SNR margin & router questions
Graham J
about £150), with the ADSL service provided by Zen. I need the Vigor for
its VPN capability.
I see typically:-
448k Up Speed : 1440k Down Speed : 12.5 SNR Margin : 62.5 Loop Attenuation
I accept that the 62.5 dB attenuation is fair for the distance.
I tried a different router - an Edimax AR-7084A (price about £20) This
typically shows:-
448k Up Speed : 2464k Down Speed : 5.5 SNR Margin : 63.5 Loop Attenuation
Clearly the lower SNR margin allows a much greater download speed. So why
do the two routers behave so differently on the same line?
At ths same location I have another line with the ADSL service provided by
Demon. I see much the same performance difference between the two routers
on that line.
I've tried more modern versions of the Vigor router - for example a V2800
and V2820 - both these show much worse performance, typically:-
448k Up Speed : 800k Down Speed : 18.0 SNR Margin : 62.5 Loop Attenuation
Can anybody explain why a premium price router should behave so poorly
compared with an economy product?
In March this year BT broke some wires leading into the village and a good
many people were without any phone or ADSL service for several days. Before
that time, my Vigor router would report:-
448k Up Speed : 1900k Down Speed : 6.0 SNR Margin : 63.5 Loop Attenuation :
When BT fixed their wires, they did something which appeared to affect the
performance of the Vigor routers. Can somebody explain this for me?
Thanks.
--
Graham J
Peter Crosland
The difference is explained by the effectiveness of the decoding/encoding
algorithm in the modem and also the ability of the modem to work with a poor
quality line. I have had a similar problem with the 2820N and indeed I
returned it to the supplier after Draytek could not provide one that work
satisfactorily. I now use a BT Business hub 2700HGV and the speed is 80%
faster than the Draytek as well as giving a rock solid connection. If you
can do with out the highest speed wireless then give one a try. You can
pick one up for less than £20 on eBay so it is not much of a risk.
As for the question of what BT have done it is anybody's guess.
Peter Crosland
Martin²
6dB SNR. Trouble is BT has
changed their DSLAM management to stick to higher SNR margin in order to
make connections more stable. You may need to press your ISP to get BT to
lower the margin.
I presume the Edimax is ADSL2 or 2+, if so it can work with lower SNR and
higher speed.
You can set the SNR on Vigor 2800 (and I presume 2820), instructions can be
found on Draytek.co.uk forum.
Regards,
Martin
nospam
>I see typically:-
>448k Up Speed : 1440k Down Speed : 12.5 SNR Margin : 62.5 Loop Attenuation
>
>I accept that the 62.5 dB attenuation is fair for the distance.
>
>I tried a different router - an Edimax AR-7084A (price about £20) This
>typically shows:-
>448k Up Speed : 2464k Down Speed : 5.5 SNR Margin : 63.5 Loop Attenuation
>
>Clearly the lower SNR margin allows a much greater download speed. So why
>do the two routers behave so differently on the same line?
You can't make such simple comparisons. The modem syncs at a speed which
gives an SNR margin set by the exchange. The default margin is 6db but the
exchange will increase it if the line looks unstable (frequent re-syncs)
which is often the case on longer lines.
The modem stays at that sync speed and as noise varies the SNR margin also
varies unless the margin gets so low that too many errors occur and the
modem will resync at a lower rate to restore the margin set by the
exchange.
You can only make comparisons by looking at sync rate and SNR margin
immediately after the modem has synced and with minimum delay between the
comparison in the hope that noise levels have not changed. Both modems
should sync with about the SNR margin set by the exchange and the
comparison will be in the sync rate achieved. From the SNR margins you
quoted it looks like you didn't do this.
That said the design and/or ADSL chipset used in the Drayteks isn't very
good on poor lines tending to sync at lower rates and resync more often
than some other cheaper modems.
If you really need the features in the Draytek I think they do a router
(2910?) that uses external modems, not sure what the requirements are for
suitable external modems.
It would be worth browsing the Draytek uk support forum
http://www.forum.draytek.co.uk/ where you will find some discussions about
modem performance and probably some talk about the router.
--
Grumps
news:ob3tf4pjkrqpuin0s...@4ax.com...
I have a Linksys router that used to sync at 10M using Nildram LLU. I
changed ISP to O2 and the same router immediately sync'd at 8M with a 13dB
margin. I swapped to the supplied O2 box and it managed a connection of 13M
with a 6dB margin. Is there something that the O2 equipment does differently
with the O2 box than with other ADSL2+ routers? I can't explain why the
Linksys won't drop the margin to get a better rate, even when it has been
left on for a few days.
