FTTC - will I get same speed from any ISP

I have FTTC from a well known ISP based in Yorkshire (allegedly). I pay for 40Mbps and received ~35Mbps for the first year or two. I now receive less than 25Mbps and the line profile appears settled around 26-27Mbps. I understand I am not more than 600m from the cabinet. The BT Broadband Availability Checker says my line should get 32.3-46.4 clean, 29.8-45.1 impacted.

I have had 3 Openreach visits. They find no fault, that the line is clean, reset the profile so I get upwards of 35Mbps but it quickly drifts down to the level I've quoted above.

The third engineer, who my isp told me was a senior engineer, confirmed all the above. He told me that the cause was contention from all the other houses on the copper. He also said that if my isp raised what I pay for to 55mbps from 40mbps then contention would cause the speed to decline by a similar percentage, so that I'd end up around the 35mbps that seems reasonable to expect when I'm paying for 40mbps.

So, I have 2 questions:

(1) Is the solution the third engineer stated - raising to 55mbps scheme - correct? My isp this morning told me the profile would drop to what I currently see, irrespective of how high it's originally configured.

(2) The isp is offering a fourth Openreach visit. This seems pretty pointless given I've had 3 already. However, the benefit from the isp is that if it only produces the same outcome they can offer me a cost-free escape from my contract as a 'solution' and then close the case. My question, therefore, is would going to another isp achieve anything, given it's the same bytes coming down the same copper?

I don't particularly blame my current isp for this - in fact, I commend them for their persistence. I'm asking this question so that I can be better informed for my next engineer visit / chat with my isp over the issue.

Thanks!

Pete

On numbers

1. No the engineer is wrong

2. Given profile resets improve things for a short while suggests the DLM system is seeing instability and slowing you done to make it stable.

So blindly switching ISP is unlikely in the long term to give you better speeds.

Have you

a) Ensured that it is not wiring in your home that is causing an issue, i.e. modem is connected to the master socket and no phone extensions in the home
b) What different ISP hardware have you tried, different VDSL2 modems behave differently and can give a jump of several Mbps

That sounds like Plusnet, who don't sell the "up to 55Mbps" product.

As for the rest of what that third engineer says, it sounds like rubbish. It would make some, in fact perhaps considerable sense if he meant cross-talk between VDSL2 lines. Contention reduces throughput, not sync (connection) speed. Cross-talk reduces sync.

I would have thought changing to any higher level product would make no difference at all to your sync, but that's a non-techie opinion.

In reply to a post by MrSaffron:

On numbers

1. No the engineer is wrong

2. Given profile resets improve things for a short while suggests the DLM system is seeing instability and slowing you done to make it stable.

So blindly switching ISP is unlikely in the long term to give you better speeds.

Have you

a) Ensured that it is not wiring in your home that is causing an issue, i.e. modem is connected to the master socket and no phone extensions in the home
b) What different ISP hardware have you tried, different VDSL2 modems behave differently and can give a jump of several Mbps

Many thanks for your reply. You've confirmed the bits I believed I did know (swapping isp makes no difference as the issue is the copper) but informed on what I didn't - i.e. setting me on a faster theoretical package won't make any difference.

All 3 engineers have stated that the line quality is excellent and the VDSL2 router is plugged into the master socket. There are no other phone extensions in the home and running directly from the test socket gets identical throughput.

Interesting point about VDSL2 hardware. I was previously running the BT white box into a isp supplied router. The isp then supplied a VDSL2 router which allowed me to drop the BT white box. I don't think this coincided with the change in speed though.

As I'm using the isp supplied router I had previously toyed with a 'for money' router, but most research suggested that would make minimal difference. Any recommendations, given you can probably guess my isp from the original post (i.e. based in Yorkshire)?

Thanks again, for taking the time to respond to my question!

Pete

Can you post the actual line stats from the router (at a minimum the sync rate, SNR, attenuation for both up and downstream plus any error stats you can get)? Also the actual "line speed" reported in the PlusNet portal (if that option is currently working)? Plus links to some Thinkbroadband speed tests?

The old Openreach modem, was it Huawei or ECI?

The ISP routers can be a bit hit and miss depending on the exact version, so running a Huawei VDSL2 modem connecting to the ISP router WAN/Ethernet port might help.

