--- a/src/main/java/jp/ac/u_ryukyu/treevnc/FindRoot.java	Mon Feb 18 17:33:49 2019 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/treevnc/FindRoot.java	Mon Feb 18 18:33:48 2019 +0900
@@ -73,6 +73,25 @@
 		soc.close();
 	}
 
+	public void multicastUpdateRectangle(ByteBuffer buf) {
 
+		try {
+			DatagramPacket sendPacket = new DatagramPacket(buf.array
+					(), buf.limit(), InetAddress.getByName(TreeRootFinderListener.Ipv6McastAddr), ConnectionParams.DEFAULT_VNC_ROOT_FINDER);
+			soc.send(sendPacket);
+		} catch (IOException e) {
+			System.out.println("cannot send UpdateRectangle.");
+			e.printStackTrace();
+		}
+
+		try {
+			DatagramPacket sendPacket1 = new DatagramPacket(buf.array(), buf.limit(), InetAddress.getByName(TreeRootFinderListener.Ipv4McastAddr), ConnectionParams.DEFAULT_VNC_ROOT_FINDER);
+			soc.send(sendPacket1);
+		} catch (IOException e) {
+			System.out.println("cannot send UpdateRectangle.");
+			e.printStackTrace();
+		}
+		soc.close();
+	}
 
 }