Comcast “admits” to blocking vonage

I have been trying to figure this one out for almost 1 year now.

I have a slingbox connected to my Dad’s Satellite.  I can watch his DirecTV stream anywhere I am and since he has 2 tuners connected to it, I dont change the channel he is watching either.  It is a pretty nice setup and it ran great for 2 years without a single glitch until my Dad decided to fire Verizon as his phone company and opt to try VOIP from Vonage.

Initially everything seemed to be working great.  Vonage phone calls worked nicely.  Sling was working as usual and all other internet services seemed to be unaffected by the new Vonage box plugged into the router.

Then one night, I was watching a hockey game when I wanted to call my Dad.  I noticed a very big change in the quality of the phone call while streaming via Sling.  I decided to change some settings in the router to compensate for this.  I am using a Linksys WRT54GL router with Tomato firmware installed on it.  I set up the QOS to give the higest precidence to Vonage and to limit the bandwidth of the Slingbox to 300kbps as I have my Sling Player set to stream at 300kbps on myside.

This change had some benefit, but did not alleviate the problem like it should have.  Next, my Dad decided to opt in for Comcast’s Performance PLUS with PowerBoost package.  This package came at quite a premium over the regular cable internet service, but was guaranteed to have 2mbps upstream.  This would be plenty for the 300kbps Slingbox and 90kbps for Vonage to function together seamlessly.  Or so I thought.

After checking the upload speeds with serveral websites as well as running a straight FTP transfer of a 100 megabyte file to my server at work, I decided that my Dad was indeed getting between 2 and 4 mbps uploads.  Really pretty good.

So we tried the Vonage with Sling at the same time test again .  Same results — choppy phone conversation but Sling worked well.  This was really odd as I gave Sling the lowest QOS priority in the router.  At this point I tried 2 other routers with exactly the same results.

I then decided to try the test in reverse.  I would run my sling box while my Dad watched it during a phone conversation.  I do not have a phone, but rater use the Skype In and Out services for my phone, but he remained using Vonage.

This test revealed an interesting finding.  There was no sound issues at all and he could watch my sling box perfectly.  I set my WRT54GL router up the same as his and tried 2 other routers as well for thoroughness.  The only way to get the choppy phone conversation was when he was streaming something up to the internet while talking on Vonage.  We checked the bandwidth during these tests and he was never even using more than 1mbps even though he clearly tested up to 2-4 mbps every time.  Also, at this point I should say that I use Time Warner Cable for my Internet.

I was stumped as to how to solve this problem.  My dad can upload files to my FTP server at close to 4mbps, but when he uses Vonage the total bandwidth he is uploading seems to be capped at under 700kbps.  During a file transfer the speed will not just be split between the 2 applications, but rather the overal maximum transfer speed drops to this 700kbps.  When we hang up the phone, it goes back up to 4mbps.  Although I could not find a solution to the problem, I did suspect there was a casue.

I assumed at this point that Comcast was doing some kind of throttling on the bandwidth during Vonage calls.  I believe that Comcast can easily tell that you are using VOIP with Vonage and could very easily change things to screw up your connection to make it seem like Vonage isnt working well.  I thought my test of the changing FTP speed proved this point, but I had no idea what to do.

Then today, I read this news at the Wall Street Journal.  This pretty much proved my theory.  If Comcast gives their guarantee NOW that they will work with Vonage to make sure the connection is clear., this pretty much indicates to me that something was up eariler even though Comcast Denies it.  They also denied (falsely) that they were throttling P2P traffic ealier this year.

I am positive that Comcast was doing something to make it seem like Vonage VOIP was an inferior product — this article further supports my theory.  I will test Sling and Vonage again over the next weeks and see if my results are different.