Changing SNR manually

My line been unstable since getting moved to LLU ADSL2+ so decided to manually change my SNR from 6db (interleaving on) to 9db (interleaving off). Noticed when i changed it, my sync speed stayed the same. Was expecting it to be lower due to the higher SNR. Could the fact i turned interleaving off be the reason?

My stats are this now:

Connection Speed 10174 kbps 1023 kbps
Line Attenuation 38.0 db 17.5 db
Noise Margin 9.00 db 12.0 db

You turned Interleaving OFF but can you be sure it is off? Unlike NM your limited stats don't show state of Interleaving. There should be fuller stats that do.

What router? How do you change Interleaving?

What were your stats before?

Its a Netgear DG834Gv5. I know Interleaving is off as my account area on the ISP website says its off (there is an option to change SNR and interleaving in there), also i ran routerstats software that says the same

Stats before were virtually identical to the ones i posted above, except the noise margin being 6db.

Edited by bobble_bob (Sat 29-Sep-12 12:30:15)

Turning interleaving off increases sync and raising the target margin reduces sync. Perhaps the 2 have cancelled each other out?

Yea was thinking that. Ping come down, SNR increased so in theory should be more stable and i got same sync. Win win hopefully

Interleaving should increase stability.

Thats my next step. If 9db SNR and interleaving off doesnt work, will try turning it on

I think you have a problem with noise, or a line fault as your sync is 2-3 megs off what would be an ideal sync for the attenuation. Something is making your line unstable and to compensate for that, the usual fix is to increase interleaving and increase the target SNR margin. The penalty of doing this would be to reduce the sync speed.

However, this doesn't fix the problem - it just masks it. To fix the problem you have to understand what it is and eliminate it. It could be something simple like your extension wiring, or it could be something hard like a line fault. The first step is to take "Full" router stats, then plug the router into the test socket and take another set of stats. Then compare them.

I had a problem about 2 years ago with stability on my line. 6 months later and lots of tests, master sock etc I replaced all the cabling to my router with shielded cables and this worked fine for years, getting very reliable connection (thats with ADSL2+ but on ADSL1 profile)

Then when i got changed to LLU last week they took off the ADSL1 profile and now im on full ADSL2 which is where the problems started. Speed doesnt bother me i just want a stable line, hence i was reluctant to go to full ADSL2+. Even though its more unstable now i can still go many hours without a disconnect, so dont know if this would class as a line fault even if i reported it

Im just hoping its not the Talk Talk kit at the exchange thats causing it

Edited by bobble_bob (Sat 29-Sep-12 16:44:49)

It could be your router. Someone else's problem here http://forums.thinkbroadband.com/zen/t/4161751-it-is...

The DG834v5 has been proven to be one that does work fine. However the earlier versions do not.

Thats what i have. Also its been fine on ADSL2+ with an ADSL1 profile (so syning at 7616),

Interesting this http://www.talktalkmembers.com/forums/archive/index....

Yea read a few people saying that speeds are slower with the netgear. Speed is fast enough for what i want though, would rather be stable

In reply to a post by bobble_bob:

My line been unstable since getting moved to LLU ADSL2+ so decided to manually change my SNR from 6db (interleaving on) to 9db (interleaving off). Noticed when i changed it, my sync speed stayed the same. Was expecting it to be lower due to the higher SNR. Could the fact i turned interleaving off be the reason?

My stats are this now:

Connection Speed 10174 kbps 1023 kbps
Line Attenuation 38.0 db 17.5 db
Noise Margin 9.00 db 12.0 db

The Netgear DG834 V5 uses a conexant chipset ,The reason it doesn't get a good sync speed and disconnects points to some degree of incompatibility with the Line card chipset that are part of the DLSAM at the exchange
You may see better speeds and higher stability using a router that has a broadcom chipset , or find one that best matches the exchange kit, As then you should be able to connect using a lower SNR margin and without interleave without experiencing random disconnects and lower speeds

Any idea what Talk Talk LLU use at the exchange?

Also would moving to LLU mean a change of DLSAM?

Edited by bobble_bob (Sat 29-Sep-12 18:59:41)

The Netgear DG834G V4 and DG834GT have Broadcom chipsets.

A move to or from LLU, or from one underlying LLU to another, involves a change of DSLAM, as on LLU, (both MPF and SMPF), the line carrying both voice and broadband goes from you to the broadband DSLAM.

With SMPF they are split on the DSLAM, in a similar way to how it is split at your end. With MPF I don't know where the split takes place.

Also the 834PN and the 834Nv1. 834Nv2 is Conexant.

In reply to a post by bobble_bob:

Any idea what Talk Talk LLU use at the exchange?

Also would moving to LLU mean a change of DLSAM?

Usually it's Infineon for CPW equipment.

In reply to a post by bobble_bob:

Any idea what Talk Talk LLU use at the exchange?

Also would moving to LLU mean a change of DLSAM?

Regarding what chipset the exchange uses I'm fairly sure i read a post on here recently( like the other day) where someone asked the same question and was answered by Matt from xilo, Matt unoIn light of the info he provided i would say that the kit you connect to is more than likely a broadcom chipset, conexant based routers do not work well on broadcom line cards
Could be why there does seem to be some reports that broadcom routers work well on tt's llu kit , maybe because more are broadcom than infineon some routers will show the brand of the chipset on the line card , in an abbreviation format
As for moving onto TT LLU from BT Wholesale's 20/21cn kit then yes I think it would

Edited by tommy45 (Sat 29-Sep-12 19:41:07)