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I have recently noticed that my Internet connectivity both over wireless and wired connections has become increasingly intermittent. I fired up command prompt and ran ping google.com -t to check out my packet loss. After running ping for a while, it looks like I'm getting about a 20% packet loss.

I also tested my ping at pingtest.net. Here's a screenshot of my pingtest:

enter image description here

I have tried power cycling my router to no avail. What other tools and methods can I utilize to diagnose my packet loss?

EDIT

Here's a sample I took using PingPlotter:

enter image description here

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migrated from serverfault.com Mar 27 '13 at 0:37

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Is this DSL or cable? What is the advertised bandwidth of the plan you pay for? What is your measured bandwidth? Is it consistently this bad or is it sometimes better? –  David Schwartz Mar 27 '13 at 0:53
    
@DavidSchwartz This is cable. Advertised bandwidth is 15 Mbps down and 3 Mbps up. Measured it's around 9 Mbps down and 2.5 Mbps up. This issue just cropped up recently, like in the past day or so. –  Bryan Roth Mar 27 '13 at 1:04
    
Can you access your modem's management pages and make sure something (like malware or a clustering downloader) isn't saturating your bandwidth? My guess is that this is an issue with your provider, but I'd rule out local traffic first. –  David Schwartz Mar 27 '13 at 1:10
    
@DavidSchwartz I was able to access the modem's control panel but it had no useful information and is pretty locked down, e.g. no access to logs. –  Bryan Roth Mar 27 '13 at 2:07

3 Answers 3

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You need to take steps to isolate the problem. Here are the steps, from nearest the host to farthest away:

  1. Verify that there is no packet loss on pings between your computer and the router or DSL modem itself.

  2. Verify that the problem is not with the current host - change the computer from which you are testing and change the network cables to the router or modem and retest.

  3. Verify that there is no packet loss between two computers on the same wired and wireless local network (in your home or office or wherever the problem is).

  4. If you are using a DSL modem, test with ping against your ISP's nameserver hosts, or if you can log into your DSL model and see the default gateway, ping the default gateway. This will eliminate routing errors or other network errors at your ISP

  5. Call your ISP and ask their tech support if they are seeing an unusual number of re-login attempts from your modem.

  6. Call your telephone supplier (if different from the ISP) and ask to do a line condition test (might take a few hours).

  7. Replace the DSL filter and the filter-to-modem wire between the phone and the modem.

  8. Replace the modem with a different model or brand that handles higher speeds.

I recently had a similar problem in my office (Talpiot neighborhood in south Jerusalem). The telco found no problem with the line. The ISP tech said he saw a lot of re-login attempts from the DSL router. I changed the telco supplied D-Link DSL 2500U to a newer Edimax DSL/Wireless switch. It turns out that the telco had upgraded line card modulation to handle higher DSL speeds and had not informed subscibers in the area that the older modems might have problems. So over the course of two frustrating weeks I went through all of the above steps and solved the problem.

A similar problem at a cutomer of mine was not resolved by the above eight steps. The problem was eventually resolved to a duplicate IP address block allocation that caused packets from a BGP router to sometimes return to the customers network and sometimes not. After the ISP swore up and down for a week that he had no routing problem we were finally able to convince him to go router-by-router and check if he hadn't allocated overlapping IP blocks. The ISP eventually found the duplicate blocks and apologized.

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Thank you so much for the useful information. I will definitely be giving the ISP a call tomorrow since this is looking more like it's an issue on their end. –  Bryan Roth Mar 27 '13 at 2:08

PingPlotter is a handy tool to use for this.

And here is a good link for how to accurately interpret traceroute results.

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PingPlotter is definitely a neat little utility. Thanks for the link to the paper on interpreting traceroute results! –  Bryan Roth Mar 27 '13 at 2:11

I would suggest trying the built in Windows tool "pathping" or WinMTR to give you a better idea where in the path the packets were being dropped. WinMTR Portable

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Thanks for mentioning pathping -- I had no idea about it. –  Bryan Roth Mar 27 '13 at 2:17

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