Last update 11 January 2013
Dynamic Line Management runs constantly on Openreach FTTC.
It operates in a different way from the BT Wholesale ADSLx one, in that line stability is in general maintained by varying high depths of Interleaving, (if Fast Path proves not to be suitable), and/or banding.
Banding is the setting of a maximum connection speed below the unstable “free” one, and a minimum one about half the maximum set.
It seems from posts on thinkbroadband forums that if banding is applied due to short-term noise trouble and disconnections, after five days or so with stability and without that noise it removes the banding.
At the time of writing, to remove banding after a fault fix the engineer has to request that from a Control Centre - I don’t know the name of it.
When a PPP connection to the ISP/CP is established by the user’s modem a message is sent to the CP’s BRAS or Radius servers to notify it of the connection speeds. This enables traffic control by the CP to avoid feeding data faster than the line can handle, as that would cause packet loss and retransmissions.
The BT IP Profile is the most-widely known about such traffic control system.