if
a=rtcp:<port> did not exist in incoming sdp, there is no need for
rtpengine to add it, because then, by default, rtcp port is one larger
than rtp port.
ICE mandates that the a=rtcp attribute is present, even if the RTCP port
is the default one.
I did check ice rfc 5245 and didn't find such requirement. Word "rtcp"
does not exist in the rfc and its ice sdp example does not include rtcp
attribute:
v=0
o=jdoe 2890844526 2890842807 IN IP4 10.0.1.1
s=
c=IN IP4 192.0.2.3
t=0 0
a=ice-pwd:asd88fgpdd777uzjYhagZg
a=ice-ufrag:8hhY
m=audio 45664 RTP/AVP 0
b=RS:0
b=RR:0
a=rtpmap:0 PCMU/8000
a=candidate:1 1 UDP 2130706431 10.0.1.1 8998 typ host
a=candidate:2 1 UDP 1694498815 192.0.2.3 45664 typ srflx raddr 10.0.1.1 rport 8998
Where did you find the requirement? Is it in some other rfc?
-- Juha