David Quinton
<gra...@nospam.zen.co.uk> wrote:
>I'm about 5km from the local exchange and use a Vigor 2600VGi router
I use a 2600 and it improved noticeably when I flashed it to the Long
Line UK firmware
(but it was a couple of years ago so can't give details - someone will
know...)
--
Free personal divertable Phone number: <http://www.bizorg.co.uk/personalnos.htm>
Adam Lipscombe
By far the best results are with a BT2700 HGV (aka 2Wire). This out performs everything else I have
tried on my line. They are dead cheap on ebay.
See here fro much discussion on this router:
http://www.the-scream.co.uk/forums/t22658.html?&highlight=2700
HTH - Adam
PeterC
> I also have a long noisy line and have tried several routers including a couple of draytechs.
>
> By far the best results are with a BT2700 HGV (aka 2Wire). This out performs everything else I have
> tried on my line. They are dead cheap on ebay.
Is there an equivalent ADSL modem that's wired? The 2700 looks good, but I
don't want wireless.
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.
Ato_Zee
> I use a 2600 and it improved noticeably when I flashed it to the Long
> Line UK firmware
lines with high attenuation there is little risk of overloading the front
end. All the long line flash seems to do is raise the gain at the high
frequency end of the spectrum to lift the high frequency BIN's
above the noise threshold.
After flashing the modem will probably report lower attenuation for
the line, which is of course untrue, attenuation is a property of
the physical line. But it does run faster.
Using DMT tool with a modem/router that supports it can
make the line run much faster by overriding the default
conservative exchange SNR margin threshold.
DMT tool won't help much if you line is unstable or noisy.
www.GymRatZ.co.uk
nospam wrote:
> If you really need the features in the Draytek I think they do a router
> (2910?) that uses external modems, not sure what the requirements are for
> suitable external modems.
>
> It would be worth browsing the Draytek uk support forum
> http://www.forum.draytek.co.uk/ where you will find some discussions about
> modem performance and probably some talk about the router.
I have draytek 2910 routers at work and home. I have always used
Draytek's own modems the Vigour100 (of which I have 3 for the 3 x ADSL
lines) Set up to "bridge" mode they just present the 2910 with the WAN
IP address no problem.
The only problem I have found recently shouldn't be an issue for the OP.
I have found that when changing to Be* Pro with a very strong line
signal, the Vigour100 was not up to the job of hitting decent upload
speeds afforded by Be "upload plus" It struggled to get anything higher
than 1.5Mbps upload so has been swapped for the BeBox again set in
bridged mode which now tops 2Mb+ .
In the current moment the sync speed is :
Download bitrate 24575.0
Upload bitrate 2555.0
So for the OP the Vigour100 (Vigour110 is it is now) would be fine.
I have one going spare now as well.
:¬)
Cheers
Pete
--
http://www.GymRatZ.co.uk - Fitness+Gym Equipment.
http://www.bodysolid-gym-equipment.co.uk
http://www.trade-price-supplements.co.uk
http://www.water-rower.co.uk
Peter Crosland
>> couple of draytechs.
>>
>> By far the best results are with a BT2700 HGV (aka 2Wire). This out
>> performs everything else I have
>> tried on my line. They are dead cheap on ebay.
>
> Is there an equivalent ADSL modem that's wired? The 2700 looks good, but I
> don't want wireless.
It is a simple change in the configuration to switch it off. There is no
wireless version.
Peter Crosland
Peter Crosland
>couple of draytechs.
>
> By far the best results are with a BT2700 HGV (aka 2Wire). This out
> performs everything else I have tried on my line. They are dead cheap on
> ebay.
>
> See here fro much discussion on this router:
> http://www.the-scream.co.uk/forums/t22658.html?&highlight=2700
>
> HTH - Adam
Don't be too put off by the awful warnings! The correct procedure is well
documented. I have installed several for friends and they are all working
AOK with no glitches. 2Wire could make even more money selling them in this
country but maybe BT have an exclusive deal.
Peter Crosland
Graham J
"David Quinton" <usenet_20...@REMOVETHISBITbizorg.co.uk> wrote in
message news:cuitf4p5ibeb54vbc...@4ax.com...
