Good news and bad news

[Rik]

BT have introduced changes to the way profiles are handled following a low sync event.

The old Max logic rules meant higher sync rates were required to be sustained for 3 days to invoke an upwards BRAS profile move, irrespective of the degree of line rate change.

Adaptive Max Logic will look at the percentage of the line rate increase to determine the period before an upward BRAS profile change is implemented. A small percentage increase in line rate may mean a wait of up to 5 days to change the BRAS profile, but where a larger percentage change occurs, the BRAS profile could change within a very short time (4-6 hours). These timescales are indicative and may vary depending upon the load on BT systems.

This way any lines that have dropped to an artificially low line rate for any reason ( e.g..
thunderstorm) and revert to a higher line rate soon after may only need to wait a short time for the higher BRAS profile to be invoked.

OTOH, if you drop a single profile step, you are likely to wait five days for the recovery, bad news for people who sync close to a profile step.

[colirv]

OTOH, if you drop a single profile step, you are likely to wait five days for the recovery, bad news for people who sync close to a profile step.

This is where it's handy to have something like the DMT tool. In the (very unlikely) event of a lost connection, I have it set automatically to resync at an SNR margin of 4, which it means it's very unlikely to change profile. I then tweak the sync rate to be just above a profile step, giving me a good SNR margin and so a stable connection.