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DownStream Sync Rates. Silly question... maybe?

paulj
Newbie
Posts: 6
Registered: ‎10-10-2007

DownStream Sync Rates. Silly question... maybe?

Hi All
I wanted to ask as silly question... Huh
I have a NetGear DG834G router running an 8Mb ADSL Max connection with plus.net. I sometimes find that my sync rate (DownStream) which is reported in the NetGear admin GUI is around 2700kbps or tonight for example it's 2200kbps.
I remember when I first had the connection set up that it was alot closer to 3900kbps and probably even higher around 2 months ago. I have had some "packet loss" which the technical ppl at Plus net investigated and said this was actually "contention ratio"... So as far as Im aware, I should getting a downstream sync rate closer to the 3900kbps meaning the IP stream should be closer to 3Mbs rather than the 2Mb Im currently getting - does that sound right?
I generally turn my router off at the power when Im not using it which is most of the day, so on average it is on around 2 hours a day. If I were to leave the router on 24/7 would the sync rate settle at a more sensible speed?
Your thoughts or comments would be appreciated. Grin
Thanks alot
Paul

11 REPLIES
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: DownStream Sync Rates. Silly question... maybe?

I suspect your downstream min SNR has been increased by BT meaning you will sync at a lower rate. Normally on Max the min is 6dB but can be ncreased to 9, 12 or 15dB.
Please post the full stats from the router as we can then tell you if that is the problem and what to do to resolve it.
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: DownStream Sync Rates. Silly question... maybe?

Hi Paul,
Here's what the BT testing shows.  Apologies, but the formatting isn't fantastic!
Downstream Link Info 
Loop Loss Loop Loss Add Text SNR Margin ErroredSeconds HecErrors CellCount Speed
48.5  16.5 0 0 6712506 2464

Basically, this shows you as having a SNR of 16.5dB which is insanely high!  This will probably mean that there is something internally causing you connection to be quite so slow.  I would strongly recommend trying to replace your filters and to ensure that your Netgear Router is connected via a filter into your master socket.
Give this a go and I'll be more than happy to test again.
paulj
Newbie
Posts: 6
Registered: ‎10-10-2007

Re: DownStream Sync Rates. Silly question... maybe?

Great thanks guys. I will try new filters & try plugging the router into the master socket etc tonight and basically try and get the 16.5db down!
I do have an house alarm, and I don’t know how this is plugged into the telephone line... I assume it must be somehow as it is centrally monitored. Would this make a difference if it didn’t have a filter on it? (I would have thought that this would only be an issue if it were making outgoing calls at the time you did the BT line tests?)
I will let you know how I get on Smiley
Community Veteran
Posts: 3,789
Registered: ‎08-06-2007

Re: DownStream Sync Rates. Silly question... maybe?

yes, it CAN make a difference so it would be worthwhile trying to find out how it's connected.
a Filtered faceplate on the master socket may be a good idea to solve it
B.
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: DownStream Sync Rates. Silly question... maybe?

Hi Paul,
An unfiltered alarm system can and possibly will cause inteference.  Often this results in a lack of connection or intermittency, but with Max, it'll just ramp up your SNR to make the line stable, causing your sync speeds to drop dramatically.
If you get the SNR to a sensible level (6 or 9dB) I'd expect you to see synchronisation speeds in the region of 3.5-5Mbps.
paulj
Newbie
Posts: 6
Registered: ‎10-10-2007

Re: DownStream Sync Rates. Silly question... maybe?

Hi Guys
Right,  Ive got a new micro filter and Ive plugged it into the master BT socket.
According to the router the sync speed and noise on the line is :
ADSL Link--------------Downstream------Upstream
Connection Speed------2848 kbps---------448 kbps
Line Attenuation-------49 db---------------15.5 db
Noise Margin-----------8 db ----------------23 db
Its worth noting that the 8db noise rating starts quite high, then seems to get lower. The lowest I can make the Noise Margin downstream is 5db, but then it seems to settle around 8-12db after a few seconds.
I assume the router noise level is the same as the snr level that "Jameseh" did earlier?
If not, I don't suppose someone at plus.net could test it for me? I will leave the router connected to the master socket ( the front door is like a trip wire waiting for the wife to come in later - wires everywhere  Grin)
Thanks guys.
I will go and see if I can work out how the alarm is plugged in...  Cry
Paul
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: DownStream Sync Rates. Silly question... maybe?

Hi Paul,
SNR stands for Signal to Noise Ratio.  It's the noise figure that you are getting with your router.
Hopefully the filtering of the alarm system will be beneficial!
paulj
Newbie
Posts: 6
Registered: ‎10-10-2007

Re: DownStream Sync Rates. Silly question... maybe?

Thanks James (and others) for all your help.  Grin
I do get better better sync rates when connecting directly to the BT master socket. Ive seen anywhere from 2800 to 3200kbps as oppsed to 2200-2700kbps.
Just in case anyone else tries to 'fiddle with their house alarm'... there are tamper devices present in the control box  Roll eyes which set my alarm off Undecided. Managed to turn of the siren (its a new house and its the first time Ive used the alarm) then download the alarm manual and worked out how to reset it.... be warned !!!
Anyway, will get the alarm service company to check if it is filtered up - there doesnt appear to be anything obvious in the master BT socket and Im not going to risk playing with the Alarm control box again  Shocked.
One _small_ question, I assume that a sync rate connection between 2501kbps to 2999kbps will get an ip stream of 2.5Mbs from BT and above 3001 bps will get a 3mb ip stream. That sound right, or is it measured in whole Mb's?
Thanks again.
Have a good evening all
Paul
paulj
Newbie
Posts: 6
Registered: ‎10-10-2007

Re: DownStream Sync Rates. Silly question... maybe?

Sorry guys.... answered my own question. Roll eyes
In case anyone else is reading this post. See ...
https://portal.plus.net/support/broadband/products/faqs_and_guides/dslmax_guide.shtml#Sync
iPaqowner
Grafter
Posts: 73
Registered: ‎22-06-2007

Re: DownStream Sync Rates. Silly question... maybe?

Quote from: Jameseh
Basically, this shows you as having a SNR of 16.5dB which is insanely high!  This will probably mean that there is something internally causing you connection to be quite so slow.

This doesn't make sense to me...surely if your SNR (Signal-to-Noise) ratio figure is high...that's a good thing?
And the sync figure should be higher the higher the SNR is?
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: DownStream Sync Rates. Silly question... maybe?

Not after you have synced to the exchange. ADSL Max should try and sync at a rate when your SNR is at 6dB so when synced you should see your SNR at 6dB. In this case the line is synced but the SNR is still at 15.5.
What may have happened is the line got noisy, disconnected a few times over a period of time so BT increases the min SNR at which the line will sync from 6dB up to 15dB to try and maintain a stable connection. This then means a lower sync rate occurs.
So a 15.5 figure means BT must have seen some bad data / connections.