[Users] how to get sdp data

hi openser users! i'm new in using OpenSER and new at this mailinglist, because I began working with OpenSER as part of my master thesis just a few weeks ago. So lets say "Hello" at you all! I need to get the sdp data transmitted in SIP-Three-Way handshake. Especially the IP-Adresses and Portnumbers of the RTP stream but didn't find a solution for this yet. Does anybody know a solution? Additionaly Information about what i'm doing in my master thesis: Take SDP Data mentioned above and send it from a PC running OpenSER to another PC working as IP-Router. On the IP-Router a traffic control filter will be added so that this router marks the DS-Field and priorizes the RTP-stream. So the PC with OpenSER works as a SIP-Proxy and as Policy-Server that configures the routers in a network. COPS Protocol is used for Communication between SIP-Proxy and IP-Router. Thank you very much and hope for useful answers. Stefan