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Every day , whenever I surf the Internet. I do see people complaining that their ADSL connection isn’t stable. They face the blinking DSL Light syndrome problem , frequent disconnection and other funny stuff. Now , if we take a look regionally (in Malaysia), people would just start to blame how bad is streamyx (our ADSL Service). They would just start to scream and call help desk which makes their blood pressure to raise and this could lead to other health problems. Trust me , there is no point of arguing how bad is their line when you don’t have the facts. In this section/part , I’ll be teaching you on how to diagnose your ADSL Connection and what the numbers do mean.

Firstly , the prerequisites :-

• An ADSL Modem (make sure you know its default username/password). Do consult the manual. If you still don’t know , then kindly use Google to find out. Simply type “model name of the modem username password”. You’ll find it
• A Direct Connection to your PC (Modem to PC). You must not be connected to a router & A Web Browser
• A bit of common sense too ! (I mean it !)

First thing first , firstly you’ll have to find out what is your modem’s configuration address. Usually , its http://192.168.1.1 or http://192.168.0.0.1 . You’ll have to consult the manual or google for it if you would like to know whats your address. Alternatively you may want to use ifconfig (Linux) or for Windows (ipconfig)

ipconfig (Windows) – Simply run the command prompt and then type ipconfig. Do take note of the default gateway (of your Network Adapter)

For linux/MacOS X  users , simply just fire ifconfig and you’ll get your default gateway address !. Once you have that , simply fire up a web browser and key in the default gateway address !

Simply key-in your modem address and it will prompt you for the username and password !

You should see a dialog prompt something like that. Now its your duty to find whats the default username/password for your router , assuming that you didn’t change it. This could be obtained from your ISP , the manual that came along with your modem or just by doing a simple Google Search !

Now once you have managed to get in to your modem configuration page. Navigate it through , this is where you’ll have to be brave and explore. But just don’t touch anything or adjust any settings. Just navigate through till you see something which outputs your ADSL data. It varies from one modem to another modem

Anyway here is mine , you can take a look if yours matches mine or not. it should be similar. As for some modem , it may not output all the stuff which you can find here. However it would give you the basics such as SNR Margin , Line attenuation and so on.

The modem statistics page ! – Outputs useful information to geeks and technicians alike !

Now , shall we break down what these terms mean and what are its optimum value. Think of these values as your blood test results .

SNR Margin (Signal to Noise Margin)

Relative strength of the DSL signal to Noise ratio. 6dB is the lowest dB manufactures specify for modem to be able to sync. In some instances interleaving* can help raise the noise margin to an acceptable level. The higher the number the better for this measurement.

• 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 no synch problems
• 20dB-28dB is excellent
• 29dB or above is outstanding

Line Attenuation

Measure of how much the signal has degraded between the DSLAM (The exchange center , may also be known as “port”) and the modem. Maximum signal loss recommendation is usually about 60dB. 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

Note – * Interleaving
Interleaving is an error correction protocol that is implemented for your line at the DSLAM (or port). With Interleaving enabled, the DSLAM  can correct errors in the data stream it receives before passing that data to your gateway router. It is usually implemented on poor lines or if you’re situated far from the nearest port/DSLAM/exchange  The largest drawback to Interleaving is that it will significantly increase your ping time, specifically to your first hop gateway router.

If Interleaving is not enabled on your line, it is configured as FastPath. FastPath allows the DSLAM to pass the data received from you to the first hop router without performing any error correction. As a result, marginal lines could experience an increase in packet loss and decrease in sync stability (i.e. frequent sync loss). However, FastPath does produce decreased ping times, especially to the first hop router. Hence giving you a lower ping time , this is a must for gamers. However its also prone to packet loss as well (as in increased chance)

Credits :- amadeo (Adpoted from here)

In the next tutorial/part , I’ll be teaching you on how to take these information which you have obtained from your modem and submit it to your ISP (especially if you’re in Malaysia and you’re using streamyx , you do know how the tech support do react). These information can give an insight to us to determine whos fault (if its yours or at their site). In the next part/tutorial , I’ll be letting you know what are the factors that affect our DSL line and how we can overcome it as well !

Tags: adsl tips, helpdesk episodes, Malaysia, streamyx, troubleshooting isp

This entry was posted on Monday, February 2nd, 2009 at 1:35 pm and is filed under Computers & Networks, My Thoughts. You can follow any comments to this entry through the RSS 2.0 feed. You can leave a comment, or trackback from your own site.