[AusNOG] ADSL2+ line sync data

Fri Sep 13 21:41:35 EST 2013

>________________________________
> From: Tony <td_miles at yahoo.com>
>To: "Beeson, Ayden" <ABeeson at csu.edu.au>; Guy Ellis <guy at traverse.com.au> 
>Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net> 
>Sent: Friday, 13 September 2013 9:55 AM
>Subject: Re: [AusNOG] ADSL2+ line sync data
> 
>
>
>You mean like this (hosted on the same website): 
>http://nbnmyths.files.wordpress.com/2010/09/dsl-speed-comparisons.jpg
>
>
>or this:
>http://www.asotel.net/files/pics/news/grafikVDSL2%29eng.png
>
>
>
>
>The other thing I'm curious about on that original graph is whether it is downstream, upstream or both combined ?
>
>If at 2000m you get either 18/1Mbps ADSL2+ or 11/11Mbps VDSL2 then thats 
fairly close to the same amount of total bandwidth (19 v's 22). This probably doesn't please the user though as they 
want faster downloads (to "obtain" the latest TV eps) and hence an 
option to choose which "DSL" you want might be of benefit depending on your intended usage of the link.
>

Sad thing about this is that doing that appears to be a good idea, but that actual best thing for performance is symmetry, due to how TCP uses ACK feedback to determine it's send rate. Congestion on the uplink, which is more likely to occur when the uplink bandwidth is lower than downlink bandwidth, will slow down downloads:

BCP69/RFC3449, "TCP Performance Implications of Network Path Asymmetry"
http://tools.ietf.org/html/rfc3449

>
>
>I'm not arguing for a FTTN network (I want my FTTH) but discussion needs to be responsible.
>
>
>
>
>regards,
>Tony.
>
>
>
>
>>________________________________
>> From: "Beeson, Ayden" <ABeeson at csu.edu.au>
>>To: Guy Ellis <guy at traverse.com.au> 
>>Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net> 
>>Sent: Friday, 13 September 2013 9:39 AM
>>Subject: Re: [AusNOG] ADSL2+ line sync data
>> 
>>
>>Absolutely no idea tbh, it's an ofcom graph, that's all I know.
>>
>>Seemed optimistic for adsl2+ as well tbh... I would have assumed closer to 1-1.5km for the crossover as well...
>>
>>Guy Ellis
<guy at traverse.com.au> wrote:
>>
>>
>>Hi Ayden,
>>
>>Do you know what VDSL2 profile was used for those tests?
>>It doesn't look anything like our results or AT&T's for that matter.
>>
>>Normally VDSL2 and ADSL2+ intersect at around the 1.6km mark!
>>
>>Regards,
>>  - GUy.
>>
>>
>>
>>On 13/09/2013 8:10 AM, Beeson, Ayden wrote:
>>> However, the bandwidth drop is even more drastic on vdsl. At a distance of even 500 metres your average bandwidth is drastically lower then where it started.
>>>
>>> http://nbnmyths.files.wordpress.com/2011/06/fttn-speed-graph.gif
>>>
>>> Unfortunately, as you can see by the graph, you have to be less than 300 metres (poor copper condition not factored in) to get the promised 50mbit and at ~500 metres+ it's
worse than adsl 2+ across the board.
>>>
>>> Guy Ellis <guy at traverse.com.au> wrote:
>>>
>>>
>>>
>>> Paul,
>>>
>>> In response to your challenge (Exercise for the reader - work out how VDSL2 would be any different)...
>>>
>>> In contrast to the current ADSL2+ network, there are 3 big differences with the proposed VDSL2 FTTN deployment -
>>> (i) shorter loop lengths (700-800m)
>>> (ii) vectoring (crosstalk--)
>>> (iii) bonding (speed++)
>>>
>>> While such a VDSL2 network is not as good as fibre, it's no where near as bad as the current ADSL2+ network.
>>> Right now some poor folks are on 6km loop lengths, there's plenty of crosstalk and getting bonding working is a challenge.
>>>
>>> Regards,
>>>   - Guy.
>>>
>>>
>>>
>>>
>>> On 12/09/2013 12:17 PM, Paul Brooks
wrote:
>>> A recent Ofcom (UK) report has a very interesting chart of ADSL2+ line speeds:
>>> Ofcom Infrastructure Report 2012 Update
>>> http://stakeholders.ofcom.org.uk/market-data-research/other/telecoms-research/broadband-speeds/infrastructure-report-2012/
>>> http://stakeholders.ofcom.org.uk/binaries/research/telecoms-research/infrastructure-report/Infrastructure-report2012.pdf
>>> Figure 4 on page 11:
>>> [cid:part3.03040307.07050500 at traverse.com.au]
>>> This chart is effectively the result of the ADSL
line-sync/attenuation curve combined with the increasing area of circles of increasing radius around the exchange - and demonstrates very clearly why so many people get low ADSL2+ line speeds.
>>> (Exercise for the reader - work out how VDSL2 would be any different)
>>>
>>> Also scatter-plots of sync-speed with line-length, as per Figure 8 from another UK report:
>>>
>>> [cid:part4.02010504.05090509 at traverse.com.au]
>>> Now every DSLAM network operator can put together similar charts - but I'm not aware of any stats for Australian networks, apart from the heat maps put out by iiNet and the adsl2exchanges.com.au site, which aren't quite what I'm looking for.
>>> For all you DSLAM operators - I would be very interested in putting together similar charts for the Australian networks, to see how our copper loop
network varies from the UK network. If anyone is willing to share data or statistics, I'm very interested in pulling together similar Australian charts - on a non-identified, aggregated, anonymised basis if you wish.
>>> Please contact me off-list - thanks.
>>> Paul.
>>>
>>>
>>>
>>>
>>>
>>>
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>>> --
>>> Guy Ellis
>>> guy at traverse.com.au<mailto:guy at traverse.com.au>
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>>
>>
>>--
>>Guy Ellis
>>guy at traverse.com.au
>>www.traverse.com.au
>>T: +61 3 9386 4435 M: +61 419 398 234
>>
>>Charles Sturt University
>>
>>| ALBURY-WODONGA | BATHURST | CANBERRA | DUBBO | GOULBURN | MELBOURNE | ONTARIO | ORANGE | PORT MACQUARIE | SYDNEY | WAGGA WAGGA |
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>>LEGAL NOTICE
>>This email (and any attachment) is confidential and is intended for the use
of the addressee(s) only. If you are not the intended recipient of this email, you must not copy, distribute, take any action in reliance on it or disclose it to anyone. Any confidentiality is not waived or lost by reason of mistaken delivery. Email should be checked for viruses and defects before opening. Charles Sturt University (CSU) does not accept liability for viruses or any consequence which arise as a result of this email transmission. Email communications with CSU may be subject to automated email filtering, which could result in the delay or deletion of a legitimate email before it is read at CSU. The views expressed in this email are not necessarily those of CSU.
>>
>>Charles Sturt University in Australia  http://www.csu.edu.au  The Grange Chancellery, Panorama Avenue, Bathurst NSW Australia 2795  (ABN: 83 878 708 551; CRICOS Provider Numbers: 00005F (NSW), 01947G (VIC), 02960B (ACT)). TEQSA Provider Number: PV12018
>>
>>Charles Sturt University in Ontario  http://www.charlessturt.ca 860 Harrington Court, Burlington Ontario Canada L7N 3N4  Registration: www.peqab.ca
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