Handling a=inactive on initial INVITE

General
1

Please can someone calrify for me how this flow should work in Janus.

Call is Inbound, INVITE towards Janus

initial INVITE (SDP contains a=inactive)

200OK from janus (SDP contains a=inactive)

straight after answer ACK

reINVITE (no SDP) —> Janus
200OK from Janus (SDP contains a=inactive)

I thought this flow was correct but i am being advised that the correct flow for this reINVITE should be

reINVITE (no SDP) —> Janus
200OK from Janus (SDP contains a=sendrecv)

and the reason is because there is no SDP on the reINVITE.

I could understand this if the initial INVITE contained a=sendrecv and media had been negotiated but it never has and the media channel has always been inactive.

Always happy to learn something new.

I have also been advised that this is the only scenario it does it and if this was done to a SIP Phone this flow would be handled in my 2nd example.

i hope this question is clear.

2

That has nothing to do with Janus. It’s up to the browser to do sendrecv, if you want so, when you receive the offerless re-INVITE. It’s the browser that must say if it’s capturing media, now, and whether they want to receive something too.

3

Many thanks for your reply, so the Janus SIP Gateway has no interaction with this it just passes to the browser to handle?