Connection speed dropping

[sparky]

I was under the impression that if you had a noisy line or a router than keeps re-synching that the DLM increased your target SN Margin? Is that the way it works?

I have had some problems with my line lately, don't know what is going on, and have tried all the usual stuff, including a different router, but every time that I re-connect, the noise margin stays constant, but my connection speed gets lower   Have just tried again as it's a nice bright sunny morning, but its dropped from 2240 to 2080. I'm reluctant to try any more for fear of dropping down to a 1.5Mb IP profile.

Link Information
   
Uptime: 0 days, 0:26:58
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 2,080
Data Transferred (Sent/Received) [MB/MB]: 2.48 / 14.79
Output Power (Up/Down) [dBm]: 12.0 / 16.5
Line Attenuation (Up/Down) [dB]: 31.5 / 50.0
SN Margin (Up/Down) [dB]: 22.0 / 5.5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 78,063
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0

[Rik]

DLM can increase your target noise margin to stabilise the line. It looks to me, though, that what you're seeing is the router negotiate the best speed it can at the time it resyncs, with a target NM of 6db. IOW, your line is picking up a lot of noise.

[sparky]

Thanks Rik. Well, there is no audible noise, it's not in my house as it happens with a different router connected directly to the test socket.

Idnet support have cottoned on to the BT phrase "line degradation" so I suppose I can do nothing until the line breaks completely! 

[Rik]

The noise would be in the MW radio band. Do you have a battery-powered MW radio?

[sparky]

Yes, I do. I did think about that.  Need to get some batteries for it, but will try that later.

Will let you know if it picks up anything.

Thanks.

[Rik]

Happy hunting.

[sparky]

OK Rik. Found some batteries.

It sounds like a car engine running whenever I put the radio near the telephone socket !

I have a ring main socket 12" away from the BT Master Socket, so I guess I will have to eliminate that as well, although putting the radio next to other sockets on the same ring main doesn't have the same effect.. Providing I eliminate my ring main, and still have the noise when a router is plugged directly into the test socket, will Idnet/BT respond to that as a fault and be able to fix it?

[Ardua]

will Idnet/BT respond to that as a fault and be able to fix it?

ISP forums are full of unhappy customers who agree to an engineer visit only to find that a charge has been levied for a No Fault Found. Mysteriously, it is often the case that the line stabilises some time after the visit. My conclusion having considered taking this route in the past is that BT has been given a licence to print money. There is no transparency and as far as I can see no appeal. Why the independent ISPs are not making more of this issue defeats me. What hold does BT have over them?

I can offer 2 further thoughts based on my own experience:

1.  Stop re-booting the router and give the system time to respond. My speed increased after 3 months and has done each month thereafter.

2.  Do as others have suggested on this forum. Move to AAISP for a month and see whether they fair any better. If they don't, you can move back after a month and owe them nothing. Slightly messy but no risk of a £200 charge.

[Rik]

As Ardua says, RFI problems are particularly difficult to get BT to act on.

[sparky]

OK Guys.  Many Thanks.

It seems we are all held to ransom by BT. I think I will for the time being, leave well alone and see if the line will sort it self out, I did have a resonably stable 4Mb profile before it all kicked off.

[jezuk1]

I've had a lot of trouble with DLM on my line, the connection has remained sync'd for long periods of time (sometimes a month or more) and then suddenly there is a resync and a significant reduction in speed for no apparent reason. The only way to restore the line back to the normal speed is to initiate the training process once again, and no surprise that once it's back to the higher speeds it's perfectly stable just like it always was. So clearly nothing permanent has changed with my physical phone line to prevent it from supporting the higher speeed that it always normally operates at!

I'm really sceptical about this system. There's a lack of information about what processes and logic are being employed within the realm of BT to determine what settings are applied and there's no way for the end user to customise them either (that i'm aware of).

[sparky]

Well, I'm still getting problems on my line, don't know what if anything I can do about it. Take a look at this log, this is happening regularly at these sort of times. The startup was me plugging in this Netgear in place of my Speedtouch to see if it would fare any better.

