Maybe I am a little bit paranoid but I have a weird idea at least for Asia. Most of the countries in Asia is blocking VoIP traffic.
I am working on a VoIP tunneling software (http://www.mizu-voip.com/Products/VoIPTunnel.aspx) used by many telecom companies in Asia.
In the last 3 years we have continuously evolved the built-in encryption algorithms but it was always cracked by the local authorities (yes, they are employing high qualified personnel for this). Last summer we decided to integrate much stronger encryption (at the cost of lower server performance) and since then the protocol was not cracked anymore.
I think that since they cannot easily crack new VoIP encryption anymore, they have decided to lower the quality for all links to keep the VoIP quality low so people have to use their national telecom service at high cost.
What do you think?
Note:
The measurement method can be very important for this (for example whether you check UDP or TCP packet loss/retransmissions)
