[asterisk-users] VPN As SIP Tunneling?

[Barry Fawthrop]

Hi All

Could a VPN be used to help with SIP Tunneling and QoS issues.

State 1:
Two IP Networks Connected via the Public Internet transmitting VoIP Traffic
Say a VoIP User and VoIP Termination Provider.
Each side can put QoS onto their part, but if QoS does NOT exist between 
them
then call quality will be bad anyhow.

State 2:
Same as above except a VPN tunnel is setup between each side.
Thus making them appear on the same network and possibly same subnet.

(1) Would this now traceroute a one hop ?
(2) Would this have a lower or higher ping time, thus latency ?
(3) With the additional Encryption etc.. if using a 1 Mbps Internet 
connection
    What would the "actual" amount available now be 700kbps, in other words
    How much overhead is there with a VPN tunnel that would reduce the 
available bandwidth ?


Thanks to all