How to Diagnose and Fix your Slow Internet Connection


Let’s say you have subscribed to a fast broadband Internet connection at home and you are getting the expected download speeds that were initially promised by the ISP.

However, sometimes it may happen that the speed of the same Internet connection slows down and then even simple websites may take forever to load on your machine.

Troubleshooting your Slow Internet Connection

There can be several reasons why you may be getting slower-than-usual Internet connection speeds. For instance, you could be accessing the web during peak hours. Or your download manager could be downloading files in the background thus consuming all the bandwidth. Or, if you are accessing the Internet over Wi-Fi, maybe you’re too far off from the wireless router.

Then there are external factors that may slow down the Internet. You are probably getting Internet through your existing phone line so if there’s a fault in the wiring, that may   negatively affect your connection speed. In fact, if your Internet connection is not stable and keeps dropping off frequently, blame the phone company.

Does Your Telephone Line Need Repair?

You don’t need any special equipment to determine if your phone line is the real culprit but before we get there, let’s run a few simple tests to discount all the other possibilities.

Test #1. Power-cycle the router and modem – unplug the cables, wait for couple of minute and then power on the modem followed by the router.

If you have been experiencing connectivity issues after a power-outage, power cycling will most probably fix the issue.

Test #2. Close all applications including any firewalls and anti-virus software. Then open to determine the actual download and upload speed of your Internet connection.

If you have Wi-Fi at your place, remove the router for a moment and connect the ADSL modem directly to your computer’s Ethernet port via a physical LAN cable. Repeat the speed test. Did you see any improvement in the connection speed?

Test #3. To ensure that none of the viruses or spyware programs are responsible for your slow Internet, open command prompt and run the following command:

netstat – b – f 5

This will easily help you figure out if any of the programs on your computer are silently connecting to the Internet without your knowledge. Should you find a strange process in the netstat result listing, kill it through the Task Manager.

Test #4. If your Internet speed woes aren’t over yet, it’s time to inspect the phone line. No, you don’t have to climb that telephone pole as the stats from your DSL modem /router will alone give the required data.

Open the web dashboard of your modem /router and note the following values for the downstream connection (not upstream). The fields are generally available under Statistics – > ADSL.

ADSL Line Stats

1. Line Attenuation (or Loop Loss) – It measures how much signal is lost between the phone exchange and your modem. Great the distance between the exchange and your home, the higher the attenuation. Anything below 50dB is considered acceptable.

2. Sync Speed (or Rate) – The speed at which the router connects to the exchange equipment.

3. SNR Margin (or Noise Margin) – This represents the difference between your current SNR (Signal-to-Noise Ratio) and the SNR that’s required to serve a particular speed. If the SNR Margin is low, you may experience frequent disconnections. Ideally, this should be 12dB or higher.

Once you have all these values, paste them into the ADSL Calculator and it will give you an estimate of the maximum speed that you get from the ISP.

If the SNR Margin is low or the Line Attenuation is high or if the calculated maximum speed is lesser than what you are paying for, the fault lies somewhere between your modem and the phone exchange. Keep a record of all these values at different times of the day and give your phone company a calls at its something that only they can fix.

Also see: Surf the Web Faster on Slow Internet

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Meet the Author

Web Geek, Google Developer Expert
Amit Agarwal

Amit Agarwal is a Google Developer Expert in Google Workspace and Google Apps Script. He holds an engineering degree in Computer Science (I.I.T.) and is the first professional blogger in India. He is the developer of Mail Merge for Gmail and Document Studio. Read more on Lifehacker and YourStory

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