Your sync speed is the speed at which you connect (synchronise) to the local exchange at. This speed is negotiated between your router and the DSLAM at the exchange and will be subject to line conditions such as your SNR Margin and line length.
When an End User logs on with maxdsl an "Event" will be sent to the DSLAM. Your modem/router will negotiate with the DSLAM what speed your line can achieve. Details of these events are monitored by the DLM (Dynamic Line Management).
Maximum Stable Rate. (MSR)
During the first 10 days on MAX details of your logon/sync events are recorded in an Event Collector which every 15 minutes then sends this information to RAMBO.
RAMBO collates events from all users and analyses each users data over a 10 day period to find the Maximum Stable Rate (MSR) for their particular line. The MSR is set from the lowest achieved rate over this 10 day period rounded down to the nearest 0.5Mb. A notification after this period is sent to the RAP profile and your ISP.
During your first ever log in to maxdsl, information is sent from RAMBO over to RAP which forwards the details over to the DSLAM at the exchange in order to set your sync speed.
Sync speeds (and Data Rates) for poorer lines can and will vary over the 10 day training period and these users may experience frequent disconnects and slower speeds until their most stable rate is found.
Even tho its sync'ed at 7.6Mbps it will still have to stabilise over the next 10 days or so. During those days your speed should increse and the lowest speed it can handle will become your maximum d/l speed.
Fault Threshold Rate.
Once your MSR has been set, BTw use this figure to calculate your Fault Threshold Rate which is in the region of 70% of your MSR.
BTw will only investigate speed related faults if your speed drops to below the Fault Threshold Level.
Data Rate (bRAS profile)
The Data Rate is the fastest speed (throughput) that you will be able to download at and is profiled by BT at the bRAS.
A maximum throughput level is needed to stop more data than your line can physically achieve being sent down the backhaul and being dropped at the DSLAM.
The DLM continually monitors your sync speed and line performance... and the system should react to any decreases within 75 minutes and any increases within 3 days.
Most customers do seem to find that their line has a Data Rate profiled at the bRAS within 3 days, although its not uncommon for some users to find that they have been profiled at 2Mb speeds for anything up to the full 10 days.
The Data Rate should not be confused with the MSR.
Some ISPs allow you to check your Data Rate.
The bRAS profile (data rate) is based on your lowest sync speed, and jumps up in 0.5Mb stages.
So although you may get higher sync speed, your bRAS profile will limit you to what throughput speed you are likely to acheive.
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