The protocol property of the RTCIceCandidateStats dictionary indicates the protocol the specified candidate would use for communication with the remote peer.
The value is one of the following strings:
tcpThe candidate, if selected, would use TCP as the transport protocol for its data. The tcpType property provides additional information about the kind of TCP candidate represented by the object.
udpThe candidate will use the UDP transport protocol for its data. This is the preferred protocol for media interactions because of its better performance profile.