Added option in sip.conf:
autoframing=yes/no
Can be set for peer/user or globally.
If this option is set, asterisk trying to use framing as suggested by remote side.
If there is no information in SDP, manually configured values will be used.
Manually, framing for user/peer or globally, can be set this way:
allow=codec:framing
for example:
allow=g729:40 ;means that asterisk must send 40ms g729 packets on incoming/outgoing calls for this peer/user
If nothing is specified, default values will be used.