diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingArpHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingArpHandler.java
index c711ded..304258f 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingArpHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingArpHandler.java
@@ -871,6 +871,11 @@
         }
 
         private void setDefaultArpRule(OpenstackNode osNode, boolean install) {
+
+            if (getArpMode() == null) {
+                return;
+            }
+
             switch (getArpMode()) {
                 case ARP_PROXY_MODE:
                     setDefaultArpRuleForProxyMode(osNode, install);
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
index 16a3e28..a831216 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
@@ -478,15 +478,15 @@
     private void setInternalRoutes(Router osRouter, Subnet updatedSubnet, boolean install) {
         Network updatedNetwork = osNetworkAdminService.network(updatedSubnet.getNetworkId());
         Set<Subnet> routableSubnets = routableSubnets(osRouter, updatedSubnet.getId());
-        String updatedSegmendId = getSegmentId(updatedSubnet);
+        String updatedSegmentId = getSegmentId(updatedSubnet);
 
         // installs rule from/to my subnet intentionally to fix ICMP failure
         // to my subnet gateway if no external gateway added to the router
         osNodeService.completeNodes(COMPUTE).forEach(cNode -> {
             setInternalRouterRules(
                     cNode.intgBridge(),
-                    updatedSegmendId,
-                    updatedSegmendId,
+                    updatedSegmentId,
+                    updatedSegmentId,
                     IpPrefix.valueOf(updatedSubnet.getCidr()),
                     IpPrefix.valueOf(updatedSubnet.getCidr()),
                     updatedNetwork.getNetworkType(),
@@ -496,7 +496,7 @@
             routableSubnets.forEach(subnet -> {
                 setInternalRouterRules(
                         cNode.intgBridge(),
-                        updatedSegmendId,
+                        updatedSegmentId,
                         getSegmentId(subnet),
                         IpPrefix.valueOf(updatedSubnet.getCidr()),
                         IpPrefix.valueOf(subnet.getCidr()),
@@ -506,7 +506,7 @@
                 setInternalRouterRules(
                         cNode.intgBridge(),
                         getSegmentId(subnet),
-                        updatedSegmendId,
+                        updatedSegmentId,
                         IpPrefix.valueOf(subnet.getCidr()),
                         IpPrefix.valueOf(updatedSubnet.getCidr()),
                         updatedNetwork.getNetworkType(),
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
index 11b22fd..672ce8b 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
@@ -61,7 +61,6 @@
 import org.onosproject.openstacknetworking.api.OpenstackSecurityGroupListener;
 import org.onosproject.openstacknetworking.api.OpenstackSecurityGroupService;
 import org.onosproject.openstacknetworking.util.RulePopulatorUtil;
-import org.onosproject.openstacknode.api.OpenstackNode;
 import org.onosproject.openstacknode.api.OpenstackNodeEvent;
 import org.onosproject.openstacknode.api.OpenstackNodeListener;
 import org.onosproject.openstacknode.api.OpenstackNodeService;
@@ -611,23 +610,21 @@
     private void resetSecurityGroupRules() {
 
         if (useSecurityGroup) {
-            osNodeService.completeNodes(OpenstackNode.NodeType.COMPUTE)
-                    .forEach(node -> osFlowRuleService
-                            .setUpTableMissEntry(node.intgBridge(), ACL_TABLE));
+            osNodeService.completeNodes(COMPUTE).forEach(node -> {
+                osFlowRuleService.setUpTableMissEntry(node.intgBridge(), ACL_TABLE);
+                initializeConnTrackTable(node.intgBridge(), true);
+            });
+
             securityGroupService.securityGroups().forEach(securityGroup ->
                     securityGroup.getRules().forEach(this::securityGroupRuleAdded));
-            osNodeService.nodes().stream()
-                    .filter(node -> node.type().equals(OpenstackNode.NodeType.COMPUTE))
-                    .forEach(node -> initializeConnTrackTable(node .intgBridge(), true));
         } else {
-            osNodeService.completeNodes(OpenstackNode.NodeType.COMPUTE)
-                    .forEach(node -> osFlowRuleService
-                            .connectTables(node.intgBridge(), ACL_TABLE, JUMP_TABLE));
+            osNodeService.completeNodes(COMPUTE).forEach(node -> {
+                osFlowRuleService.connectTables(node.intgBridge(), ACL_TABLE, JUMP_TABLE);
+                initializeConnTrackTable(node.intgBridge(), false);
+            });
+
             securityGroupService.securityGroups().forEach(securityGroup ->
                     securityGroup.getRules().forEach(this::securityGroupRuleRemoved));
-            osNodeService.nodes().stream()
-                    .filter(node -> node.type().equals(OpenstackNode.NodeType.COMPUTE))
-                    .forEach(node -> initializeConnTrackTable(node.intgBridge(), false));
         }
 
         log.info("Reset security group info " +
@@ -933,22 +930,9 @@
 
         @Override
         public void event(OpenstackNodeEvent event) {
-            OpenstackNode osNode = event.subject();
-
             switch (event.type()) {
                 case OPENSTACK_NODE_COMPLETE:
-                    eventExecutor.execute(() -> {
-                        try {
-                            if (useSecurityGroup) {
-                                initializeConnTrackTable(osNode.intgBridge(), true);
-                                log.info("SG table initialization : {} is done",
-                                                            osNode.intgBridge());
-                            }
-                        } catch (IllegalArgumentException e) {
-                            log.error("ACL table initialization error : {}",
-                                                            e.getMessage());
-                        }
-                    });
+                    resetSecurityGroupRules();
                     break;
                 case OPENSTACK_NODE_CREATED:
                 case OPENSTACK_NODE_REMOVED: