Hi, AFAIK sip-router already supports async TLS (maybe I'm wrong) but devel doc still says that it's not supported:

http://sip-router.org/wiki/cookbooks/core-cookbook/devel#tcp_async

------------------------------------------------------ tcp_async Alias name: tcp_buf_write

If enabled, all the tcp writes that would block / wait for connect to finish, will be queued and attempted latter (see also tcp_conn_wq_max and tcp_wq_max).

Note: Using TLS over asynch TCP is not supported at the moment. If you use TLS you have to disable asynch TCP! -------------------------------------------------------