dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
3555
share rss forum feed

bjlockie

join:2007-12-16
Ottawa, DSL
Reviews:
·TekSavvy DSL

[DSL] predicting vdsl speed from adsl line stats

I used this: www.speedguide.net/dsl_speed_calc.php
I want to predict my vdsl speed from my current adsl line stats.
The calculator says I can sync at 24Mbps (for vdsl) but it only has one number.
I assume it is download so would upload be a percentage of download?
Btw, I think I am on a remote and I don't know if there is a closer remote.
Bell's says I can't get the 50Mbps tier but that could mean I can pay for upto 50Mbps bu still get sub 25Mbps speed.



squircle

join:2009-06-23
Oakville, ON

It would probably help if you'd post your line stats.



Guspaz
Guspaz
Premium,MVM
join:2001-11-05
Montreal, QC
kudos:23
reply to bjlockie

Impossible. The technologies are different, the loop length is potentially different (may not be on the same remote). There's no correlation whatsoever. You could have a terrible quality adsl1 line that can't hold a 5 meg sync, but be able to get 50/10 on VDSL2, or you could have a great ADSL1 line with fantastic stats but be unable to get 25/10 because you're just a little bit too far from the DSLAM.

Example: my attenuation on ADSL1 was 35, my attenuation on VDSL2 is 6. So any prediction of my VDSL2 speeds using my former attenuation would have been pointless.
--
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org


InvalidError

join:2008-02-03
kudos:5

said by Guspaz:

Impossible.

It is not impossible. ADSL1 line stats do give you a general idea of how close the nearest remote might be and how clean the line up to that point appears to be which are still useful bits of information to estimate a worst-case scenario.

In your case, 35dB attenuation obviously puts you in VDSL2 no-mans-land unless a closer remote gets involved, which it did.

For others like me who are seeing 2-12dB attenuation on ADSL1, we are obviously on one the closest remotes we are likely to ever get on for the foreseeable future so SNRM on those would have a fairly good correlation with VDSL2 results: if your ADSL1 SNRM is pretty much maxed-out (24+dB), you will likely have no problem getting 25/10 or even 50/10 but if your SNRM is "low" (under 20dB), you likely have problems on your line that will need sorting out - if the lower frequencies (ADSL1) are messed up, chances are the rest of the wiring's passband is just as bad or worse and if the lower frequencies are clean, chances are the rest of it will be at least decent.

Based on my 25.5dB SNRM and 10dB attenuation on ADSL1, I am reasonably confident that I would have no problem getting at least 25/10 and Bell's site says my address qualifies for 50/10.

bjlockie

join:2007-12-16
Ottawa, DSL
Reviews:
·TekSavvy DSL
reply to squircle

Current Noise Margin: 18.7 dB (Downstream) 9.7 dB (Upstream)
Current Attenuation: 11.7 dB (Downstream) 6.4 dB (Upstream)
Current Output Power: 12.0 dBm (Downstream) 11.8 dBm (Upstream)
DSLAM Vendor Information: Country: {0xB5} Vendor: {BDCM} Specific: {0x94A1}


morisato

join:2008-03-16
Oshawa, ON
Reviews:
·TekSavvy Cable
·TekSavvy DSL
·ELECTRONICBOX

Your upstream attenuation puts you around 600-800 Meters From your Slam if its an Oslam Your upload will suffer greatly if its a 7330 you could get 25/10 easily might be close on 50/10 depending on actual distance
--
Every time Someone leaves Sympatico an Angel gets its wings.


xtrocky

join:2007-08-29
Orleans, ON

Hi guys,

I was actually going to ask the same question. As I don't really understand the DSL stats, could someone provide me with some ballpark numbers on my line stats? I'm thinking of getting 25/10 mbps in the near future and wondering if I'll be able to get the full speed.

Bandwidth (Up/Down) [kbps/kbps]: 797 / 19.453
Output Power (Up/Down) [dBm]: 11,5 / 14,0
Line Attenuation (Up/Down) [dB]: 9,5 / 16,0
SN Margin (Up/Down) [dB]: 18,5 / 12,5

Thanks
Rocky



Mike2009

join:2009-01-13
Ottawa, ON
kudos:3

Your stats are great. You should ask for the full upload speed.


xtrocky

join:2007-08-29
Orleans, ON

Good to here. Thanks for your help!


morisato

join:2008-03-16
Oshawa, ON
Reviews:
·TekSavvy Cable
·TekSavvy DSL
·ELECTRONICBOX

Xtrocky I would disagree your stats indicate a distance of 1 km or more, Upload speed will be iffy depending on the type of slam your Connected to, Though of course they could move u closer. Oslam you will not get service unless lucky, 7330 should hold solid but be close to caps.
--
Every time Someone leaves Sympatico an Angel gets its wings.



