De FAQ do Tefus , seção "Alguns conceitos básicos sobre o serviço de internet":
if Telus has oversubscribed your trunk cable (has too many customers with
ADSL on the set of cables going from
your place to your ADSL port), then
there will be interference between
your set of telephone wires carrying
your ADSL signal and the signal on the
telephone wires of the person next to
you in the cable bundle. When this
happens, BOTH your ADSL modem and the
other ADSL modem slow down until the
bit-error-rate decays to an acceptable
level. This is completely automatic -
you have NO control over this. Now,
extend this over multiple connections.
As the load on the system imposed by
users increases (time-of-day) the
amount of interference increases. ALL
the modems then start to throttle -
quite correctly - so that everyone
gets at least as much of the pie as
they can get without robbing their
neighbour.
Another thing - the higher the maximum
ADSL transfer rate, the LOWER the
number of ADSL pairs that are allowed
in a cable bundle because the
higher-frequency-signals used to
achieve the higher ADSL transfer rate
spread further from your pair than the
lower-frequency-signals used for a
lower ADSL transfer rate.
So, the result of the above is that if
Telus offers high-speed ADSL to
everyone - and a cable that has been
working fine with an ADSL-pair-density
originally set for 1.5Mb/s is suddenly
faced with a lot of those people
upgrading to 3MB or 6Mb/s, guess what
happens? The higher interference
caused by the higher-transfer-rate
signals causes EVERYONE to slow down,
because there are more EXISTING ADSL
pairs in that cable than the enhanced
or extreme-speed-service can support.
And it only gets worse for every
customer Telus upgrades from standard
to enhanced or extreme service.
Now, please note that this
trunk-cable-interference occurs on the
Telus side of the demarc. You have NO
control over this - trunk-cable ADSL
density is a function of decisions
made by Telus sales. IMO, from the
results being shown, both enhanced and
extreme service is massively
oversubscribed - and a whole bunch of
enhanced and extreme users should be
downgraded back to 1.5Mb/s to allow
the system to recover stability at
that rate.
Portanto, parece que o seu ISP simplesmente tem muitos assinantes de alta velocidade no seu pacote de cabo. Meu palpite é que, ao redefinir o roteador, você está reiniciando a linha na sua velocidade normal e, em seguida, novamente deslizando colina abaixo, à medida que a interferência das outras linhas começa a penetrar.