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uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

Router that sets Sync Speed not Noise margin?



 
 
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  #1  
Old November 26th 08, 11:22 AM posted to uk.telecom.broadband
Invalid
external usenet poster
 
Posts: 150
Default Router that sets Sync Speed not Noise margin?

Does anyone have a pointer to either a piece of software, a model of
router or a router command line instruction, which allows the maximum
ADSL sync speed to be set rather than the target noise margin? (I know
DMT and Routerstats both allow the target SNR to be tweaked).

I have a fairly long (3.5km) reasonable quality line (Rx Attenuation
40db). The line is all overhead, and the noise levels vary by 4-5db
between day and night. I currently use an ex Sky DG834GT with the DGTeam
firmware which allows the Rx Noise target to be tweaked.
Currently the firmware is set up to re-establish connection in the event
of a loss at about 90% of the exchanges 6db target. That ensures it
resync's at 6300-6400 in the event of a dropout at night (to preserve
my 5500 BRAS profile).

Unfortunately if I get a dropout during the day when the line is at its
best (which happens occasionally - once per week?), the same setting
will resync at 7000+. This is OK during the day, but in the evening the
noise levels rise and the error rates make the line unusable ( it
doesn't drop out just has high retransmission rates (60 error seconds
per minute!!!) A manual resync drops the speeds to 6300-6400 and the
error rates go down to 1 or 2 per 15 minutes.

I would like to be able to tell the modem to resync at 6300-6400
regardless of the SNR at the time of the dropout. Any ideas how to do
this.
--
Peter R Cook
  #2  
Old November 26th 08, 04:14 PM posted to uk.telecom.broadband
Peter Crosland
external usenet poster
 
Posts: 1,463
Default Router that sets Sync Speed not Noise margin?


Does anyone have a pointer to either a piece of software, a model of
router or a router command line instruction, which allows the maximum ADSL
sync speed to be set rather than the target noise margin? (I know DMT and
Routerstats both allow the target SNR to be tweaked).

I have a fairly long (3.5km) reasonable quality line (Rx Attenuation
40db). The line is all overhead, and the noise levels vary by 4-5db
between day and night. I currently use an ex Sky DG834GT with the DGTeam
firmware which allows the Rx Noise target to be tweaked.
Currently the firmware is set up to re-establish connection in the event
of a loss at about 90% of the exchanges 6db target. That ensures it
resync's at 6300-6400 in the event of a dropout at night (to preserve my
5500 BRAS profile).

Unfortunately if I get a dropout during the day when the line is at its
best (which happens occasionally - once per week?), the same setting will
resync at 7000+. This is OK during the day, but in the evening the noise
levels rise and the error rates make the line unusable ( it doesn't drop
out just has high retransmission rates (60 error seconds per minute!!!) A
manual resync drops the speeds to 6300-6400 and the error rates go down to
1 or 2 per 15 minutes.

I would like to be able to tell the modem to resync at 6300-6400
regardless of the SNR at the time of the dropout. Any ideas how to do
this.



Sounds like a classic case of RF interference caused by better medium wave
propagation during darkness.What you need is a router/modem that can deal
with high error rates without dropping the connection. It also seems that
the exchange target SNR of 6dB is simply too high to give a reliable 24/7
connection. Given the way the BT dynamic line management works what you are
trying is unlikely to ever work successfully because you are forcing the
equipment to work well outside the range at which it can function reliably.
Having suffered a similar problem for many months and with much effort from
BT the final solution was to use router modem designed for noisy and varying
quality lines. Having used various Draytek, Netgear, Dlink and ZyXel I ended
up using 2Wire 2700HGV. I since installed these at two other problem sites
and they really are the dog's gonads. My line will not reliably support more
than 2500 but the 2wire stays synced day after day at 3,500. You can pick
one up on eBay for around £20 or so where you will find them badged as BT
Business hubs. BT do have a prototype filter that reduces the effect of
severe RF interference which is in the form of an ADSL filter faceplate for
NTE5 sockets but I doubt you will get that installed on an unbundled Sky
line!

Peter Crosland


  #3  
Old November 26th 08, 06:59 PM posted to uk.telecom.broadband
Invalid
external usenet poster
 
Posts: 150
Default Router that sets Sync Speed not Noise margin?

