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BT Wholesale Max product glossary
Sunday 18 June 2006 09:40:00 by Andrew Ferguson

The launch of the Max products by BT Wholesale in April 2006 has brought a number of new terms to the UK broadband scene, here we try to outline in simple terms the more common terms and acronyms.

  • Line Sync Speed - this is the speed your ADSL modem has negotiated with the DSLAM. The line sync speed can alter at anytime with a Max product, it is not fixed. If your ADSL modem drops the line a lot (e.g. more than 10 times in an hour) then the BT systems may alter the target noise margin, which has the effect of making the modem negotiate a lower sync speed which will hopefully be more stable. By having a higher noise margin your ADSL connection will hopefully be more immune to spikes in the noise on the line.
  • BRAS Data Rate - this figure is set by systems run by BT Wholesale, it is not visible to the end-user in their ADSL modem or routers configuration pages. If your router is showing a Data Rate value it is actually showing you the line sync rate. The BRAS Data Rate has 16 values it can be set to, and these are documented here. Which value you are given is determined by the BT systems looking at your line sync speed. When you first regrade to a Max product the default Data Rate is 2Mbps, but within 75 minutes it should alter to match the value corresponding to your line sync rate. If your line sync rate varies at anytime after this then the BT systems check whether the BRAS Data Rate has changed. If it needs to drop, then this will happen immediately, if your line sync speed has improved the BRAS Data Rate will only increase if the higher line sync speed is maintained for three days. The BRAS Data continues to behave in this way no matter how long you have had a Max service, i.e. it is not fixed at the end of the 10 day training period.
  • MSR - Maximum Sustainable Rate - this is the one figure that is set at the end of the 10 day training period, and is purely recorded for fault finding purposes. The systems record the lowest sync speed seen in the 10 day training period.
  • FTR - Fault Threshold Rate - this figure is derived from the MSR, i.e. it is 70% of the MSR. So if you have an MSR of 1152kbps, your FTR will be 800kbps. If you report a fault on the ADSL line, and the line sync speeds are under this FTR value, then BT Wholesale will look into why the sync is consistently low. NOTE: This is referring to line sync speeds and NOT the figures shown by speedtests, also occasional drops of line sync speed, e.g. due to a storm, or the neighbours electric hedge trimmer will not count as a fault.

If you have any questions about the Max products in general try asking in our BT Wholesale section.

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