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mikec1
Aspiring Contributor
663 Views
Message 1 of 22

Coincidence or skullduggery?

I've posted before on this forum regarding an unexplained and frustrating overnight drop in Infinity 2 speeds from 60 Mbps to 45 Mbps.

 

It's a long and frustrating story but after several rounds with BT I gave up long ago on trying to get the original speed restored and have had to do with 45 Mbps, which has remained unnerringly constant in every test since around last April.

 

Yesterday I negotiated another 12 month BT contract and as part of that belatedly took the opportunity to downgrade to Infinity 1, which I was advised now has an upper speed limit of 55 Mbps. Indeed the new contract particulars give an estimated download speed for me of between 52 and 55 Mbps, and a minimum guaranteed speed of 46 Mbps.

 

As my connection for the past year has never quite got up to 46 Mbps, I was curious and re-checked the speeds this morning (the very first day of the new contract remember). Lo and behold both the BT Wholesale and Ookla speed checkers reported that my download speed was now 51.5 Mbps - almost a 15% increase!

 

How can that be? I was categorically assured throughout the earlier complaint process that my connection was technically incapable of achieving speeds in excess of 45 Mbps! (Not that I believed that for one minute)

 

I can only imagine that, unless there's been a very peculiar and magical coincidence, there are hands behind the BT screens twiddling download speed dials - again something that's been categorically denied.

 

Anyway, at least the 'downgrade' from Infinity 2 to Infinity 1 has resulted in an increased download speed - long may it last. But based on previous experience I'd better not hold my breath!

 

Incidentally, when I belatedly realised that my actual Infinity 2 download speed fell into the Infinity 1 range a few months after its cap was raised from 38 to 52 Mbps, I tried to get a refund but was told that I'd left it too late! Bless 'em!

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21 REPLIES 21
Guru
655 Views
Message 2 of 22

Re: Coincidence or skullduggery?

Neither ... Both ADSL and VDSL systems use complex algorithms to set linespeed ... after an initial line IP is set (automatically) by dynamic line management. It's not a human process, it's a computerised fully automatic one that runs under pre-defined rules and conditions. There are various aspects of "unwanted"conditions that can and often exist ... crosstalk, impulse noise on the copper pair, atmospheric disturbance (storms), and so on. Even the temperature of the copper cores in telephone wires on the final "mile" could cause an effect, allbeit small. The sum total of your connection is the result of a plethra of conditions being automatically analysed by ongoing line algorithms to ensure as consistent as possible a good end user experience. And if it falls within the parameters of acceptibility, it's healthy.
mikec1
Aspiring Contributor
632 Views
Message 3 of 22

Re: Coincidence or skullduggery?

Thanks for your response Roger but sorry, I heard all that before in 2015 when others were trying to explain the overnight drop in my download speed from 60 to 45 Mbps. It is still my opinion that that could not have been due to any drifting technical conditions or algorithms.

 

Nothing in your response seems to explain the immediate 15% increase in download speed on renewal of the contract to magically meet the new minimum contract condition. And there's certainly been a performance intervention in reducing my upload speed from 19 to 10 Mbps overnight - that's definitely been triggered by the switch to Infinity 1 with its reduced upload speed cap.

 

The evidence I've accumulated over a period of some years now seems to rule out the effect of algorithms and physical effects in my case, so I stand by my conclusion.

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Guru
626 Views
Message 4 of 22

Re: Coincidence or skullduggery?

Points taken ... but also bear in mind that because you have entered a new contract, but more so, a different product your line will have been totally reset ... discarding all past historical line information. So now DLM is treating your line as if it was a new one. It will try differing methods of error correction and other things whilst always try to adhere to a set of "preferred" conditions. For example, if errored second count is extremely low it will maintain a fastpath condition ... if counts rise because of burst impulse noise, sooner or later it will invoke interleave ... and one of about fifteen permutations of interleave depth, both on the upstream and (or) downstream data paths. The more it has to invoke, the greater the loss in clean linespeed. The algorithms are designed to be ever changing and flexible to sustain the line condition. (without humans).
Extankerman
Contributor
610 Views
Message 5 of 22

Re: Coincidence or skullduggery?

