FTTC Speed Decline

[Anonymous]

Just another update G.INP was re-enabled on the line, delay went back to 0ms so that's fast path right? I never had a problem with latencies in the past though and G.INP was always enabled at 4/1, that did change to 8/1 in the past month though. G.INP came back on at 8/1 interleave and my current sync speed is now identical to the max attainable rate at around about 61Mbps (57Mbps throughput) with a noise margin that currently stands at 6.3dB on the downstream. 1 day 15 hours since the resync and 0 errors on the line thus far. FEC's keep having random 15 minute meltdowns. Went to bed last night at 20K, got on the PC about 17:00pm and 90K, checked just now and 95K, everybody just keeps telling me to stop worrying about them numbers, just wanted to report them anyway. Fingers crossed things remain stable. I have read that if dlm thinks my line is stable enough my noise margin could even decrease and give even better speeds by raising my max attainable and lowering my noise margin to 5, 4 or even 3dB, if that happens great.

If this corrosion was the issue all along I'm astonished this wasn't found sooner. By all means look through my thread history and check the screenies in my old threads, had these data sync and noise margin issues ever since I switched to BT from Virgin Media back in 2016.  Data sync lowers, noise margin increases and bam banded. Max attainable stays the same then eventually lowers too. Never any noise in the quiet line test, HUB only ever really went down on 14 day cycles, it just never made any sense to me. I have been monitoring my line recently through the stats and also thinkbroadband and honestly I don't think anyone is even on FTTC near here, it was one of the reasons I switched to BT to begin with, Virgin Media was overly congested and most people will be attracted by speed and less about consistency, and now I have all the stats at my disposal, crosstalk seems to be even less than an issue than I thought. Obviously there are lots of people connected to FTTC, but I still believe most are on VM, we also have two FTTC Huawei cabinets in our area, I'm connected to the one that serves a different area entirely, whereas the other one covers most of the area I live in. Just wanted to waffle on and point that out.

One question I have though if my line does remain stable when will the estimates begin to adjust based on my current line condition? I have clearly had a fault causing the banding and data sync rates to gradually drop since 2016, so my current estimates, at least with BT are really low. 32Mbps minimum guarantee with a estimate of 40-50Mbps. Telephone checker estimates are still accurate with A range 67Mbps with a B impacted low of 44Mbps, and my observed rate has now switched to 61Mbps sync as of today. If I was to sign up for another contract with BT I wouldn't want to do so at those estimates. Most of the other competitor sites (won't name them) seem to base them around the telephone checker estimates, and those estimates are prone to increase or decrease based on the current line conditions, just thought I'd ask before I post this. 

[Anonymous]

Another update - The stats continue to look stable at the moment. dlm is currently testing the 3dB noise margin. Not quite sure why my noise margins are higher than most though. Upon resyncs my noise margins since testing 5, 4 and now 3 always sync at .5 or .7 instead of 5.0, 4.0. 3.0. If things remain as they are that corrosion found on the wire may have been the issue afterall. Approaching 5 years of having this lowering sync rate problem and everybody said regular dropouts was the issue, which I was always adamant it was not, as it was never frequent enough. Not only did it continue to lower my sync rates over a long period of time but it was banding me at every step too. 

Based on the stats below I am now very close to what I had when I first signed up to the service (On a full cabinet) an engineer years ago said my line was about 580m as it didn't follow the quickest path via roads.

If things continue to stay as they are the only issue left is INPRein =1. It was enabled when my line went to test the lower noise margins 5, 4 and 3dB. Throughput is now like 5Mbps short of the sync rate (3% overhead loss vs 8% or so loss) Fast.com and BTW Performance Tester flicks between 62 and 63Mbps. The upload speeds are still inconsistent, but I don't think that can be resolved. dlm reset did nothing for upstream and that continues to float between 14 and 16Mbps. It keeps dropping everytime a resync occurs at the moment.

BT still believes I can only achieve Superfast Fibre 1 with Halo unavailable. Even though the current package I'm on out of contract is Halo 1. BT continues to think my line is only capable of 40-50Mbps with a minimum guarantee speed of 32Mbps even though my line issues seem to have been resolved if the line remains stable.

Max Observed Downstream Speed, Max Observed Upstream Speed, Observed Date - Via Broadband Availability Telephone Checker.

71.19

15.21

2021-04-07

[picktech]

Just a thought but you could buy an even better router than bt supplies with a vpn and the like all ready in there, as for the speed it is usually them playing about to get you to sign a contract, or is it me just cynical,