Le 30/12/2013 19:03, *Ali Pey* wrote:
200 OK is a proper respond in this scenario as FS did receive the Update for an existing SIP session. Codec negotiation is a different story and is negotiated through SDP (Offer/Answer).
But why does FS receive such an UPDATE request unstead of an INVITE one ? Is this because the "UPDATE" string is included in the "allow:" field it sends in its own INVITE requests ? Is it possible to have FS not including this string ? And how could I have this string not included ?
If FS responds with a 4XX response code, the call would very likely be dropped which probably be a less desired outcome.
With other UACs I use, responding 488 to an INVITE request from OVH (my VoIP provider) does not drop the call. OVH sends quickly a new INVITE with compatible SDP and the call goes on. So I should prefer to receive an INVITE... and see what happens.