> On Tue, 21 Oct 2008 22:10:06 +0100, "Graham J"
> <gra...@nospam.zen.co.uk> wrote:
>
>>I'm about 5km from the local exchange and use a Vigor 2600VGi router
>
> I use a 2600 and it improved noticeably when I flashed it to the Long
> Line UK firmware
>
> (but it was a couple of years ago so can't give details - someone will
> know...)
Two years ago the SNR margin would often drop to 2dB (similar attenuation
at 62dB) and although the router would claim to have a connection it would
not carry any significant traffic - even pinging the Zen default gateway
would fail most of the time. Rebooting would always cure the condition, and
the SNR margin would stay at about 5dB for a few days. Speed was typically
1900kbits/sec
So I installed the Long Line firmware in the self-same V2600VGi router;
performance then became more reliable. The SNR margin varied between 4dB
and 8dB, attenuation was reported as 63.5 dB, and speed dropped slightly to
1800kbits/sec.
The only change since then is that BT broke the wires in March. And since
then the SNR margin has been 12dB to 14dB (loss 63 dB) and speed only about
1300kbits/sec.
I tried converting the router to standard firmware and now see no difference
whatever between the two versions of firmware.
--
Graham J
Graham J
"Martin²" <ne...@give.one> wrote in message
news:f6GdnSaMf99bDGPV...@posted.plusnet...
Thanks. Looked through the forum back to mid 2005, seacing for "set snr
margin" :::
The topic at:
http://www.forum.draytek.co.uk/viewtopic.php?t=11628&highlight=set+snr+margin
suggests that you can't set the SNR margin - it's in the wishlist ...
Similarly:
http://www.forum.draytek.co.uk/viewtopic.php?t=11385&highlight=set+snr+margin
The term "codinggain" might be relevant ...
http://www.forum.draytek.co.uk/viewtopic.php?t=9173&highlight=set+snr+margin
.. says that it isn't supported in the chipset.
If you know of specific instructions can you please post a link?
--
Graham J
PeterC
Thanks Peter, that's useful to know.
Martin²
I said:
>> You can set the SNR on Vigor 2800 (and I presume 2820),..
but it can't be done on the 2600 range ;-( I have 2600VGi as well ).
Regards,
Martin
Graham J
"Martin²" <ne...@give.one> wrote in message
I know it can't be done on the 2600 range.
But I can't find anything on the Vigor forum to show me how it can be done
on the 2800 or 2820. Please can you post a link to suitable instructions
--
Graham J
Peter Crosland
One other thing to consider is your mains power supply. If you are in a
rural area served by overhead cables it is quite common, and indeed almost
normal, for there to be fluctuations in the voltage. Even fluctuations that
might otherwise go unoticed can cause a broadband connection to drop. My
router is run off a small dedictaed UPS expereince shows never a week goes
by without my UPS being activated. On average it happens two or three times
week.
Peter Crosland
ianh
> > I'm about 5km from the local exchange and use a Vigor 2600VGi router
> > (price about £150), with the ADSL service provided by Zen. I need the
> > Vigor for its VPN capability.
>
We are 9.6 km from the exchange and are running an ADSLnation X modem
straight out of the box on one line and it syncs ok. on my 2nd line i
have the same setup and it just wont sync..
speed isnt the best... 160 D 352 U 63.9db D 31.5db U snr
varies between 0.4 and 1 D and 7 U
but its better than dial up...
Ian H
Martin²
>But I can't find anything on the Vigor forum to show me how it can be done
>on the 2800 or 2820. Please can you post a link to suitable instructions
Sorry, haven't got time to look for it.
It was discussed when the 2800 come out, and IIRC it's done via telnet
instruction.
Try searching the forum, or raise new question.
Regards,
Martin
Graham J
[snip]
>> :
>>
>> When BT fixed their wires, they did something which appeared to affect
>> the performance of the Vigor routers. Can somebody explain this for me?
>
>
> One other thing to consider is your mains power supply. If you are in a
> rural area served by overhead cables it is quite common, and indeed almost
> normal, for there to be fluctuations in the voltage. Even fluctuations
> that might otherwise go unoticed can cause a broadband connection to drop.
> My router is run off a small dedictaed UPS expereince shows never a week
> goes by without my UPS being activated. On average it happens two or three
> times week.
I take your point, but in my case the router will stay connected for days at
a time. Even if the connections drops it re-establishes itself almost
immediately.
The issue is the unreasonably high SNR margin exhibited only by Vigor
routers, and only since BT broke the wires (jamming too many joints in a
junction box that was too small) in March.
--
Graham
Graham J
"Martin²" <ne...@give.one> wrote in message
But I have searched the forum, and all recent posts still show it as a
wish-list item !!
