[Freeswitch-users] Need cluster architecture suggestion

Hi Guys, What will be the best setup architecture to handle 50k subscriber registration and approximate 30k concurrent calls? We are planning to use opensips/kamailio proxy server for load balance & to handle registration and multiple freeswitch servers to handle media. Database will be MySQL. Is this good way? OR anybody have any other proposed architecture which can be helpful? Moreover Is there any way we can change codec realtime based on internet connectivity speed? Please let us know your thoughts. Thanks in advance.