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Split off from Noisy phone line when router connected

Community Veteran
Posts: 1,613
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Registered: 29-06-2010

Split off from Noisy phone line when router connected

Luke is incorrect to say that uncapping the upstream will affect your downstream - as they both use completely different frequencies, the only difference is that the unused "gap" between up and down is much smaller. There should be a diagram somewhere...

When the upstream is capped, only half of the section identified as upstream is used, leaving a larger gap between the two. Uncapping the upstream will mean that the return "Ack" packets will go faster, and the feel of your connection will definitely be better. You upload more than you think you do...
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Community Veteran
Posts: 5,152
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Registered: 10-06-2010

Re: Noisy phone line when router connected

Quote from: LukeS
@Jaggies - You're describing ADS2+ in theory and not the product we get from BT Wholesale. Additionally, My communications degree and four years experience provisioning and fixing broadband make me qualified to say "Uncapping your upload will affect your download"

Would you mind explaining why that would be the case then? Or do you feel your degree and experience means giving an explanation is beneath you? Perhaps if we had more details or a proper explanation then we'll all be able to stop advising people incorrectly.
I was thinking that the separation of upstream and downstream signal is somewhat more complicated than simply that they are on different frequencies, perhaps something to do with echo cancellation. But if a capped upstream operates with a high SNRM, that implies the upstream power output is that same whether it's capped or uncapped.
LukeS
Grafter
Posts: 203
Registered: 09-05-2014

Re: Noisy phone line when router connected

@ejs
I was merely pointing out that it's more correct to say that uncapping the upstream will have an affect on the downstream rather than 'it definitely won't'
ADSL2+ is a technology used world wide but it's adapted by each supplier in different ways. We use Wholesale Broadband Connect via Openreach's 21st Century Network. Explaining exactly how it works is impossible as you'd need to be an Openreach engineer. However, as you've alluded to, uncapped upstream uses slightly more resources and there is a greater need for error correction.
We're going a little bit off topic as tich731 appears to be suffering from worsening intermittent connection.
Superuser
Superuser
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Re: Noisy phone line when router connected

Quote from: LukeS
You're describing ADS2+ in theory and not the product we get from BT Wholesale.

Hi Luke,
Echoing ejs' desire to be able to correctly advise users (it's constant education around here); are you stating that the BT Wholesale product does not confirm to the ADSL2+ standard by intent or more simply making the point that in the real world (with all of the imperfections in BTOR's infrastructure) BT Wholesale's products do not perform to the expectations derived from theory?
In simple terms, is the supplied product off-spec or due to infrastructure defects, it is likely to perform off-spec?
Quote from: LukeS
Explaining exactly how it works is impossible as you'd need to be an Openreach engineer

From experience, I think that many of the bright sparks around here know far more than your typical broadband Openreach engineer.  I've shown many engineers SNRM plots to help inform them about the problem they've come to investigate, only to be told "it means nothing to me" or "you do realise that all that monitoring you are doing is degrading your performance".  No disrespect intended, but I think the majority of them know very little about the detail of telecommunications operation.
However, as you suggest, this is off topic, would you therefore please consider raising a new thread so that those of us interested in understanding better have the opportunity to do so.
Kevin
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Re: Noisy phone line when router connected

The only way I have seen uncapping the upstream affecting the downstream is when the upstream is unstable and this triggers the DLM to increase the downstream default noise margin.
This is different to Annex M which uses some of the downstream frequencies and can really kill the downstream
Community Veteran
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Registered: 29-06-2010

Re: Noisy phone line when router connected

@ Luke S
I don't want to start a tit-for-tat argument, and I don't have a degree, but I have worked in ADSL tech support since 2000 and know (generally!) whereof I speak.
Practical experience - when I first joined Plusnet in 2010 it was on a capped upstream, and I noticed the difference from my previous supplier straight away. Came on here and asked the question and Jo-Jo arranged to have my upstream uncapped, and within a few hours all was back to normal.
So yes, while technically there may be a slight negative effect on the downstream in certain circumstances, the benefits of the uncapped upstream far outweigh the slight risk of slowing the downstream. And in any case, the  upstream can always be capped again if it fails to improve the connection.
LukeS
Grafter
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Registered: 09-05-2014

Re: Noisy phone line when router connected

Quote from: Townman
Hi Luke,
From experience, I think that many of the bright sparks around here know far more than your typical broadband Openreach engineer. 

By Engineer, I was referring to a network infrastructure engineer.  Tongue
To clear up any confusion surrounding this issue. I've dealt with thousands of circuits and in my experience I've never seen downstream increase as a result of uncapping the upstream (Unless the mod order performs and DLM reset). However, I have seen connections lose a small amount of downstream and although I have the educational background to theorise why that might be I can't say for sure. At some point in the future it could be something I look into at more detail.
If you compare BT's WBC product vs Sky or TalkTalk product there are quite a lot of differences.
Community Veteran
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Re: Split off from Noisy phone line when router connected

That's all very nice, but what proportion of those thousands of lines lost a small amount of downstream? Why are Plusnet so adverse to doing certain things on the basis it might make things worse (disregarding any potential benefits)?
From that Ofcom report into broadband speeds, Plusnet's ADSL2+ download speeds aren't any better than BT's, but Plusnet's ADSL2+ upload speeds are certainly worse. Don't take that the wrong way, I'm not suggesting BT download speeds are better because their upload speeds are better. I was only comparing them to show that Plusnet don't appear to have gained anything on the download side from all the capped uploads.