Thu, 2011-09-01 18:55:56 - Administrator login successful - IP:192.168.0.2
Thu, 2011-09-01 18:54:28 - Router start up
Fri, 2011-09-02 01:33:25 - Loss of synchronization :1
Fri, 2011-09-02 01:49:55 - Loss of synchronization :2
Fri, 2011-09-02 02:39:26 - Loss of synchronization :3
Fri, 2011-09-02 02:54:57 - Loss of synchronization :4
Fri, 2011-09-02 03:21:27 - Loss of synchronization :5
Fri, 2011-09-02 05:07:29 - Loss of synchronization :6
Fri, 2011-09-02 05:22:30 - Loss of synchronization :7
Fri, 2011-09-02 09:28:26 - Administrator login successful - IP:192.168.0.2
Fri, 2011-09-02 09:35:57 - Administrator login successful - IP:192.168.0.2

I'm still coming out of it with this:-

ADSL Link Downstream Upstream
Connection Speed 2240 kbps 448 kbps
Line Attenuation 49 db 15.5 db
Noise Margin 6 db 23 db

But I'm wondering if I would be better off powering off my router when I've finished with it in the evenings, rather than risk this noise problem which seems to occur overnight ?  Any thoughts?

[Rik]

If it's always overnight, then a power down may be a good move.

[sparky]

Its interesting (well, I could think of other words!) to see so many members of this and other forums complaining about BT line problems lately. They seem to be getting worse.  Mine has changed again.

Whether it's related or not, I don't know. As per my first post here, I have been unable to connect at a speed that correlates to my noise margins since the night of 30th/31st July (a Sat/Sun night). Before that I had a reasonably constant 4Mb profile. My SNR has remained constant at 6db. Yesterday, that changed. I noticed yesterday morning that my line speed had dropped significantly over night after a cluster of re-synchs and that my SNR had gone up to 12db overnight. A reboot of my router initially brought up a connection of 4096, this does drop after several re-synchs, so all is not perfect, but this is the first time I have got an initial connection of over 2500 since 31st July.

I then find out, that overnight, coinciding with this change, my neighbour has moved from BT to SKY LLU. Her switchover, was that night. Presumably, that is when they pick up the wires and move them?

Now I know that because we live next door to each other doesn't mean the wires are next to each other at the exchange, but doesn't it sound like work at the exchange is impacting my line?

[Rik]

Or on the road, Sparky. Do you have any work being done in preparation for fibre?

[sparky]

Well Rik,  the current date for our exchange to go FTTC is March 2012 although back a few months, it was Dec 2011, so I would think it might be a bit early for that. Although you never know. I haven't seen anything obvious.

Our village (pop approx 2500) is a bit out on a limb (3km) from the exchange though, so even though the exchange will get upgraded, I don't hold out a lot of hope for us getting FTTC.

[Rik]

The reason I asked is that they're working on our cabinet at the moment, and I've had a number of resyncs, presumably as they move connections around.

[mervl]

Our village (pop approx 2500) is a bit out on a limb (3km) from the exchange though, so even though the exchange will get upgraded, I don't hold out a lot of hope for us getting FTTC.

I had the same sort of problems on Orange LLU then WBC as sync speeds declined through 5.5Mbps, 4.1 and then down to 2.2 before rising to 4.5Mbps on WBC so I'm sure the exchange equipment can make a difference; whilst NM stayed at their standard 9. However, there might be hope as I'm in the same situation in a similar size remote village 3km+ from the suburban exchange, and they have brought FTTC to the local cabs straight away once the exchange was enabled (which surprised me due to the low population compared to the rest of the exchange area, and the cr*ppy underground local loop with hundreds of repair joints and hardly a pavement left untouched by BT digs over the last 20 years), and so far after two months it's been a steady 32Mbps sync at well over 600m from the cab,  and actual downloads in the 18-30Mbps range. Still at an average speed locally of 3.5Mbps, it's had few takers and no publicity!

Just out of interest in terms of timing, the cabs first appeared throughout the village in April a couple of metres from the existing cabs, and FTTC services became available in mid-July a couple of weeks after the 1st July enablement date for the exchange. Not in a Conservation Area, of course!

[Lance]

I wonder if the rubbish lines were being seen as expensive to maintain and that is why BT went for FTTC so that at least some of the line was sorted.

[sparky]

mervl,

You have given me hope!   

[mervl]

I wonder if the rubbish lines were being seen as expensive to maintain and that is why BT went for FTTC so that at least some of the line was sorted.

Um, I thought BT would only dig for a voice fault which still uses copper doesn't it? Perhaps BT accountants were hoodwinked and thought there was a saving (though the fact a few OR engineers live in the village or if BT wangled a free duct off of the County Council's cycleway works might have something to do with it)? Digs were between me and the cab, so I can only assume that VDSL may be much better at coping with the joints, and presumably suffers much less from (crosstalk) interference, at least until either more of the locals cotton on to the benefits of FTTC or the rains come!

[Rik]

Cross talk should be low, as only short distances are involved. For the same reason, the number of joints is greatly reduced and, hence, the likelihood of corrosion/water infiltration.