Are multiple 183s from the endpoint that changes the SDP allowed? I'm under the impression this is broken, similar to http://wiki.freeswitch.org/wiki/NDLB#NDLB-allow-nondup-sdp
... which is why when the codec changes, FS freaks out and cancels the call because of codec negotiation error.
Does that NDLB flag allow this, too?

First has: audio 10116 RTP/AVP 0 101 13
Second has:  audio 49020 RTP/AVP 8 13 101
PCAP: http://ge.tt/7MpyBwJ

Can someone point me to the specific RFC so I can tell the supplier to fix it?
And just curious.. what would make this allowed? A re-INVITE..?

-Avi