LLU Line Underperforming?

Hi
I've just had my line regraded from 20CN ADSL to ADSL2+ LLU through a TalkTalk reseller.

My previous adsl stats were 21.5db attenuation and a stable 8.1snr.
With these figured I would have expcted around 19000kbps sync going off the kitz and farina checkers.

My current stats are:
ADSL Link Downstream Upstream
Connection Speed 15897 kbps 1022 kbps
Line Attenuation 24.5 db 14.9 db
Noise Margin 6.1 db 9.3 db

This seems a bit on the low side? My snr is around 6.4 most of the time but varies between 5.8 and 6.7 depending on time of day.

Is there some sort of line management on the talktalk llu stuff even through a reseller? the DMT tool shows line line as having 64 depth interleaving on too, will this affect sync speed? Also - I seem to remember that the target margin in 9db - maybe this is not helping either?

I should also point out that my router is plugged directly in to the nte5 socket which no extensions.

Any suggestions are most welcome!

line attenuation jumps around 4-5db when switching to adsl2/+

my line attenuation is 25.5 and i get around 15800 sync speed so i think you're line is performing just fine.

Hi
Yes - Im aware that attenuation jumps by about 3db but the checkers use your ADSL1 attenuation to estimate your ADSL2+ sync. at the attenuation i was at and even now I should be syncing higher. Heck I've seen people with an origional attenuation of 28db getting better sync then me.

Well to maximise performance matching router chipset and DSLAM

it could give a massive boost 2-3mbps is possible though its hard to do it sometimes

my DSLAM is broadcom and matching it with a broadcom gets me around 1800kbps extra.

Though every line is different in perfect conditions you would be syncing at 18+ Mbps

Edited by epyon (Wed 14-Mar-12 16:15:44)

Yes, you're right! You should be syncing at 18-19 Meg on 6 dB NM.

I thought so too - so far I've tried a DG834GT and a Tomson 585v6. Any ideas?

Is there some sort of line management on the talktalk llu stuff even through a reseller?

Depends on who the reseller is.

. . .

No, but I'm getting 19 Meg with a DG834GT on 26 dB attn but with 3 dB NM Fast path. So you should be able to get similar on lower attn, but higher NM.

Have you got stats from test socket? Removed ring wire, checked extensions, swapped filters ... ?

In reply to a post by XRaySpeX:

No, but I'm getting 19 Meg with a DG834GT on 26 dB attn but with 3 dB NM Fast path. So you should be able to get similar on lower attn, but higher NM.

Have you got stats from test socket? Removed ring wire, checked extensions, swapped filters ... ?

Reseller is Vivacity

When the line was enabled it has (and still has for the moment) the maximum interleaving on - I know on ADSL1 this affected your max sync - not sure if it applies here tho.

My Router is plugged in to the BT master socket - no extensions. Have tried a DG834GT and 585v6.

No extensions to check - also tried two other filters.

Is it into the master with just the short ADSL cable, or are you using a plug-in phone extension between the two?