diff --git a/api/src/main/java/com/cloud/network/NetworkModel.java b/api/src/main/java/com/cloud/network/NetworkModel.java
index eb496ac4e0b..c212e6319eb 100644
--- a/api/src/main/java/com/cloud/network/NetworkModel.java
+++ b/api/src/main/java/com/cloud/network/NetworkModel.java
@@ -125,6 +125,10 @@ public interface NetworkModel {
      */
     String getNextAvailableMacAddressInNetwork(long networkConfigurationId) throws InsufficientAddressCapacityException;
 
+    String getUniqueMacAddress(long macAddress, long networkId, long datacenterId) throws InsufficientAddressCapacityException;
+
+    boolean isMACUnique(String mac, long networkId);
+
     PublicIpAddress getPublicIpAddress(long ipAddressId);
 
     List<? extends Vlan> listPodVlans(long podId);
@@ -364,4 +368,8 @@ public interface NetworkModel {
 
     boolean checkSecurityGroupSupportForNetwork(Account account, DataCenter zone, List<Long> networkIds,
                                                 List<Long> securityGroupsIds);
+
+    default long getMacIdentifier(Long dataCenterId) {
+        return 0;
+    }
 }
diff --git a/engine/components-api/src/main/java/com/cloud/network/addr/PublicIp.java b/engine/components-api/src/main/java/com/cloud/network/addr/PublicIp.java
index 7132094ce11..54a99fdf367 100644
--- a/engine/components-api/src/main/java/com/cloud/network/addr/PublicIp.java
+++ b/engine/components-api/src/main/java/com/cloud/network/addr/PublicIp.java
@@ -40,7 +40,11 @@ public class PublicIp implements PublicIpAddress {
     }
 
     public static PublicIp createFromAddrAndVlan(IPAddressVO addr, VlanVO vlan) {
-        return new PublicIp(addr, vlan, NetUtils.createSequenceBasedMacAddress(addr.getMacAddress(), NetworkModel.MACIdentifier.value()));
+        long macIdentifier = NetworkModel.MACIdentifier.valueIn(addr.getDataCenterId());
+        if (macIdentifier == 0) {
+            macIdentifier = addr.getDataCenterId();
+        }
+        return new PublicIp(addr, vlan, NetUtils.createSequenceBasedMacAddress(addr.getMacAddress(), macIdentifier));
     }
 
     @Override
@@ -279,5 +283,4 @@ public class PublicIp implements PublicIpAddress {
     public boolean isForRouter() {
         return _addr.isForRouter();
     }
-
 }
diff --git a/engine/orchestration/src/main/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestrator.java b/engine/orchestration/src/main/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestrator.java
index ebf3415b2f2..d1ab423bc6b 100644
--- a/engine/orchestration/src/main/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestrator.java
+++ b/engine/orchestration/src/main/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestrator.java
@@ -1283,7 +1283,7 @@ public class NetworkOrchestrator extends ManagerBase implements NetworkOrchestra
         nicProfile.setIPv4Gateway(ipv4Gateway);
         nicProfile.setIPv4Netmask(ipv4Netmask);
 
