services (HBO, Netflix, Amazon Prime Video)

They are becoming more and more popular in Spain, the UK and across Europe, for an interesting price it is possible to watch your favourite series or films without commercials anytime and on different devices (TV sets, IPADs, Laptops, Smartphones etc.). Because this video consumption is individual, the way it arrives to you is different from IPTV.

The first thing you need to know is that the content is delivered from a server through an “Internet” service.

Both HBO and Netflix start by downloading a quite big amount of video data during a short period of time (between 100-200MBytes in the first 2minutes) and then burst with a certain frequency (see examples below). All of them have an Upstream Bandwidth consumption of less than 0.5Mbps.

With OTT services what is important is the Downstream Bandwidth but this is relative as it is only matters when the movie starts (up to 75Mbps with Netflix) and then an average of 15Mbps maximum in bursts (that still leaves more than 85Mbps available for a 100Mbps subscription). Thus, upstream Bandwidth is not impacted at all by OTT services.

HBO

Bandwidth profile over a 300Mbps and 100Mbps FTTH subscriber’s line.

Through a 300Mbps subscriber’s line with an ONU (Optical Network Unit) + Router, whenever a new video is started it consumes 20Mbps in Downstream during the first 80 seconds and then bursts of 15Mbps of 4 seconds, every 10 seconds. Upstream bandwidth consumption is around 0.5 Mbps.

Through a 100Mbps subscriber’s line using a Home Gateway, whenever a new video is started it consumes 10Mbps in Downstream during the first 100 seconds and then bursts of 10Mbps of 4 seconds, every 10 seconds. Upstream bandwidth consumption is around 0.5 Mbps.

Netflix

Bandwidth profile over a 300Mbps and 100Mbps FTTH subscriber’s line.

Through a 300Mbps subscriber’s line with an ONU + Router, whenever a new video is started it consumes 60Mbps in Downstream during the first 20 seconds and then bursts of 4-6Mbps of 1 seconds, every second. Upstream bandwidth consumption is around 0.5 Mbps.

Through a 100Mbps subscriber’s line using a Home Gateway, whenever a new video is started it consumes 75Mbps in Downstream during the first 10 seconds and then bursts of 12-18Mbps of 1 seconds, every 2 seconds. Upstream bandwidth consumption is around 0.5 Mbps.

Amazon Prime Video

Amazon Prime’s Video follows a similar path to Netflix and HBO. It downloads, during 8 seconds at 50Mbps, a video chunk of around 60Mbytes (less than its competitors) and then bursts of 2 second width at 15Mbps every 4 seconds (more if needed).

VIDEO Hosting Platforms:

Youtube / Vimeo

Among all the services, the one that is really Bandwidth thirsty is Uploading/Downloading videos. But there is not always a clear relationship between the line speed and the time it takes to upload a video.

As seen in the graphs below, uploading a video of 699Mbytes in YouTube takes 26 seconds using a 600Mbps FTTH line and only 58 seconds over a 100Mbps FTTH line (1/6 speed but only *2 in time spent).

Watching a YouTube video is also not very relevant regarding Bandwidth consumption with similar behaviour as OTT services: Burst of 4Mbps, with 2 seconds every 4 seconds.

Twitch

Another supposed Bandwidth Hungry application is Twitch where you can broadcast live (many users use it for showing how to play a video game).

In order to see how much it consumes, my son and I did a live stream while playing League of Legends (LoL). Results surprised us with only 5Mbps consumed in Upstream and around 10Mbps in Downstream (related to the Video game)

Steam

Downloading a 9GBytes Videogame from STEAM.

This is a clear example that Bandwidth is not the only factor implied during the “Download” process. With a 600Mbps FTTH line there was no bottleneck due to the network itself, with a peak at 671Mbps and then at 400Mbps for a certain period. However, the server was not capable of delivering all the data related to that video game in less than 520 seconds (almost 9 minutes) or what is the same, at an average speed of 12Mbps.

Wrapping up: What should I consider when deciding on bandwidth?

Now that you know the impact on bandwidth of the different services, it’s time to consider what offer is the one that will better suit your needs and use it to negotiate among the offers from different Telecommunications companies.

Let’s conclude with three examples:

1. A family unit enjoying Triple play services (Phone calls, IPTV and Internet). They usually watch some TV channels and also Series and Movies. They make use of Internet to Surf, upload/download pictures, watch YouTube videos and from time to time also upload a video to YouTube. For them, an offer of 50Mbps (even asymmetric with a lower upstream Bandwidth i.e. 10Mbps) is usually more than enough. 

2. Same family but now an HBO/Netflix subscription and watching Series/Movies in different sets simultaneously. In this case, downstream bandwidth is important so a subscription of 100Mbps (again, not needed to be symmetric) is a better option. If 4K series/movies is consumed, then, upgrading to a higher Bandwidth subscription will be required.

3. YouTuber, broadcaster, or any kind of media content producer that needs to share content with others. If this is your case, then, upstream bandwidth is important to you. Go to offers where they remark “Symmetric” and select the speed. Remember that for Fibre to the Home networks, the upstream bandwidth is allocated per user by the master located at the Telecom premises and the number of users connected shares that 1.25Gbps. Thus, if 10 users are requesting 300Mbps at the same time (supposing they have all a subscription of 300Mbps symmetrical), it will be more likely that you will get around 100Mbps (300Mbps is the maximum that you will get if all Bandwidth requests from all users at that moment is lower than 1.25Gbps). 

Enrique Areizaga, Co-Founder & CEO, GPONDoctor
Image Credit: 350543 / Pixabay