SNR and Line Attenuation

Could some one please explain this for me

Modem Status
Connection Status Connected
Us Rate (Kbps) 128
Ds Rate (Kbps) 384
US Margin 25
DS Margin 28
Trained Modulation ADSL_G.dmt
LOS Errors 3
DS Line Attenuation 21
US Line Attenuation 12
Peak Cell Rate 301 cells per sec
CRC Rx Fast 109
CRC Tx Fast 40
CRC Rx Interleaved 0
CRC Tx Interleaved 0
Path Mode Fast Path

Is my Down Stream 21db?
 
US = Upstream
DS = Downstream

I'm assuming "Margin" means "Noise Margin" (higher = better, and your figures are very good)

Attenuation (lower = better, and your figures are very good)

Your figures are similar to mine when I had DSL384... You should be good to go if you ever decide to upgrade to 4Mbps (or beyond with ADSL2+)

Don't know much about the rest, sorry.
 
@Nutz: Good to hear that your line is now working correctly. Please post your final noise/DMT plot in your Volt/Amps thread when you have a chance for final comparison purposes. Your case seems to be one of the very few success stories!

As you have mentioned line attenuations of 60dB+ don't usually give good speeds due to noise problems but there do appear to be one or two exceptional cases. His attenuation is 10dB higher than yours which would mean that his router only receives 1/10 of the power that yours does but it still seems able to deliver a 2Mbps service and possibly higher which is quite impressive. It will be interesting to see if he can increase the speed reliably to either 3 or 4Mbps.

@jeppe777: How did you finally get the linestats from the Mega 100WR?
 
Last edited:
im gonna have to get them to bump me down to 1024, my snr dropped to 6 at around 5 o clock, my connection is very unreliable, especially during video streams, what difference in snr will i see if i go down to 1024?
 
Considering upgrading to 4meg. Would it be possible with my SNR/Attenuation?


SNR Margin 40.1 Downstream 21.0 Upstream
Line Attenuation 35.4 Downstream 18.5 Upstream
Errored Seconds 3 0
Loss of Signal 0 0
Loss of Frame 0 0
CRC Errors 3 0
Data Rate 384 128 kbps
Latency FAST FAST

Router last reset on the 12/12/2007.
 
Considering upgrading to 4meg. Would it be possible with my SNR/Attenuation?


SNR Margin 40.1 Downstream 21.0 Upstream
Line Attenuation 35.4 Downstream 18.5 Upstream
Errored Seconds 3 0
Loss of Signal 0 0
Loss of Frame 0 0
CRC Errors 3 0
Data Rate 384 128 kbps
Latency FAST FAST

Router last reset on the 12/12/2007.


yip - should work 100%
 
@ocean-addict: Oh no! It sounds as though you may have to shift down into the slow lane.

If you decrease your line speed your noise margin should increase by 2~3dB or possibly even more. This might be enough to make the line stable but you really need to check on your noise margin variation over time though - this seems to be quite substantial. Your last posting indicates that it varies by more than 5dB i.e. from 11dB to 6dB at certain times. If the noise fluctuations are really large then it is possible that they will still affect your line even at a lower speed. There is a program called routerstats that is very useful in such situations. It plots a graph of the variation in the downstream noise margin over time from your router. Try to get some plots at 2Mbps and then downgrade to 1Mbps to see if there is any improvement. Unfortunately the combination of a 62+dB attenuation together with large noise fluctuations could really limit your ADSL speeds.

http://www.vwlowen.co.uk/internet/files.htm

Take a look at Nutz's latest plot of his noise margin. You can see that there is still some variation in the noise margin but it is now manageable and no longer causes regular dropouts.
http://i210.photobucket.com/albums/bb147/jannie40/14dec0529snr.jpg
 
Last edited:
@Yotch - I downloaded Router stats software but being a non-fundi on routers I did not seem te be able to get much further than that.....couldnt find my routers stats page URL Any idea if it can work with my Telkom ADSL 5102G router? :confused:
 
@Leftfoot: If I remember correctly Nutz did have routerstats running on his Telkom 5102G when he introduced the program to myADSL. I did manage to get it running on my 7300G after viewing some of his graphs. This is what I did but if you are still having problems I'm sure that Nutz will be able to advise you further. Post again if you are still having problems.

