VOIP Over HTTP Tunnel

Hi All,

I have developed a VOIP Application, that uses PJSip to communicate over SIP channel. This application is working fine until the user is behind the proxy blocking my communication. I have searched from the different forums that there is a way called HTTP Tunneling. I want to ask you about:
- Can we achieve this through HTTP Tunneling, i.e. VOIP over HTTP Tunnel
- If yes then how?

I have looked at one of the forum there was some sample code to communicate through HTTP Tunneling, in which he first make the connection with the proxy server and passes the destination address and port in the headers of the request to the proxy, the proxy in returns establishes the connection and return 200 code. Then there was mentioned to communicate as you want as the proxy will then act as a tunnel and doesn't filters the packet being transfered.

Link: http://www.codeguru.com/cpp/i-n/interne ... php/c6209/

I am bit confused about this approach, as lets suppose we have created the connection with the proxy that internally has connected with my desired destination:
Will all the communication performed after that i.e. SIP communication will be through this HTTP Tunnel?
If not the how can i tell the PJSip to use this tunnel for communication

Please guide me in this regard. Thanking in advance.

Regards,
Ghazanfar

PJSIP has own lib for nat traversal.
http://www.pjsip.org/pjnath/docs/html/index.htm

IMHO, ICE (+STUN,TURN) is more correct way for SIP applications.