AAISP gets TalkTalk to fix overhead issue affecting VDSL2
Some AAISP customers are now back to enjoying the full speed of their VDSL2 circuits, the problem was most noticeable on the faster VDSL2 lines i.e. connecting at 60 Mbps and with actual throughput from speed testing running several Mega bits per second below that people would expect.
AAISP after some testing of their own, got TalkTalk to do the same testing and after some test changes that fixed the problem all the AAISP TalkTalk backhaul VDSL2 connections have had the change rolled out to them. Whether this improvement/bug fix affects all TalkTalk Wholesale VDSL2 circuits or just AAISP we don't know, but we would presume TalkTalk has checked and implemented any changes needed for all its wholesale customers.
The fix is described as a change to "overhead accounting mode in use for VDSL customers." i.e. the throughput was lower than would have been expected. On BT Wholesale VDSL2 circuits the general rule is that maximum throughput should be ~96% of the sync speed, but there are some combinations of ReTx that do see the maximum throughput dropping to ~91%.
If you are an AAISP whose speed has dropped and sync speeds are at their normal level and nothing has improved yet, then restart the authentication on your router or the more old fashioned turn off and turn on should see the line pick up the changes.