diff --git a/core/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java b/core/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java
index 06f62d7c095..83c288926bd 100644
--- a/core/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java
+++ b/core/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java
@@ -3832,7 +3832,7 @@ public abstract class CitrixResourceBase implements ServerResource {
     		Network nw = setupvSwitchNetwork(conn);
     		String bridge = nw.getBridge(conn);
     		String result = callHostPlugin(conn, "vmops", "ovs_delete_flow", "bridge", bridge,
-    				"vmName", cmd.getVmName());
+    				"vmName", cmd.getVmName(), "reCreate", "true");
     		
     		if (result.equalsIgnoreCase("SUCCESS")) {
     			return new Answer(cmd, true, "success to delete flows for " + cmd.getVmName());
diff --git a/scripts/vm/hypervisor/xenserver/vlanRemapUtils.py b/scripts/vm/hypervisor/xenserver/vlanRemapUtils.py
index 0f582d89dba..322d347007c 100644
--- a/scripts/vm/hypervisor/xenserver/vlanRemapUtils.py
+++ b/scripts/vm/hypervisor/xenserver/vlanRemapUtils.py
@@ -506,13 +506,21 @@ def doAskPorts(bridge, vifNames):
 
 	return ",".join(ofports)
 
-def doDeleteFlow(bridge, ofports, macs, remap):
+def doDeleteFlow(bridge, ofports, macs, remap, reCreate):
 	for i in macs.split(","):
 		delFlow(i)
 		log("Delete flows for %s" % i)
 
 	remap = strip(remap)
 
+	if reCreate == "false":
+		for j in remap.split("/"):
+			delARPFlow(j)
+			delDHCPFlow(j)
+			delDHCPClientFlow(j)
+			delDropFlow(j)
+		return
+
 	# remove our port from arp flow
 	inport = getGreOfPorts(bridge)
 	if len(inport) == 0:
@@ -589,12 +597,13 @@ if __name__ == "__main__":
 		doCreateFlow(bridge, vifName, mac, remap)
 		sys.exit(0)
 	elif op == "deleteFlow":
-		checkArgNum(6)
+		checkArgNum(7)
 		bridge = sys.argv[2]
 		ofports = sys.argv[3]
 		macs = sys.argv[4]
 		remap = sys.argv[5]
-		doDeleteFlow(bridge, ofports, macs, remap)
+		reCreate = sys.argv[6]
+		doDeleteFlow(bridge, ofports, macs, remap, reCreate)
 	elif op == "setTag":
 		checkArgNum(5)
 		bridge = sys.argv[2]
diff --git a/scripts/vm/hypervisor/xenserver/vmops b/scripts/vm/hypervisor/xenserver/vmops
index 69cde7f9880..2781fa081ad 100755
--- a/scripts/vm/hypervisor/xenserver/vmops
+++ b/scripts/vm/hypervisor/xenserver/vmops
@@ -723,6 +723,7 @@ def ovs_write_vm_log(bridge, vmName, vmId, seqno, vifNames, macs, tag, vlans, of
 def ovs_delete_flow(session, args):
     bridge = args.pop('bridge')
     vm_name = args.pop('vmName')
+    reCreate = args.pop('reCreate')
 
     macs = ovs_get_mac_info_from_log(vm_name)
     vlans = ovs_get_vlans_info_from_log(vm_name)
@@ -732,7 +733,7 @@ def ovs_delete_flow(session, args):
         return 'ERROR_LOG'
 
     vlanRemapUtils(session, {"op":"deleteFlow", "bridge":bridge, \
-            "ofports":ofports, "macs":macs, "remap":vlans})
+            "ofports":ofports, "macs":macs, "remap":vlans, "reCreate":reCreate})
 
     remove_ovs_log_for_vm(vm_name)
     return 'SUCCESS'
@@ -779,7 +780,7 @@ def ovs_set_tag_and_flow(session, args):
         return 'SUCCESS'
 
