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[markthomas]

I've been having problems (slow speed) since BT switched my ADSL across to their MAX service a year or so ago. I have spent many hours on the phone to their help desk over the course of the last 12 months and have even had a visit from a BT engineer, but the problems still persist. The engineer claimed that he had fixed the issue by disconnecting my phone extension sockets but this doesn't appear to be the case.

I am hoping that someone on this forum can help confirm whether I am stuck with this until BT upgrade their network or whether there is in fact some underlying technical issue which can be resolved.

When I was initially switched over to the MAX service my downstream connection speed was approx 1.8mb. I live in a rural location and to be honest whilst I suspect this may be bad news for most of you if I could achieve this speed today I would be quite happy!

The downstream connection speed seems to have reduced over time to the point that it is now 480k. My IP profile is 350k. To try and resolve the issue I have already done the following over the past few months:

Connected my router to the test connection in the master socket
Disconnected all phone extensions
Replaced router with Speedtouch 585V6 (from NetGear DG834G)
Replaced ADSL filter with XF-1E

Here are the current connection stats from the Speedtouch 585:

Modulation:   G.992.1 Annex A
Bandwidth (Up/Down) [kbps/kbps]:   448 / 480
Data Transferred (Sent/Received) [MB/MB]:   1.32 / 4.68
Output Power (Up/Down) [dBm]:   11.5 / 12.5
Line Attenuation (Up/Down) [dB]:   31.5 / 61.0
SN Margin (Up/Down) [dB]:   18.0 / 15.5
Vendor ID (Local/Remote):   TMMB / 
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 / 8
CRC Errors (Up/Down):   0 / 0
HEC Errors (Up/Down):   0 / 0

I know my line attenuation is high which is probably the main cause of the issue but would you expect better than my current sync speed? I was hoping for at least 1mb if not higher.

Since switching to the Speedtouch I have also tried using the DMT tool to decrease the SN Margin. However this resulted in severe line instability so I had to switch it back.

I am currently paying for BT option 3 which seems a little pointless if I can barely get a 512k service. I don't know if switching ISP's would help, phoning the help desk doesn't seem to get me anywhere.

Any help would be much appreciated.

Thanks.

[kitz]

Sorry to be the bearer of bad news, but your line attenuation of 61dB is likely to be the problem. 
That indicates that you are on a very long line which are much more subsceptical to SNR Margin fluctuations, which will be the cause of your stability issues.

The fact that your SNRM is now at 15.5dB indicates that you are on the highest Max profile in order to stablise the line with a target SNR of 15dB.  The default max profile is 6dB (which is what your line will first have been when you got maxed), and this has the unfortunate side effect of vastly reducing the maximum speed at which you are able to connect at.  Each step up decreases the maximum speed.

~ How unstable is your line right now?
I'm not sure from those stats, how long the line has been up for and how many errors it tends to rack up.
~ What speed connection was your line on before being maxed and how stable was it back then?

A 61dB line should sync higher than you are seeing, but there are some lines that just cant cope.



There is a point at which Max doesnt work so well on some long lines, and some ISPs will transfer these lines back to a fixed rate product in order to try and achieve some stability.
Unfortunately BT isnt one of the ISPs that will transfer their customers back to a "fixed rate line", since BTw are gradually doing away with this service.

However, there is something available on Max dsl which may help stabilise your line and thats asking if BT can ask BTw to transfer you over to something called "BT IPStream Max - Capped Rate Profile". This option is available in profile 500, 1000 & 2000 which are the equivalent of the old fixed rate products of 512kb, 1Mb & 2Mb.  Obviously your line wouldnt handle the "Max Premium - Capped Rate Profile 2000" but it may possibly cope with Capped Rate Profile 1000 (61dB is a bit border line) and BT may be prepared to try you on it.
If not then Profile 500 should work fine... and at least that would five you a steady 512kb connection which is more than you currently have.

Your ISP may not have heard of the Capped rate Product, but it should be available for them to order via the BTw system.

Before doing all that though - it may be worth while grabbing a copy of routerstats and use it to monitor your SNRM.  There may be a pattern that emerges that could point to a cause of the times when your SNRM dips - which could be something like heating/lighting or other type of Electromagnetic Interference.

