ADSL Max target SNR oddities

Could someone try this and confirm what I have been seeing ?

Normal target SNR on resync - 10dB (has been for ages).
Stable line - resyncs once or twice a week. Speeds around 2.5-2.8Mb

OK - here we go. Switch off router for a couple of minutes.
Switch on again.
Resyncs at target SNR of 14dB(!!). This is consistent - not a one-off.
Speed is of course WAY down. If I don't intervene, it will stay here.
Dead stable, but slow.

Force a resync from the router command line - resyncs at normal 10dB.

It looks a bit like BT Wholesale has set the DSLAM to resync at a much
higher target SNR than usual when a complete loss of signal occurs
(rather than a noise/error threshold failure). Or is it my router which
is requesting the high SNR target ? (Draytek 2800VG).

John

John Livingston wrote:
> Could someone try this and confirm what I have been seeing ?
>
> Normal target SNR on resync - 10dB (has been for ages).
> Stable line - resyncs once or twice a week. Speeds around 2.5-2.8Mb
>
> OK - here we go. Switch off router for a couple of minutes.
> Switch on again.
> Resyncs at target SNR of 14dB(!!). This is consistent - not a one-off.
> Speed is of course WAY down. If I don't intervene, it will stay here.
> Dead stable, but slow.
>
> Force a resync from the router command line - resyncs at normal 10dB.
>
> It looks a bit like BT Wholesale has set the DSLAM to resync at a much
> higher target SNR than usual when a complete loss of signal occurs
> (rather than a noise/error threshold failure). Or is it my router which
> is requesting the high SNR target ? (Draytek 2800VG).
>
> John
Seriously dunno..

Any idea what your BRAS is?

The Natural Philosopher wrote:

> Seriously dunno..
>
> Any idea what your BRAS is?
>
Steady at 2Mb.

John

"Peter Crosland" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) et...
>> Could someone try this and confirm what I have been seeing ?
>>
>> Normal target SNR on resync - 10dB (has been for ages).
>> Stable line - resyncs once or twice a week. Speeds around 2.5-2.8Mb
>>
>> OK - here we go. Switch off router for a couple of minutes.
>> Switch on again.
>> Resyncs at target SNR of 14dB(!!). This is consistent - not a one-off.
>> Speed is of course WAY down. If I don't intervene, it will stay here.
>> Dead stable, but slow.
>>
>> Force a resync from the router command line - resyncs at normal 10dB.
>>
>> It looks a bit like BT Wholesale has set the DSLAM to resync at a much
>> higher target SNR than usual when a complete loss of signal occurs
>> (rather than a noise/error threshold failure). Or is it my router which
>> is requesting the high SNR target ? (Draytek 2800VG).
>
>
> I have had similar problems with the Draytek range. It seems that Draytek
> have skewed their algorithm quite a lot in favour of stability rather than
> speed. Having favoured Draytek for years I have given them up and switched
> to 2Wire 2700HGs that are badged as BT Business hubs and are often
> available on eBay for less than £20. Unless you need some of the more
> esoteric facilities of the Draytek then the win hands down in stability
> and speed.

Certainly the older Vigor routers (2600 etc) give better performance on poor
or long lines.

As a compromise I use a Vigor ethernet router (a 2910) configured for PPPoE
connected to a cheap Edimax router configured in bridge mode (i.e. as an
ethernet modem) This gives the functionality I require (multiple LAN-LAN
VPNs) together with good sync speed and nominal 6dB SNR margin. I also have
two separate phone lines, each with an ADSL service, therefore two Edimax
routers and the Vigor configured for load balancing.

--
Graham J

John Livingston wrote:
> The Natural Philosopher wrote:
>
>> Seriously dunno..
>>
>> Any idea what your BRAS is?
>>
> Steady at 2Mb.
>
> John
Well in which case, its not going to gain you anything by getting a
better synch rate.

Unless you can force it to consistently synch > 2.5Mbps.

You may be able to tweak the router to go for better speeds.

John Livingston wrote:

> Could someone try this and confirm what I have been seeing ?
>
> Normal target SNR on resync - 10dB (has been for ages).
> Stable line - resyncs once or twice a week. Speeds around 2.5-2.8Mb
>
> OK - here we go. Switch off router for a couple of minutes.
> Switch on again.
> Resyncs at target SNR of 14dB(!!). This is consistent - not a one-off.
> Speed is of course WAY down. If I don't intervene, it will stay here.
> Dead stable, but slow.
>
> Force a resync from the router command line - resyncs at normal 10dB.
>
> It looks a bit like BT Wholesale has set the DSLAM to resync at a much
> higher target SNR than usual when a complete loss of signal occurs
> (rather than a noise/error threshold failure). Or is it my router which
> is requesting the high SNR target ? (Draytek 2800VG).

Do you have a decent ISP that has people who speak competent English and
understand what you're talking about ? Get them to check with BT. They CAN
fiddle with this stuff.