     #delete old flows first
-    ovs_delete_flow(session, {"bridge":bridge, "vmName":vm_name})
+    ovs_delete_flow(session, {"bridge":bridge, "vmName":vm_name, "reCreate":"false"})
 
     if vlanStr.startswith("/"): vlanStr = vlanStr[1:]
     if vlanStr.endswith("/"): vlanStr = vlanStr[:-1]
diff --git a/server/src/com/cloud/network/ovs/OvsNetworkManagerImpl.java b/server/src/com/cloud/network/ovs/OvsNetworkManagerImpl.java
index 0481a0d8c64..7dd23eb6170 100644
--- a/server/src/com/cloud/network/ovs/OvsNetworkManagerImpl.java
+++ b/server/src/com/cloud/network/ovs/OvsNetworkManagerImpl.java
@@ -182,16 +182,20 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 			return;
 		}
 		Long userVmId = work.getInstanceId();
-		UserVm vm = null;
+		VirtualMachine vm = null;
 		Long seqnum = null;
+		Long vmId = work.getInstanceId();
 		s_logger.info("Ovs working on " + work.toString());
 		final Transaction txn = Transaction.currentTxn();
 		txn.start();
 		try {
-			vm = _userVMDao.acquireInLockTable(work.getInstanceId());
+			vm = _userVMDao.acquireInLockTable(vmId);
 			if (vm == null) {
-				s_logger.warn("Ovs unable to acquire lock on vm id=" + userVmId);
-				return ;
+				vm = _routerDao.acquireInLockTable(vmId);
+				if (vm == null) {
+					s_logger.warn("Ovs unable to acquire lock on vm id=" + userVmId);
+					return ;
+				}		
 			}
 			
 			String vlans = getVlanMapping(vm.getAccountId());
@@ -224,7 +228,14 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 			}
 		} finally {
 			if (vm != null) {
-				_userVMDao.releaseFromLockTable(userVmId);
+				if (vm.getType() == VirtualMachine.Type.User) {
+					_userVMDao.releaseFromLockTable(vmId);
+				} else if (vm.getType() == VirtualMachine.Type.DomainRouter) {
+					_routerDao.releaseFromLockTable(vmId);
+				} else {
+					assert 1 == 0 : "Should not be here";
+				}
+				
 				_workDao.updateStep(work.getId(),  Step.Done);
 			}
 			txn.commit();
@@ -382,6 +393,10 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 			return;
 		}
 		
+		if (instance.getType() == VirtualMachine.Type.DomainRouter) {
+			return;
+		}
+		
 		long accountId = instance.getAccountId();
 		DomainRouterVO router = _routerDao.findBy(accountId, instance.getDataCenterId());
 		if (router == null) {
@@ -452,7 +467,13 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 				 _workDao.update(work.getId(), work);	
 			} finally {
 				if (vm != null) {
-					_userVMDao.releaseFromLockTable(vmId);
+					if (vm.getType() == VirtualMachine.Type.User) {
+						_userVMDao.releaseFromLockTable(vmId);
+					} else if (vm.getType() == VirtualMachine.Type.DomainRouter) {
+						_routerDao.releaseFromLockTable(vmId);
+					} else {
+						assert 1 == 0 : "Should not be here";
+					}
 				}
 			}
 			txn.commit();
@@ -500,6 +521,7 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 		final Transaction txn = Transaction.currentTxn();
 		txn.start();
 		VlanMappingVO vo = _vlanMappingDao.findByAccountIdAndHostId(accountId, hostId);
+		assert vo!=null: "Why there is no record for account " + accountId + " host " + hostId;
 		if (vo.unref() == 0) {
 			_vlanMappingDao.remove(vo.getId());
 			_vlanMappingDirtyDao.markDirty(accountId);
@@ -622,7 +644,7 @@ public class OvsNetworkManagerImpl implements OvsNetworkManager {
 		}
 		
 		if (vmIds.size() > 0) {
-			scheduleFlowUpdateToHosts(vmIds, true, null);
+			scheduleFlowUpdateToHosts(vmIds, false, null);
 		}
 	}
 
diff --git a/server/src/com/cloud/network/ovs/dao/VlanMappingVO.java b/server/src/com/cloud/network/ovs/dao/VlanMappingVO.java
index 6f1cbf738be..3376c05e465 100644
--- a/server/src/com/cloud/network/ovs/dao/VlanMappingVO.java
+++ b/server/src/com/cloud/network/ovs/dao/VlanMappingVO.java
@@ -64,10 +64,12 @@ public class VlanMappingVO {
 	
 	public void ref() {
 		ref++;
+		setRef(ref);
 	}
 	
 	public int unref() {
 		ref--;
-		return ref;
+		setRef(ref);
+		return getRef();
 	}
 }