Rex Leyland
13th Jun 2010, 11:56
Is it true that when you change to a super adsl service there is a 2 week stabilisation period? This means that you get an interrupted service whilst the exchange equipment is supposed to be trying to balance and optimise the service. It's happening to me right now and although is terribly annoying, I am assured that after a fortnight my service should be a minimum of 6 megs.
Somebody please confirm either way.
Thanks.
I believe 10 days is quoted - Google 'Bras profile' (no, not that)
5711N0205W
14th Jun 2010, 11:31
This is from Plus Net but should hold true for any service using the BT Wholesale product;
Broadband Terminology Guide (http://www.plus.net/support/broadband/speed_guide/broadband_terminology.shtml)
During the first 10 days your connection will be given a value known as the Maximum Stable Rate (MSR). The MSR is the lowest sync speed (line rate) achieved in the last 10 days, not as the name suggests, the maximum sync at which the line was stable.
Here's an example. My new ADSL2+ connection syncs at variable rates between 8 and 10Mbps. It's stable at 8Mbps but occasionally drops the connection at 10Mbps. If conditions change, (perhaps I plug in a phone extension or change the microfilters), I now see the modem synching unreliably at 256kbps and dropping every 5 minutes. I then replace all my microfilters and the line returns to the previously seen pattern. In this case my MSR would be 256kbps but I'd probably see a stable 8Mbps download rate and synch at 9Mbps after the line had stabilised.
The MSR value is just used to work out when a drop in sync speed would be considered a fault*. It's important to understand it is not a guarantee of speeds that you should expect for your connection and that ADSL2+ and Max are rate-adaptive. This means your speeds will vary throughout the lifetime of your connection. We don't publish your MSR value as part of your broadband service...think of it as for administrative purposes only. However, if you'd like to see what data transfer speed you are receiving on your connection please see your BRAS Profile.
What BOAC said.
The BRAS profile is responsible for regulating the maximum throughput (data rate) you will receive on your broadband service. Initially this is set to 2Mbps (if the line rate is above 2272kbps), but it will increase if your line can support higher speeds than this. The first data rate increase should take place within 75 minutes of your first connection. Your BRAS profile however, changes only when a stable connection has been made for a period of time; this may be up to 3 days in some cases. The BRAS Profile will also drop should the line rate decrease significantly.
And DLM (Dynamic Line Management)
DLM is a feature that is run on all Max and ADSL2+ services that are provided by BT Wholesale, to analyse line performance information on their network. It uses this information to determine whether or not a line is unstable and, if it is, will make some configuration changes to try and stabilise the line at the fastest possible speed.
Generally, the performance of a broadband line is reviewed on a daily basis, unless it is what BT refer to as a 'flapping line' or one which drops the connection regularly. These are generally reviewed more frequently. Once a line has been stabilised, the DLM changes become less frequent.
It is only when a line experiences a period of instability where this process is restarted. The reconfiguration of these lines will involve changes in the 'line profile'. Once a change to a line profile has been requested, there is a delay of approximately 2 hours before the change is actually made. When this change occurs, there is a brief drop in connection, typically for about 30 seconds.
Where there is a deterioration in service the speed at which the DLM will react will depend upon the severity of the problem. A connection which drops once a day will see profile changes occur less quickly than if a line was disconnecting far more frequently.
DLM for ADSL2+ is able to use banded profiles. Initially, all lines are configured to run in a fully rate adaptive mode. That means there isn't really any maximum or minimum capability of the broadband service within technical capabilities.
For lines which drop frequently, a banded profile can be applied, which will restrict a line's connection speed from connecting at a level which it can't maintain. Banded profiles operate with a minimum and maximum connection speed band. For example, one banded profile will control the connection speed from between 3.3 and 6.6Mbps.