UAS Astersik start re_invite after 900s (15min)

Invite receive to Asterisk with :
Session-Expires: 1800;refresher=uac
Min-SE: 90
Supported: timer, 100rel

But Asterisk (UAS) start re_invite after 900s (15 min)

In the sip cofig I set canreinvite = NO & nat=NO

Where is asterisk ‘refresh the invite after 15 min’ set?
Why asterisk send re_invite to UAC while in invite packet set refresher=uac ?
Only when I set session-timer=refused asterisk stop sending re_invite after 15 min.
I test it in both asterisk version 11 & 13 both same

Thanks in advance for your help

canreinvite is deprecated, because it suggests it applies to all re-invites. It is now called directmedia.

You are describing correct behaviour. If a peer refreshed a session exactly on the 1800 mark, network delays would take it over the limit, and packet losses and retransmissions would do so even more.

1800 is the drop dead time, not the time for the actual refresh.

RFC 4028 has this wording in two places:

It is RECOMMENDED that this refresh be sent once half the session interval
has elapsed. Additional procedures for this refresh are described in
Section 10.


Thank you David for advice. It was very helpful.
Is there any way to change the refresh time to more/less than half of the session interval elapsed?