ADSL line diagnostics how-to

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MyWorld

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I have skimmed through a few threads on the forum, but could not find anything to satisfy my need, so if it has been answered already please point me in that direction and close this thread.

I would like to know how to diagnose your line to see if it is performing as it should, what tests should one run on the router and how do one interpret the data?

For one, I read allot about attenuation, what is a good value on it and what is bad?

The reason I'm asking is because I get terrible speeds from overseas but local downloads fly!

My DSL stats:

DSL 4096 kbps / 512 kbps

noise margin upstream: 12 db
output power downstream: 7 db
attenuation upstream: 11 db

:confused:
 
on a 4mb you will always get terrible speeds on international cause its shaped to hell, you need to multi-thread your downloads on international, free download manager is pretty good for this. local will always be quick as there is no shaping (I think).
 
MyWorld , your 4 megabit specs are acceptable even if it is a bit low . SNR ideal value is to be above 10...at 6 it disconnects and does a resync.

Attenuation above 50 you might get problems when the line gets wet.

other than that you should try a download manager like getright/flashget.

and also play with unshaped saix/unshaped verizon.
 
how do you test for this info:-
noise margin upstream:
output power downstream:
attenuation upstream:
 
your 4 megabit specs are acceptable even if it is a bit low
Click to expand...
What is a bit low? The upload rate? Or something else?

I know nothing of this, so that is why I'm asking.
:p
 
Explanation of line stats: http://mybroadband.co.za/vb/showpost.php?p=1239914&postcount=7

Regarding how fast the line should be, you need to do a test on www.speedtest.net (try www.speed.io also). Both will auto-detect that you are from South Africa, but on speedtest.net you will need to choose a (city) location explicitly. You should get about 3200-3500Kbps down and 400-440Kbps up.

Once you've confirmed your local speeds, go back to speedtest.net and choose an international mirror (e.g. London, UK or Washington, USA) and re-do the test. Post your results here.

What ISP and type of product are you using? If you find your international speeds low, you should give IS Fibre Semi-shaped a try - I find it to be extremely fast for international access. You can get it prepaid from www.axxess.co.za if you want to try it before committing to a monthly account and then get your capped/monthly account from www.nexus.co.za or www.openweb.co.za if you decide to switch to it.

Good luck.
 
From www.speed.io :

Results from http://www.speed.io
(Copied on 2008-10-09 17:34:41)
Download: 3461 Kbit/s
Upload : 424 kbit/s
Connects : 2667 conn/min
Ping: 31 ms

And for the second one,www.speedtest.net :

Download: 3462 kb/s
Upload: 430 kb/s
Ping: 39 ms

International is dismal:
Ping: 746 ms
Download: Between 660 - 2259 Kbit/s ( 2 tests, two very different results)
Upload: 250 Kbit/s

Telkom intenet ISP.
 
Those are good results (for local). I would say your line is working properly ;)

MyWorld said:
Telkom intenet ISP.
Click to expand...

There's your problem right there. Telkom = SAIX. SAIX = pathetic on 4Mbps lines for international access.

I would highly recommend you go ahead and try IS Fibre semi-shaped (it will be a little more expensive, though). If you want to see a direct comparison of SAIX and IS Fibre Semi-shaped, have a look at the link in my signature.
 
fz1 said:
Explanation of line stats: http://mybroadband.co.za/vb/showpost.php?p=1239914&postcount=7

Regarding how fast the line should be, you need to do a test on www.speedtest.net (try www.speed.io also). Both will auto-detect that you are from South Africa, but on speedtest.net you will need to choose a (city) location explicitly. You should get about 3200-3500Kbps down and 400-440Kbps up.

Once you've confirmed your local speeds, go back to speedtest.net and choose an international mirror (e.g. London, UK or Washington, USA) and re-do the test. Post your results here.

What ISP and type of product are you using? If you find your international speeds low, you should give IS Fibre Semi-shaped a try - I find it to be extremely fast for international access. You can get it prepaid from www.axxess.co.za if you want to try it before committing to a monthly account and then get your capped/monthly account from www.nexus.co.za or www.openweb.co.za if you decide to switch to it.

Good luck.
Click to expand...

My line was installed yesterday, got my router and ISP today, seems like my line is very good?