Would that I had the speeds that you have, gentlemen! I have Infinity 1 but the download speed has never been better than the minimum guaranteed of 14 Mbps. After all the nonsense of last weekend (well documented elsewhere) the service was eventually restored to some sort of consistency but now my average download speed is 12.5 Mbps and the already pathetic upload has dropped by a similar proportion.

 

I am convinced that someone, somewhere is 'twiddling knobs'; the question is, how do we pin down BT? Is the regulator doing anything about this? Has there been any contribution from the moderators, in relation to this issue?

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Distinguished Sage
Distinguished Sage
594 Views
Message 6 of 22

Re: Coincidence or skullduggery?

If you thought about it for just one second, what is the point and advantage of anybody 'twiddling knobs' even if that were possible, which it isn't. Why would you deliberately upset a customer?

Extankerman
Contributor
585 Views
Message 7 of 22

Re: Coincidence or skullduggery?

BT don't seem too fussed about whether they have upset customers or not. The absence of any sensible information is bound to lead to speculation. By the way, I have thought about it for more than a second.

Guru
569 Views
Message 8 of 22

Re: Coincidence or skullduggery?

Trouble is ... "The absence of any sensible information" is the bit most people have trouble with, unless you have an indepth knowledge of both BT data transmission line algorithms ... or physics in general. Just because it's uncomprehensible by some doesn't mean BT are to blame ... they're far too busy running the network and constantly updating systems and algorithms to stop people complaining. And even BT can't defy the laws of physics! 😉
Distinguished Sage
Distinguished Sage
560 Views
Message 9 of 22

Re: Coincidence or skullduggery?

Do you honestly think that there is a person sitting at BT/Openreach with the job of checking ever ones line and "twiddling a button" to slow speeds down shortly after they have become a customer and conversely the person has to "twiddle a "button" to turn up the speed just after you re-new or change your package.

 

The most likely reason is because, as has been pointed out by RogerB, your line/DLM has probably been reset when you changed your package. 

 

You will find out in the next few days if that was the reason because if the noise/fault that caused DLM to lower the speeds in the first place have not been resolved, DLM will start to lower the speeds again until it finds the best speed to maintain a stable connection and you may find yourself back to where you were.

mikec1
Aspiring Contributor
532 Views
Message 10 of 22

Re: Coincidence or skullduggery?

Thanks for all your comments above on this interesting but vexed subject.

 

It has been asked above why BT would wish to deliberately upset a customer. Let's ask the reverse. If it is within BT's power simply and perhaps routinely to 'reset' a line when a service contract changes, thereby effecting a significant performance boost (if even in the short term), why would they choose not to do that when faced with an official complaint about a very significant drop in download speed - such as the one I raised almost 2 years ago when my download speed suddenly dropped by 25%?

 

All I got was shrugs from the administrators and implausible reasons from a 'technical expert' who could only suggest things such as a significant increase in the number of local subscribers. What, overnight? And in a fully developed suburban district! It was she who told me that, based on some specialised tests she carried out on my line, I couldn't expect to get any more than 45 Mbps  - which was the point at which I realised I was banging my head against a brick wall.

 

That's how the situation remained until now, when the magic (and previously technically impossible) 15% increase in download speed materialised. Perhaps it won't last, as has been suggested. I'll report back after the customary 10 days of settling down time has elapsed.

 

With regard to the point that 'even BT can't defy the laws of physics', a fairly recent experience with BT's offshore call centre indicated that they think they can. When, as an aside to the main topic of conversation I happened to mention my dissatisfaction with the significant speed drop about 18 months before, the call handler said 'not to worry, I'm going to refresh the line now and the speed will be restored whilst you're on the line'.

 

When I expressed incredulity, based the previous painful history, I was again assured that 'refreshing the line would solve the problem'. Perhaps they did try to 'reset' the line but, perhaps needless to say, it made no difference at all. If the line did have that extra 5 Mbps to give, it didn't give it to me then (last November).

 

Perhaps the proposed separation of Openreach from BT will make them more directly accountable and accessible to customers having service level issues, but again I won't hold my breath.

 

It's been nice chatting with you, but reality is dawning again so I'd better sign off for now.

 

I'll make a note to come back in 10 days or so with news of any change in my windfall speed increase.

 

Kind regards

 

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