Your original DSLAM (a Huawei) was installed in 2010 and a 2nd DSLAM was installed at a later date.
The 2nd DSLAM will also be a Huawei.
Take a walk to your local green PCP cabinet and some point. It should have 2 fibre cabinets within close proximity.
Compare the 2 fibre cabinets to the pictures on the page I linked in my earlier post.
Both the Huawei DSLAM's should have G.INP as every Huawei DSLAM has it.
It's possible the drop in attainable is because 1 DSLAM is much busier so there's much more crosstalk in the tie pairs.
It could also be that you've been moved to the DSLAM that is much further away from the PCP.
DSLAM's can be right next to the PCP but they can also be up to 100m away. The further away they are the lower your line is likely to sync.
Getting the ISP to get OpenReach to change the DSLAM isn't possible.
If you are below the minimum guaranteed line rate you could request a port swap but AFAIK* there's no way in the system to request a specific port on a specific DSLAM.
The system could automatically allocate you a port on the same DSLAM.
*AFAIK - I tried getting OpenReach to change me from an ECI DSLAM to a Huawei DSLAM back in January 2017 and was told that wasn't an option in the system.
I had to cease my line and reorder FTTC to get on the Huawei cabinet.
Edited by j0hn83 (Tue 04-Jun-19 13:48:01)