, the ALMS will then drop the target noise margin down to 3db allowing the modem to drop its noise margin
Hmmm, I was about to question the concept of 'allowing a modem to drop margin', since modem's generally hang on to a connection regardless of variations in noise, as long as they can maintain sync with the DSLAM.
But, thinking further, are we saying that ALMS tells the modem to only allow the margin to drop so far, but to voluntarily reconnect if the margin falls below some ALMS-controlled threshold? From a quick look at G.992 (/G.997) I see that 'Minimum Noise Margin' is a defined parameter, and does indeed seem to support such behaviour.
If that's the case, then it would be interesting to see what happened if a user tried to 'tweak' the target. ALMS may decree (say) that the target is to be 12db, and the minimum is to be 6db. If a user then tweaks the 12dB margin down to circa 6dB, then every reconnect could be quickly followed by a 'low margin' event, triggering another reconnect, triggering another 'low margin' event, and so on... I do hope they've thought this through.
- 7LM