In message , Peter
Crosland writes

Does anyone have a pointer to either a piece of software, a model of
router or a router command line instruction, which allows the maximum ADSL
sync speed to be set rather than the target noise margin? (I know DMT and
Routerstats both allow the target SNR to be tweaked).

I have a fairly long (3.5km) reasonable quality line (Rx Attenuation
40db). The line is all overhead, and the noise levels vary by 4-5db
between day and night. I currently use an ex Sky DG834GT with the DGTeam
firmware which allows the Rx Noise target to be tweaked.
Currently the firmware is set up to re-establish connection in the event
of a loss at about 90% of the exchanges 6db target. That ensures it
resync's at 6300-6400 in the event of a dropout at night (to preserve my
5500 BRAS profile).

Unfortunately if I get a dropout during the day when the line is at its
best (which happens occasionally - once per week?), the same setting will
resync at 7000+. This is OK during the day, but in the evening the noise
levels rise and the error rates make the line unusable ( it doesn't drop
out just has high retransmission rates (60 error seconds per minute!!!) A
manual resync drops the speeds to 6300-6400 and the error rates go down to
1 or 2 per 15 minutes.

I would like to be able to tell the modem to resync at 6300-6400
regardless of the SNR at the time of the dropout. Any ideas how to do
this.



Sounds like a classic case of RF interference caused by better medium wave
propagation during darkness.What you need is a router/modem that can deal
with high error rates without dropping the connection. It also seems that
the exchange target SNR of 6dB is simply too high to give a reliable 24/7
connection. Given the way the BT dynamic line management works what you are
trying is unlikely to ever work successfully because you are forcing the
equipment to work well outside the range at which it can function reliably.
Having suffered a similar problem for many months and with much effort from
BT the final solution was to use router modem designed for noisy and varying
quality lines. Having used various Draytek, Netgear, Dlink and ZyXel I ended
up using 2Wire 2700HGV. I since installed these at two other problem sites
and they really are the dog's gonads. My line will not reliably support more
than 2500 but the 2wire stays synced day after day at 3,500. You can pick
one up on eBay for around £20 or so where you will find them badged as BT
Business hubs. BT do have a prototype filter that reduces the effect of
severe RF interference which is in the form of an ADSL filter faceplate for
NTE5 sockets but I doubt you will get that installed on an unbundled Sky
line!

Peter Crosland


Thanks Peter for the input. I agree with your diagnosis that its Medium
Wave RF at night. It's not an unbundled Sky line, I simply use an ex-Sky
router bought from E-bay for £10 and reflashed with the DGTeam firmware.

The line is a BT line, and at 6300-6400 it is more than sufficiently
reliable for my needs. Once established at that speed it drops once or
possibly twice a week [usually as the result of a big noise spike which
I presume comes from one of the agricultural workshops dropping the arc
welder or something ].

Its just that when it does so I want it to reconnect at a speed that
gives 5 or 6dB at night. If the drop does occur at night then all is
well. Its when it happens during the day and I get a 7000+ (I have seen
as high as 7500ish running reliably at v low error rates during the day)
sync speed the router will hang on to the line very well at night, its
just that the error rates skyrocket and retransmission causes the real
throughput to go to hell in a handbasket.

I am actually very happy with 6300-6400 ( and a 5500 Bras profile) give
where I live. Its a fair bit higher than my neighbours get, and is the
result of taking some care with the internal wiring.

I will try for a 2700HGV and see whether that deals with the problem.

Thanks
--
Peter R Cook
  #4  
Old November 26th 08, 09:27 PM posted to uk.telecom.broadband
Peter Crosland
external usenet poster
 
Posts: 1,463
Default Router that sets Sync Speed not Noise margin?



--
Peter Crosland
"Invalid" wrote in message
...
In message , Peter
Crosland writes

Does anyone have a pointer to either a piece of software, a model of
router or a router command line instruction, which allows the maximum
ADSL
sync speed to be set rather than the target noise margin? (I know DMT
and
Routerstats both allow the target SNR to be tweaked).

I have a fairly long (3.5km) reasonable quality line (Rx Attenuation
40db). The line is all overhead, and the noise levels vary by 4-5db
between day and night. I currently use an ex Sky DG834GT with the DGTeam
firmware which allows the Rx Noise target to be tweaked.
Currently the firmware is set up to re-establish connection in the event
of a loss at about 90% of the exchanges 6db target. That ensures it
resync's at 6300-6400 in the event of a dropout at night (to preserve
my
5500 BRAS profile).

