diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 75a3567..5d339a0 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -392,8 +392,8 @@
         openstack --os-cloud devstack-admin --os-region "$REGION_NAME" router set --external-gateway $EXT_NET_ID $ROUTER_ID
     fi
 
-    # This logic is specific to using the l3-agent for layer 3
-    if is_service_enabled q-l3 || is_service_enabled neutron-l3; then
+    # This logic is specific to using OVN or the l3-agent for layer 3
+    if ([[ $Q_AGENT == "ovn" ]] && is_service_enabled q-svc neutron-server) || is_service_enabled q-l3 neutron-l3; then
         # if the Linux host considers itself to be a router then it will
         # ignore all router advertisements
         # Ensure IPv6 RAs are accepted on interfaces with a default route.
@@ -420,6 +420,11 @@
 
             # Configure interface for public bridge
             sudo ip -6 addr replace $ipv6_ext_gw_ip/$ipv6_cidr_len dev $ext_gw_interface
+            # Any IPv6 private subnet that uses the default IPV6 subnet pool
+            # and that is plugged into the default router (Q_ROUTER_NAME) will
+            # be reachable from the devstack node (ex: ipv6-private-subnet).
+            # Some scenario tests (such as octavia-tempest-plugin) rely heavily
+            # on this feature.
             local replace_range=${SUBNETPOOL_PREFIX_V6}
             if [[ -z "${SUBNETPOOL_V6_ID}" ]]; then
                 replace_range=${FIXED_RANGE_V6}