Symptom
CUBE received INVITE with G.723 and send out INVITE with G.729 incorrectly.
SDP of the incoming INVITE
m=audio 6000 RTP/AVP 8 0 4 101
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:4 G723/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
SDP of the outgoing INVITE
m=audio 26788 RTP/AVP 8 0 18 101
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=ptime:20
the following voice class is configured under both incoming and outgoing dial peer.
voice class codec 1
codec preference 1 g711alaw
codec preference 2 g711ulaw
codec preference 3 g722-64
codec preference 4 g729r8
codec preference 5 ilbc
codec preference 6 clear-channel
Conditions
voice-class codec which not include G.723 is configured on both incoming and outgoing dial peer