You first need to find the correct screen in the router which contains the downstream and upstream noise margins i.e. the page that gives you figures like the linespeed and attenuation etc. In the case of the 7300G the menu selection is Config -> Wan -> ADSL. After opening up this page, right click the mouse and choose properties. This should give you the correct page address for routerstats i.e. in the case of the 7300G it should be http://192.168.1.254/adsl.asp . This information together with the IP address of your router should be all that you need to get it working. In your case the IP address is probably not 192.168.1.254.

Now open up routerstats. Choose the toothed wheel icon - Routerstats configuration. Fill in the correct URL to router 'stats' page i.e. in my case http://192.168.1.254/adsl.asp . Fill in the correct router username and password - in my case admin and admin. Make sure that the remember password box is checked. Now open the Router search text tab. Check the box Use source and then press the Get Page button. If you have done everything correctly you should get a page of source code which you can look through carefully to find the downstream noise margin value. You are nearly done. Follow the routerstats instructions carefully on how to 'train' routerstats to record this value. If you have trained it correctly but you are not seeing any trace on the plot after a few minutes your noise margin may be out of range - just check to be sure and change the graph axis limits if necessary.

Another thing you might also be interested in is the bits per tone information from your router. From Internet Explorer type telnet://192.168.1.254 (use the IP address of your router). Enter your username and password as above. Type the command wan adsl linedata far OR wan adsl linedataf1. One of those commands should give you a matrix of tone data which you can then plot out in MS Excel.

Now just copy and paste the tone data into notepad. You only need the lines from tone 0-31: onwards. Using the editor just remove all the text including the : i.e. tone 0-31: tone 32-63: etc. so that you just have a matrix of numbers i.e 16 columns with 8 rows. In notepad just join row 2 onto the end of row 1. Repeat until you have joined all the rows in order into one long row. Make sure that you don't put any of the rows in the wrong order i.e. the single row must look like this row1 row2 row3 row4 row5 row6 row7 row8. Now put spaces between all of the pairs i.e. 00 00 00 00 24 -> 0 0 0 0 0 0 0 0 2 4 etc.

You should now have a single row that looks like this -
0 0 0 0 0 0 0 0 2 4 5 5 6 6 6 7 7 6 6 6 6 6 6 6 5 5 5 5 5 3 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 3 2 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 2 2 3 2 2 3 3 3 4 3 3 5 6 6 6 6 6 5 5 6 6 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 4 5 5 4 4 4 4 4 4 4 4 4 4 4 3 3 0 0 2 3 3 3 3 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 2 2 2 2 2 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Once you have done that Open Excel. From notepad copy the whole row and paste it into a single cell in Excel. Under the Data menu there is a menu Text to Columns. Select that and choose delimited. Then click Next and tick Space as the delimiter. Then click Finish. Select all the cells containing data in the first row. On the toolbar click the chart wizard and select the column chart type. Choose the first subtype and plot the graph. If everything has been entered correctly there should be a zero in row 65 i.e. at tone 64 - this is the pilot. This is a very rough method to view the bits per tone and doesn't provide any of the additional features that DMT does like the SNR per tone.

Sign up for a free account at www.photobucket.com and upload your graphs and post the links.
 
No problem! :)

The 5102g is usually configured for ip 10.0.0.2 u:admin p:admin.

The first screen that opens in your web browser shows the line specs on the bottom.

What you do : where the SNR value entry is - right click that number in IE (or whatever browser) - and you'll see something like - http://10.0.0.4/m_status.htm - (this is on my netgear)

Now - copy that url into the URL section of routerstats (yellow gear icon(Router login & logout)) & provide the admin/password for authentication of router access.

When you do go into routerstats - click on yellow gear icon again - router search text tab - then get page -> this should provide an exact active copy of your line specs page.

Lastly - highlight for example SNR value down - and click the Rx noise..

Usually i'm only interested in the SNR down - but you can log up to all 6 values (does tend to go a bit wrong using more than 3 values)

Click save , then the disc icon aswell. You should be configured :)

PS: just play with the frequency of plotting..default 60sec intervals - max 250 point plots per screen shift. i usually set it to 5 sec polling and 10000point plot for a nice long 12 hour stint capture.
 
Last edited:
so network load does cause fluctuation? with regards to contention ratios and so on, which part of my internet connection is being 'shared'? the last mile from my house to the exchange, or the x.25 link leaving the exchange?
 
Just moved into my new house. Readings are as follows:
- Downstream attenuation: 6 :)
- SNR: 35
Loving this!
 
Top
Sign up to the MyBroadband newsletter
X