  Today, SIP is a protocol par Excellence in the field of communication over
Internet. But, the fact that it belongs to the application layer constitutes a
weakness vis-a-vis the NAT traversal. This weakness is due to the way in which
the server replies to the requests of clients on the one hand. On the other, it
is caused by the dynamic allocation of UDP ports for emission and reception of
packets RTP/RTCP. The TURN Protocol may face this weakness. However, its use
requires a certain number of exchanges between the clients and a TURN server
before establishing the multimedia sessions and this increase the latent time.
In this article, we propose to adapt TURN protocol for applications based on
SIP protocol such as telephony over Internet, conference video, etc. This
adaptation optimises the establishment of multimedia sessions by integrating a
manager of TCP connections and multimedia flow controller into SIP Proxy
server.