Specifically:
http://www.forum.draytek.co.uk/viewtopic.php?t=11628&highlight=set+snr+margin
--
Graham J
Ato_Zee
> The issue is the unreasonably high SNR margin exhibited only by Vigor
> routers,
Ideally you need a modem that supports DMTtool, BT Voyager 240,
Linksys WAG54GS (if you twist their arms for the firmware that
supports DMTtool). DMTtool comes in different versions for different
models of modem. I was 12dB SNR and 2.528Mbps with a Draytek,
went to 4.768 and down to 3dB but still stable with DMTtool and
WAG54GS.
Both modems were around a tenner on eBay.
Being able to set your own target SNR is a great plus.
DMTtool seems aimed at Linux based Broadcom chipset
modem/routers.
Peter Crosland
>>> the performance of the Vigor routers. Can somebody explain this for me?
>>
>>
>> One other thing to consider is your mains power supply. If you are in a
>> rural area served by overhead cables it is quite common, and indeed
>> almost normal, for there to be fluctuations in the voltage. Even
>> fluctuations that might otherwise go unoticed can cause a broadband
>> connection to drop. My router is run off a small dedictaed UPS expereince
>> shows never a week goes by without my UPS being activated. On average it
>> happens two or three times week.
>
> I take your point, but in my case the router will stay connected for days
> at a time. Even if the connections drops it re-establishes itself almost
> immediately.
It is still relevant because the mdem and the DSLAM may regard these as
signs that the line is of poor quality and reduce the speed or raise the
target SNR to compensate.
> The issue is the unreasonably high SNR margin exhibited only by Vigor
> routers, and only since BT broke the wires (jamming too many joints in a
> junction box that was too small) in March.
Draytek have used an algorithm that is not very good at achieving the best
performance out of the line. The end result is that the stability of the
line is given priority over out and out speed. As has been suggested before
the realistic way to improve matters is to try something like the 2700HGV by
2wire that in my experience achieves much better performance than any
Draytek does i.e. in my case the stable speed rose from 2000 to 3500 and has
remained so since. The cost of trying this is around £20 which is not much
really. As for the statement about BT jamming too many joints into the
junction box what exactly does it mean and where has this information come
from? How exactly are you suggesting this has caused the problems you have
experienced? I am sorry to say that sounds more like an urban, or rural,
myth than reality.
Peter Crosland
Graham J
> As for the statement about BT jamming too many joints into the junction
> box what exactly does it mean and where has this information come from?
> How exactly are you suggesting this has caused the problems you have
> experienced? I am sorry to say that sounds more like an urban, or rural,
> myth than reality.
This came from the BT technician that I spoke to some days after the event.
It may of course be lies, or irrelevant.
The original fault occurred in March, and many (20+) customers (in a village
of 100+ households) had no phone service. After several days the service
resumed; and the two lines coming into my property both showed reduced
performance once the repair was complete.
This type of fault has happened several times before, it just has not
affected me personally. Neighbours have complained of no phone service and
asked to use my phone to ring BT to log the fault. When several have asked
that favour, I've often looked for the Openreach van and spoken to the
technician - usually the explanation has been that the faults were created
by the previously attending technician.
When the fault affected me, I pressed the reparing technician about it who
explained about jamming too many joints into the one junction box; and that
a proper repair would entail the installation of a second junction box.
These appear to be black pods fitted on a pole. Some months later, I spoke
to another technician who explained that the new junction box had been
fitted so there should be no further risk of faults introduced inadvertently
by technicians attending to carry out other work.
As to why the repair has affected the ADSL performance is anybody's guess.
And why the problem particularly affects Vigor routers is even more of a
mystery. It is known that the Vigor routers perform less well on long noisy
lines (and prior to March the Long Line firmware on a V2600 did make an
improvement, whereas now the performance is the same regardless of which
version of firmware I use).
I suspect the issue is some sort of crosstalk that the Vigor perceives as
noise. I've tried V2600, V2800 and V2820. When I use a cheap Edimax router
in place of the Vigor the circuit initialises with the same SNR margin and
speed as the Vigor (typically 12dB and 1300kbits/sec for the V2600; 18dB and
800kbits/sec for the V2820) ; and within seconds reports an improvement to
6dB and 2400kbits/sec.
Another possibility is that the re-wiring necessitated the use of different
DSLAMs at the exchange; and that these perform differently.
--
Graham J
John Livingston
It isn't possible - directly - on the 2800. The chipset doesn't support
this.