Unfortunately if I get a dropout during the day when the line is at its
best (which happens occasionally - once per week?), the same setting
will
resync at 7000+. This is OK during the day, but in the evening the noise
levels rise and the error rates make the line unusable ( it doesn't
drop
out just has high retransmission rates (60 error seconds per minute!!!)
A
manual resync drops the speeds to 6300-6400 and the error rates go down
to
1 or 2 per 15 minutes.

I would like to be able to tell the modem to resync at 6300-6400
regardless of the SNR at the time of the dropout. Any ideas how to do
this.



Sounds like a classic case of RF interference caused by better medium wave
propagation during darkness.What you need is a router/modem that can deal
with high error rates without dropping the connection. It also seems that
the exchange target SNR of 6dB is simply too high to give a reliable 24/7
connection. Given the way the BT dynamic line management works what you
are
trying is unlikely to ever work successfully because you are forcing the
equipment to work well outside the range at which it can function
reliably.
Having suffered a similar problem for many months and with much effort
from
BT the final solution was to use router modem designed for noisy and
varying
quality lines. Having used various Draytek, Netgear, Dlink and ZyXel I
ended
up using 2Wire 2700HGV. I since installed these at two other problem sites
and they really are the dog's gonads. My line will not reliably support
more
than 2500 but the 2wire stays synced day after day at 3,500. You can pick
one up on eBay for around £20 or so where you will find them badged as BT
Business hubs. BT do have a prototype filter that reduces the effect of
severe RF interference which is in the form of an ADSL filter faceplate
for
NTE5 sockets but I doubt you will get that installed on an unbundled Sky
line!

Peter Crosland


Thanks Peter for the input. I agree with your diagnosis that its Medium
Wave RF at night. It's not an unbundled Sky line, I simply use an ex-Sky
router bought from E-bay for £10 and reflashed with the DGTeam firmware.

The line is a BT line, and at 6300-6400 it is more than sufficiently
reliable for my needs. Once established at that speed it drops once or
possibly twice a week [usually as the result of a big noise spike which I
presume comes from one of the agricultural workshops dropping the arc
welder or something ].

Its just that when it does so I want it to reconnect at a speed that gives
5 or 6dB at night. If the drop does occur at night then all is well. Its
when it happens during the day and I get a 7000+ (I have seen as high as
7500ish running reliably at v low error rates during the day) sync speed
the router will hang on to the line very well at night, its just that the
error rates skyrocket and retransmission causes the real throughput to go
to hell in a handbasket.

I am actually very happy with 6300-6400 ( and a 5500 Bras profile) give
where I live. Its a fair bit higher than my neighbours get, and is the
result of taking some care with the internal wiring.

I will try for a 2700HGV and see whether that deals with the problem.


My email address is valid. If you email me I can let you have some notes on
the setup. On eBay you will find 2700HGVs from below £20 to £40 and above.
No need to pay much more than £20. My experience is that if I connect during
the morning the 2700 will cope with an increase in noise by 6dB or so
without dropping although the error rate gets quite high but it just carries
on.

Peter Crosland


  #5  
Old November 27th 08, 12:06 AM posted to uk.telecom.broadband
Some1
external usenet poster
 
Posts: 5
Default Router that sets Sync Speed not Noise margin?

On Wed, 26 Nov 2008 16:14:00 -0000, "Peter Crosland" wrote:

Snip

Sounds like a classic case of RF interference caused by better medium wave
propagation during darkness.What you need is a router/modem that can deal
with high error rates without dropping the connection. It also seems that
the exchange target SNR of 6dB is simply too high to give a reliable 24/7
connection. Given the way the BT dynamic line management works what you are
trying is unlikely to ever work successfully because you are forcing the
equipment to work well outside the range at which it can function reliably.
Having suffered a similar problem for many months and with much effort from
BT the final solution was to use router modem designed for noisy and varying
quality lines. Having used various Draytek, Netgear, Dlink and ZyXel I ended
up using 2Wire 2700HGV. I since installed these at two other problem sites
and they really are the dog's gonads.


Snip

Exactly what I have done, used the 2700's (for customers)
--
The End
  #6  
Old November 27th 08, 04:30 AM posted to uk.telecom.broadband
Martin²
external usenet poster
 
Posts: 848
Default Router that sets Sync Speed not Noise margin?

