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>) 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