The property RTCSessionDescription.sdp is a read-only string containing the SDP which describes the session.
The value is a string containing an SDP message like this one:
v=0 o=alice 2890844526 2890844526 IN IP4 host.anywhere.com s= c=IN IP4 host.anywhere.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 m=video 51372 RTP/AVP 31 a=rtpmap:31 H261/90000 m=video 53000 RTP/AVP 32 a=rtpmap:32 MPV/90000
// The remote description has been set previously on pc, an RTCPeerConnection
alert(pc.remoteDescription.sdp);