[asterisk-users] asterisk tries reinvite when incompatible codecs on call legs

[Frederic Van Espen]

Hi,

I just ran into what seems to be an issue on re-invites. I'm not sure if
it's a bug or as designed, so I thought I'd ask the question.

Here's my setup:
- Asterisk 1.8.13.0
- Phone A: Polycom ip331, only allowed to use ulaw, canreinvite=yes
- Phone B: Polycom ip330, only allowed to use alaw, canreinvite=yes

Phone A calls the extension of phone B.

After the normal call setup asterisk tries the reinvite:
- To phone B it sends an SDP which asks alaw and connection information
of phone A
- To phone A it sends and SDP with only the connection information of
phone B

Phone A responds to this with a 488 Not acceptable here.

Asterisk ACK's and sends another set of reinvites to both phones with
the correct codecs and connection information (the asterisk box itself).

Both phones reply 200 OK. Asterisk ACK's and immediately sends BYE to
both phones.

Is this normal behaviour? I would expect one of two things:
- Asterisk intelligently does not even try reinvite because of the
incompatible codecs.
- Asterisk tries the reinvite anyway, but does not end the call if it
fails.

To be sure, I also tested this on asterisk 1.8.15.0 and
certified-asterisk-1.8.11-cert4. Both have the same result.

Any help would be very appreciated!

Cheers,

Frederic Van Espen