Tweak help required

i've just changes isp from pipex (>2meg)to vivacity (>8meg).
i do understand that the line may take a week or so so settle down, and
allow sync at the highest speed for my line.
i have a netgear DG834GT modem/router (ex-sky, reflashed to latest netgear
firmware) connected via cat5 to my pc, and wireless to 4 others, and i read
somewhere (maybe here) that it is possible to change the snr ratio to
improve speeds, but sadly i don't really understand this.
my settings (via the router) are

ADSL Link Downstream Upstream
Connection Speed 7936 kbps 448 kbps
Line Attenuation 37.0 db 23.0 db
Noise Margin 5.4 db 22.0 db

the noise margin of 5.4db is the bit that worries me, seems a bit low? sadly
i understand enough to want it right, and am happy to send the router
commands to change things, but not enough to know if this is right, or if
better can be achieved.
also, am i best powercycling the router each day to force a resync for this
week or so, or just leave it alone.

current speed test
http://www.dslzoneuk.net/speedtest/s....php?id=489455
thanks for any help.

tony h wrote:
> i've just changes isp from pipex (>2meg)to vivacity (>8meg).
> i do understand that the line may take a week or so so settle down,
> and allow sync at the highest speed for my line.
> i have a netgear DG834GT modem/router (ex-sky, reflashed to latest
> netgear firmware) connected via cat5 to my pc, and wireless to 4
> others, and i read somewhere (maybe here) that it is possible to
> change the snr ratio to improve speeds, but sadly i don't really
> understand this. my settings (via the router) are
>
> ADSL Link Downstream Upstream
> Connection Speed 7936 kbps 448 kbps
> Line Attenuation 37.0 db 23.0 db
> Noise Margin 5.4 db 22.0 db
>
> the noise margin of 5.4db is the bit that worries me, seems a bit
> low? sadly i understand enough to want it right, and am happy to send
> the router commands to change things, but not enough to know if this
> is right, or if better can be achieved.
> also, am i best powercycling the router each day to force a resync
> for this week or so, or just leave it alone.
>

You are within a whisker of the maximum that BT Max product will support so
stop worrying and enjoy a speed many others would love to have!


Peter Crosland

In message <46013654.0@entanet>, tony h <(E-Mail Removed)> writes
>i've just changes isp from pipex (>2meg)to vivacity (>8meg).
>i do understand that the line may take a week or so so settle down, and
>allow sync at the highest speed for my line.
>i have a netgear DG834GT modem/router (ex-sky, reflashed to latest netgear
>firmware) connected via cat5 to my pc, and wireless to 4 others, and i read
>somewhere (maybe here) that it is possible to change the snr ratio to
>improve speeds, but sadly i don't really understand this.
>my settings (via the router) are
>
>ADSL Link Downstream Upstream
>Connection Speed 7936 kbps 448 kbps
>Line Attenuation 37.0 db 23.0 db
>Noise Margin 5.4 db 22.0 db
>
>the noise margin of 5.4db is the bit that worries me, seems a bit low? sadly
>i understand enough to want it right, and am happy to send the router
>commands to change things, but not enough to know if this is right, or if
>better can be achieved.
>also, am i best powercycling the router each day to force a resync for this
>week or so, or just leave it alone.
>
>current speed test
>http://www.dslzoneuk.net/speedtest/s....php?id=489455
>thanks for any help.
>
>
I am not sure what you are asking for.

As you already seem to have almost 8Meg to the exchange, there seems to
be little you could do to improve the speed of that link in the chain.

The ADSLMax target is a 6db noise margin. If the SNR drops below that (I
think for any significant period) the router/exchange will resync at a
lower speed. If the SNR rises much above 6db, then they will resync at a
higher speed.

I think you are referring to situations where lines have a widely
varying SNR - possibly caused by external interference. This can fool
the system into setting the speed too high, and when the noise bursts
occur, the line drops. By the time it resync's the noise pulse has gone
away, and the line a gain synch "too fast". In these circumstances, some
routers can be tweaked to tell the exchange to target a higher basic SNR
- thus synching at a LOWER but more reliable speed.

If it reliably resync's at the figures you have quoted, I think you are
probably better just letting it get on with it.

The 5Meg transfer speed is probably reasonable, depending on the time of
day, congestion at your exchange, any traffic shaping done by audaciti,
any congestion on their backbone (I note their T's & C's only guarantee
20% of rated speed - or 1.6M on your line) and any slowdown between you
and the speed test server.

Given that the server seems to report in 1M blocks, its a bit difficult
to judge. Best I ever get is about 85% of the rated line speed
(overheads, latencies etc.) and that is on a good day . In your case
that would be about 5.9M - does the server round up or down?
--
Peter R Cook

>The ADSLMax target is a 6db noise margin. If the SNR drops below that (I
think for any significant period) the router/exchange will resync at a
lower speed. If the SNR rises much above 6db, then they will resync at a
higher speed.

that is my worry, at the moment noise margin (snr?) is 5.1db /22, i was
wondering if it's worth (or possible) trying to force the router to think
it's about 6.5db. as i say though, first day on higher speed, so ganna take
a week to ten to settle, but i just dont want to settle permamently at a
lower connection that is possible for my line and equipment, as they say 'a
little knowledge is a dangerous thing..' and i just dont know enough....

thanks for the replys.

tony h wrote:
>> The ADSLMax target is a 6db noise margin. If the SNR drops below
>> that (I
> think for any significant period) the router/exchange will resync at a
> lower speed. If the SNR rises much above 6db, then they will resync
> at a higher speed.
>
> that is my worry, at the moment noise margin (snr?) is 5.1db /22, i
> was wondering if it's worth (or possible) trying to force the router
> to think it's about 6.5db. as i say though, first day on higher
> speed, so ganna take a week to ten to settle, but i just dont want to
> settle permamently at a lower connection that is possible for my line
> and equipment, as they say 'a little knowledge is a dangerous
> thing..' and i just dont know enough....

