BT Infinity Sync/Speed drop

OK... please bear with me.

Moved house 4 years ago. Had infinity 2 installed. Have been running at top 80/20 speed up until recently. About a year ago swapped hub for Billion 8800NL and could see my max attainable rate was around 88000/90000 and I was on 79999/19999 speed. This has been like this up until about 3 weeks ago.

Kids complained that they had issues with xbox so looked at router stats and I'd dropped to 20000 down despite max attainable rate still being around 88000. Rebooted router and my max attainable rate dropped to 71000 and my speed was 71000. Rebooted again, stayed the same. Logged a fault with BT. They did some checks outside and said there was a line fault. They worked on it while I was away on holiday and I chased up on my return last weekend. They said they had fixed it, but my max attainable rate had dropped further to 68000 and speed around 67000.

An engineer has just came round and checked the line from my internal socket and said there's no fault. He's requested a line reset and told me about the 10 day retrain. I've currently got a max attainable rate of 69000 and a current speed of 59000.

Really don't know what to do as I'm about 200-250m from the cab and the cab is about 20m from the exchange.

Massively frustrated, any advice?

Edit: Added some screens of router stats at various points:

Normal stats as in pre-fault for the last 4 years
Pre-Fault

Post-Fault
Post-Fault

Just now, after reset
Current

Edited by MrGimper (Mon 11-Jun-18 14:47:51)

10 day retrain - and I won millions on the lottery at the weekend, both are equally false.

On a DLM reset the line should run freely for a day or so and then the DLM will intervene, this can reduce speeds or if options like lower noise margins kick in will speed you up, or G.INP can speed you up too.

One issue is that we have a big gap in the data from a year ago to three weeks ago, it may be that cross talk has been increasing i.e. result of more people taking the service and slowed your attainable down and possibly even slowed the sync speed down a bit, therefore it may be that current sync of 59 Mbps is a lot closer to what your sync was just before the fault.

The G.INP value of 3 on the current stats shows G.INP is off, and that can be worth a good chunk of speed and generally takes a week for the DLM to decide its fine to switch it back on.

NOTE: The switching off/on of the various elements can happen at anytime i.e. the 10 days to settle down is nothing of the sort since as conditions vary over time and the inputs to the DLM system change it will make its mind up based on the algorithms accordingly.

Thanks for your feedback. With respect to the big gap in data, I'm a bit of a sucker for visually checking these stats regularly on my router, and I'm 99.99% happy that there wasn't any creeping death around a month ago.

In reply to a post by MrSaffron:

10 day retrain - and I won millions on the lottery at the weekend, both are equally false.

BT say the same with FTTP as well, which makes me laugh, and you can argue that with them until you are blue in the face, so it just shows that BT Support have no clue what they are saying.

Paul

Ok - was worth mentioning.

The G.INP coming back on might be a 5 to 10 Mbps improvement so watch for the G.INP showing 48 in the stats, but should be obvious from the speeds you are getting.

Will G.INP increase my attainable rate, or just my rate?

Brain is not totally sure on the answer to that one as the modems I've had did not show the attainable

G.INP will increase both your rate and attainable but only if previously your line was interleaved.

Edited by WilliamGrimsley (Tue 12-Jun-18 11:42:54)

Thanks
Current settings for interleaver from router.

D (interleaver depth) 1137
I (interleaver block size in bytes) 64

My speed dropped suddenly about 6 weeks ago after almost 2 years of a solid 80/20 with 75 down and 19 up, the up speed is still the same,but the down is now 65, nothing else has changed in the stats, it almost as if the wick has been turned down at BT's end, at the same time BT started to offer me a new product which guarantees 100 down, maybe I am being cynical but BT won't look into the issue until the speed drops below 65,so is this an attempt to encourage me to move to the new product