diff --git a/ctrl-add-ext.sh b/ctrl-add-ext.sh
new file mode 100755
index 0000000..c8e7d25
--- /dev/null
+++ b/ctrl-add-ext.sh
@@ -0,0 +1,20 @@
+#! /bin/bash
+controller="localhost onos9vpc onos10vpc onos11vpc"
+me=`hostname`
+controller=`echo $controller | sed "s/$me//g"`
+switches=`ifconfig -a | grep sw |grep -v eth | awk '{print $1}'`
+
+function host2ip (){
+   ip=`grep $1 /etc/hosts |grep -v "ip6"|  awk '{print $1}'`
+   echo $ip
+}
+
+url=""
+for c in $controller; do
+  url="$url tcp:`host2ip $c`:6633"
+done
+echo $url
+for s in $switches; do
+    echo "set switch $s controller $url"
+    sudo ovs-vsctl set-controller $s $url
+done