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[moxy]

I'm having aggro with my BT internet dropping out. A B T engineer says the exchange line is o.k. and their internet people says nothing wrong with their server. I've swapped out everything possible, ripped out my house wiring, and installed a new DECT phone system and routers x 3, speedtouch 330 modems x 2 [ all in turn], from the master jack, and the internet still drops out at irregular intervals.
I'm 99.9% sure the fault is to line, I will do final checks tomorrow. Would the info below mean anything to anyone, or indicate something amiss?
 
Statistics Downstream Upstream
Line Rate 5696 Kbps 96 Kbps
Noise Margin 12.1 dB 6.0 dB
Line Attenuation 44.0 dB 27.0 dB
Output Power 19.7 dBm 10.5 dBm
K (number of bytes in DMT frame) 179 4
R (number of check bytes in RS code word) 14 16
S (RS code word size in DMT frame) 1 16
D (interleaver depth) 16 1
Super Frames 631889 631887
Super Frame Errors 1394 768
RS Words 42968498 2685519
RS Correctable Errors 203666 15298
RS Uncorrectable Errors 11035 0
HEC Errors 1255 0
OCD Errors 24 0
LCD Errors 0 0
ES Errors 0 0

regards, moxy.

[mr_chris]

It's a pity that we hear of some BT engineers that obviously don't care about thier job, (I really wish they were all like Ezzer!)

Line Rate 5696 Kbps 96 Kbps
Noise Margin 12.1 dB 6.0 dB
Line Attenuation 44.0 dB 27.0 dB

96kbps upstream!! It should be 448kbps. You don't have a massively high attenuation, and the 5696kbps downstream rate suggests your line is ok.

Are those figures taken from the master test socket or the router's normal plug-in point? Have you tried with the master socket faceplate removed so the modem is the ONLY thing that's plugged in the whole house - no extensions or anything?

You are probably going to have to badger for a second BT engineer to come out, unfortunately

[moxy]

Thanks for the reply, mr chris, the figures were obtained by accessing the BT Voyager router via Internet Explorer [192.xx.1.1] and was just a random snapshot, Im running at 72 KBs at the minute. The router is plugged into the master socket, [face plate removed], and house wiring disconnected, regards, moxy.

[roseway]

Do you ever hear crackling on the phone? A normal downstream connection but a poor upstream one is fairly commonly associated with a crackly line.

[supercooper]

I had a fault in just like this one. 

The First BT Engineer fobbed it off and made the connection worse

The Second BT Engineer was great and re-routed the line on a differant pair back to the exchange which cleared the fault even though the line always tested as ok. 

If you have a second Engineer attend and he find no faults again, maybe you can suggest a differant pair?

But before you get another bill from BT it's always a good idea to test your connection from the BT test socket with a known working filter and modem/Router.


Chris

[kitz]

Hi Moxy

I'm not sure how long your router had been up for when you took those stats, but theres a fair few errors on the line, meaning that at times your router is having problems "hearing" the adsl signal and having to say "pardon" and re-request the data packets.. once this gets too severe, then the line can drop out completely.
This often occurs due to Noise on the line and when your SNR drops too low.  It can be the result of either a line fault, or electromagnetic interference from another source.

[moxy]

kitz, that's exactly what's happening, sometimes after a dropout it will connect immediately, other times 1/2 an hour or more. Nothing has altered with regards electrical devices etc near my p.c. router.  roseway, a silent line test is crystal clear, although when I first reported the fault, the line was occasionally very noisy. Supercooper, a different pair sounds good, but I can't help thinking it's a server fault, and everything is plugged into my master socket with the faceplate removed, [i.e. BTs bit]. Thanks to all for your suggestions, regards, moxy.

[Ezzer]

It aslo depends how the fault was raised and by the sounds of it it may have been a frames chap who tested the line as they only work at the exchange. If the line tests ok then that esentaly tests for the normal voice telephony and means there is a good foundation for broadband but broadband can suffer from a whole extra range of problems.

[kitz]

Its not likely to be a server fault.  Loss of Sync can only occur somewhere between you and the exchange.
Some people may not realise this, but even if your ISP went bang, your router Green DSL light would still remain lit as that indicates a connection to the DSLAM at the exchange and its actually why adsl is classed as Always On.

