Although the fiber optic offers offer us specific speeds, the truth is that there are two cases in which you will not be able to enjoy all the speed that you had contracted with the operator. No matter how much you have contracted the symmetric fiber, you will only fully enjoy it when you have 100, 300 and 600 Mbps. And, if in your case you have contracted a tariff with 1 Gbps or 10 Gbpsthings change.
The speed of fiber optics has a limit in these cases, so much so that operators have had to put back in the fine print that this is not the maximum speed that they will be able to achieve in their homes or workplaces. But why does it happen?
940 Mbps or 8 Gbps is the limit
If in your case you have a rate of 1 Gbps at home or in your office, you may have already verified on your own by doing a speed test on your PC that it is connected by ethernet that you do not reach 1,000 Mbps. In general, the maximum that it will reach will be 940Mbps. And the same goes for 10 Gbps fiber. At the moment it is Orange and Digi that offer this speed, however, in their tests they have been able to show that the maximum download speed remains around 8 or 8.5 Gbps.
Although with the fiber, when everything goes by FTTH, the speed that arrives would have to be the one contracted, in these two specific cases it will not always be like that. The key to this is in the way we connect to the router, since the main factor that limits speed is the Ethernet cable.
Although the RJ45 port of most fiber routers is Gigabit, it is not possible to fully reach 1 Gbps of speed because the cable needs a reserved space for him Ethernet frame encapsulationwhere a margin known as overhead, or extra cost, with the aim of guaranteeing the delivery of the data. However, it will be different if we use a 2.5G Ethernet port or even a 10 Gbps port for a 1,000 Mbps connection.
For example, Digi does not warn that the maximum speed will be approximately 8 Gbps, so they recommend us to have wired connection Category 6A RJ45 and a 10 Gbps network card or 10 Gbps Thunderbolt 3 adapter in the computer.
With the WiFi connection it is different
The wireless connection limit is different. More than anything, because we meet Wi-Fi 6 routers that reach a speed of 3 or 6 Gbps and, although GPON equipment has a limit in the sfp transceiver, we will be able to reach up to 1 Gbps. And with an XGS-PON device, that limit goes up to 1.5 Gbps. Therefore, if we have a device with these characteristics, we will have the possibility of enjoying the 1 Gbps rate to the fullest.
We can experience a loss of 50 or 60 Mbps on Gigabit networks. Instead, in a 10 Gbps network we will lose between 1.5 or 2 Gbps of speed due to two essential factors: there is also overhead and the correction of errors made by the operators to provide stability in the connection to the clients. The latter means that they use that additional bandwidth to add the appropriate correction, limiting the speed much more.
And it is that, the maximum speed of XGS-PON could become 9,953.28Mbpsthe main drawback of adding error correction is that the speed will only be able to reach 8.5Gbpsas Orange showed for example in the presentation of XGS-PON.
However, there is also the possibility of reaching higher speeds if we use the so-called jumbo frames. We refer to frames of more than 1,500 bytes, which are used in Ethernet connectivity by default. In this way, a maximum speed of up to 9.4 Gbps could be reached. Although, if 9,000-byte frames are used, the speed increases to 9.8 Gbps.