Don't worry about it Tony! The 6Db is just a target. It will fluctuate for
various reasons from time to time and this is quite normal.

Peter Crosland

thanks peter.


"Peter Crosland" <(E-Mail Removed)> wrote in message
news:46014a9a$0$8736$(E-Mail Removed)...
> tony h wrote:
>>> The ADSLMax target is a 6db noise margin. If the SNR drops below
>>> that (I
>> think for any significant period) the router/exchange will resync at a
>> lower speed. If the SNR rises much above 6db, then they will resync
>> at a higher speed.
>>
>> that is my worry, at the moment noise margin (snr?) is 5.1db /22, i
>> was wondering if it's worth (or possible) trying to force the router
>> to think it's about 6.5db. as i say though, first day on higher
>> speed, so ganna take a week to ten to settle, but i just dont want to
>> settle permamently at a lower connection that is possible for my line
>> and equipment, as they say 'a little knowledge is a dangerous
>> thing..' and i just dont know enough....
>
> Don't worry about it Tony! The 6Db is just a target. It will fluctuate for
> various reasons from time to time and this is quite normal.
>
> Peter Crosland
>
>
>

In message <46015080.0@entanet>, tony h <(E-Mail Removed)> writes
>>The ADSLMax target is a 6db noise margin. If the SNR drops below that (I
>think for any significant period) the router/exchange will resync at a
>lower speed. If the SNR rises much above 6db, then they will resync at a
>higher speed.
>
>that is my worry, at the moment noise margin (snr?) is 5.1db /22, i was
>wondering if it's worth (or possible) trying to force the router to think
>it's about 6.5db. as i say though, first day on higher speed, so ganna take
>a week to ten to settle, but i just dont want to settle permamently at a
>lower connection that is possible for my line and equipment, as they say 'a
>little knowledge is a dangerous thing..' and i just dont know enough....
>
>thanks for the replys.
>
>
Your logic is the wrong way round. You can't "force the router to think
its 6.5" you can only tell the (some) router to synch AT 6.5 minimum.

If you tell the router to sync at a higher SNR, then the line speed will
GO DOWN. The relationship (for a given line) is higher speed=lower SNR.

As Peter Crosland says stop worrying. My Netgear often shows 1db SNR at
night while maintaining a perfectly solid link (at 6M)
--
Peter R Cook

tony h wrote:

> i've just changes isp from pipex (>2meg)to vivacity (>8meg).
> i do understand that the line may take a week or so so settle down, and
> allow sync at the highest speed for my line.
> i have a netgear DG834GT modem/router (ex-sky, reflashed to latest netgear
> firmware) connected via cat5 to my pc, and wireless to 4 others, and i read
> somewhere (maybe here) that it is possible to change the snr ratio to
> improve speeds, but sadly i don't really understand this.
> my settings (via the router) are
>
> ADSL Link Downstream Upstream
> Connection Speed 7936 kbps 448 kbps
> Line Attenuation 37.0 db 23.0 db
> Noise Margin 5.4 db 22.0 db

Those numbers are very good.


> the noise margin of 5.4db is the bit that worries me, seems a bit low? sadly
> i understand enough to want it right, and am happy to send the router
> commands to change things, but not enough to know if this is right, or if
> better can be achieved.
> also, am i best powercycling the router each day to force a resync for this
> week or so, or just leave it alone.
>
> current speed test
> http://www.dslzoneuk.net/speedtest/s....php?id=489455
> thanks for any help.

Just leave it be and only reboot the router if you need to. Daily rebooting is
*not required*.

Graham

Invalid wrote:

> The 5Meg transfer speed is probably reasonable, depending on the time of
> day, congestion at your exchange, any traffic shaping done by audaciti,
> any congestion on their backbone (I note their T's & C's only guarantee
> 20% of rated speed - or 1.6M on your line) and any slowdown between you
> and the speed test server.

I totally agree. My synch speed is 8128kbps and my prodile is 7150 kbps but only
rarely does a speed test return as high as 6000 kbps. 5000 is much more the norm
and it's slower during periods of heavy activity of course such as ~ 2000 kbps

Graham

tony h wrote:

> >The ADSLMax target is a 6db noise margin. If the SNR drops below that (I
> think for any significant period) the router/exchange will resync at a
> lower speed. If the SNR rises much above 6db, then they will resync at a
> higher speed.
>
> that is my worry, at the moment noise margin (snr?) is 5.1db /22, i was
> wondering if it's worth (or possible) trying to force the router to think
> it's about 6.5db. as i say though, first day on higher speed, so ganna take
> a week to ten to settle, but i just dont want to settle permamently at a
> lower connection that is possible for my line and equipment, as they say 'a
> little knowledge is a dangerous thing..' and i just dont know enough....

If there are no problems don't worry !

You've heard the phrase "if it's not broken, don't fix it" I hope ?

Graham