The only time you loose sync is when your router and the DSLAM cant hear each other...  If it was the DSLAM then everyone in your town connected to that dslam would also loose their connection.
The error count further indicates problems hearing the signal on the telephone line (this is the only place this occurs).. hence the deduction that the fault lies either with the telephone line or your own equipment*.



*Your own equipment can be router/phones/internal wiring/interference.

[moxy]

Interesting info there, thanks. As mentioned, I have used 3 different voyager 2110 routers and 2 USB modems, the modems seem to hang on longer than the routers, is there a logical reason? The line has been up and down like a yo-yo in the last hour, I’ve taken some stats just now, are there any facts I can present to BT



   Line Mode   G.DMT       Line State   Show Time   

 
Latency Type
Interleave       Line Up Time   00:00:04:12   

 
Line Coding   Trellis Off       Line Up Count   1   

   

 
Statistics               Downstream   Upstream   
Line Rate                 6336 Kbps   448 Kbps   
Noise Margin                12.4 dB   18.0 dB   
Line Attenuation          44.0 dB   27.0 dB   

 
Output Power    19.7 dBm   11.8 dBm   



ADSL BER Test - Result

The ADSL BER test completed successfully.
   

   Tested Time   20   
   Total Transferred Bits   114765312   
   Total Error Bits   6652   
   Error Ratio   9.27e-06   
regards, moxy

[kitz]

Your SNR Margin at that particular snapshot in time looks ok.. and the current sync speed is ok for your line length.

Some of the errors that we normally look at are these ones:-

RS Uncorrectable Errors 11035 0
HEC Errors 1255 0
OCD Errors 24 0

and these one
RS Correctable Errors 203666 15298

are the ones that have been corrected due to the Interleaving process being switched on.


I have used 3 different voyager 2110 routers and 2 USB modems, the modems seem to hang on longer than the routers, is there a logical reason?

Not really, the 2110 has a broadcom chipset and  is normally pretty good at hanging on..  although which modem? the Voyager 105s and ST 330 had a damn decent reputation for a usb modem and why BT engineers often use them.

>> are there any facts I can present to BT

If you have a bit of spare time you could use routerstats on the 2110 (which is the same as the 2100)  to monitor whats happening on your line. 
In particular interest would be the  downstream SNR Margin which it will graph for you.
http://www.kitz.co.uk/routers/log_routerstats.htm

[moxy]

Thanks again, Kitz, I am starting to get out my depth now, but I shall continue tinkering, regards, moxy.

[moxy]

 Kitz, I downloaded your DMT tool v8 and have added results as an attachment, do they throw any further light on any possible problems?

[attachment deleted by admin]

[kitz]

Theres something very odd about that DMT capture in that its showing your line attenuation at 15.5dB, whilst stats posted earlier show 44db.  Attenuation shouldnt fluctuate, so either your router has mis-reported that figure or you have a line fault.  Judging from the sync rate, its more likely a mis-report so Im going to ignore it for now.

For a connection time of 3 hours, but over nearly 10 hours, youve had 2246 errored seconds (37mins)
Your UAS would tend to show that perhaps you had a period where things were really bad (this is one of the most serious types of errors) and is when you start loosing the connection.
From that its not too hard to make the assumption that over time your SNR gradually got worse,then you probably had a period where the errors all came at once causing a resync at the lower speed.

Reading the SNR fluctuations on DMT is harder than via routerstats because its done as a %, but if Ive done my sums right then the worst dip of -20% shows a fluctuation of down to around 7.5dB which is ok at your current sync during the one hour period of monitoring. 

I think whats happened is that at the time you did that, the lower sync of 5024 meant your line was a lot more stable.


Moxy, can I ask do you switch the router off ever,(eg when you go to bed) or is it left on all the time?

[moxy]

Thanks for your comments, Kitz. I leave/have left my router switched on permentantly since it's installation, even though I turn off my p.c. The fact that the "internet" lamp on my router was unlit one morning was my first sign that something was iffy, ( for 2 years or so, 3 lamps, power, DSL and internet, were always on. I went into my sudy this morning, no connection, so I'm running the DMT test again from router reset, would it give you any additional info if I posted a copy, thanks again, moxy.