In reply to a post by ian72:

Can you post the actual line stats from the router (at a minimum the sync rate, SNR, attenuation for both up and downstream plus any error stats you can get)? Also the actual "line speed" reported in the PlusNet portal (if that option is currently working)? Plus links to some Thinkbroadband speed tests?

Errr, all the isp VDSL2 router offers is:

Connection time: 1 days, 12:41:24
Data Transmitted/Received: 8.7 GB / 193.7 GB
Line state: Connected
Connection time: 1 days, 12:42:34
Downstream: 27.36 Mbps
Upstream: 8.726 Mbps

The latter 2 lines apparently reflect the current state of my line profile.

This is not ADSL or variant thereof.

In reply to a post by MrSaffron:

The old Openreach modem, was it Huawei or ECI?

The ISP routers can be a bit hit and miss depending on the exact version, so running a Huawei VDSL2 modem connecting to the ISP router WAN/Ethernet port might help.

The old Openreach is ECI B-FOCuS V-2FUb/r Rev B.

My current router is the Plusnet Hub One, a re-badged version of the standard BT issue, I believe.

Does the Hub 1 not give better stats? I think in the BT version there is something in help that allows you to get stats from the router but I haven't used the PlusNet version.

In reply to a post by ian72:

Does the Hub 1 not give better stats? I think in the BT version there is something in help that allows you to get stats from the router but I haven't used the PlusNet version.

Unless there's a 'secret' way in, I don't think so. From the A-Z on the router management screens:


A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A
Access Control
Add new game / application
Add new game / application - IPv6
Admin password, Change
ADSL settings
B
Backup hub settings
Brightness
Broadband settings
Plusnet Broadband, Set username and password
C
Change admin password
Change wireless channel - 2.4 GHz wireless
Change wireless channel - 5 GHz wireless
Change wireless key - 2.4 GHz wireless
Change wireless key - 5 GHz wireless
Change wireless security - 2.4 GHz wireless
Change wireless security - 5 GHz wireless
Connectivity check
D
Desktop Help
Devices, Show connected
DHCP Settings
DHCP Settings - IPv6
DHCP Table
DMZ
Dynamic DNS
E
Edit a game / application
Event Log
F
Firewall
Forgotten admin password
G
Gaming
H
Home network
Hub lights, change brightness
I
Internet settings
IP Address, Change
IP address of Home Hub
IPv6 address of Home Hub
IPv6 Configuration
IPv6 Gaming
IPv6 Pinholes
J
K
L
Hub lights, change brightness
M
N
Network Map
O
P
Password - Forgotten Hub Manager Password
Port forwarding
Preventing a device connecting to the Internet
Q
R
Reset Hub to factory defaults settings
Reset wireless settings to default
Restart / Reboot Hub
Restore hub settings (back-up configuration)
S
SSID / Wireless Network Name, Change - 2.4 GHz wireless
SSID / Wireless Network Name, Change - 5 GHz wireless
Supported games and application
T
Troubleshooting
U
UPnP
V
Virtual Server
VPN compatibility
W
WEP, WPA, Select wireless security - 2.4 GHz
WEP, WPA, Select wireless security - 5 GHz
Wireless channel, Change - 2.4 GHz
Wireless channel, Change - 5 GHz
Wireless connections, Enable or Disable - 2.4 GHz
Wireless connections, Enable or Disable - 5 GHz
Wireless key, change - 2.4 GHz
Wireless key, change - 5 GHz
Wireless security - 2.4 GHz
Wireless security - 5 GHz
Wireless settings, reset to defaults
WPS (Wireless Push Button connection), enable or disable
X
Y
Z

When I was on ADSL my Billion router gave me the kind of measurements you've referred to, but when I moved to fttc through the OpenReach white box or now through the combined modem/router there are no visible line stats.

What does the "Troubleshooting" page take you to? I think on the Home Hubs going to help, troubleshooting would give stats.

In reply to a post by ian72:

What does the "Troubleshooting" page take you to? I think on the Home Hubs going to help, troubleshooting would give stats.

I take it back! I was about to say that link only goes to an info page telling you to restart your router etc. But there is a 'Helpdesk' link on that page which, luckily, I clicked. I'm very sorry for doubting you!

