Hello, I have the following scenario. 1. Client send request to port A of Server. 2. Server sends reply and ask Client to send request to port B. 3. Client sends request to port B. I am confused how to send the request to port B. I am looking into the function "regc_tsx_callback" in file sip_reg.c. Any help would be highly appreciated. Best Regards, Muhammad Usman Shahid, Engineer National University of Sciences and Technology, School of Electrical Engineering and Computer Sciences.