I have some issues with SRTP and FreeSWITCH. After a successful call after a period of time, call is hungup due to bad authentication. It looks the phone is starting to rekey but is not "telling" the server back. Can you provide me with some more information about what is the rekey time? SDP crypto line seems to always remain same here. I have tried using snom models and I could talk hours with sdp line changing.