> The a=encryption:optional tag is a Microsoft extension held over(Snom has
> removed it in recent beta builds I have).  We do not support it and will not. 
> Grandstream uses RTP/SAVP, Snom will be doing RTP/SAVP in 7.1.33 (in beta),
> Polycom does the dual m= line for RTP/SAVP and RTP/AVP.  Offering crypto in an
> RTP/AVP is wrong please refer to RFC3711 where it clearly states "The RTP
> specification establishes a registry of profile names for use by higher-level
> control protocols, such as the Session Description Protocol (SDP), to refer to
> transport methods. This profile registers the name "RTP/SAVP"."
 
I understand. It is clear for me.
 
> Chris,Heiko and I have had a few exchanges in email...
> He's a verynice guy very preceptive to the changes required to support
> this properly.  He said he'll be trying out the two m-linemethod soon.
 
Great news :)
 
Chris