Fiber is already a reality in Spain and we have put aside, with few exceptions, ADSL. There are more than fifty million accesses installed according to data from mid-2020 if we refer to FTTH fiber, but also millions of accesses using HFC. But what are the limits of fiber ? Where is the limit or what does it allow us?
We know, according to studies, that the maximum speed that ADSL offers us (or offered us) is 20 megabytes or 30 megabytes in case of using technologies such as VDSL. But what does fiber allow us? What do the limits depend on? What do operators offer us? We solve the main doubts.
Differences between FTTH and HFC
We should consider the difference between FTTH and HFC. We usually talk about fiber in general terms but it is not enough, in reality, to call fiber optics as a generalization, but there are different ones. FTTH is Fiber to the home and HFC stands for Hybrid Fiber Coaxial or what is the same: fiber optic to the home or hybrid fiber-coaxial respectively.
What is the difference between them? Very briefly, the main distinction between the two is that in the first case the fiber cable enters our house and in the second case it does not enter but the fiber remains in the node and a coaxial cable is used to our house, which Allows connection to the Internet. FTTH fiber has advantages such as immunity to interference or that the speed hardly decreases while it reaches several kilometers but, on the other hand, the higher cost. For their part, HFC technologies have a more resistant and cheaper coaxial cable and it is a less expensive or less delicate installation but it has a significant drawback: the speed can be lower depending on the length of the cabling so here we would find a more limited technology (although, obviously, better than the conventional ADSL that we had until a few years ago)
Maximum speed Spain
Movistar offers since January 2021 a total of 1 Gb for all users who had previously contracted 600 Mbps. There are also contract options of 100 Mb and 600 Mb but the maximum of Telefonica’s operator would be 1 Gbps for all users who look for the highest speed. It is not the only one that already offers this speed: Vodafone includes in some of its rates the possibility of contracting 1 GBps optical fiber in addition to the 300 Mbps or 600 Mbps fiber that is usually common in all operators. Up to 1 GBps are also offered by other operators: Orange and Yoigo already sell 1,000 Mbps, which is currently the highest limit.
What does 1 Gbps fiber allow us?
Movistar will be the last of the big four to reach 1 Gbps, but is it worth betting on this speed ? Do we really need it or is it enough to have 600 Mbps in our house? The service provider Fastmetrics has made calculations on the speed differences in daily tasks according to what we would have contracted. According to these data, what 1000 Mbps (or 1 Gbps) fiber would allow us would be the following:
We could download a song of about four minutes in 0.03 seconds compared to 0.3 seconds for 100 Mbps fiber optics. For its part, a two-hour movie in HD that occupies about 4.5 GB, we could have it in just 25 seconds. According to this American provider, to download the same file, in HD, with 100 Mbps we would have to wait around four and a half minutes. An HD television program of about 45 minutes would only take 5 seconds compared to 50 seconds with 100 Mbps fiber. This would mean a significant reduction in time in almost everything . In a matter of a minute or two you could download entire seasons from Netflix or Disney+ to take offline on your mobile phone or tablet if you want to travel. Or Spotify playlists that would download, at home, in less than a minute (note that each song would take just 0.03 seconds to download)
Limits
The capacity of the infrastructure is finite, both due to the speed of data transfer due to physical factors, in terms of the limitations of optical technology, and the associated energy consumption. If we focus on the limitations of technology, the transfer of information using the fiber optic support has to do with light and its reaction with silicon, which is the material with which the current optical fiber is made. Although light reaches 300,000 km / s in a vacuum, over fiber optics it reaches “only” 200,000 km / s, then we already have a first limitation due to the support, which results in a transfer speed of 1.5 Tbps according to the latest advances, and this speed is achieved by combining 40 Gbps channels.
If light travels through the silicon at a slower speed than through a perfect vacuum, the solution is to apply changes to the silicon… right? And that is as easy, as shown by some research, like modifying the wiring so that, between the silicon fibers, there are some hollow tunnels through which the photons can travel. And this advance allows it to reach 299,910 km / s in transfers, that is, up to 73.7 Tbps by combining 96 256 Gbps channels.
The limits of hardware
Fiber optic data transfer can continue to grow at the speed level, but it requires hardware to support it, and we enter in terms of router, network card, storage units and others. It will be useless if you contract a 1 Gbps rate with your operator if your computer is old or your network card is not capable of keeping up, for example. Nor would it make sense if we bet on an outdated and old router.Therefore, even if the rate of fiber optics was favorable, the evolution of hardware has to accompany the same rate as necessary, as long as it is intended to achieve the maximum transfer speed that fiber optics allows at all times. It would be logical in terms of hardware of the operators themselves (routers, repeaters …) but it would not always accompany in case of installed computers, etc.
Limits in technology and installation
Given the above, the transfer speed enjoyed by the end user does not only depend on the possibilities of the technology, but also on the limitations imposed by the rest of the infrastructure . Thus, one must also consider the technology between the OLT and the ONT and the ability of the splitters to “spread” the data that is transferred in these light beams. And they are not the only components of the infrastructure that can limit, to a greater or lesser extent, the maximum capacity of fiber optics.
Nor can we forget the interests of Internet providers that, depending on demand and competition, among other factors, deploy new technologies and enable higher transfer peaks. Therefore, the latter is also another “cap” that plays against the limits of fiber optics, which, being far beyond what we enjoy, is still little more than a utopia.
Speed and fiber testing
During the last years we have seen continuous tests of fiber to know what speed it can reach, the maximum that this technology allows. Every year, every few months, we see a new study that tells us how fiber “flies”. For example, in 2018 the Australian operator Telstra and the Ericsson company were able to demonstrate that fiber optics could go at 30.4 Tbps. “The highest spectral efficiency per fiber pair ever achieved in a real environment, allowing bandwidths of 30.4 Tbps” , explained both companies in a study within the “Networks of the future” program. According to this test, the equivalent would be the emission of 1.2 million 4K Ultra HD videos in streaming broadcast simultaneously.
But the record does not stop there and the technologies continue to be tested and continuously improved. In mid-2020 a new test showed that we could still go further. A test in August 2020 in Japan shows that a speed of 178 Tbps could be reached, a figure that would be equivalent to sending 22.25 TB per second. What does this mean? According to the tests carried out, we could download practically the entire Netflix library in less than a second. It is a system known as Geometric Shaping and “combines signal patterns that alter the phase, brightness and polarization of the waves”. This would mean that if current fiber optic cables have a bandwidth of up to 4.5 THz (or 9 THz in some cases) using a new way of modulating light, the speed could be tripled, achieving frequencies of 16.8 Hz.
The marked limit is 1 petabit per second on fiber optics. A transmission achieved at the end of 2020, in December of that year, in which the NICT of Japan and Bell Labs of Nokia, among other companies, achieved the first transmission in the world that exceeded the speed of 1 petabit per second on a fiber single core multimode optics. Although progress is continuous and it will be a matter of months, in 2021, we continue to advance and extend the limits of fiber a little more until we can see how far it is capable. What is clear is that we still have a long way to go to make the most of it.
Check your speed – Speed Test
How fast are you? We are far from being able to download the entire Netflix library but we are close to being able to download a movie in a second. To check your speed, just go to the speed test website and tap on the button that you will see on the screen: Start speed test . The web page will automatically show you how fast you are downloading and how fast you are uploading on the Internet at home, how many Mb per second. So you can check if it is according to what you have contracted.