[markthomas]

Thanks for all your advice... I had a feeling that the attenuation was going to be the main issue.

The router had only been up for a few minutes when I grabbed the stats, however the connection is quite stable albeit very slow.  i will re-post the stats tonight when I get home as it will have been up for 24 hours.

Prior to being MAX'd I was on a 2mb service which was fairly reliable, I used to get random disconnects but probably only once every month or two.  When I was initially put onto the MAX service the connection was totally unreliable, however moving the router to the master socket seemed to improve things.

I suspect you are right in that my line is just not suited to the MAX service.  I will run router stats and do some monitoring as you suggest.  I am a little confused by SRNM and what would be classed as a reasonable figure on a line with an attenuation of 61db.  Is a lower SNRM better?  Could you provide a little more information on how this works?

One other thing I forgot to mention is that when I was using the DG834G it used to initially sync at 1.8mb after a reboot, but would then drop to 480k after approx. 10 mins.  Does this indicate any other problem with my line or configuration at the Exchange?

Once again thanks for all your advice.  I just want to make sure there is nothing else I can change on my router/telephone connection before going back to my ISP (again).

[Ezzer]

Once your attenuation sits at 60db or more then max can become tetchy, given the fact you had 2mb running semi reliably sounds as if the snr was initaly good as officialy the threshold for 2mb is 43db loss though if the snr is at 20-30 then you can start adding on some db's although 61 I would have thought is pushing it

snr with fixed speed reads as better the higher the no. target is >9db, any less then your prone to drop outs particualy at around 6db or less, with max it's snrm so the figures read differently so as close to 6 the better. sounds as if a regreade to a 1 )or 2 again if you want) mb service would be youbest reliable option

[kitz]

>> Prior to being MAX'd I was on a 2mb service which was fairly reliable,

In that case it may be worth asking your ISP if they could trial you on the "Max Premium - Capped Rate Profile 2000" product.  TBH you would have to push very hard for this stating that you previously had a 2Mb fixed rate product that works fine and you would like that service restored.
I say push hard because anything over 43dB attenuation is supposed to struggle on the fixed 2Mb rate and BTWholesale have rules which they strictly adhere to.

>> by SRNM and what would be classed as a reasonable figure on a line with an attenuation of 61db.

Very hard to say - all lines are different. Quality of the copper line, local interference, how the line is routed and if it passes anything that may introduce EMI, how many other users are using their connections (crosstalk)... also allow that different routers may report the attenuation differently.   
As a rough guide I've produced a maximum adsl speed calculator.  Its based on average lines with a Target SNRM of 6dB. 
Its not gospel, but its possibly recognised within the adsl community as about being the most accurate for average lines, but I must stress it is only a guide.
Also bear in mind it calculates for rate adaptive technology.. and that fixed rate technology works slightly differently.

>> Is a lower SNRM better?  Could you provide a little more information on how this works?

Higher SNR Margin is better.  Also note that I also talk about Target SNR and whilst the 2 are related they are different things.  Fixed rate adsl doesnt utilise a Target SNR. - See Line Stats - Attenuation and SNR.

>> was using the DG834G it used to initially sync at 1.8mb after a reboot, but would then drop to 480k after approx. 10 mins.

hmmmm - not sure perhaps local interference affecting it (eg monitor etc)... but could also be a large amount of errors racking up when the line was in use caused the line to become more unstable.  The router goes through several alarm states before it will actually loose sync, depending on the severity of the issues at each stage.
Also its normal to see SNRM lower in the evenings when more people are at home using their connections. 
If a subsequent resync picked back up at 1.8Mb, I say that it is a fair bet that symptom is a "local issue" (internal wiring/router/EMI) rather than anything at the exchange end.

[edit]

Ezzers reply wasnt there when I started mine - but Ive posted anyhow.

[markthomas]

Thanks for all your advice, I really appreciate it.

Just for your info here are the stats from my router tonight, I assume that the number of errors is acceptable?  The connection is very stable.