Upstream 256 kbps
Downstream 512 kbps
SNR Margin (Upstream) 13.0 db
SNR Margin (Downstream) 30.0 db
Line Attenuation (Upstream) 4.5 db
Line Attenuation (Downstream) 13.5 db
:D


 
Last edited:
fz1 said:
Yup, looks great. Should work beautifully when you upgrade to 4Mbps. Now go upgrade. You won't regret it. It's quite something downloading at 400+KB/sec.
Click to expand...

I am sure it's quite something to see a 3g Cap runs out in 2-3 hours :sick: Thanks Telkom.
 
I am sure it's quite something to see a 3g Cap runs out in 2-3 hours Thanks Telkom.
Click to expand...
That will not just happen, I download something from the news servers and it flies for the first 150Mb, then dies down to a 6kbps crawl (and it is supposed to be cached). Might just be the IS news server, but so far my 30Gb local is in no danger.
 
Modem Status​
Modem Status
Connection Status Connected
Us Rate (Kbps) 640
Ds Rate (Kbps) 4096
US Margin 14
DS Margin 10
Trained Modulation ADSL_G.dmt
LOS Errors 0
DS Line Attenuation 30
US Line Attenuation 16
Peak Cell Rate 1509 cells per sec
CRC Rx Fast 0
CRC Tx Fast 0
CRC Rx Interleaved 0
CRC Tx Interleaved 0
Path Mode Fast Path


DSL Statistics
Near End F4 Loop Back Count 0
Near End F5 Loop Back Count 0
Click to expand...

OK so this is what my telkom 105wr router says. is it any good.:confused:
Also it seems that if I connect my telephone/fax without a pots filter my speeds drop to 640/640.
 
Confu3ed, please refer to: http://mybroadband.co.za/vb/showpost...14&postcount=7

Your stats are just okay (not great, not terrible). Specifically, your downstream noise margin of 10dB is on the low side. However, you don't seem to have any CRC errors which is great news. As long as you are getting the speeds you should be getting, don't worry about it.

As for connecting other things to the line without a filter, I think that's pretty normal. Those other devices must be introducing noise to the line when they are hooked up, which will decrease your noise margin further. I think if your noise margin drops below 6dB, the exchange will drop you down to a slower speed and re-check your noise margin. It will repeat this process until it finds what it thinks is a suitable trade-off between speed and an acceptable noise margin. In your case, it finds that dropping you to 640Kbps increases your noise margin to an acceptable level.
 
fz1 said:
Confu3ed, please refer to: http://mybroadband.co.za/vb/showpost...14&postcount=7

Your stats are just okay (not great, not terrible). Specifically, your downstream noise margin of 10dB is on the low side. However, you don't seem to have any CRC errors which is great news. As long as you are getting the speeds you should be getting, don't worry about it.

As for connecting other things to the line without a filter, I think that's pretty normal. Those other devices must be introducing noise to the line when they are hooked up, which will decrease your noise margin further. I think if your noise margin drops below 6dB, the exchange will drop you down to a slower speed and re-check your noise margin. It will repeat this process until it finds what it thinks is a suitable trade-off between speed and an acceptable noise margin. In your case, it finds that dropping you to 640Kbps increases your noise margin to an acceptable level.
Click to expand...

thanks;)
 
OK so this is what my telkom 105wr router says. is it any good.
Click to expand...
US Margin 14
DS Margin 10
DS Line Attenuation 30
US Line Attenuation 16
Click to expand...

From the link fz1 posted in one of his posts:
"Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. The higher the number the better for this measurement. In some instances interleaving can help raise the noise margin to an acceptable level.

6dB or below is bad and will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems* (but see note below)
20dB-28dB is excellent
29dB or above is outstanding
Click to expand...
Line Attenuation
Measure of how much the signal has degraded between the DSLAM and the modem. This is largely a function of the distance from the exchange. The lower the dB the better for this measurement.

20dB and below is outstanding
20dB-30dB is excellent
30dB-40dB is very good
40dB-50dB is good
50dB-60dB is poor and may experience connectivity issues
60dB or above is bad and will experience connectivity issues"
Click to expand...
 
Help with these adsl stats, is that attenuation high or is it normal?

Mode: ADSL_2plus
Type: ATM
Status: Up

Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (dB): 273 120
Attenuation (dB): 195 105
Output Power (dBm): 25 -3
Attainable Rate (Kbps): 23880 1116
Rate (Kbps): 2048 511
D (interleaver depth): 1 1
Delay (msec): 0.25 0.24
 
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