What is MaxDSL?
"MaxDSL" or more correctly ADSLMax is a new range of products
that are available from BT Wholesale in April 2006. It is
not a new standard of adsl, but does have a few differences to the
traditional adsl we may be used to.
The first being that as well as increases in downstream speeds, upstream
speeds will also get a boost.
The most important difference is that the maximum speed that you will
be able to get will be "rate adaptive".
What is the ADSL MAX product set?
Product |
Old Contention Ratio equivalent |
DownStream Speed |
UpStream Speed |
|
|
|
|
BT IPStream Max |
50:1 |
288kbps - 8128kbps |
64kbps - 448kbps |
BT IPStream Max Premium |
20:1 |
288kbps - 8128kbps |
64kbps - 832kbps |
BT DataStream Max |
ISP set |
288kbps - 8128kbps |
64kbps - 448kbps |
BT DataStream Max Premium |
ISP set |
288kbps - 8128kbps |
64kbps - 832kbps |
How does ADSL Max differ from traditional
ADSL?
Traditionally the maximum speed that we are able to achieve is set
on a BT database which is loosely based around the length of lines
and distance from the local exchange.
As has been shown in the past, this database can be wrong, and lines
that may be able to get 2Mb speeds have not been able to do so simply
because the database is wrong. Conversely the opposite has been found
to be true and some 2Mb lines have had to be downgraded to 1Mb or
512kb to maintain a stable connection.
MaxDSL does not work like this, instead new equipment in the
exchange will be able to monitor your connection and ensure that
you get the best reliable speed.
Its not unknown for some lines to sometimes be able to support better
speeds, but something such as a change in weather can cause a connection
to become unstable.
What does Rate Adaptive mean?
That your maximum connection speed is determined by the quality
of your line. Since line quality can vary over time, special equipment
(RAMBO) installed in the exchange is used to monitor your line performance
and adjust the connection speed accordingly whilst on maxDSL.
According to BT, the actual line rate supportable will be determined
during the first 10 days of use, after which time the highest stable
rate possible will be set.
Users downstream speeds will be between 256kbps* to 8Mbps with
increments being in 0.5Mbps increments in between these two figures.
Upstream speed increments are 32 kbps.
*The downstream will actually go as low as 160kbps,
however this can be reported as a fault, and BT will try and bring
the line back up to a minimum of 288kbps.
See here for How ADSL Max Works
Is there any way I can find out what speed I
am likely to get?
Unfortunately until you actually have the service you wont know exactly.
The BT checker should give you an indication of what BT estimates
your line will be capable of. You can see the BT estimate for your line by putting your phone number in this sites ADSL checker.
Be aware that from experience this figure is sometimes
on the conservative side.
This site has a Maximum Speed Estimator for DSL Max & ADSL2+ here
Mr Saffron from thinkbroadband has also
produced another good "guestimator" which
estimates your maximum line speed based on your current line
stats here.
All exchanges which are to be maxdsl enabled are now
"live". Exchange status can be checked from the Plusnet
User Tools site.
Your line will not automatically be upgraded as this is down to the
individual ISP's submitting your line for upgrade. This process may
take several months to be completed.
BTWholesale Bulk Speed regrade process.
ADSLMax should not be confused with the ongoing/recent BTw Bulk regrade
process.
The Bulk speed regrade process is whereby an ISP has paid BTw a fee
to upgrade all their customers connections to a maximum of 2Mb if
their line can sustain it.
This project is a fairly mammoth undertaking as millions of lines
are being upgraded.
This process is costing ISPs a fair bit (£5+VAT
per customer) but its still much cheaper than doing it on
an individual basis (£11.00+VAT).
© 2005
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