The DLM system then cannot interpret the data for all lines on that DSLAM.
Woah, thats pretty bad. Not being able to interpret data for the bad device is kinda fair enough, but to mess up everyone else's figures on the DSLAM is not good
I'd take a stab at Asus too, but there also have been problems with a few of the older Drayteks which do not appear to play nice on Openreach's cabs.
Even so... how can it be allowed to screw up the data for everyone else on the cab. Surely there must be some code they could put in to properly escape individuals set of data. Thus they can use ILQ Grey for the offending line.
I'm not quite sure what they can do about the existing rogue modems.. no doubt they should be able to track back and identify which line it belongs to. They should be able (in time) to be able identify the modem type and contact the manufacturer... who will hopefully be able to provide new firmware. The problem then is.. would all users update the firmware?
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I didn't think UPBO was anything to do with the DLM, I thought it was mostly based on the length of your own line.
You are correct. Spectral Power Management is completely separate to DLM management.
I have also seen mine vary between resyncs - even using the same modem, but its not DLM related.
Spectral Management (UPBO & PSD masks) are used to lessen the effects of crosstalk. eg:
On ADSL/ADSL2+ to stop shorter lines drowning out longer ones.
On VDSL to stop VDSL lines drowning out ADSL/ADSL2+
Sometimes your modem can give you a little bit of a power boost (AGC) if there has been a lot of bitswap in an attempt to keep the line in sync... but there is still supposed to be a max figure. Not sure what it is on VDSL because of all the different profiles, but it was 20dBm for ADSL2+
Thats one of the reasons why there is the huge possibility for some of the ASUS modems to cause havoc on some DSLAMs as they are about the only modem I know of whereby it allows you to completelely turn off UPBO and adjust the AGC GAIN... thus affecting every other connected line.
There was quite a long thread on here a few years ago about it. These ASUS modems totally over-ride DSLAM spectral management which is a DSL standard and not really supposed to be tweaked by the EU at all.