Thanks for the good advice, DanB!
I thought about this to be honest.
Yes, FS can add header with X-EndpointTransport: tls and opensisp can detect this.
But... I am still not sure how let opensips know that it should use tls instead of udp for invite to endpoint.
I tried to use
force_send_socket(tls:my_IP:5061);
But looks like I can't convert transport by this.

Will try to send by
t_relay("tls:1.2.3.4:6677");

Probably it is the question more for opensips list in this case but It is related I hope.

Will be grateful for advice
Thanks

> Date: Wed, 8 Oct 2014 11:45:48 +0200
> From: danb.lists@gmail.com
> To: freeswitch-users@lists.freeswitch.org
> Subject: Re: [Freeswitch-users] fs_path with a 'transport' parameter
>
> Hi Yuriy,
>
> We have solved this issue by adding a custom header with the transport
> OpenSIPS need to use when sending the call out (extract that info in
> OpenSIPS, eg: X-EndpointTransport: udp).
> A more elegant solution would be custom ruri params being sent out by
> FreeSWITCH, however not sure how doable that would be technically
> speaking since the transport is automatically written out from the one
> you set in fs_path.
>
> Hope this helps,
> DanB
>
> On 07.10.2014 21:06, freeswitch-users-request@lists.freeswitch.org wrote:
> > I can add transport parameter I need on FS side, but how opensips will
> > >know that it should use a different transport for INVITE to an endpoint?
>
>
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