This is what it says:
----------------------------------------------------------------------------
1. Product name: Plusnet Hub
2. Serial number: +081441+NQ81827741
3. Firmware version: Software version 4.7.5.1.83.8.263 Last updated 22/03/19
4. Board version: Plusnet Hub One
5. DSL uptime: 1 days, 13:50:22
6. Data rate: 8726 / 27363
7. Maximum data rate: 8719 / 51664
8. Noise margin: 5.9 / 19.0
9. Line attenuation: 33.8 / 22.2
10. Signal attenuation: 34.4 / 19.8
11. Data sent/received: 8.7 GB / 193.8 GB
12. Broadband username: *******@plusdsl.net
13. 2.4 GHz Wireless network/SSID: DataPerceptions
14. 2.4 GHz Wireless connections: Enabled (802.11 b/g/n (up to 144 Mb/s))
15. 2.4 GHz Wireless security: WPA2
16. 2.4 GHz Wireless channel: Automatic (Smart Wireless)
17. 5 GHz Wireless network/SSID: DataPerceptions-AP-5g
18. 5 GHz Wireless connections: Enabled (802.11 a/n/ac (up to 1300 Mb/s))
19. 5 GHz Wireless security: WPA2
20. 5 GHz Wireless channel: Automatic (Smart Wireless)
21. Firewall: Default
22. MAC Address: 08:d5:9d:95:09:20
23. Modulation: G.993.2 Annex B
24. Software variant: AA
25. Boot loader: 1.0.0
-----------------------------------------------------------------------------------------

Hope the above info provides some insight! And many thanks!

With kind regards,

Pete

Cool, I thought it was there somewhere...

This line:

10. Signal attenuation: 34.4 / 19.8

That is the SNR and the downstream SNR at 19.8 is very high and is where your speed is disappearing. The fact engineers have reset this in the past (which is when your speeds have jumped up) suggests there is an issue with your line and DLM keeps increasing the margin to stabilise things.

EDIT : As pointed out by MHC the line I meant to quote was:

8. Noise margin: 5.9 / 19.0

Edited by ian72 (Mon 20-Jan-20 17:08:38)

Two key figures in that:

Attenuation 22.8 or 19.8 and Max Data 51664

For 600m line those are about what I would expect however, something is pulling the line down on reboot/resync as it is working with a 19.0 dB margin and that is what teh sync is down around 25000

How you overcome that, I am not sure.

Try powering everything down and leaving for a hour. Disconnect every cable.
Then power up teh modem/hub without any connections at all and leave alone for 10 minutes. Then make the connection from modem to socket. Again, do nothiong else for 10 minutes, then reconnect a single PC and access stats.

In reply to a post by ian72:

Cool, I thought it was there somewhere...

This line:

10. Signal attenuation: 34.4 / 19.8

That is the SNR and the downstream SNR at 19.8 is very high and is where your speed is disappearing. The fact engineers have reset this in the past (which is when your speeds have jumped up) suggests there is an issue with your line and DLM keeps increasing the margin to stabilise things.

Think you have misquoted - 19.8 is the attenuation, there is also a 19.0 margin on a separate line.

Hi MHC,

Thanks for this. I will try what you suggested tomorrow when I'm home alone!

I'll post the results.

Many thanks, in the meantime.

It just allows everything to quiten down then minimal "noise" when teh reconnection is made. It may also be worth switching off the fridge, freezer and central heating a few minutes before you reconnect.

Oops, selected wrong line by accident.

OP here. The 4th Openreach engineer visited today. He found a small issue with the phone cable from the pole to the house and replaced it. And did a line reset. He told me to disregard any speed variation for 10 days so the DLM could settle my line profile.

He also said that all measurements taken were excellent and there's no reason why I shouldn't be getting much nearer to the 40Mbps that I pay for.

For what it's worth, this is the before and (current) after, taken from the Plusnet router stats page:

- Data rate from 8726 / 27363 to 8904 / 39950
- Maximum data rate from 8726 / 52755 to 8904 / 55301
- Noise margin from 6.0 / 19.5 to 6.2 / 13.3
- Line attenuation from 33.8 / 22.2 to 33.6 / 22.1
- Signal attenuation from 34.2 / 19.8 to 33.9 / 20.2

Assume the changes are good, not bad as the speed is currently as good as I can reasonably expect, albeit subject to revision through the DLM process?

I'll come back in 10 days, in case anyone is interested in how this ended!

Thanks!

