Thursday, August 16, 2007

Evil Skype

The first time I used Skype some years ago I went like: wow! This stuff is fantastic. It worked completely out-of-the-box and the voice quality for international calls was better even from a regular phone line.

For the type of distributed development work we do in JBoss skype was a saver. If only it could handle better conference calls with more than 3-4 people we wouldn't even need special conference call lines.

Then last month this weird thing happened. My development laptop who was on a cycle of suspends-resumes for a week or so (I avoid shutdowns/reboots unless there is a very good reason) started behaving strange.

My regular dependency library updating for building the JBoss Application Server seemed extremely slow; then it almost halted. I wasn't doing anything on the PC but the network lights on the adsl router were blinking like crazy. What was that?

I used tcpview to check my network connections. There were thousands of TCP connections coming from skype.exe to all sorts of destinations. I killed skype.exe and it took almost 15 minutes for my laptop to recover. After googling around a bit I found out that skype had elected my laptop to become a SuperNode.

For the service I'm getting from Skype I wouldn't mind my PC to relay some info here and there (as long as I have precise control over the allocated bandwidth or the ability to turn this feature off), but certainly this supernode thing wasn't working as it should in my case. It ate up all my bandwidth.

Then today, a friend forwarded this very interesting link about skype's internals.

Now I am really scared.

1 comment:

Paris Apostolopoulos said...

Dimitri ...consider testing (at least) Gizmo. It provides similar quality service and it seems to be more Open!