SNR has increased, a lot.

I was connected at about 2700 down 625 up with a forced 4.5DB SNR (non forced it did sit at 6.5db)

I recently asked for interleaving to be activated on my line to see if it reduced errors, it didnt have that much of an effect and just increased my ping time so I asked Vivaciti to turn it back to fast.

Since then, when I returned home for my lunch, I noticed my ping time was a lot less, now only about 22secs on speedtest as opposed to 50+, however on my router my SNR has now shot up to 16.5db and my downstream connection is 1150.

Any ideas as to why this may be? I have raised it with Vivaciti, this is uncharacteristic of my line, after about 4-5weeks of monitoring the connection my snr has rarely risen above 7db and generally I always get a connection over 2000kbps.

Anyone know whats going on?

I am fully aware that the line is rate adaptive and the snr can be affected by many things, but it's too much of a coincidence that they turned my line back to fast mode and now it is running at 40% of the speed.

You can see here the speedtests conducted since joining Vivaciti, that last one does look completely out of place!

Edited by deleted (Fri 26-Jun-09 17:56:18)

Hi

Difficult to say without seen your stats .can you please post your full stats


Regards Jeff

Current stats


ADSL Link________ Downstream__Upstream
Connection Speed__1159 kbps____575 kbps
Line Attenuation___60.0 db ______35.5 db
Noise Margin______16.3 db______9.8 db

Used to be


ADSL Link________ Downstream__Upstream
Connection Speed__2677 kbps____657 kbps
Line Attenuation___60.0 db ______35.5 db
Noise Margin______4db__________9.8 db

Edited by deleted (Fri 26-Jun-09 18:46:50)

It has sync'd at a lower speed giving a higher SNR margin.

If you re-sync the DSL connection what SNR does it re-sync at? If it re-sync's somewhere around the same figure it may be your target margin has increased.

In your first post you said you forced it to sync at 4.5, how are you forcing it to sync at this SNR?

I cannot affect the SNR as it is now, even if i adjust it through dgteam firmware on my dg834gt it has no change.

When I resync it sits at 16db and as i said, it won't change.

Fortunately I have a few spare routers:

BT Businesshub - 2wire2700hgv
Netgear dg834gt
Netgear dg834 v1
Thomson ST585v6

Of the above I can alter the snr on two of them with dmt tool or the dgteam firmware, all of them connect showing that 15/16db snr which has really brought my speeds down from the 2.5mb I was getting to just under 1mb, this is really annoying me know.

If it aint broke don't try to fix it comes to mind and I wish I hadn't asked them to change the line to interleaved, as I fear none of this would of happened, grrr.

Edited by deleted (Sat 27-Jun-09 11:42:30)

Hi
it looks as if your target SNR has been reset to 15db . This can be caused by having an unstable line or if you reconnect too often . It is done automatically by the system .

Your stats do not show what sort of errors you are racking up.

you could expect to connect at 2560Kbps .If you can get your Target snr down to 6 .But that is going to take many weeks even with a very stable line . Your ISP can ask BT to reset it but generally it takes a lot of persuasion.
The first thing is don't make it worse by trying different routers . I wouldn't reconnect more than once a day.
see the link for further info.
http://www.kitz.co.uk/adsl/linestats.htm
Regards Jeff

Thanks Jeff but I am through LLU with C&W so BT profiling system isn't relevant, it should connect at the fastest speed each time I connect, I need to get them to reset my SNR back to 6DB, it had been working fine connected at 2500+ still only at a 1mb connection atm though

You may not have BT's IP Profile system but I believe even on LLU there is a system to control 'Target SNR' to attempt to stabilise a line...

I have asked Vivaciti to reset my target SNR, it is now sitting at 17DB and causing me speeds of sub 1mb.

The line is perfectly comfortable with a 6DB target SNR and this see's speeds of 2mb+ which I was happy with, hopefully, they will get his actioned soon!

I thought a higher SNR was better? We are talking SIGNAL to noise ratio, after all?