Graham

Peter Crosland wrote:

> > Could someone try this and confirm what I have been seeing ?
> >
> > Normal target SNR on resync - 10dB (has been for ages).
> > Stable line - resyncs once or twice a week. Speeds around 2.5-2.8Mb
> >
> > OK - here we go. Switch off router for a couple of minutes.
> > Switch on again.
> > Resyncs at target SNR of 14dB(!!). This is consistent - not a one-off.
> > Speed is of course WAY down. If I don't intervene, it will stay here. Dead
> > stable, but slow.
> >
> > Force a resync from the router command line - resyncs at normal 10dB.
> >
> > It looks a bit like BT Wholesale has set the DSLAM to resync at a much
> > higher target SNR than usual when a complete loss of signal occurs (rather
> > than a noise/error threshold failure). Or is it my router which is
> > requesting the high SNR target ? (Draytek 2800VG).
>
> I have had similar problems with the Draytek range. It seems that Draytek
> have skewed their algorithm quite a lot in favour of stability rather than
> speed. Having favoured Draytek for years I have given them up and switched
> to 2Wire 2700HGs that are badged as BT Business hubs and are often available
> on eBay for less than £20. Unless you need some of the more esoteric
> facilities of the Draytek then the win hands down in stability and speed.

My Origo router holds the line with under 4 dB SNR margin !

Graham

Graham J wrote:

> I also have two separate phone lines, each with an ADSL service, therefore two
> Edimax
> routers and the Vigor configured for load balancing.

Interesting. How easy is that to set up ?

Graham

"Eeyore" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
>
> Graham J wrote:
>
>> I also have two separate phone lines, each with an ADSL service,
>> therefore two
>> Edimax
>> routers and the Vigor configured for load balancing.
>
> Interesting. How easy is that to set up ?

Vigor 2910 is dual WAN ethernet router

WAN | General Setup : enable WAN1 & WAN2, give each a meaningful name. I
chose Load Balance Mode = According to Line Speed and specified the speeds
reported by the respective modems. (Note that one account is with Zen, who
report the BRAS profile, the other is with Demon who AFAIK do not, but some
speed tests confirmed the actual speed related appropriately to the line
speed.) Then Active Mode = Always On

This achieves used of both lines, irrespective of nature of traffic.

The VPN definitions allow you to specify the WAN - essential for correct
operation when the request is incoming.

WAN | Internet Access : specify PPPoE (as previously noted the modems are
really Edimax routers set in Bridge Mode) with Client Mode enabled, and the
respective ISP-supplied username & password.

WAN | Load Balance Policy : specify here those services that **must** use a
specific line. SMTP servers for the respective ISPs, also DNS servers if
you wish. I also found it necessary to specify the WAN for some online
banking. Wife uses Scoris for marking exam papers and we expected to have
to restrict that to one WAN line, but so far it hasn't failed when using
both.

Have syslog running so you can track down any problems that might arise.

The only funny I've found is that the USB port on the 2910 (and on the 2820
I tested) does not reliably drive my Deskjet 1220C printer, whereas the
Vigor 2600 used to work perfectly. I suspect that the more modern routers
intend the USB port for a WAN channel rather than an IP printer. So for the
moment the printer is shared off one PC (means that PC must be always on to
allow other users acces tot he printer!)

Hope this helps.

--
Graham J

Graham J wrote:

> "Eeyore" <(E-Mail Removed)> wrote
> > Graham J wrote:
> >
> >> I also have two separate phone lines, each with an ADSL service,
> >> therefore two Edimax routers and the Vigor configured for load balancing.
> >
> > Interesting. How easy is that to set up ?
>
> Vigor 2910 is dual WAN ethernet router
>
> WAN | General Setup : enable WAN1 & WAN2, give each a meaningful name. I
> chose Load Balance Mode = According to Line Speed and specified the speeds
> reported by the respective modems. (Note that one account is with Zen, who
> report the BRAS profile, the other is with Demon who AFAIK do not, but some
> speed tests confirmed the actual speed related appropriately to the line
> speed.) Then Active Mode = Always On
>
> This achieves used of both lines, irrespective of nature of traffic.
>
> The VPN definitions allow you to specify the WAN - essential for correct
> operation when the request is incoming.
>
> WAN | Internet Access : specify PPPoE (as previously noted the modems are
> really Edimax routers set in Bridge Mode) with Client Mode enabled, and the
> respective ISP-supplied username & password.
>
> WAN | Load Balance Policy : specify here those services that **must** use a
> specific line. SMTP servers for the respective ISPs, also DNS servers if
> you wish. I also found it necessary to specify the WAN for some online
> banking. Wife uses Scoris for marking exam papers and we expected to have
> to restrict that to one WAN line, but so far it hasn't failed when using
> both.
>
> Have syslog running so you can track down any problems that might arise.
>
> The only funny I've found is that the USB port on the 2910 (and on the 2820
> I tested) does not reliably drive my Deskjet 1220C printer, whereas the
> Vigor 2600 used to work perfectly. I suspect that the more modern routers
> intend the USB port for a WAN channel rather than an IP printer. So for the
> moment the printer is shared off one PC (means that PC must be always on to
> allow other users acces tot he printer!)
>
> Hope this helps.

Very interesting thanks.

Graham