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[phil612]

Hi
as you'll guess I'm a bit of a newby at this,  I'm looking for some impartial advice on what I should expect from my ISP BT and BT Openreach, I can't fault them on the personal level of service, its just the outcome that's dissapointing. I've been struggling with BT over the performance of our link for a couple of months now, prior to that it was generally "stable". I didn't check the hub stats at all (didn't now how to) but judged the performance by my ability to watch the BBC website weather forecast video, it was adequate, and how well COD4 played online a bit glitchy but certainly playable.

I live in a pretty remote area so I'm not expecting stellar performance (exchange distance est 7.2km), but  over the last couple of months the performance has been all over the place. Each time I've called a fault in I get several days, perhaps even a week or more, of reasonable speeds up to the lines best rating as we've been previously told  of 1Mbs, then gradually it degrades  back down to <200Kbs  at one stage it was as low as 20Kbs.  The support team in India do their bit and the Openreach engineer has been out twice so far and he's due back on monday.  On the last trip out one week ago he swapped the master socket to one that includes the adsl filter in it, an NTE5 I believe, my hub is plugged directly into it with a 2metre cable, and for a few days download speeds were transformed 1Mbs+ (deep joy), however one week later it was down to 120Kbs.
Is this level of variation to be expected, I'm now much more conscious of the performance and I'm now checking the hub stats and using the BT Speedtester more regularly, but I fear I'm now guilty of just focusing on the figures.
 
Today my BT homehub 5210 reports the
line as DSL Connection 
Link Information
Uptime: 1 day, 3:47:34
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 544
Data Transferred (Sent/Received) [MB/MB]: 29.51 / 131.46
Output Power (Up/Down) [dBm]: 12.0 / 14.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 10.0 / 13.0
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 1,059 / 0
FEC Errors (Up/Down): 0 / 285,464
CRC Errors (Up/Down): 0 / 10,099
HEC Errors (Up/Down): 0 / 7,349
Line Profile: Interleaved

I wish I'd kept  copies of the earlier ratings but the line was from memory
 rated as Up 448 Down 1088 and the line profile was Fast rather than interleaved. The FEC/CRC/HEC figures have always been  in the hundreds and possibly thousands. Twice I've had to ask the  support team in India to reset the line rating as 1Mbs and it looks like its changed back again in the last couple of days.
 Am I expecting too  much to get 500K+ consistently on a line of 7.2Km with 63.5dB attenuation .

[waltergmw]

Hi Phil and welcome,

Assuming your line distance estimate is reasonable, I'm surprised you ever achieved 1 mbps.

Your actual attenuation is likely to be around 80 dB but can't usually be reported as the standard max figure is as your modem says.

If you are prepared to fiddle you might get a better performance from a 2Wire modem which you might find via e-bay or Amazon.
They're a bit tricky to set up but we can tell you how to.

I'm guessing that your house wiring has already been "mazimised"; i.e. disconnect all bell wires, use a filtered faceplate or an ADSL nation one in the master socket and avoid all star wiring.
http://www.kitz.co.uk/adsl/socket.htm

Kind regards,
Walter

[roseway]

Hi and welcome,

[Walter posted while I was preparing this, but I'll post it anyway]

First I must say that your attenuation is almost certainly more than the reported 63.5 dB. That figure is the highest which many routers will report, and if the exchange is over 7 km away then the actual attenuation is likely to be a lot more.

This unfortunately means that your connection is very vulnerable to interference, and is always likely to be problematical. Looking at your figures, it seems probable that the instability that it's suffered from has caused your target noise margin to be raised by DLM which will have resulted in a slower but more stable connection.

When you asked the support team to reset your line rating to 1 Mbps, this isn't possible, but what they could have done is to get your target noise margin reset to its default value of 6 dB. This would have increased your connection speed for a while, but it would probably have made the connection less stable, and DLM would soon have increased the target margin again.

So I'm afraid that, unless BT can find an actual fault on the line, you're probably going to have to live with the poor performance. You've got a filtered faceplate with the router plugged directly into it, and this is the best technical situation at your end.