A measure of control over SNR is possible by altering ADSL MAXDNRATE and
ADSL CODINGGAIN, accessible via the telnet command line. They aren't
documented well, so you have to experiment.
John
Graham J
"Ato_Zee" <ato...@hotmail.com> wrote in message
news:deiMk.107986$wG3....@newsfe23.ams2...
But I need the VPN capability offered by the Vigor.
However I have a work-around. I now use a Vigor 2910 (i.e. Dual-WAN
ethernet router) and an Edimax router configured in bridge mode as the
modem. This works fine; and one can still communicate directly with the
Edimax router to monitor the line state and statistics. In due course I
will connect a second edimax router and set up the Vigor to perform load
sharing.
--
Graham J
Graham J
"John Livingston" <nu...@spambin.com> wrote in message
news:4901cc4f$0$18317$da0f...@news.zen.co.uk...
Yes, I tried both of them. I can reduce performance, but not increase it.
Possibly useful for increasing reliability ...
--
Graham J
The Natural Philosopher
A firmware update on my very old one resulted in an undocumented flag
being set to basically turbocharge the chip to an inch of its life. I
was getting massively fast speeds and dozens of dropouts.
As a result the connection was almost unusable, and BT dropped my noise
margin to 15dB.
When I found the undocumented thing by trying every parameter that
telnet revealed, my sync speed dropped by HALF and I had to get my ISP
to get BT to reset the noise margin to something saner.
What this shows is that despite what the DSLAM suggests, the router can
be set to ignore it, but you may well trade speed for reliability.
nospam
>> A measure of control over SNR is possible by altering ADSL MAXDNRATE and
>> ADSL CODINGGAIN, accessible via the telnet command line. They aren't
>> documented well, so you have to experiment.
>Yes, I tried both of them. I can reduce performance, but not increase it.
>Possibly useful for increasing reliability ...
MAXDNRATE just limits the maximum sync rate. CODINGGAIN squeezes some
(notional) additional signal gain out of the modem which increases the
reported SNR and so the sync rate for a given SNR. The penalty is more
susceptibility to noise, probably more and/or bigger errors. When I was
using a 2700 I had coding gain up a couple of clicks to ensure I synced at
8128 and got the last BRAS profile step without it it would sometimes sync
at 8096 or 8064.
--
Peter Crosland
All noted. I think you have come to the wrong conclusions but I can see how
you might have done this. Changes to the distribution wiring would not
involve a change of DSLAM. Of course it is remotely possible that the DSLAM
you are on had to be changed for another reason but even so it would be
unlikely that there would be any difference in performance. There may be a
problem with crosstalk but you are going to find it very difficult indeed to
get anything done about it by Openreach. As for the difference when you
changed to the Edimax the DSLAM would recognise the difference in equipment
and AFAIK it would reinitialise the line. In any case you cannot get a
meaningful comparison of modem performance unless it is done over a period
of several days and nights. During that time the DSLAM will try and maximise
the line speed according to how stable it is. The process is not perfect but
given a few days it does generally work.
My experience with the Vigor 2600, 2800 and 2820 over a period of six
months, with the ordinary and long line firmware, suggested that the
connection was more reliable at the cost of sync speed with the latter. I
also found that the 2820 was significantly worse than the earlier models.
During the last ten months I tried Edimax, Netgear, Dlink, Linksys and Zyxel
modems as well as the Draytek models. They showed varying, and not very
consistent, results and none would reliably sync at more than 2500-3000 on a
line that had synced reliably at 3600 for three years and often remained
connected for several weeks at a time. Indeed the 2820 was so bad it would
not synce above 2000 and often less. Extensive work by a series of Openreach
engineers found various minor faults but no improvement in sync speed was
achieved. Eventually after a lot of pressure being applied to the BT
Chairman's office and my ISP a specialist Openreach engineer became
involved. As a result of conversations with him I decided to try a BT
Business Hub which is a badged version of the 2Wire 2700 HGV. This showed an
immediate improvement in sync speed and remained connected regardless of the
strong RF interference that exists on my line particularly at night. After
the line stabilised it has remained synced at 4200 to 4300 for the last two
monthsand has currently been connected for 29 days. As a result of my
experiments I have installed 2Wires at several other sites with long and
noisy lines. All have shown a significant increase in speed along with rock
solid reliability. I have to say that before I discovered the 2Wire I was a
firm advocate of Draytek but no longer. In fact I am so confident it would
improve your connection I would be please to lend you a spare one free of
charge!
