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Author Topic: Slow Infinity  (Read 1159 times)

bbnovice

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Slow Infinity
« on: July 09, 2019, 06:37:49 PM »

Hi

It has been a long time since I posted here but I would appreciate some advice.

I have been on BT Infinity for very many years getting a download speed of around 70Mb.

In April I renewed my BT contract for another 18 months. The new tariff I called  SUPERFAST FIBRE PLUS and, which according to the BT blurb offers and average of 67Mb – that is slightly lower than I had received previously. That I accepted.

A week later (according to the BT Wholesale Speed Checker site) the download IP (the max achievable speed according to that site) was suddenly dropped to 60.66Mb with a throughput of around 57Mb. Since then the IP profile has remained unchanged but the throughput is now averaging around 52Mb.

I logged this as a fault with BT. They would not accept this as a fault as the 52Mb is above their “minimum guaranteed speed”. I argued that I would not have renewed on that tariff if I had been aware that 7days later my speed would deteriorate so much.

I raised several formal complaints, the first of which was closed unilaterally by BT on the grounds it was not in breach of the minimum speed rules. However I persisted and forced them to send an OR engineer who visited today.

He immediately detected a battery fault about 400 metres from the premises but thought that this was not the cause of the slowdown in speed.
He was very thorough and replaced incrementally every piece of kit in my network, stripped out every extension and disabled the WiFi. He then used this cut down network (and his own laptop) for conducting tests at every stage.

To cut a long story short, what he found was perplexing. He demonstrated there were no faults in the HG612, the Home Hub and my desktop. His snazzy diagnostic kit reported that the theoretical maximum downstream rate on my line is 74Mb with an actual rate of 72Mb. The SNR was 3.3 and he considered the line to be very stable. Using a HH6 the connected speed to the modem was reported as being 69Mb which is what he was expecting. However, the actual throughput would not exceed about 54 Mb no matter what.

He concluded that there was no fault as from OR’s perspective the line is  providing a stable connection of 69Mbs (the history of the last 30 days DLM behaviour was reviewed and corroborated this was stable) which is close to the maximum theoretical speed that this line can support.   
 
His opinion is that there is something happening on the ISP side (congestion? speed cap?) which is preventing the 69Mb throughput from actually being achieved  por even coming anywhere close.  As BT now prevents OR from viewing what is going on at the ISP end he could only speculate. He advised me to report all of his findings in detail to BT but was highly sceptical that they would do anything about it, and would just close the complaint as “no fault found”.

Has anybody else encountered anything like this before? And if so, I would appreciate some guidance as to how to tackle BT.             
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gt94sss2

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Re: Slow Infinity
« Reply #1 on: July 09, 2019, 07:02:05 PM »

I have been on BT Infinity for very many years getting a download speed of around 70Mb.

In April I renewed my BT contract for another 18 months. The new tariff I called  SUPERFAST FIBRE PLUS and, which according to the BT blurb offers and average of 67Mb – that is slightly lower than I had received previously. That I accepted.

The difference in the advertised speed is due to changes in advertising rules - it should not make any difference to the speed achieved.

Quote
Has anybody else encountered anything like this before? And if so, I would appreciate some guidance as to how to tackle BT.             

It would be interesting to see the stats from your line. However, its possible that the fact that you can't get more thamn 54MB (over ethernet not WiFi I assume) could be due to congested links from your exchange to BT Retail (the ISP).

Does the maximum speed decrease below this in the evenings? (peak periods?) If so, this is another possible sign of congestion.

These links are maintained by BT Wholesale not the ISP side or Openreach.

It might be worth posting a concise version of your post on the BT Community Forums outlining what has happened and asking if a moderator can check for signs of congestion of at your exchange (you will have to say which one it is!) given that the OR engineer has said the physical line is fine.  Your modem stats may also be asked for.

The moderators are the only official BT staff on the forum and they are a special team who will 'own' your issue until its resolved -  I've had very positive experiences with them in the past - though it may take them a few days to pick up your case after you are asked to submit details to them.
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Weaver

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Re: Slow Infinity
« Reply #2 on: July 09, 2019, 09:05:29 PM »

Clarification, my apologies very tired this evening. Is this 54 Mbps of actual, measured TCP downstream throughput?

