o2 LLU - wow!

[[TW]Fox]

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

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

 

[[TW]Fox]

Shame we can't get interleaving turned off on o2

Can you explain what this is and what it means to me that we cant turn it off?

Worryingly I was just on Teamspeak and was still getting a bit of packetloss

 

[[TW]Fox]

Thanks for the advice guys.

Before I try these settings can you explain what each of them does?

 

[[TW]Fox]

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.

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!

 

[[TW]Fox]

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.

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.

Thanks for the advice

 

[[TW]Fox]

ADSL and ADSL2 use exactly the same frequency range. ADSL2 gets an extra 4Mbps by virtue of being more efficient.

So I should stick with ADSL2?