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[snadge]

I wondered if someone could shed some light on this? I seen it on Andrews & Arnold website, just what are these 'settings' I wonder that can cause DOUBLE the line speed over BT...lol...maybe I should ask them

http://aaisp.net.uk/kb-broadband-bebt.html

Key advantages of Be based services

    We provide more download for the same money on Be than BT making it cheaper for people that download a lot, such as businesses
    Be have targets for loss and latency and jitter in their network making it clear that they are prepared to operate an uncongested network. BT do not.
    Be have better settings typically allowing higher speeds than BT even on the same line (in some cases twice the speed).

[guest]

Upstream is fastpath on Annex M and d/s is 3/6dB selectable by user. Fastpath can be selected by users via web panel.

I know how you ended up there snadge (sod.ms), Rev K doesn't update a lot of that stuff now so don't take it as gospel mmm? Edit - for example when he wrote that BT DLM didn't offer a 3dB profile.

Oh and Surprise! if you hadn't worked out who I was on other places. rizla is a nick only in use here now, long long time since it was my "main".

[kitz]

I think the claim of twice the speed may be pushing it on your average line!!!! 
but the user configurable interface means that you can push your line to the limits if its stable enough.  The fact that theres no IP profile and no waiting around for the DLM to change can be hugely beneficial to some lines.  Its also nice that you can change settings yourself from the CP without having to ask CS.

Im on the non-interleaved 3dB profile (which applies to both up and downstream)..  and also annex_M which gives me around 2.6Mb upstream.   However dont forget that if you go for annex_m then youre more than likely to lose speed on your downstream.

>>> I wonder that can cause DOUBLE the line speed over BT

hmmm..
Each 3dB of SNRM is going to give you on average 800kbps.. up to a maximum of 1200kbps.
Turning off Error Correction will give you some additional sub-channels by removing the OOB designated frequencies (see FEC) and allow those bins to be loaded with useful data, so thats upto 32kbps of speed for each frequency no longer classed as OOB.
No DLM IPprofile means that you get what you sync at minus normal TCP/IP type overheads.

However its also worth pointing out that Be* mark some frequencies as unavailable, which could cost you some speed if you are on a short line.

Although technically it is possible, I think the lines that do get double wouldnt be too many...  and they would have previously had to have been on a pretty carp BT profile.

[guest]

The section he's looking at kitz dates from about 4-5 years ago.

Its my fault, I linked sod.ms/fast in a different place and he/she has gone from there and we're now here

Edit - someone else can explain the Reverand Kennard to him/her. All I can say these days is that Shaun can type more accurately and I can't

[burakkucat]

Huh?

This grumpy old black cat hasn't a clue about what has been posted in this thread. 

[HPsauce]

I presume it's old information comparing ADSL to ADSL2+ and also maybe factoring in Annex M?

[guest]

Huh?

This grumpy old black cat hasn't a clue about what has been posted in this thread. 

Don't worry about it, its old stuff and AAISP is not your average ISP. Quite apart from having an ordained minister (USA, for the lulz when he was on holiday) in charge its a techie-only zone. It's expected you understand things like zonefiles for example and the best tech support is over IRC (which is likely to get you sorted within minutes),

tl;dr AAISP is about as far as you can get from a mass-market ISP in the UK.

Edit - if they had better usage limits I'd consider going back to them, for now Sky works best.

[snadge]

@ Kitz - wont the amount you get per db (when lowering SNRM) depend on your bit-loading? for me when I was on 13Mb ADSL2+ and 16Mb ADSL2+ I was getting about 2,500k for 3db decrease because I was able to load across all bins (or just about) - when my sky line was recently broken and I only got 3.5Mb for a few days (still adsl2+) I was able to push it too 6Mb by lowering down to 3db...I wasnt using many bins then ...which is odd? , I dunno if I posted any screenshots on here of DMT Tool while it was like that, we may have been able to see... anway, ive always been able to get 2-3Mb increase when dropping to 3db SNRM, for e.g. if I put in my Netgear(s) now I will get 15.5Mb - reduce to 3db and I get 18.1Mb, thats 2.5Mb increase - but it makes sense that if your only loading across half as many bins then your likely to get half as much, for e.g. perhaps loading across 256 bins in ADSL1 would yield about 1200k for 3db.

@ Rizla - aha!! your there... I'm gunna have to stop using the same username across forums too, im being tracked!! hehe.. I'm a "he" , just so you know - yeah I used your speed test link and had a browse, I had a feeling it would be old but I thought the claims of double speed had to be shared on here, I didnt think of SNRM/Interleaving/non-profile etc, when he said 'settings' I thought he meant standard routing settings...not 'tweaking'.

call me stupid... but what does tl;dr mean?

