Skaparna av Skype gjorde ju Kazaa innan, så det är lite fulkod på gång, min teori är att pga du har en 100/100 uppkoppling så snor Skype din bandbredd för att routa andras telefonsamtal:
"Skype is a dangerous little piece of software. It works great, yes, but you have no idea how it accomplishes that.
For one, it does a lot of shit that you might not want. As opposed to most other instant messengers which simply talk to a central server and open individual connections when they are actually needed, Skype is peer to peer software. It constantly keeps a lot of connections to different Skype users around the world open and probes for new ones, without you noticing. If you internet connection is fast enough, it will use you as a "super node", which is a kind of mini-server that keeps other Skype users in your vincinity up to date. All of this is done without asking or notifying you, and it does not really care if your bandwidth is limited or meant for something else either... if it's there and it's fast, it will use it up." [sic]
Källa: http://www.reddit.com/r/todayilearned/comments/w2vu2/til_the_...
Mitt förslag är att du dumpar skiten och använder dej av något annat alternativ, t.ex. TeamSpeak, Mumble, Google Hangouts...