Pete

2 days, 10 days or 100 days the DLM is always active, how fast it gets down to a relatively unchanging speed depends on not just the line but the random noise environment it is subject to

In reply to a post by MrSaffron:

2 days, 10 days or 100 days the DLM is always active, how fast it gets down to a relatively unchanging speed depends on not just the line but the random noise environment it is subject to

Thanks - I get it. I probably expressed what the engineer told me incorrectly. DLM is constant, but how long would you expect the line profile speed to settle to a (more or less) constant level after a profile reset?

I understood the engineer to mean that DLM would start with the max I pay for and drift down until the error rate became acceptable, and that it would do this over a few cycles, over (presumably) a few days in order to fully sample line conditions.

Assuming there is no change to the physical nature of the line between the cabinet and my house, this seems (to me) a reasonable understanding of DLM, but I'm very happy to stand corrected!

This morning I get approximately the same stats from my router as the 'After' data I posted yesterday. Happy days! For the time being....

Pete

Correct the profile starts at an open setting, and while its usual to drift down in various steps as the error rate is reduced it might take 2 days or it might take 30.

10 days is probably a good average, but what you have at 10 days can still change and that is the key point.

Also it is not always down, if the first few days are bad but following weeks are perfect the DLM can recover on its own.

Yes, I get it, thanks. Given I was stable for a year or two on ~33Mbps download and then, recently it fell to ~26Mbps this must have been DLM adjusting downwards, as you said.

Hopefully the recabling the OpenReach engineer implemented between pole and house will have corrected any physical issue that would have caused DLM to dial me down.

All the best,

Pete

Your before and after stats are quite telling.
Look at the very high noise margins.

The line is capable of around 55Mb, you pay for 40Mb, but it looks like DLM previously capped/banded your line at 27.4Mb.

DLM caps lines for multiple resyncs in a short time period.
Don't reboot the router multiple times. Turn it off completely if you are having any work done that involves power being turned on and off.
DLM sees repeated disconnections as instability wether they are done manually or not.

The DLM reset has removed the cap and got you back to 40Mb.
As long as the line doesn't resync multiple times the sync speed shouldn't reduce again.

The engineer discussing 10 days training is a reference to the ADSL DLM.
The FTTC DLM starts its thing immediately after a line goes live (or right after your DLM reset).

not read everything but yeah high noise margin indicating possible REIN/SHINE noise or a flappy line (on/off a lot)

also, do yourself a massive favour and get rid of the [censored] Hub One - it is a BT HH 5A with the poor Lantiq chipset - mine and its replacement they sent out kept slowing my throughput (not sync) after 3-4 days... soon as I put a BT HH 5B in which has a broadcom chipset (which are well known for high speeds and solid stability) my speed increased slightly and never had a problem..
a little known fact is that BT replaced the HH 5A (Lantiq) as quick as they could with the HH5B (Broadcom) because it was causing lots of problems...

since then I have put in a Zyxell VMG8924-B10A (Broadcom - unlocked) which allows me to pull advanced stats from it using DSL-stats program.

used it as proof when plusnet speed weent from 80Mb to 55Mb and Openreach changed the MGALS mid live connection..."well the MGALS has dropped by 'X'Mb lets drop the mininum speed by the same 'X'Mb too" I complained face to face with an Openreach boss about that, they cant do that mid a live conection otherwise you could have me paying for 80Mb and let it whittle down to 5Mb and keep me paying the premium.

one of the issues is (and no offence to the enginners who DO know a lot) - but their remit is "in and out as fast as possible...not there to fix speed , only to get it working and stable" - every single engineer says that, when i start showing them print offs of graphs of SNRM, Line Attenuation, QLN, - BEFORE and AFTER they shrug and say "you know more than me mate"... says a lot about them, the UK biggest Internet Provider???

it should also be stated that MAX ATTAINABLE RATE - is always 'inflated' by Interleaving, so if your not on fastpath (like me) so error protection is on... my sync is now 64Mb, it says my max attainable is now 77Mb but really its 70Mb, if errorprotection is turned off I get 69Mb and it reports max as 70Mb - thats about 10% less, for me but could change depending on the speed itself

Just a quick follow-up from OP. The recable seems to have fixed it. Here are the stats from my router from the date of the engineer's visit:

Date Down Up
22/01/2020 39950 8904
23/01/2020 39950 8897
24/01/2020 38171 8886
28/01/2020 33478 8852
31/01/2020 38171 8803
03/02/2010 33478 8894
05/02/2020 33478 8834
07/02/2020 34956 8849

Thanks to everyone who helped me here!

Pete