Sorry that I can't sound more encouraging.

PS Walter's suggestion to get a 2-wire modem (BT Business Hub) is a good one.

[phil612]

Roseway, Walter
thanks for the welcome. I'm only now starting to look a round the site to see how much useful information there is. I'd never appreciated how the ADSL operated as a protocol, its certainly more complex than I thought and I know I've only scratched the surface.  Its a bit  of a steep learning curve to achieve by Monday, but I'm going to work my way through the site/old discussions that way  I can at least ask and challenge any points offered by BT.

In the mean time, if I understand correctly from what you've said,  the times I've checked and seen download speeds of 500-900K have simply coincided with a period of "re-stabilisation" following the ISP team in India effectively restarting the line characterisation process.   Each time I complained they simply reinitiated the process, but after 10days or so the IP profile was re-established at around 350Kbps.    Similarly, although the Openreach engineer may have solved a specific fault, the improvements he has made are very unlikely, ever to result in a line capable of consistently supporting the 1Mbs as I thought it could.

Just one thought what, if any, relationship is there between audible noise on the telephone  and ADSL. I've run a BT17070 option 2 quiet line test and there's an audible hum, but it might be the handset.  The phone was plugged directly in to the master socket and everything else unplugged. 

Thanks for the suggested alternative hub, was it the 2700hgv?

Thanks again

[kitz]

>> certainly more complex than I thought and I know I've only scratched the surface

It is..  even we often learn and see new things occur. 

---

Im afraid its highly unlikely that any line over 63dB can be guaranteed to reach 1Mb and stay there.  There are a few that do, but most wont.  The best you can do really is try keep the line stable and give it the best chance you can by doing all the usual stuff with your wiring.

As mentioned each time the connection is reset it may temporary receive the higher speeds, but once the evening comes and SNR starts to drop (which it will do for most lines as it normal for signal to be weaker in the evenings when more people are at home using their connections and other electrical items).  During this time your router wont be able to hear the signal as strong.. and as the SNR starts to fall then the errors start to rack up until eventually the line drops out completely.

From your stats, I can see that this is what is happening on your line. Although on the stats the line has been up for a day, theres a good chance that all those errored seconds occured during a time frame in the evening.  The LoS shows that at some point the signal just became too weak for your router and the exchange to be able to communicate at the higher speed and had to drop down to a lower speed to be able to get a better signal strength.  (Higher speeds require higher frequencies to be used).

>> Just one thought what, if any, relationship is there between audible noise on the telephone  and ADSL.

Yes there is a very strong relationship.  Noise on the physical line will reduce your SNR.

[phil612]

Two BT engineering visits later  I can report some progress on  the situation. 
A noisy line was logged by the support engineer (BT support not Openreach) that visited monday, and yesterday Openreach found a wiring error on the line as it entered the house. He wasn't completely certain that it was the source of the problem as the audible line noise present on Monday had already dissapeared. One theory presented was the amount of rain we've had locally was causing transient problems on the line.

So today the stats have completely changed again.  see attached.The FEC figure is still climbing steadily, but the IP profile is now 1250 compared to 500 yesterday.  It'll be interesting to see how the stats fluctuate over the next few days.

[attachment deleted by admin]

[attachment deleted by admin]

[kitz]

>> One theory presented was the amount of rain we've had locally was causing transient problems on the line.

Possible.

>> Openreach found a wiring error on the line as it entered the house

Hopefully this is/was the cause of your problems.
Wiring error?   Is it possible that water could be getting in if the outer sheath was damaged?

>> IP profile is now 1250 compared to 500 yesterday

 

>> The FEC figure is still climbing steadily,

and will very likely continue to do so...  FECs show that interleaving and error correction are working as it should.
Rapid rises in CRCs are really the ones to look out for and which can cause problems.

>> It'll be interesting to see how the stats fluctuate over the next few days.

Indeed.. lets hope though that it was the wiring and this has sorted it for you