Hello,

I think I met a case similar to the one solved by [1] . Quoting this case :

* res_pjsip: Handle deferred SDP hold/unhold properly.

Some SIP devices indicate hold/unhold using deferred SDP reinvites. In
other words, they provide no SDP in the reinvite.

A typical transaction that starts hold might look something like this:

* Device sends reinvite with no SDP
* Asterisk sends 200 OK with SDP indicating sendrecv on streams.
* Device sends ACK with SDP indicating sendonly on streams.

Now, I would like to configure an Asterisk instance to act as those SIP
devices, ie to defer all SDP signaling in ACK.

This is for testing purpose as I would like to reproduce in a lab an issue with those SIP devices.

1. Is it possible ? I can use any Asterisk version for implementation.
2. Alternatively, do you know any softphone “implementing SDP in ACK” ?
3. Alternatively, do you know any SIP hardphone implementing this ?
4. Suggestions ?

[1]
http://lists.digium.com/pipermail/asterisk-code-review/2016-April/019483.html

Cheers