diff --git a/server/src/com/cloud/network/NetworkServiceImpl.java b/server/src/com/cloud/network/NetworkServiceImpl.java
index 2bf9f402d34..29a36b9fe5f 100755
--- a/server/src/com/cloud/network/NetworkServiceImpl.java
+++ b/server/src/com/cloud/network/NetworkServiceImpl.java
@@ -3044,6 +3044,7 @@ public class NetworkServiceImpl extends ManagerBase implements  NetworkService {
             _accountGuestVlanMapDao.update(guestVlanMapId, accountGuestVlanMapVO);
         } else {
             Transaction txn = Transaction.currentTxn();
+            txn.start();
             accountGuestVlanMapVO = new AccountGuestVlanMapVO(vlanOwner.getAccountId(), physicalNetworkId);
             accountGuestVlanMapVO.setGuestVlanRange(startVlan + "-" +  endVlan);
             _accountGuestVlanMapDao.persist(accountGuestVlanMapVO);