Uptime:   1 day, 0:40:51
Modulation:   G.992.1 Annex A
Bandwidth (Up/Down) [kbps/kbps]:   448 / 480
Data Transferred (Sent/Received) [MB/MB]:   13.20 / 42.27
Output Power (Up/Down) [dBm]:   11.5 / 12.5
Line Attenuation (Up/Down) [dB]:   31.5 / 61.0
SN Margin (Up/Down) [dB]:   18.0 / 14.0
Vendor ID (Local/Remote):   TMMB / 
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):   2 / 0
FEC Errors (Up/Down):   48 / 42
CRC Errors (Up/Down):   2 / 2
HEC Errors (Up/Down):   2 / 2

I will talk to BT about switching back to a fixed service and see how I get on...

Thanks.

[Ezzer]

your error are fine, between 1-5 mins then on rate adaptive up to 1000 hec/crc errors, 14000rs. fixed speed or without interleaving 60-100 crc/hec errors over the same time is the acceptable level unless all the errors come in clumps/bursts

[kitz]

Thats actually very stable..
In fact I would normally expect to see way more FEC errors than that.

[markthomas]

Well I have just spent 1hr 25 mins going round in circles inside the BT Broadband phone system...

I spoke to 2 different people on the "options team" who stated that I could be switched back to a fixed product but then subsequently managed to lose my call to someone who didn't have a clue what I was calling about!

Anyway the 3rd person on the "options team" has said that I can be switched back to a 2mb service and is going to call me back at 2pm tomorrow.

I'll let you know what they say...

[kitz]

Good luck and fingers crossed.

Like I say - be prepared at one point if they say they cant do fixed lines anymore since they only provide on Maxdsl, and just in case be ready to respond with the phrase "BT IPStream Max - Capped Rate Profile 2000"

[markthomas]

Just an update on what is happening with my ADSL max problems...

Having spent many hours on the telephone to BT broadband and being told by several people that I could be transferred back to a fixed rate product I failed to actually get to speak to anyone who could action it.  I have now obtained a MAC key from BT and I'm in the process of transferring to another ISP who offer both MAX and fixed rate products.  I even had to complain to get the MAC key as it had now arrived within 5 days!

The new ISP has recommended that I try their MAX product first, they will quickly transfer me to the fixed rate product if it proves unsuccessful.  Their reason for this is that their line tests show that they can provide a 3-4mb service (I am highly doubtful of this).  I am now waiting for the switch over to see what happens.

One thing I have noticed is that the mapping engine on Samknows.com shows some pretty weird statistics for my local area.  It suggests that I am 1920m from the exchange and can get a 1.5mb service, however other properties which are 2300m from the same exchange can get a 3mb connection!  Can anyone explain this?

Thanks,

Mark.

[jid]

They maybe able to provide faster speeds than BT, depending on the ISP i suppose?

[kitz]

Thats a shame - about the same time I mentioned the Maxcapped profile to you - I also mentioned it to someone else the same day.. and hes now afaik happy syncing on a higher and stable capped rate line.

>> It suggests that I am 1920m from the exchange

Thats straight line distance... BTw cables hardly ever go straight line - they are more likely to follow roads. - line checker.
The maximum rates come from the BTw data base.. and are usually based on the average sync speed in your area.

>> their line tests show that they can provide a 3-4mb service

Which ISP?  AFAIK nearly all of them access the BTw database for their information.

[markthomas]

The new ISP is UKOnline, they still sell a fixed rate 2mb product as well up to 8mb MAX.  I assumed that the information on samknows.com wasn't straight line but the actual line length.

Your line checker states 1.9k direct and 3k by road.  The main problem is that there is a big hill between me and the exchange and the road (and cables I assume) go round it!

I'll just wait and see what happens with UKOnline... I have no idea where they got the 3-4mb figure from.  I have no doubt I will end up switching to the fixed rate product at some point.

Thanks,

Mark.

[jid]

The new ISP is UKOnline, they still sell a fixed rate 2mb product as well up to 8mb MAX.  I assumed that the information on samknows.com wasn't straight line but the actual line length.

Your line checker states 1.9k direct and 3k by road.  The main problem is that there is a big hill between me and the exchange and the road (and cables I assume) go round it!

I'll just wait and see what happens with UKOnline... I have no idea where they got the 3-4mb figure from.  I have no doubt I will end up switching to the fixed rate product at some point.

Thanks,

Mark.

Correct me if I am wrong Kitz, but don't UK Online use ADSL2+?

If so this is most likely how they are promising faster speeds!