diff --git a/demo-scripts/Sprint-4/network-change.sh b/demo-scripts/Sprint-4/network-change.sh
new file mode 100755
index 0000000..4fd49f9
--- /dev/null
+++ b/demo-scripts/Sprint-4/network-change.sh
@@ -0,0 +1,138 @@
+#! /bin/sh
+
+function Wait {
+  echo "press ret> "
+  read
+}
+
+function port_down {
+  echo "Taking down $2 port $3"
+  Wait
+  dsh -w $1 "sudo ifconfig $2-$3 down"
+  echo "done"
+}
+function port_up {
+  echo "bring up $2 port $3"
+  Wait
+  dsh -w $1 "sudo ifconfig $2-$3 up"
+  echo "done"
+}
+
+function port_change {
+  port_down $1 $2 $3
+  port_up $1 $2 $3
+}
+
+function switch_remove {
+  echo "taking switch $2 out"
+  Wait
+  dsh -w $1 "sudo ovs-vsctl set-controller $2 tcp:127.0.0.1:6639"
+  echo "done"
+}
+
+function switch_back {
+  echo "taking switch $2 back"
+  Wait
+  ctrl="tcp:127.0.0.1:6633"
+  dsh -w $1 "sudo ovs-vsctl set-controller $2 $ctrl"
+  echo "done"
+}
+function switch_go_back {
+  switch_remove $1 $2
+  switch_back $1 $2
+}
+
+function link_down {
+  echo "remove link from sw $2 port $3"
+  n=`dsh -w $1 "sudo tc qdisc show dev $2-$3" | grep netem | wc -l`
+  if [ $n -eq 1  ]; then
+    echo "dsh -w $1 sudo tc qdisc change dev $2-$3 root netem loss 100%"
+    dsh -w $1 "sudo tc qdisc change dev $2-$3 root netem loss 100%"
+  else 
+    echo "dsh -w $1 sudo tc qdisc add dev $2-$3 root netem 100%"
+    dsh -w $1 "sudo tc qdisc add dev $2-$3 root netem loss 100%"
+  fi
+  echo "done"
+}
+function link_up {
+  echo "add link from sw $2 port $3"
+  n=`dsh -w $1 "sudo tc qdisc show dev $2-$3" | grep netem | wc -l`
+  if [ $n -eq 1  ]; then
+    echo "dsh -w $1 sudo tc qdisc change dev $2-$3 root netem loss 0%"
+    dsh -w $1 "sudo tc qdisc change dev $2-$3 root netem loss 0%"
+  else 
+    echo "dsh -w $1 sudo tc qdisc add dev $2-$3 root netem loss 0%"
+    dsh -w $1 "sudo tc qdisc add dev $2-$3 root netem loss 0%"
+  fi
+  echo "done"
+}
+function link_change {
+  link_down $1 $2 $3
+  link_up $1 $2 $3
+}
+
+function ilink_down {
+  echo "remove link from $2"
+  n=`dsh -w $1 "sudo tc qdisc show dev $2" | grep netem | wc -l`
+  if [ $n -eq 1  ]; then
+    echo "dsh -w $1 sudo tc qdisc change dev $2 root netem loss 100%"
+    dsh -w $1 "sudo tc qdisc change dev $2 root netem loss 100%"
+  else 
+    echo "dsh -w $1 sudo tc qdisc add dev $2 root netem 100%"
+    dsh -w $1 "sudo tc qdisc add dev $2 root netem loss 100%"
+  fi
+  echo "done"
+}
+function ilink_up {
+  echo "add link at $2"
+  n=`dsh -w $1 "sudo tc qdisc show dev $2" | grep netem | wc -l`
+  if [ $n -eq 1  ]; then
+    echo "dsh -w $1 sudo tc qdisc change dev $2 root netem loss 0%"
+    dsh -w $1 "sudo tc qdisc change dev $2 root netem loss 0%"
+  else 
+    echo "dsh -w $1 sudo tc qdisc add dev $2 root netem loss 0%"
+    dsh -w $1 "sudo tc qdisc add dev $2 root netem loss 0%"
+  fi
+  echo "done"
+}
+function ilink_change {
+  ilink_down $1 $2
+  ilink_up $1 $2
+}
+
+
+#port_change onos9vpc swa1 eth2
+#port_change onos10vpc swb3 eth4
+#port_change onos11vpc swc5 eth2
+
+#switch_go_back onos9vpc swa1
+#switch_go_back onos10vpc swb3
+#switch_go_back onos11vpc swc3
+
+#echo "link down between swa4 and swa3"
+#Wait
+#link_down onos9vpc swa4 eth2 
+#link_down onos9vpc swa3 eth4 
+#echo "link up between swa4 and swa3"
+Wait
+link_up onos9vpc swa3 eth4 
+link_up onos9vpc swa4 eth2 
+
+echo "link down between swb4 and swb3"
+Wait
+link_down onos10vpc swb4 eth2 
+link_down onos10vpc swb3 eth4 
+echo "link down between swb4 and swb3"
+Wait
+link_up onos10vpc swb3 eth4 
+link_up onos10vpc swb4 eth2 
+
+echo "link down between network 1 and network2"
+Wait
+ilink_down onos9vpc tapa0 
+ilink_down onos10vpc tapb0 
+
+echo "link up between network 1 and network2"
+Wait
+ilink_up onos10vpc tapb0 
+ilink_up onos9vpc tapa0