Em 10-03-2021 05:48, Darac Marjal escreveu:
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
Dear Darac Marjal,
Thank you very much for your detailed and didactic explanation.
It helped me to understand a little more how things work.
But I'm still don't know what value I use to configure the upload and
download speeds on my load balance tp-link tl-r470t+ router.
Should I use the maximum speed, average speed or minimum speed?
Thank you very much,
Markos
