Progressive 8Mb/s drop in 3 weeks on a solid line

[#1]

Other than the farce when G.Inp was introduced (from which my original 49Mb/s and 8ms ping never fully recovered), my FTTC line has been pretty solid since it was installed 2 years ago. >90% of the resynchs being me rebooting the router or trying to find a better gateway. However, over the last few weeks, my speed has started to fall. Here is the TBB speed check plot. It is pretty obvious.

http://i222.photobucket.com/albums/dd237/Zadpics/146012285080942855689-graph_zpsda0bmbjs.png

A progressive 8Mb/s loss over 3 or so weeks. I ticketed PN and their tests show nothing, although the profile has dropped back, matching the speed loss I am seeing. Latency hasn't changed over this period, at around 11ms to bbc.co.uk. Power cycling the ECI modem (something that only gets done very rarely) didn't change anything. It is worth stating that there are very few line resynchs over this period - 1 or maybe 2, following a power drop.

Anyone with any thoughts?

Mike.

[#2]

Hi you say you have a ECI modem is it the BT Openreach one and are you connected to a ECI cab ? 

I ask because i was G.INP enabled yesterday and i have a Openreach modem on a ECI cab and lost around 4Mb of speed and my ping increased ii'm thinking that the openreach ECI modem isn't G.INP compatible and causing the speed drops It's a guess at this stage based on what i'm seeing myself and your issue sounds kind of like the same in loosing speeds with G.INP enabled.   

[#3]

I've just had a quick search of google and apparently the ECI modem isn't G.INP compatible yet.

[#4]

Yes, it is the BT supplied ECI modem. Running (I believe) into a Huawei cabinet. When G.inp was rolled out last year, my upload and download dropped off instantly (see the graph) and going from memory, ping went to 20-something. So nice of BT to roll out cab firmware which was incompatible with the modem they supplied me.

So, so far as I know, G.inp was still running (in its updated form) since last year. I wonder if BT recently rolled out a firmware update for cabs.

[#5]

Hi Zad,

My connection speed has dropped ~70% since the beginning of March, I have graphs to prove it, perhaps the same is happening to you? I'm still trying to work out whether it's Plusnet, BT or my equipment.

https://community.plus.net/t5/Fibre-Broadband/Broadband-speed-dropping-steadily-since-beginning-of-M...

Thanks, Chris.

[#6]

It may possibly be related. The BT stats are showing that I'm using most of the capacity that is theoretically available, but the capacity is getting less and less. In your instance it seems to be using less of the capacity available.Also, my slowdown seems to be accelerating (it lost another 1/2 Mb since yesterday) whereas yours is tailing off. It might still be the same issue though, just manifesting in different ways.

I have to say though, neither "feel" like a phone line problem. If it were water ingress or RFI, the speed would be up and down, and I would be getting lots of resynchs. Equally, if it were crosstalk noise from other users, it would take longer, and I would imagine vary with the time of day.

Right now, it has the smell of a firmware problem, possibly with the exchange side of things. Something like a memory leak causing gradual progressive slowdown when dealing with particular modem drivers. Do you have a Huawei or an ECI modem? Right now, I'm considering buying a Huawei to replace mine, at least I could get stats off it then, and it may deal with G.Inp better.

[#7]

This is interesting. I connected two week ago - possibly the first person on a new DSLAM. First connect was nearly 80 but that soon dropped to the low 70s - OK as the estimate was 67-80.

The stats displayed on the HUB 1 are limited but I could see that the s/n margin was always dropping back from the 6dB target within a day or so and by the end of the second week the sync was down to 64. Some evenings I also get the huge dip in throughput but that seems like a different thing.

My hub is connected to a dual socket faceplate by a short cable so hopefully its not local interference. I think only a BT visit will completely reassure me that's its just line length and to be expected  and not a problem with the cable.

[#8]

Hi Zad,

So your "current line speed" is dropping, while mine is still at 38.6 Mbps? That does sound like we have different issues.

I'm using a Plusnet Hub One, I don't know if that's ECI or Huawei but its menus look a lot like a BT Hub 4.

The smooth tailoff does definitely look like something algorithmic rather than random, but it could be either Plusnet or BT deliberately throttling me, or as you say a firmware bug (can't be local as I have rebooted the modem).

Good luck with your investigation, let us know when you find out!

Thanks, Chris.

[#9]

Well, according to PlusNet support, the drop isn't big enough to be flagged as a fault! Does anyone with any experience know if me purchasing a Huawei modem might help regain my speed and deal with G.Inp better? Having an ECI modem on a Huawei cabinet seems to be the worst of both worlds. Does the "new" PN all-in-one modem/router box have user accessible stats? I find not being able to access stats very frustrating.

Also, is the 40Mb product upload speed really a feeble 2Mb/s? Everyone else seems to be on 40/10. Is the latency equally horrible? I mostly use my net connection for WoW playing+voice chat, BBC iPlayer and YouTube (not at the same time) so don't need huge upload, but 2Mb does seem feeble, and I need low latency for gaming. Right now I seem to be paying £22:50 a month for the £17:50 product. Being out of contract is making me wonder if another supplier might be a bit more enthusiastic about chasing up the problem.

