VoIP users are discovering problems because telecom companies are blocking this type of traffic across the net.
Telcos in the US and other countries are reluctant to have their bandwidth encroached on by traffic from which they earn no revenue, and have been challenged over similar alleged incidents of VoIP blocking. Blocking VoIP traffic is technically difficult, but not illegal, and blocking specific types of internet traffic is on the increase.
Luxembourg-based VoIP provider Skype, now owned by eBay, has been particularly controversial. Skype is used by 75m people. But not everyone wants Skype on their network.