diff --git a/devstack/lib/ovn_agent b/devstack/lib/ovn_agent
index db488634950..e44112f6fc5 100644
--- a/devstack/lib/ovn_agent
+++ b/devstack/lib/ovn_agent
@@ -260,7 +260,7 @@ function create_public_bridge {
     ovs-vsctl set open . external-ids:ovn-bridge-mappings=$PHYSICAL_NETWORK:$ext_gw_ifc
     if [ -n "$FLOATING_RANGE" ]; then
         local cidr_len=${FLOATING_RANGE#*/}
-        sudo ip addr add $PUBLIC_NETWORK_GATEWAY/$cidr_len dev $ext_gw_ifc
+        sudo ip addr replace $PUBLIC_NETWORK_GATEWAY/$cidr_len dev $ext_gw_ifc
     fi
 
     # Ensure IPv6 RAs are accepted on the interface with the default route.
@@ -274,7 +274,7 @@ function create_public_bridge {
     sudo sysctl -w net.ipv6.conf.all.forwarding=1
     if [ -n "$IPV6_PUBLIC_RANGE" ]; then
         local ipv6_cidr_len=${IPV6_PUBLIC_RANGE#*/}
-        sudo ip -6 addr add $IPV6_PUBLIC_NETWORK_GATEWAY/$ipv6_cidr_len dev $ext_gw_ifc
+        sudo ip -6 addr replace $IPV6_PUBLIC_NETWORK_GATEWAY/$ipv6_cidr_len dev $ext_gw_ifc
         # NOTE(numans): Commenting the below code for now as this is breaking
         # the CI after xenial upgrade.
         # https://bugs.launchpad.net/networking-ovn/+bug/1648670
diff --git a/devstack/plugin.sh b/devstack/plugin.sh
index 7bd1ea52aed..71dd93b6ee2 100644
--- a/devstack/plugin.sh
+++ b/devstack/plugin.sh
@@ -116,15 +116,6 @@ if [[ "$1" == "stack" ]]; then
                 configure_ovn_plugin
                 start_ovn
             fi
-            if is_service_enabled br-ex-tcpdump ; then
-                # tcpdump monitor on br-ex for ARP, reverse ARP and ICMP v4 / v6 packets
-                sudo ip link set dev $PUBLIC_BRIDGE up
-                run_process br-ex-tcpdump "/usr/sbin/tcpdump -i $PUBLIC_BRIDGE arp or rarp or icmp or icmp6 -enlX" "$STACK_GROUP" root
-            fi
-
-            if is_service_enabled br-int-flows ; then
-                run_process br-int-flows "/bin/sh -c \"set +e; while true; do echo ovs-ofctl dump-flows br-int; ovs-ofctl dump-flows br-int ; sleep 30; done; \"" "$STACK_GROUP" root
-            fi
             ;;
         extra)
             if is_service_enabled q-sriov-agt neutron-sriov-agent; then
@@ -141,6 +132,15 @@ if [[ "$1" == "stack" ]]; then
                     fi
                 fi
             fi
+            if is_service_enabled br-ex-tcpdump ; then
+                # tcpdump monitor on br-ex for ARP, reverse ARP and ICMP v4 / v6 packets
+                sudo ip link set dev $PUBLIC_BRIDGE up
+                run_process br-ex-tcpdump "/usr/sbin/tcpdump -i $PUBLIC_BRIDGE arp or rarp or icmp or icmp6 -enlX" "$STACK_GROUP" root
+            fi
+
+            if is_service_enabled br-int-flows ; then
+                run_process br-int-flows "/bin/sh -c \"set +e; while true; do echo ovs-ofctl dump-flows br-int; ovs-ofctl dump-flows br-int ; sleep 30; done; \"" "$STACK_GROUP" root
+            fi
             ;;
     esac
 elif [[ "$1" == "unstack" ]]; then