code: function onSDPDescription(id,rtcId,data)
      {
          if(scope._servConn.useRTC)
          {
              if(scope.hasWebRTCSupport())
              {
                  var peer   = getOrCreatePeer(id);
                  peer.rtcId = rtcId;
                  peer.onServerMessage(JSON.parse(data));
              }
              else
              {
                  scope._servConn.sendRTCState(false,id);
              }
          }
      }
docs: invoked when received sdp offer/answer from server