A few (4) DLM interventions later and my primary line, running happily for months at 67Mb, looks a little different.
Banded like a boss.
Harsh.
Do you happen to have any indication of what the trigger was? (Errors/Retrains).
I doubt whether 'just crosstalk' (which is more of a constant) on its own has caused that. Lower sync, entirely possible. Banding, unlikely.
My line has had about 4 DLM interventions over the past few months, but its been high rates of E/Secs in the 10's of 1000's and it has relented in between.
From the pre ASSIA info I had (which was available to ISPs too) it would have been most likely excess retrains over a fairly short time frame that would cause an ILQ scarlet situation - resulting in probable banding. I'm not sure what changes have been made since as they remain pretty tight lipped these days. I do know that during a scarlet situation DLM has the capability to look at some other factors such as FEC/SNRm. To make 4 changes in less than 2 weeks shows DLM was not a happy bunny.
SNR and max attainable shows surplus, but level of INP not given and unsure if your surplus varies over the course of the day.
Pure speculation but the line was possibly flapping all over the show or throwing an exceedingly high amount of errors.
I physically notice when my starts throwing 1000's of Errors, pages take an eon to load, speeds drop to just a few Mbps and vids buffer. I'm quite sure you will have noticed that type of situation, but then again do you /did you have G.INP and that may have made a little difference. If you do then LEFTRS type errors may be the important ones that DLM takes note of.
I also wonder just how possible it could be that during activation of the 2nd pair, something has been disturbed on the 1st.
I could be talking out of my backside as I have very little info to go on from what you've told us, but my instincts are screaming that's not normal crosstalk.
I doubt this will actually get resolved
Depends on what BTw quotes for your line estimate. If it was an engineer install your ISP should use the clean range.
- That said some ISPs of late tend to be using the MGAL figure which can vary from ISP to ISP and doesnt take into account past performance.
Banding is extremely hard to get rid of without an engineer reset.
However like you say, problem is crosstalk on 2x pairs within the same cable. It's a known high risk situation.
Roll on that VM cable day which no doubt cant come soon enough.
Whats line 2 performance like?