o2 LLU - wow!

[TW]Fox

[TW]Fox

[TW]Fox

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Hi guys,

I've whinged and I've moaned about my awful internet on here for years, and you've all tried and tried to help me sort it out. So I thought I'd share with you some good news.

As you'll be aware I've been with Plusnet for years, syncing at between 1 and 1.5mbit depending on how much I tweak my router. I could get 1mbit with standard settings of 1.5mbit if I turned the SNR ratio on my DG834GT down to 1%. My upload was 448kb.

Well, today my O2 LLU package was activated and amazingly, at default settings, I immediatly synced at the following rates. How is this even possible? It's brilliant. The internet is.. actually useable. Everything is literally twice as quick - downloading files at 240kb/s instead of my previous 120kb/s record!

My line stats are now:

ADSL Link Downstream Upstream
Connection Speed 2406 kbps 772 kbps
Line Attenuation 69.5 db 38.6 db
Noise Margin 6.5 db 5.8 db
Click to expand...

Now, I get the impression there is no training period on LLU so I can start fiddling right away. With the noise margin as it is, is it worth trying the SNR ratio trick like I used to use with PN? With it set to 1% as it was with PN, I get a staggering 3.4mbit :eek:
 

Moeks

Moeks

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Good, glad you have a half decent connection at last. My grandparents have Sky ADSL, it's awful, they don't even sync at 1mbit/sec ...I find using the internet at their house decidedly onerous ...at least anything but basic websites anyway ...they wont change their provider though as they don't see the problem, and think it's all too much hassle. Of course they don't know what they are missing, and I know it could be improved upon.

I'm lucky enough to be in a great area for Virgin Cable, used to be Blueyonder around here, this was one of the first areas to get high speed cable rolled out and it's always been great. I have a 20mbit connection and I can download at upto 2.4mb/sec if the server I am downloading from can manage it, so I must be getting very near what it says on the tin.

I guess this isn't available in your area, or you would already have it.
 
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benftl

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Interleaving is usually the default config used and it's basically an additional bit of error checking that increases latency. Fast Path is what you get when Interleaving is turned off, it reduces latency but can result in an unstable connection.

TBH, with your line being as bad as it is, Interleaving is probably the best option.

Regarding the training period, you're right in that there is no such period with O2 LLU. Tweak away, reduce that SNR and see what happens / how stable your connection remains :)
 
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benftl

benftl

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Expanding a little on that, based on your long line I'd recommend:
  • Trying ADSL1; to do this, go to Advanced ADSL Settings and make sure that G.DMT is the only box that is ticked / on, then click apply, wait two minutes and check your sync rate

  • Make sure that Double Upstream (Annex M) and Extend R.T.C. frequency (Annex M) are both off

  • If the ADSL1 setting made no difference, try it with ADSL2 ticked / on and everything else off (make sure ADSL2+ is off, also)

Let us know how you get on.
 

benftl

benftl

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ADSL uses a lower frequency set than ADSL2, and ADSL2 is lower than ADSL2+. Seeing as you have such high attenuation on your line there's no way you'll reliably use these higher frequencies that ADSL2 runs on so by changing modulation from (default) ADSL2+ to ADSL2 or even standard ADSL, you could see a gain in sync rate.
 

[TW]Fox

[TW]Fox

[TW]Fox

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benftl said:
ADSL uses a lower frequency set than ADSL2, and ADSL2 is lower than ADSL2+. Seeing as you have such high attenuation on your line there's no way you'll reliably use these higher frequencies that ADSL2 runs on so by changing modulation from (default) ADSL2+ to ADSL2 or even standard ADSL, you could see a gain in sync rate.
Click to expand...

I will try this tommorrow, thanks!

Currently I am seeing speeds that are at least twice that I've ever had before on this line. I am downloading from the Microsoft website at almost 250kb/s - previous I was amazed to get over 110kb/s.

Why is there such a dramatic increase in performance simply by moving to LLU?

It's still the same rubbish line, right? I'm amazed!
 

Mattus

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Glad that you've finally made progress, Fox. Those speeds are pretty good, considering how long the line is! I can only assume that the hardware used by O2 plays along more nicely with the chipset in your router.

Moeks said:
My grandparents have Sky ADSL, it's awful, they don't even sync at 1mbit/sec ...I find using the internet at their house decidedly onerous
Click to expand...

To be fair, you need to know more about the line stats before bashing the provider for low sync speed. Sky LLU is generally pretty good - it may well be that the line is just very long or needs some attention from an engineer. Alternatively, the house's internal wiring could be very bad.
 

ncjok

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[TW]Fox said:
Worryingly I was just on Teamspeak and was still getting a bit of packetloss :eek:
Click to expand...
If you are pushing your connection with a DG834GT/DGTeam set to 1%, giving you an SNR margin of around 1 dB, then you are doing very well to maintain sync. This is going off my previous thoughts here.

Assuming your ISP has sufficient capacity out of the exchange, which could be significant if we're referring to peak time usage, then I think that the packet loss you experience when using real-time apps such as VoIP is due to excess bit errors along your line. One indication of this would be an accumulation of CRC errors (CRC and ES values in the DGTeam output from Diagnostics -> Display detailed ADSL driver informations).

You might find an improvement if you can get the interleaving depth increased, although this will have a negative impact on latency. Apart from that I think you'll be left to increase the target noise margin (via DGTeam or a profile change request) if you feel the packet loss is too severe.
 

[TW]Fox

[TW]Fox

[TW]Fox

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ncjok said:
If you are pushing your connection with a DG834GT/DGTeam set to 1%, giving you an SNR margin of around 1 dB, then you are doing very well to maintain sync. This is going off my previous thoughts here.
Click to expand...

I'm not doing that at the moment - that was just the setting used on my previous ISP (So when I got home and it had resynced to O2 I was still using that setting for a bit).

Assuming your ISP has sufficient capacity out of the exchange, which could be significant if we're referring to peak time usage, then I think that the packet loss you experience when using real-time apps such as VoIP is due to excess bit errors along your line. One indication of this would be an accumulation of CRC errors (CRC and ES values in the DGTeam output from Diagnostics -> Display detailed ADSL driver informations).

You might find an improvement if you can get the interleaving depth increased, although this will have a negative impact on latency. Apart from that I think you'll be left to increase the target noise margin (via DGTeam or a profile change request) if you feel the packet loss is too severe.
Click to expand...

Thanks for the advice :)
 
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