If so, packet loss is also a possible contributor to loss of performance in download/upload speed tests that use eg TCP. This is either a kind of badness or natural traffic management happening somewhere in the internet path, not necessarily in your line even, where packets are getting thrown away. This could either be due to
  • data corruption (mangled packets getting detected as such and thrown away), or
  • congestion (too much traffic, no room for all the packets coming into a router or a link), or
  • traffic management by a router.
I recently had a case of slow upload because of data corruption. I reconfigured the link settings so that the modem was using more conservative settings and this reduced the link speed but in fact the gains from fixing the problem outweighed the link speed reduction and made measured transfers actually a good deal faster. What was happening before was that additional copies of mangled data had to be resent and this wasted effort was what was slowing things down. Once the data corruption was fixed, no more wasteful retransmission of extra duplicate data, so no slowdown.
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bbnovice

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Re: Slow Infinity
« Reply #3 on: July 09, 2019, 09:28:35 PM »

gt9 – thanks for the reply

The OR engineer had confirmed that the connection is good and is performing as expected. He cannot explain the reduction I am seeing in throughput and suspects that there is some sort of issue on the BT side (as the relevant ISP). I always disable WiFi and all connections to other devices whilst running speed tests.
 
The throughout speed is fairly constant and does not vary by time of day, but as the OR guy confirmed, it’s about 14Mb less than it should be. Because the throughput speed is fairly constant he did not think it is being caused congestion. It’s almost as though I have been placed on a lower BT packages (eg Fibre Unlimited).  He urged that I contact BT over this, but didn’t think they would be at all helpful.

Ideally I would like to set up the HG612 and get the stats but unfortunately I am also dealing with family illness at the moment, and have already spent too much time on this. So that will have to wait for another day unfortunately.

This whole issue has been the subject of 3 formal complaints with BT. They have shrugged off the last 2 saying that as I am getting more than 40Mb I don’t have a case and they unilaterally closed the complaints. So this is attempt number 3 at achieving a resolution  – I must be masochist !!

I note your tip about the Community Forum, but I think I will let the formal complaint run on first. I don’t want to have too many hares running at once.

Weaver – also thanks
I’m not sure of what you mean by “Is this 54 Mbps of actual, measured TCP downstream throughput?” as my technical knowledge is limited.
The 54Mb is the actual throughput figure reported by the BT Wholesale Speed Test site – similar values were reported when using other sites such as OOKLA.
Today the OR engineer replaced all items in the internal network incrementally and tested the speed at each stge. Eventually we ended up with a network comprising just his laptop, and a replacement modem (HH6) with a wired connection. No other devices were connected, all extensions were disconnected, and the modem was connected directly to the OR faceplate. WiFi was disabled. After all that the throughput speed was unchanged. The OR guy said that the speed was very much lower than he would have expected.   
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gt94sss2

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Re: Slow Infinity
« Reply #4 on: July 09, 2019, 11:01:59 PM »

Ideally I would like to set up the HG612 and get the stats but unfortunately I am also dealing with family illness at the moment, and have already spent too much time on this. So that will have to wait for another day unfortunately.

Sorry to hear about the family illness.

It is possible to get some basic line stats from the HH6 - if you go to the modem's GUI under Advanced/Technical Log/Information
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Weaver

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Re: Slow Infinity
« Reply #5 on: July 09, 2019, 11:27:38 PM »

Understood. :-) You’ve answered my question, thanks for that. So as you say, the figure is from speed testers such as speed test web apps or other such apps. The reason I ask is that sometimes people quote maximum link speed capability figures that are reported by modems (‘stats’) and these represent the very best possible speed limit abilities, but are nothing to do with tests involving actual data transfers. I just wanted to clarify as to which kind of reported figure that was. Thanks.
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bbnovice

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Re: Slow Infinity
« Reply #6 on: July 10, 2019, 12:13:52 PM »

Here are some statistics. Do these numbers seem OK?

9th July

Maximum actual speed that could be supported by the line (according to the OR engineer’s diagnostic equipment) = 72.04/14
Downstream connected speed between exchange and the modem (actual sync) (according to the engineers diagnostic equipment) = 69.15
IP Profile (according to the BT Wholesale speed checker) = 60.47/20
Speed (according to the BT Wholesale speed checker) = 54.88/10.93

There are very few errors on the line which is why the downstream SNR is as low as it is (3.3). The line has been very stable over the past 30 days history.

The internal network, connected devices and equipment in the house were all tested by the OR engineer and no faults or issues were found.

The OR engineer believes that there is no physical problem with the connection, but the actual throughput seems to be somewhat lower than expected.
 
10th July

The IP Profile has dropped a bit today but I’m not surprised bearing in mind all the messing around on the line yesterday.

