Maxdsl (Update)

[Realist]

Some more info regarding Maxdsl.

I'd like to clear up a few misconceptions about how the MAX DSL service works and specifically answer a question that is becoming a theme.

I want to explain a few terms first.

Line Speed
This is the speed at which your equipment and the DSLAM Sync up at, this may change every time you turn your router off or you have a disconnection.
NOTE: The kinds of things that will have an influence on this are;
• Distance from the exchange
• Line Quality
• SNR and Attenuation
• Your internal wiring within your premises, i.e. Filters, extensions etc.
• Your Router or Modem
• The Firmware or Driver for the Router or Modem

Max Stable Rate:
ONLY after the first 10 days is this decided, it’s done on the basis of the performance of the line over the previous rolling 10 day period. Once this has been decided it will set a profile for the line on the BT BRAS and from that your throughput is determined.
NOTE: Due to patents etc, BT will not disclose what analysis is done on the line to determine this value.

Throughput:
This is how much data can to pass across the line. This is your actual speed while browsing and downloading etc.

Fault Threshold:
Once the Max Stable Rate is determined so will the Fault Threshold. This is 30% less than the Max Stable Rate. This will determine if BT will investigate any complaints about speed or not.
NOTE: It is very important to understand that your Throughput has nothing to do with this at all. BT will only investigate a possible speed problem if your LINE SPEED is less than the Fault Threshold.

BRAS Profile:
Once the line has a Max Stable Rate then BT will give it a profile which is done on the BRAS. This profile will determine the maximum Throughput a line can have. This is done because between the DSLAM and then BT’s core network there are chunks of bandwidth and to use that bandwidth in the most effective way possible they won’t allocate more that the Max Stable Rate to a line, this will prevent bandwidth being wasted.
NOTE: This value will always be in ½ Meg increments so it will only ever be something like 2meg, 2.5meg, 3meg 3.5meg etc.

So then the answer to the question

Q: What speed should I get during the 1st 10 days?

A: Once the line has been provisioned and the circuit is a MAX DSL line, the very first time that your router syncs up, that LINE SPEED is used to set a temporary BRAS profile for the line for the first 10days. After the 1st ten days & once the Max Stable Rate is set the BRAS profile will change and allow more Throughput.

A possible scenario:
My line is provisioned as MAX DSL, my router syncs up for the 1st time at 5.3 Meg, BT set the BRAS profile up as 5 Meg, even if my line syncs up at a faster speed during the 1st 10 days my throughput will not be more than 5 Meg. When my line is given the Max Stable Rate, the BRAS profile will change and I may get more or less Throughput depending on the performance over the previous 10 days.
(So for those of you unlucky enough to sync at 2 meg for the first time even if your line syncs at a faster speed after that for the 1st 10 days you will only get 2 Meg Throughput.)

Read and take note.

Laters