"Downstream Retransmission High" doesn't seem good to me. On all the other stats I have seen on here, it seems to be set to Low. Thoughts? The quoted range also seems at odds with:

FTTC Range A (Clean)

45.5

32.4

9

6.2

--

Available

Test Outcome	Pass
Test Outcome Code	GTC_FTTC_SERVICE_0003
Description	No problem found, OAM test is not currently supported on this line.
Main Fault Location	OK
Sync Status	In Sync
Downstream Speed	38.3 Mbps
Upstream Speed	11.7 Mbps
Appointment Required	N
Fault Report Advised	N
NTE Power Status	PowerOn
Voice Line Test Result	Pass
Bridge Tap	Not Detected
Radio Frequency Ingress	Not Detected
Repetitive Electrical Impulse Noise	Not Detected
Cross Talk	Not Detected
Estimated Line Length In Metres	796.2
Upstream Rate Assessment	Very Good
Downstream Rate Assessment	Reasonable
Interference Pattern	Not Detected
Service Impact	No Impact Observed
Home Wiring Problem	Not Detected
Downstream Policing Discard Rate	0.0
Customer Traffic Level	Upstream and Downstream Traffic Detected
Profile Name	0.128M-44M Downstream, Retransmission High - 0.128M-15M Upstream, Error Protection Off
Time Stamp	2016-04-01T05:00:00

Parameters	MIN	MAX	AVG
Down Stream Line Rate	39.9 Mbps	43.9 Mbps	41.5 Mbps
Up Stream Line Rate	11.5 Mbps	11.8 Mbps	11.7 Mbps
Up Time	834.0 Sec	900.0 Sec	899.8 Sec
Retrains	0.0	1.0	0.0

Current and Last 15 Minute Bin Performance
Parameters	Last Traffic Count(Upto 15 mins)	Current Traffic Count(Upto 15 mins)
Start Time Stamp	2016-04-13T14:15:06Z	2016-04-13T14:30:06Z
Ingress Code Violation	0	0
Egress Code Violation	0	0
Errored Seconds	3	0
Severely Errored Seconds	3	0
Unavailable Seconds	0	0

[#10]

Yes the 40mb package is 2mb upload, those who have 10mb upload would have purchased the package when it was 40/10 and therefore they stay on that speed.

What kind of stats do you want to see? You could always go on ebay and have a look for a cheap bt home hub 5 or possibly a hub one!

[#11]

Luckily I do have a BT appointment booked. Over 3 weeks my line rate has progressively dropped from a first connect of 80M down to 62M on a new DSLAM with 67-80 estimate. After a sync the Hub 1 shows a S/N margin of around 6.3dB but this then starts to drop and within days is below 5dB - and the next sync is lower by another 5-10% to achieve the 6dB target margin - and so on.

For the margin to be steadily decreasing I can only think the downstream power is being reduced - but this stat - along with error counts - is not shown on the Hub 1

[#12]

Update time.

PlusNet arranged for a BTO visit today, the chap came and did a line test, pronounced it clean, and also fitted a Ver.3 faceplate (was previously a BT fitted Ver.2). Speed has increased from 35.64 Mbps to 37.45 Mbps (+1.8 Mbps) but interleaving has kicked in and I have lost 8ms of ping. I don't remember if interleaving takes a chunk of bandwidth too, but I had expected if anything that he would do a reset and I might have reclaimed some speed. However, he didn't do any cabinet work, so I guess a reset isn't possible and it interpreted the new filter as interference and backed off. I guess this means I now have to wait 2 or 3 weeks to see if interleaving (or whatever it is) drops off.

The BTO guy just seemed to be geared for home line testing, so wasn't able to comment on if it might be a firmware problem, or an exchange/cab issue, and said I should contact my ISP. Fearful of a £50 charge, I did ask in my ticket if a replacement modem might have been appropriate rather than calling out an engineer, but nothing was forthcoming.

What is interesting is that from what I saw of his stats, the line capability is a potential 56Mbit. I also saw that the line needed to be below 22Mbit to be classed as a problem! Which doesn't really help me. I had hoped he would have at least reset the line at the cab, but that's not part of his remit.

What stats do I want to see from a modem? Well, the line synch speed (so I don't have to rely on TBB speed tests and the network in between), line attenuation and margin, synch up-time, preferably something that shows the frequency channels/bins, software version (so I can see if it has been push updated). The usual stuff.

Does the PN Hub 1 play nicely with Huawei cabs and G.Inp? Failing that, what model Huawei modem am I looking for on Ebay?

Cheers again,

Mike.

Postscript: The speed decrease stopped shortly after my initial contact with PN support, which might imply that something to do with a remote test had some effect on the degradation. It didn't improve until today, but the speed test was remarkably consistent, with both Down and Downx6 reading exactly the same. Not sure what that indicates, but it never happened before.

[#13]

Hello,

If I'm right DLM resets are done from the property and not the cabinet. Also if no fault on the line was found a reset wouldn't take place.

IIRC the hub one and home hub 5 support G.INP (only down) however don't quote me on that. Let's just hope you stay synched and DLM plays nicely and removes interleaving. This can take days to weeks

[#14]

I also received a visit from a BTO engineer. He changed my previous ADSL faceplate for a BT mark 3 and just ran lots of tests which came up with nothing. He said he had done a DLM reset but I noticed no difference.

So I was left with a 62Mb/s sync but no explanation as to why the line speed had been dropping from an initial 79Mb/s and why the S/N margin falls after a sync. The measured line length is also a fair bit more than the road distance to the cabinet. It was a new DSLAM which I was activated on only 4 weeks ago.

I thought the speed had at least bottomed out, but today it fell sharply yet again - to a line rate of 55Mb/s (the estimate was 67-80)

[#15]

So are the PN Hub One and BT HH 5 the same beast internally? It would be nice to have better WiFi and an integrated modem / router, but if it doesn't support G.Inp Up and down then I'm not sure it will improve matters. They do seem to be a bit cheaper on Ebay than the standalone Huawei modem.

Anyway, the line resynched at 1am this morning (no stats difference that I could see) then just now at around 2:30pm, which would be almost exactly 48 hours since the BT chap connected things back up. Ping has dropped to nearly the old level (13ms vs 11ms) but sadly no speed improvement. Still waiting for a Ticket update anyway.