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TommyBjorkberg
Beginner
943 Views
Message 1 of 6

Sharing my experience with Ultrafast

Hi all, 

I thought I would share some of my experiences with BT Ultrafast Broadband which I had installed a while back. As someone who worked in the industry for tha past 20+ years you can imagine I can sometimes be a nerd reegarding new services and like to lool udenr the bonnet. 

One I first got the Ultrafast service it work perfectly for the first 3 weeks but then noticed that there was a number of restarts in the middle of this night mainly between 3-5am (I keep an monitor actve on my Broadband line). I had been getting 280-300 Downstream pretty consistantly and modem was always synced at 300mbps+ with the line card. I live less than 150m from the cabinet and the copper lines are very good into my proprty so within the range for G.Fast Range A (Clean). 

Anyway after 3 weeks I notced the Sync speed had droppped significantly and would not sync with the mincard any higher than 200mbps and sometimes only 100mbps and the line also fell below speed guarentee for a few of the tests using BTs tool. Anyway I reported the issues and was assigned and engineer the very next day (excelent work BT).  After some troble shooting we couldnt really find an underlying issue but it was obvious something was not right so the BT engineer went out of his way to call in a favour and we did a shift and lift in the cbainet and switched ports onto which I was connected and straight away the modem sync speed was back to over 300mbps (great work BT). 

I was asked to monitor the service for a few days to see if it was stable or not and this is when I came accross an interesting behaviour betweeb the modem and the linecard. 

The setup in my home is the Hub is in the living room and I am connecting some devices over wifi and I also have some devices connected with Powerline Ethernet Adapters Solwise AV2 1200 which provides great speed. 

What I discovered was that when doing anytype of speed test activities on wifi or connected via ethernet straight to the hub the symc speed between the modem and line card stayed constant however when doing any type of speed test on my PC which is one room over and connected via POE the modem sync speed drops significantly when DL test is in progress.  Ofcourse its probably the case that the broadband connection between the modem and line card has a higher real world throughput than the POE connection between my PC and the modem as there but this would also be true using wifi in various locations in the house as signal streanght vary. 

So for whatever reason if using wifi or ethernet plugged straight into the Hub the speed between modem and device (wifi or fixed connected) dosnt matter and modem always synced at the highest speed 300mpbs+ but when using a device connected via POE and the bandwidht used gets high the modem sync speed drops with 30% and the actaul Broadband connects slows down. 

I am a bit baffled between this behaviour and would not expect the connection between the modem and the line card act as a throtle no matter what my home setup is. For example if I have 4K streaming and few other things going everything is fine and if I at the same time run a speed test on my PC the pverall broadband speed drops by 25-30%. 

The only thing I can think of is that there is some issue when using wired connection and if there is any buffering or packet loss between modem and device due to mismatch in throughput between modem and line card and modem and device the modem starts to panic and throtle the whole connection. 

Anyone else have this experience and also is there a way to resolve this ?

 

/Tommy 

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pippincp
Sage
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Message 2 of 6

Re: Sharing my experience with Ultrafast

Can you post evidence of your connection being throttled between modem and line card? What part of the industry were you in for 20+yrs as that is the first thing I would expect.

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TommyBjorkberg
Beginner
905 Views
Message 3 of 6

Re: Sharing my experience with Ultrafast

Dear Mr Guru. 

First thank you for your reply althoug I do find the tone of your reply a bit condecending and hostile but to answer your points see below: 

1. I never said that BT is activly throtheling the Ultrafast Braodband Line but with the behaviour I am experiencing the end result is similar to being throtled when doing certain activities such as Speed test or downloading large files etc, any activity that pushes the Download limit. 

I have attaced a link to video in which you can see how the moden is synced at 300+mbps with theh line card and once I start the BT whole sale speed the modem sync speed drops dramatically indicating I am no longer getting the throughput I would normally and once the DL part of the test is over sync speed resumes to over 300mpbs again.  

https://www.dropbox.com/s/0h2ynrfcbt57e8b/IMG_2427.MOV?dl=0

The same behaviour occures with any speed test or FTP transfer I have tried. 

2. Not sure what my industry expereince has to do with the behaviour observed as this was mentioned in the contex of "this makes me a telecoms nerd who likes to get to the bottom of things" but sinc you asked I spent 15 years working for Ericsson in various roles starting from Engineering ending with a number of Senior Management Roles, I then moved to Telefonica UK where I ran several departments (Fixed & Mobile Infrastructure) before moving to ZTE as a Director for 5G (Fixed Optical & Mobile). If you want to know more just search my name in LinkedIn. 

Now when we got this out of the way I would like to summarise what I am experiencing. 

1. If a device is connected to the Ultrafast HUB via WIFI there is no issue with modem sync speed no matter how good or bad the signal is, I am able to get 250mpbs throughput using speed test on my mobile phone. 

2. If a Device is connected directlly to the Hub using an ethernet connection there is also no issue and as expected the throughput ia a bit better mostly staying steady at aroun 270Mbps download. 