Blah123

@aei.ca
reply to bjlockie

In the near future, I am planning to switch to teksavvy's 25/10 or 15/1. With my current DSL stats, I wonder if I can get 25/10 full speed. If not then maybe I should consider cable.

Downstream Upstream
SNR Margin (dB): 22.6 6.0
Attenuation (dB): 23.0 6.5
Output Power (dBm): 19.7 12.6
Attainable Rate (Kbps): 10816 1088

Thanks.



STN

join:2004-12-29
Canada
reply to bjlockie

I would agree mostly with InvalidError but Guspaz has some points.

Guspaz could be correct if you would end up changing DSLAMs, however if the new DSLAM is right beside the old DSLAM then the numbers could be a bit relevant.

Assuming you stay on the same port or close by, InvalidError has a decent write up, however ADSL attenuation is based on lower frequencies, and actually only a small slice of them, and is known to be erratic. If you have a noise spike in the freqs that are used for attenuation calculations but remaining freqs are mostly clean then attenuation would be overstated. The reverse could be true if you have lots of noise but not in the freqs used for attenuation calculations.

When you boil it down you could do nothing more than guesstimate, it would be unreliable.


morisato

join:2008-03-16
Oshawa, ON
Reviews:
·TekSavvy Cable
·TekSavvy DSL
·ELECTRONICBOX

For a Guesstimation Upload attenuation is generally this simple 6.5 would suggest your 650 meters ballpark 5 would be 500 meters etc.. 10 is 1 Kilometer etc.. So you get the idea its a Estimation and is not ideal but assuming your Within Possible distance your likely already on The remote nearest you, IE Oslam or 7330 and all u can do is hope.
--
Every time Someone leaves Sympatico an Angel gets its wings.


InvalidError

join:2008-02-03
kudos:5
reply to STN

said by STN:

Guspaz could be correct if you would end up changing DSLAMs, however if the new DSLAM is right beside the old DSLAM then the numbers could be a bit relevant.

30dB puts him over 2km from his previous DSLAM so as far as VDSL2 service from the same site is concerned, that would place it in the no-way-in-hell category.

As for the likelihood of attenuation estimation being made based on a frequency that has non-representative characteristics, this can be easily determined by looking at the bit-loading graph on modems that support that feature. On a good line, it should be almost flat across the spectrum apart from the pilot tone, possibly some suppressed/keyed tones and roll-off at either/both ends.


STN

join:2004-12-29
Canada

But he's asking as a end user. Can you try and do some more detailed analysis, yes you can try. But his question wasnt from a tech looking at DMT graphs. I'm giving him some general comments on end users trying to "predict my vdsl speed from my current adsl line stats"

I forgot how one-upity these forums are.


SLAMtech

join:2009-12-03
kudos:1
reply to bjlockie

Having perfect adsl stats doesn't guarantee perfect vdsl2 stats. Bridge Taps/End taps and gauge changes effect vdsl2 much more. As well as the PSD noise and wideband frequencies effecting your pair. ADSL handles the above much better and generally around 3km is around where Max attainable (8128/800) goes downhill.

There are lots of additional factors and you can't go by distance alone. Had a customer at 980 meters with attainables of 56 down and 18 up and it was even on encap with a 7330. Also had customers with less distance and lower attainables.


morisato

join:2008-03-16
Oshawa, ON
Reviews:
·TekSavvy Cable
·TekSavvy DSL
·ELECTRONICBOX

Well Slam Tech 7330s are pretty good at pushing i;ve installed a fibe tv @ 1350 before, sucessfully But we both know put that distance on a Oslam and kiss your sync goodbye p:)
--
Every time Someone leaves Sympatico an Angel gets its wings.


InvalidError

join:2008-02-03
kudos:5
reply to STN

said by STN:

But his question wasnt from a tech looking at DMT graphs.

It is someone asking here about line stats and such requests at least used to lead to "download the modem-appropriate DMT version and post a screen cap" so local techies can have a look at it.

morisato

join:2008-03-16
Oshawa, ON

Up Attenuation is a Indicator heh beyond that oh well. Starcraft hots time p:) why for is noone excited?
--
Every time Someone leaves Sympatico an Angel gets its wings.