Top-posting Darac's excellent long response. Here's a data point for you. The effective bandwidth increase from 10Mb/s ethernet to 100Mb/s ethernet was achieved by simply using more conductors. Already in the connectors and cabling. But no one added capacity upstream specifically for that. Just added more customers and infrastructure.
Top-posting Darac's excellent long response. Here's a data point for you. > The effective bandwidth increase from 10Mb/s ethernet to 100Mb/s ethernet > was achieved by simply using more conductors. Already in the connectors and > cabling. But no one added capacity upstream specifically for that. Just > added more customers and infrastructure. > > On Wed, Mar 10, 2021, 2:48 AM Darac Marjal <mailingl...@darac.org.uk> > wrote: > >> >> On 09/03/2021 23:20, Markos wrote: >> >> Markos wrote: >> >> >> I'm a Debian user and have already configured a router TL-R470T+ to >> >> connect >> >> with 2 providers (by PPPoE and dynamic link). And I'm using the TL-WR841ND >> >> V10 router only as an access point. >> >> >> >> Now I'm in doubt as to how I will set the Upstream and Downstream >> >> Bandwidth >> >> for each ISP if every time I do a test (for example on www.speedtest.net >> >> <http://www.speedtest.net> <http://www.speedtest.net>) I find a different >> >> speed that can vary from 2 to >> >> 20 Mbps? >> >> >This isn't really a Debian issue, but let me take a stab at it: >> >> >Disconnect network A. Run a speed test. >> >> >Connect network B, disconnect network A. Run a speed test. >> >> >Connect network A again, and now you have values for A and B to >> >plug into your router. >> >> >-dsr- >> Hi Dan, >> >> Yes, you are right, it is not a specific Debian issue. >> But I don't know where to ask for help. I'm having trouble finding reliable >> answers to configure this router. >> There are many videos on Youtube but with contradictory information. >> I searched on the TP-link website and posted a question on the forum but I >> didn't have an answer. >> I did what you suggested, but throughout the day the speed varies. >> So my question is, what a speed value mean if it varies throughout the day? >> >> I think you're getting into fundamentals of how your internet is >> provided. I'm not a networking engineer, so some of the detail of the >> following might be off, but this is how I understand it to work. The most >> popular broadband around at the moment is ADSL. This is, in VERY broad >> strokes, an extension of the older analogue modem technology. But, instead >> of the data being modulated into audible sound, it's modulated into >> ultrasonic sound. Instead of dialling into a server halfway across the >> country, with ADSL the sound only needs to carry as far as your local >> telephone exchange. Blocks of frequency, all above human hearing, are used >> and the total frequency range (and therefore data bandwidth) is MUCH higher >> than before. (Incidentally, because ADSL is fully above human hearing, this >> is why we can use a "microfilter" to split the data and voice frequencies, >> meaning you can use your phone without disrupting the internet). >> >> Now, here is the first reason why the speed can vary throughout the day. >> ADSL is, fundamentally, trying to push wires which were only rated for >> voice frequencies beyond their limits. Sure, all data transmission >> technologies have an analogue medium, but Cat5e Ethernet cable is designed >> to fully handle the frequencies being passed across it. The copper phone >> lines to your telephone exchange might be half buried in water, they might >> run alongside a train track, they might follow the twisty route of a >> suburban road, rather than taking the most direct route. The upshot of this >> is that the amount of noise on your line probably isn't constant. Your ADSL >> modem will be constantly monitoring the signal-to-noise ratio of the >> various blocks of frequency, and the two ends will negotiate which to use. >> To put it simply, bad weather can reduce your bandwidth. >> >> Another issue that might affect your speed is "contention". Contention is >> a more broadly-applicable issue. You see it on ADSL broadband, but you see >> it more commonly on Cable broadband. Contention basically means that some >> part of the connection between your house and the ISP's central servers is >> oversold. Taking the ADSL system as an example, let's put ourselves in the >> shoes of a fledgling ISP. We are provisioning a neighbourhood for ADSL. >> Let's say that, theoretically, ADSL can go up to 50Mbps per line and that >> there are 100 houses being served by this one exchange. That means we need >> a 5Gbps link between the exchange and our servers, right? But they're SO >> expensive! And, no-one's actually bought ADSL yet, let alone the "Top >> Speed" package. If we buy the 1Gbps link, we can save massively. So, people >> start buying ADSL and they're getting 10Mbps speeds. Wow! That's fast >> compared to 56kbps! 20 people buy it. 50 people buy it. Excellent, we're >> still only at half the capacity of our big link. Oh, but here's a >> technology update and ADSL can now reach 25Mbps. As you can see, as more >> and more people buy ADSL, and the ADSL routers get cheaper and faster, the >> pressure on the uplink increases. Now, as this happens, your ADSL modem >> will still report the fast speed. As far as it's concerned, it's >> established a, say, 25Mbps connection with the telephone exchange. Now, if >> it's 3am, perhaps you CAN download at close to that speed. But what if it's >> 7pm? And it's the season finale of "Lilliput's Got Talent". Suddenly, >> you've got dozens of people trying to download masses of data. Everyone is >> still connected to the telephone exchange at high speed, but the over-sold >> uplink can't transfer all of that data, so everyone's bandwidth slows to a >> crawl. >> >> So, what can you do about it? Well, you probably can't complain to your >> ISP. They probably sold you your internet as "Up to Xmbps", because they >> know that the rated speed is rarely achievable. You MIGHT be able to switch >> to an alternative technology; if speed really matters to you, consider >> buying a "dedicated line". This will bypass the contention issue and, >> depending on the physical technology used may be less susceptible to the >> environment. Alternatively, you could just decide "does this matter to me?" >> Broadband IS important to qualty of life online these days, but ultrafast >> broadband is not so much. Have a think about what's "fast enough" for you. >> >> >> >> Thank you for your attention. >> Markos >> >>