3. If a device is connected to the Ultrafast Hub using Power Over Ethernet (1200 AV2 adapters into the next room) and I do anything that pushes the bandwidth to the maximum i.e speed test or File transfere the Ultrafast Hub starts lowering the sync speed drastically and when finished immediatly resumes syncing at normal speeds again. 

After some investigating this leads me to some conclusions or I should say hypothetical conclusions which is the following. If you have a perfect connection between deivce and Ultrafast Hub such as Wifi or Direct connection from device to Ultrfast hub there is no issue. But if you have any form of home network sitting behind the ultrfast hub such as using POE in case which might introduce some packet loss or jitter between Device and Ultrafast Hub which in case causes any buffer in the Ultrafast hub to fill up and once this has happened the Hub or Lice card starts acting as a throtle and reduce sync. 

Ofcourse I dont know for sure I dont have an analayser between modem and line card or can can via the Ultrfast Hub GUI see CUP/Memory Utilization, buffer level etc. 

What I would expect no matter how my home network is configured is that if I have a good connection between my Ultrafast Hub and the Linecard in the cabinet this shoudl always operate at the best available speed and not drop the line speed between Hub and Linecard if there is a connection issue between Hub and device. The result of this behaviour is that If I am streaming TV in one room, using some tablets and some one playing playstation at the same time evrything is good but If I then at the same time decide to start a file transfer or run speed test from my PC the Ultrfast Connection will reduce is speed by about 1/3 for the whole house. 

Personally and again this is just my view, I belive this behaviour is incorrect and that there could be an issue in the Ultrafst Hub that decides to drop the Downstream sync rate if experiencing any buffering and packet loss issues then effect leading to throteling of the connection in it self. 

I have only done my investgation using the standard Home Hub supplied by BT as I dont have the seperate Huawei router or one from ASUS, Zyxel etc at my disposal but it would have been interesting to see if they exhibit the same behaviour not. 

Your help and feedback is mych appreciated and I hope you are having a good day. 

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Keith_Beddoe
Distinguished Sage
Distinguished Sage
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Message 4 of 6

Re: Sharing my experience with Ultrafast


@TommyBjorkberg wrote:

The setup in my home is the Hub is in the living room and I am connecting some devices over wifi and I also have some devices connected with Powerline Ethernet Adapters Solwise AV2 1200 which provides great speed. 

What I discovered was that when doing anytype of speed test activities on wifi or connected via ethernet straight to the hub the symc speed between the modem and line card stayed constant however when doing any type of speed test on my PC which is one room over and connected via POE the modem sync speed drops significantly when DL test is in progress.  Ofcourse its probably the case that the broadband connection between the modem and line card has a higher real world throughput than the POE connection between my PC and the modem as there but this would also be true using wifi in various locations in the house as signal streanght vary. 

So for whatever reason if using wifi or ethernet plugged straight into the Hub the speed between modem and device (wifi or fixed connected) dosnt matter and modem always synced at the highest speed 300mpbs+ but when using a device connected via POE and the bandwidht used gets high the modem sync speed drops with 30% and the actaul Broadband connects slows down. 



Powerline adaptors are know to interfere with broadband, as they share the same frequency spectrum. Interference will cause the sync speed and throughput to drop, The more data they carry, the greater the inteference. You would be better to run Ethernet cable if possible.

Interference to broadband caused by powerline adapters or broadband extenders

 

TommyBjorkberg
Beginner
885 Views
Message 5 of 6

Re: Sharing my experience with Ultrafast

Hi,

I can partially buy this I say partially as I have seen with my own eyes in a lab settings that G.Fast can work perfectly well with POE. If this is a known issue don't you think that there is some design issue with the power supply/onbord power unit of the Home Hub which is unable to filter out any interfering signals. I remember in the fast various home consumer electronics devices such as TVs etc could experience issues when using a powerful drill plugged in on the same electronic circuit but all these issues have mainly been solved using better power unit design and components. just feel a strange that my broadband service would be effected by something plugged into my power sockets.
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Keith_Beddoe
Distinguished Sage
Distinguished Sage
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Message 6 of 6

Re: Sharing my experience with Ultrafast

Its the fact that the adapters work by transmitting radio frequency signals over domestic mains wiring, which is not designed for carrying RF (Radio Frequency), as it s not a proper balanced transmission line, and is actually very unbalanced.

As a result of this, quite a lot of RF is radiated from the mains wiring, and from any devices plugged into the mains.

This RF will find its way into the phone wiring, especially if the wiring is close to the mains. Some radiation will be present on the hub power supply unit, and at those frequencies, will easily migrate to the low voltage side of the power unit.

You can reduce the effect of this interference, by making sure that none of the phone wiring of any extensions, are near to the mains wiring.

Plugging the home hub into a filtered mains socket, may help, although many are not that good at filtering RF, and are mainly just surge protectors.

You are never going to eliminate the interference from powerline adaptors, so you either have to put up with the reduction in broadband speed, or run some Ethernet cables, and not use any powerline adaptors at all.