Peter Crosland
John Livingston
MAXDNRATE gives problems when the line is set to interleaved. I found it
would usually fail to train - repeated unsuccessful attempts. It seems
to work for others though. I guess it might depend on the DSLAM vendor
or firmware.
John
Graham J
> I have to say that before I discovered the 2Wire I was a firm advocate of
> Draytek but no longer. In fact I am so confident it would improve your
> connection I would be please to lend you a spare one free of charge!
Can I manage the 2Wire remotely?
Will it support multiple LAN to LAN VPN connections? Alternatively can I
configure it in bridge mode so I can use a Vigor for the VPN connections?
--
Graham J
Bob
I've been following this thread with keen interrest since my experience is
similar to yours. I live in Milton Keynes where the broadband provision by
BT had left a lot of no-go areas due to the planning of a minimal number of
large exchanges with many parts connected by long lines.
In my part of MK we only managed to achieve any broadband connection a
couple of years ago after pressurising BT to install new cables to reduce
the line loss (see www.bb4mk.co.uk) so that for the last couple of years I
have enjoyed a reliable 3 Mbps.
However in the last few months my connection speed has deteriorated so much
that I expect my BRAS rate to imminently fall from my current 2.5 Mbps
speed to 2 Mbps. The cause of this problem seems to be cable crosstalk from
the leased lines to a nearby pub which connects to their data centre during
licensing hours adding a variable 5 or 6 db to my line noise. From what I
can make out they use BT Kilostream.
I have tried replacing my original Zyxel P660R modem with a Billion 5200S
which although initially connects faster than the Zyxel soon falls to a
lower speed when the noise increases at the start of opening hours. From
you comments, I am currently awaiting delivery of a 2Wire BT Business Hub
so hopefully that will improve my speed but it will still be interesting to
make a comparison between the different modems should this not be achieved.
I have also had a call from Openreach today who have booked an appointment
for next week. Any suggestions on what I should ask them?
Bob Brewer
Peter Crosland
You can use it in bridge mode and AFAIK it does support multiple VPN but
don't ask the details as I don't use either. No doubt someone on here can
tell you more.
Peter Crosland
Peter Crosland
Whilst there could be a problem with crosstalk from other users are you sure
it is not related to the hours of darkness? It is quite common for the noise
level to rise by 6dB or more at night.
Peter Crosland
Bob
The noise levels tracks pub opening hours from mid-day to midnight also
noise disappeared when pub was shut for refurbishment. Pub also agrees that
noise levels track their data transfer times. The cables are entirely
underground.
Bob
Peter Crosland
Noted. BT/Openreach should be able to address that problem. I assume you
have done all the usual checks on wiring and run the router from the master
socket?
Peter Crosland
Martin²
>But I have searched the forum, and all recent posts still show it as a
>wish-list item !!
Ok, I have had a look for myself, and here is what I meant in my post:
On the Draytek 2800 you can set 'maxdnrate' and 'codinggain', via telnet
commands.
(You can NOT do it on 2600 or 2820 ! )
That can help to set compromise between speed and stability. I would have
liked to have it, when my line run on BT std 6dB and suffered lot of
disconnections, I could have set the max speed to equivalent of SNR of say
7.5dB which would be ideal for my line.
However, back in the spring BT changed the way their DSLAM / BRAS works,
they have gone for stability at all cost and my SNR was initially set to 15,
took long time to come down to 12. I had to battle hard via my ISP to get BT
so reset it to 9 ! Consequently my speed dropped from 2.8Mb/s at 6dB to just
1.6Mb/s !
I think that is your problem too.
The only way to avoid this BT nonsense, is to go LLU. O2 / Be is now
available here, but at higher cost, and the best I could expect is to get
back to 2.8Mb/s again.
Regards,
Martin
Graham J
"Martin²" <ne...@give.one> wrote in message
Yes, I played with "codinggain". "Auto" gives the best performance. I
didn't try "maxdnrate" since I couldn't see how it would force an increase
in speed. There's no "mindnrate" ...
I now have an Edimax router configured as a bridge and a Vigor router to
give me the VPN support. The Edimax router immediately gets 5.5dB SNR
margin and 2400 kbits/sec. After 24 hours the BRAS profile increased from
750 to 2000 - so probably this is all I can expect.
In fact the router is a V2910 so I have a second Edimax router on a second
ADSL line with a different ISP, and have the router load balancing between
the two lines - seems to work ok ...
Thanks anyway.
--
Graham J