No capacity crisis

May 2020

Any national crisis these days presents a real test for the internet, and proves what I have been saying for ages, that it really has become a utility and should be regulated and supported as such, just like electricity, water, gas and so on.

However, it’s managing itself quite well.  I recently looked back at what I wrote in 2001, after the dreadful 9/11 attacks.  The CNN, ABC and New York Times web sites were quickly overwhelmed and were switched off.  When they came back, most of the content had vanished and connecting to them was difficult anyway as the network was clogged and often impossible to access.

This is because of the way the internet works; in order to see a web site, you must connect directly to it.  You are a visitor, not just a viewer, and all websites have a limit to the number of simultaneous visitors they can manage.  Broadcast media, such a radio, will always beat the internet hands down on this score, as they can have unlimited numbers of listeners.

However, in the last twenty years, the way websites and the internet are managed has grown up and the UK is now one of the world’s most advanced digital economies.  It’s just as well; as soon as Coronavirus hit us it was clear that the internet would be a very important a means of imparting information and transacting business. 

Websites can now very quickly and easily increase the numbers of possible visitors if they need to.  But would the network, the physical wires through which all the data flows, be up to the job?  Could it handle the many working from home?  Just as the pubs were closed, BT, whose network is easily the biggest in the UK, issued some reassuring figures which also shed an interesting spotlight on our online habits.

I had not realised it, but the network capacity required for work-related applications represents only a fraction of the demands we all place on the network at home.  The real bandwidth hogs are films, live streaming (sport, for example) and, especially, online video gaming.  Online conferencing (Skype and the like) which have obviously seen such a huge increase in use recently, are much less hungry for bandwidth.

Data transmission across the internet is measured in terabytes per second (Tb/s).  Before Coronavirus, BT never saw usage of more than 17.5Tb/s and that was always during the evening peak, when we all went home and watched something, or played some video games.  Rather to my surprise, this was more than three times the usual daytime peak of only about 5Tb/s, even with every computer in every company in the land hard at work.

Accordingly, BT built its network to accommodate that evening peak with masses of headroom in case of any extra special demand.  Even after Coronavirus forced so many people to start working from home (and no doubt increased the demand for Netflix during the day) the daytime traffic only increased to about 7.5Tb/s initially, still under half the evening peak in more normal times.

Plenty of spare capacity is built in because it is surprisingly cheap.  Even if it proves insufficient, the engineers can very rapidly deploy extra equipment to boost it.  

Ultimately, if forced to, network providers also have the option to slow down various activities on the internet to allow more important traffic room to move. 

Before Coronavirus, the highest levels of traffic that BT had ever experienced were when a new online video game called Red Dead Redemption was launched.  If the worst that BT ever has to do is slow down something that sounds as ghastly as that game to accommodate some public service traffic, I suspect it’s a privation we could all survive.

A few links...

How does the internet work? BBC Schools simple explanation:
https://www.bbc.co.uk/bitesize/topics/z7wtb9q/articles/z3tbgk7

BT and Coronavirus – their response
https://btplc.com/coronavirus/index.htm

Virgin Media and Coronavirus – their response
https://www.virginmedia.com/help/coronavirus-update

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