Next we have the ICE lines, which is the mechanism chosen for NAT traversal in WebRTC. You can find a very didactic and comprehensive explanation of ICE here. ICE is complex enough to deserve its own post, but I will try to explain its SDP lines in an understandable way.
These lines are the same as the two ICE lines before but for TCP traffic. Please note that the priority is the lowest – i.e 1509957375 is larger - as TCP is not optimal for real-time media transportation.