How dirty is your fibre network?

Submitted by fredrik.nyman on Thu, 02/28/2019 - 09:37

 We all know that a big portion of the content in fibre networks comes from adult websites but this post is about a different kind of dirtiness, namely how coal and oil makes surfing on the Internet contribute to global warming.

It’s a well established fact that burning fossil fuel release carbon dioxide to the atmosphere which contributes to trapping heat radiated from the sun and thus the global temperature increases. Many countries burn oil or coal to generate electricity and that electricity powers the routers and switches in the network. The more dirty fuels your country use the larger the impact to the climate.

Dirty electricity

On you find a live interactive map that shows how much carbon dioxide (CO2) that is released into the atmosphere for every kWh of electricity generated. The figure vary from day to day depending on what resources are at use - a cold winter day might see a lot more dirty fuels in the mix due to extra power plants needed. A windy day might increase energy from wind turbines and reduce the carbon mix.

So how much carbon is it then? Lets do some math.

A 24-port fibre switch used in the access network to connect 24 homes consumes about 30W of energy as base consumption. Add to that 26 fiber optical modules (24 homes + two uplinks) that on average needs 0.7W each and the grand total is 30 + 18.2 = 48.2W.

A day has 24 hours, a year has 8 760 hours. So in one year that switch consumes 48.2 * 8 760 hours = 422 232 Wh. Divide by 1000 to get the (k)ilowatts; 422 kWh.

Let's say that the Swedish CO2 per kWh of electricity is 55g, then that switch generates 55 * 422 = 23 210g or 23kg of CO2 emissions every year. If all of that comes from fossil fuels then it’s a net contribution to the atmosphere.

A broadband network connecting 100,000 customers might have about 4200 switches. So 100,000 fibre homes in Sweden would yield about 97 tons of CO2 per year.

Now, lets have a look at Germany. The CO2 per kWh is significantly higher, about 230g per kWh. Same calculation for 100,000 fibre homes and the result is 407 tons of CO2 per year.

Then we have Poland at around 680g CO2 per kWh. 100,000 homes in Poland would generate 1,200 tons of CO2 per year. And in Estonia with a whopping 1150g per kWh the result is more than 2,000 tons of CO2 just to surf on the Internet and just from the access equipment. Add to that the power needed for the computer, the home network switch and the core network of the operator and you can probably double or even triple the numbers.

This is one of the reasons why Waystream introduced the low power optical module that averages in on 0.3-0.4W per port instead of the 0.7W of traditional modules. At 0.3W in the same scenario as above the switch power consumption is cut down to 331 kWh per year. Recalculating the CO2 emissions from the example above with 100,000 homes connected then looks like this

Table: CO2 emission in tons per year for 100,000 connected homes based on snapshot carbon mix 2019-02-11 from

Country Standard SFP Waystream Superlowpower SFP
Sweden 97 76
Germany 407 319
Poland 1200 945
Estonia 2000 1600

Using lowpower optical modules in the network equipment has a significant impact on the carbon footprint of your fibre network. It also has an impact on your wallet. Less power consumed means lower power bill, and for those that also have to use air-conditioning to keep the equipment cool during hot summer days, well… less heat generated means less cooling and an additional saving of cooling costs.

Good for the climate, good for the power bill and good for the cooling costs.

That’s a win-win-win situation.

Blog posts

Turn on automation of your FTTH network

Submitted by fredrik.nyman on Mon, 04/01/2019 - 09:08

The distributed nature of a fiber to the home network means that you will have equipment spread out and you might not always do the on-site installation yourself. If every switch has to pass your desk for pre-configuration port before getting deployed into the field you will need to deal with the logistics of getting the units from your warehouse via your desk, packing and unpacking, and clearly marking them so that the right unit goes into the right location.


Submitted by fredrik.nyman on Thu, 03/21/2019 - 09:51

I love acronyms. You got three of them in the title of this post.

In recent years we got Software Defined Networking (SDN) and Network Function Virtualization (NFV). Many of the large telcos have invested millions into research of these subjects and are pushing the industry in this direction. Telefonica has expressed high ambitions to move to a completely SDN/NFV enabled network in record time. All the big ones are involved.

Keeping product lines around

Submitted by fredrik.nyman on Fri, 03/15/2019 - 09:50

Building fibre to the home networks are different from any traditional enterprise or telecommunications network. One of the main differences is the time it takes to complete the network. You make a plan, design a an architecture with VLANs and redundancy and imagine how this will scale as the number of connected customers increase. But then the years go by, because building a fibre network to connect every home in the community can take decades.

Save the planet - work from home

Submitted by fredrik.nyman on Thu, 03/07/2019 - 10:30

In my last post i revealed how dirty a fiber network can be depending on the source of electricity powering the network. I showed how a typcial 24-port access switch might contribute anything between 23kg to 485kg of carbon dioxide per year to the atmosphere depending on the electricity mix and how that can be reduced with lowpower optical modules.

How do you troubleshoot IoT devices?

Submitted by fredrik.nyman on Fri, 02/15/2019 - 13:00

Continuing on the subject of troubleshooting the network. Troubleshooting MPEG video has the benefit of a user that can tell you if it doesn't work and you can simply ask that user if the problem persists once you have fixed it. But what if there isn't any obvious way to determine if things are working, for example is that trashcan really signalling that its' full or does the temperature device really update the building climate control properly?

How to see what your users see

Submitted by fredrik.nyman on Mon, 02/11/2019 - 10:21

Live broadcast TV is one of the most popular services in fibre networks. You can get high quality pictures because there is enough bandwidth to send video uncompressed. But the nature of broadcast media is that it is very sensitive to packet loss or jitter. There is no retransmission of packets because it is live – you can’t hold the stream to get a lost packet back.