Is there some software (like DMT) to set SNR for the 2700HGV ?
Or the 1801HG ?

Thanks,
Martin


  #7  
Old November 27th 08, 10:37 AM posted to uk.telecom.broadband
Peter Crosland
external usenet poster
 
Posts: 1,463
Default Router that sets Sync Speed not Noise margin?

Is there some software (like DMT) to set SNR for the 2700HGV ?
Or the 1801HG ?



Not that I am aware of. In any case experience suggests that it is
counterproductive to do so.

Peter Crosland


  #8  
Old November 28th 08, 03:44 AM posted to uk.telecom.broadband
Martin²
external usenet poster
 
Posts: 848
Default Router that sets Sync Speed not Noise margin?

Is there some software (like DMT) to set SNR for the 2700HGV ?
Or the 1801HG ?


Not that I am aware of. In any case experience suggests that it is
counterproductive to do so.
Peter Crosland


My line previously run at 2.8M/s at 6dB SNR, with random and fairly frequent
disconnections. The 1801HG I use still worked at 1dB, so when it
disconnected it was with good reason and higher SNR made no difference.
Now BT got me stuck at 1.7M/s at 9dB and I STILL get the disconnections,
'cos at times there is noise on the line.
I would like to be able to set the SNR at 7.5dB, or if that is not possible
then 6dB, which was OK with me.

What ADSL modem (router) can do that ?
TIA
Regards,
Martin


  #9  
Old November 28th 08, 10:35 AM posted to uk.telecom.broadband
Peter Crosland
external usenet poster
 
Posts: 1,463
Default Router that sets Sync Speed not Noise margin?

Is there some software (like DMT) to set SNR for the 2700HGV ?
Or the 1801HG ?


Not that I am aware of. In any case experience suggests that it is
counterproductive to do so.
Peter Crosland


My line previously run at 2.8M/s at 6dB SNR, with random and fairly
frequent disconnections. The 1801HG I use still worked at 1dB, so when it
disconnected it was with good reason and higher SNR made no difference.
Now BT got me stuck at 1.7M/s at 9dB and I STILL get the disconnections,
'cos at times there is noise on the line.
I would like to be able to set the SNR at 7.5dB, or if that is not
possible then 6dB, which was OK with me.

What ADSL modem (router) can do that ?



I don't know if there is and as I said I think it would be
counterproductive. Just changing the target SNR is rather a blunt instrument
and will not necessarily cure the problems you are encountering. Perhaps you
need to investigate the reasons for the noise and see if you can eliminate
it. Also remember that noise on the line is not the only cause of random
disconnections. They could be caused by fluctuations in mains voltage or
intermittent faults in the wiring between you and the exchange. Finding, and
eliminating, faults can be a long and painstaking job and it is crucial that
you don't jump to conclusions. A systematic approach is crucial as is the
rule of only changing one thing at a time. Have you systematically checked
all the obvious things like your own wiring and conducted tests using just
the test socket behind the NTE5 faceplate?

Peter Crosland


  #10  
Old November 28th 08, 11:32 AM posted to uk.telecom.broadband
Ato_Zee
external usenet poster
 
Posts: 343
Default Router that sets Sync Speed not Noise margin?


Now BT got me stuck at 1.7M/s at 9dB and I STILL get the disconnections,

'cos at times there is noise on the line.
I would like to be able to set the SNR at 7.5dB, or if that is not
possible then 6dB, which was OK with me.

What ADSL modem (router) can do that ?


I've used DMT tool with BT Voyager 240 (non-wireless)
and LinkSys WAG54GS (wireless - with the right
LinkSys firmware flash).
WRT noise, I substantially reduced my noise problems
by moving my router next to the NTE5 and chaining
two ADSL filters, make sure you plug the router into
the first one. The extra stage of filtering seemed to
help.
Used the original BT quad extension as a draw wire
to pull in CAT5, the wiring between floors had the
phone extension wiring next to unshielded mains
wiring.
There are many household items that generate
transient and continuous RF noise, low energy
lamps, switch mode PSU's, TV's, microwaves,
boilers, etc.
DMT tool will let you set a better target SNR
-BUT- it won't help with noise bursts, your line
runs faster for a while, then the noise bursts
put you back to 12 to 15db, depending on
how bad the noise is, and you are soon back to
dialup speeds.
Maybe your disconnections are due to a dry joint
between the router and the exchange
 




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