[guest]

tl;dr = too long;didn't read

Its a gaming thing - where people put up walls of text/snapshots to prove their point. Its generally moved on from there to being a summary of a post where people who know the basics can get the gist of the post quickly.

I didn't know if you were a he or a she as it seemed like more than one person was posting over on Sky forums when you had your split pair fault, which you'll remember I diagnosed weeks before it got sorted

[snadge]

@ Rizla - yeah the problem there (on Sky Forums) was the account is in HER name, but I use it... so when officially complaining etc I have to pretend to be her, after a while I just started addressing emails or messages from us both, thats probably why...hehe.

yeah you had it right on the money... split pair, how does that happen BTW... if you answered already Iam sorry..I suffer with memory problems

[guest]

It happens because people make mistakes. I'm sure some of the older BT guys here would remember different times when standards were enforced a lot more rigorously.

From what I remember on your case, you got ADSL & phone switched from the Easynet DSLAM/BT phone system to the Sky SVBN kit. At that point you could hear other people on the phone, the BB speed went down and the phone either didn't ring or rang when there was no incoming call?

The problem IMHO is that you went to Sky with this and said it affected BB and voice. Pick one, never both.

Sky told BTO and off down the rabbit hole you went, the more visits and D-Side changes (with associated new faults - battery short?) the further from the basic problem they got. Like I said to you near the start, you simply need to talk to the frames guy for that exchange and he'd have sorted it.

NB - I'm not convinced BT would have handled it differently. A friend has worked for BT's faults dept (call centre) for near enough 30 years and I really couldn't type her views on BT now. Suffice it to say she thinks you have as much chance of your ISP getting a voice fault fixed on a BT line as you have of BT Retail getting it done. I'd tend to agree.

[snadge]

@ Rizla - no I was on an WLR3 & ISAM not Easynet DSLAM, but I was swapped to SVBN and routed through a split leg, but at same time a developing fault up my end happened, whats the odds both happen at exactly the same time, it seems like this split leg caused the fault up my end to get worse (pop its ugly head up), there really was 2 faults happening at same time (just Like I told the engineers one after the other) , the HR Fault / Battery Contact got fixed which repaired the phone end of it, but the wideband noise remained and 3-4 weeks later that was found to be a split leg..??  I would have loved to know if I didnt get moved to SVBN would the HR Fault / Battery Contact still have happened... cos all was fine until they swapped me over.... god, WHAT a nightmare that was!!

[kitz]

>>> wont the amount you get per db (when lowering SNRM) depend on your bit-loading

Yep.. exactly.  The average 800kbps comes from BT's mouth which is why you will often find reference to that figure. 
You are right though that adsl2+ lines will obviously see more benefit, because of more sub-channels available, but there are way too many variables for anyone ever to be able to quote a definite figure.



The hard facts are:-
~ 3dB of SNR is needed to reliably load 1 bit
~ data rate in the frame is 4,000 symbols per second  - therefore approx 4kbps.
The later figure is not quite so straight forward because various things come into play - 4kbps is near enough and commonly used without going into silly decimal places.

In the real world adding 3dB of SNRM  is highly unlikely to result in an increase in the bit loading of each and every one of the 256/512 sub-channels because:-

~ The lower frequencies may already be fully bit loaded.
~ Certain tones arent designated for data transmission and/or are OOB.
~ PSD masks affect the maximum bit loading in certain tones.  Not all lines are the same - BT use different masks depending on line length..  but the PSD mask prevents full bit loading up to about tone 85 on my own line which is about where I start to see full bit loading.
~ Certain tones may just not have enough SNR to load any bits regardless.
In the first 3 instances no amount of lowering your SNRM will have any difference to the overall data throughput.

Then theres variable things like bit-swapping 'reserving' a certain amount of SNR, whether the line is interleaved.. or rather the depth of error correction... and QAM - dont ask me about that its beyond anything Ive ever gone into because Im not a mathematician and no good at equations.

But you will find that lowering the SNRM by 3dB wont necessarily mean that all sub-channels magically get an extra 4kbps


By lowering the SNRM by 3dB:-

Short lines are most likely to see gains across the mid - higher frequencies.
Even very good and short lines still often see only 14 bits loaded in the lower frequencies for one or more of the reasons mentioned above.

Long lines are most likely to see a gain in the lower frequencies.. and it may extend the sub-channel range, but because longer lines are more susceptible to noise, they may not benefit too much at the later end of the lines range.

Even if in a perfect world a line was able to fully load each and every sub-channel and none of the variables nor a PSD mask were in force.. then the maximum would be*

adsl1 sub-channels

33 to 255 = 223 - 2 (pilot & nyquist) = 221 in use * 4kbps = 884 kbps

adsl2+ sub-channels.

33 to 511 = 479 - 2 (pilot & nyquist) = 478 in use * 4kbps = 1912 kbps

*If Ive made an error in those calculations please let me know.