IP Profile 56.99/20
Sync speed (according to a HH6 which I have borrowed) = 65.31/13.63
Speed (according to the BT Wholesale speed checker) = 52.72/10.67
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dorzb

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Re: Slow Infinity
« Reply #7 on: July 17, 2019, 11:47:34 AM »

Here are some statistics. Do these numbers seem OK?

9th July

Maximum actual speed that could be supported by the line (according to the OR engineer’s diagnostic equipment) = 72.04/14
Downstream connected speed between exchange and the modem (actual sync) (according to the engineers diagnostic equipment) = 69.15
IP Profile (according to the BT Wholesale speed checker) = 60.47/20
Speed (according to the BT Wholesale speed checker) = 54.88/10.93

There are very few errors on the line which is why the downstream SNR is as low as it is (3.3). The line has been very stable over the past 30 days history.

The internal network, connected devices and equipment in the house were all tested by the OR engineer and no faults or issues were found.

The OR engineer believes that there is no physical problem with the connection, but the actual throughput seems to be somewhat lower than expected.
 
10th July

The IP Profile has dropped a bit today but I’m not surprised bearing in mind all the messing around on the line yesterday.

IP Profile 56.99/20
Sync speed (according to a HH6 which I have borrowed) = 65.31/13.63
Speed (according to the BT Wholesale speed checker) = 52.72/10.67

Has anything changed yet? I had exactly the same issue a year ago, and it turned out BT put my line on the 50mbps contract rather than 67mbps. Don't know if this is the same case for you.
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bbnovice

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Re: Slow Infinity
« Reply #8 on: July 20, 2019, 08:26:08 PM »

Hi dorzb

Apologies for the later reply but only just seen your post.

The speed has got worse since I last posted. According to the BT Wholesale Checker today:

IP Prodile 58.36/20
Actual speed 49.52/11.67

According to the HH6 the download sync speed has dropped to 66.84

The exchange was down for broadband (not voice) intermitently on the 17th. BT Customer Services told me that these outages were affecting large numbers of customers connected to this exchange.

Also the result of the official complaint I received on the 16th - I can take a run as I'm getting better than 40Mb and there are absolutely no problems at this exchange. Well that was untrue wasn't it !

I queried the contract set up but was told this is for the fastest speed.

So I've gone from an average actual speed of 71Mb (which I enjoyed for a long time) to 49-50Mb and BT expect me to accept this as "normal". 

As far as I'm concerned there's something very fishy going on with BT.



     



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kitz

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Re: Slow Infinity
« Reply #9 on: July 22, 2019, 04:29:48 PM »

Quote
So I've gone from an average actual speed of 71Mb (which I enjoyed for a long time) to 49-50Mb and BT expect me to accept this as "normal".

Crosstalk will be to blame for a large chunk of it .   
I got full 80Mbps for 4/5 years, but the last year or so that has eroded further so that now I can only sync at ~65Mbps.  My biggest noticeable loss was when my immediate neighbour went from adsl2 to FTTC last year and I lost >8Mbps in one fell swoop.  :/
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fat jez

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Re: Slow Infinity
« Reply #10 on: July 22, 2019, 07:27:25 PM »

Crosstalk will be to blame for a large chunk of it .   
I got full 80Mbps for 4/5 years, but the last year or so that has eroded further so that now I can only sync at ~65Mbps.  My biggest noticeable loss was when my immediate neighbour went from adsl2 to FTTC last year and I lost >8Mbps in one fell swoop.  :/

My line used to sync at ~100Mbps when FTTC first went in.  Now I get around 84Mbps (SNR OF 12dB) It was as low as 78Mbps at one point, then Virgin Media came to our estate and I think a few jumped ship and the speed went back up.

However, i’d expect crosstalk would have been reflected in the max sync speed the OR engineer could see on his test equipment.
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bbnovice

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Re: Slow Infinity
« Reply #11 on: July 31, 2019, 06:27:52 PM »

Hi Jez/Kitz

Sorry not to have replied earlier but I have been away.

If crosstalk is truly the cause then I suppose I will just have to accept it. I just wish that OR and/or BT could be honest though - its a pain having to suffer such a downgrade in speed but I would accept it if they provided a reasonable explanation. As it is they just treat you like dirt and just parrot "..its above the OFCOM minimum..." .... so live with it!

I've closed the BT complaint - its just not worth any more wasted hours.

Regards BBN
 
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fat jez

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Re: Slow Infinity
« Reply #12 on: July 31, 2019, 08:50:40 PM »

Crosstalk would affect your sync speed, but it should also be reflected by the sync speed that the OR engineer’s test equipment shows the line to be capable of.
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