-        if (nicProfile.getMacAddress() == null) {
+        if (nicProfile.getMacAddress() == null || !_networkModel.isMACUnique(nicProfile.getMacAddress(), network.getId())) {
             try {
                 String macAddress = _networkModel.getNextAvailableMacAddressInNetwork(network.getId());
                 nicProfile.setMacAddress(macAddress);
diff --git a/engine/orchestration/src/test/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestratorTest.java b/engine/orchestration/src/test/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestratorTest.java
index a95f0e36475..e3989737112 100644
--- a/engine/orchestration/src/test/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestratorTest.java
+++ b/engine/orchestration/src/test/java/org/apache/cloudstack/engine/orchestration/NetworkOrchestratorTest.java
@@ -396,6 +396,7 @@ public class NetworkOrchestratorTest extends TestCase {
         when(testOrchestrator._ipAddressDao.acquireInLockTable(Mockito.anyLong())).thenReturn(ipVoSpy);
         when(testOrchestrator._ipAddressDao.update(Mockito.anyLong(), Mockito.any(IPAddressVO.class))).thenReturn(true);
         when(testOrchestrator._ipAddressDao.releaseFromLockTable(Mockito.anyLong())).thenReturn(true);
+        when(testOrchestrator._networkModel.isMACUnique(Mockito.anyString(), Mockito.anyLong())).thenReturn(true);
         try {
             when(testOrchestrator._networkModel.getNextAvailableMacAddressInNetwork(Mockito.anyLong())).thenReturn(macAddress);
         } catch (InsufficientAddressCapacityException e) {
diff --git a/engine/schema/src/main/java/com/cloud/network/dao/NetworkDaoImpl.java b/engine/schema/src/main/java/com/cloud/network/dao/NetworkDaoImpl.java
index 4b299085612..8066b89b4b9 100644
--- a/engine/schema/src/main/java/com/cloud/network/dao/NetworkDaoImpl.java
+++ b/engine/schema/src/main/java/com/cloud/network/dao/NetworkDaoImpl.java
@@ -462,8 +462,8 @@ public class NetworkDaoImpl extends GenericDaoBase<NetworkVO, Long>implements Ne
     public String getNextAvailableMacAddress(final long networkConfigId, Integer zoneMacIdentifier) {
         final SequenceFetcher fetch = SequenceFetcher.getInstance();
         long seq = fetch.getNextSequence(Long.class, _tgMacAddress, networkConfigId);
-        if(zoneMacIdentifier != null && zoneMacIdentifier.intValue() != 0 ){
-            seq = seq | _prefix << 40 | (long)zoneMacIdentifier << 32 | networkConfigId << 16 & 0x00000000ffff0000l;
+        if (zoneMacIdentifier != null && zoneMacIdentifier != 0) {
+            seq = seq | _prefix << 40 | (long)zoneMacIdentifier << 32 | networkConfigId << 16 & 0x00000000ffff0000L;
         }
         return NetUtils.long2Mac(seq);
     }
diff --git a/engine/schema/src/main/java/com/cloud/vm/dao/NicDao.java b/engine/schema/src/main/java/com/cloud/vm/dao/NicDao.java
index 70a2558e2d4..96a1b6e3bd1 100644
--- a/engine/schema/src/main/java/com/cloud/vm/dao/NicDao.java
+++ b/engine/schema/src/main/java/com/cloud/vm/dao/NicDao.java
@@ -95,7 +95,7 @@ public interface NicDao extends GenericDao<NicVO, Long> {
 
     List<NicVO> listByVmIdAndKeyword(long instanceId, String keyword);
 
-    NicVO findByMacAddress(String macAddress);
+    NicVO findByMacAddress(String macAddress, long networkId);
 
     NicVO findByNetworkIdAndMacAddressIncludingRemoved(long networkId, String mac);
 
diff --git a/engine/schema/src/main/java/com/cloud/vm/dao/NicDaoImpl.java b/engine/schema/src/main/java/com/cloud/vm/dao/NicDaoImpl.java
index 3618785c1b8..78966a09e97 100644
--- a/engine/schema/src/main/java/com/cloud/vm/dao/NicDaoImpl.java
+++ b/engine/schema/src/main/java/com/cloud/vm/dao/NicDaoImpl.java
@@ -420,9 +420,10 @@ public class NicDaoImpl extends GenericDaoBase<NicVO, Long> implements NicDao {
     }
 
     @Override
-    public NicVO findByMacAddress(String macAddress) {
+    public NicVO findByMacAddress(String macAddress, long networkId) {
         SearchCriteria<NicVO> sc = AllFieldsSearch.create();
         sc.setParameters("macAddress", macAddress);
+        sc.setParameters("network", networkId);
         return findOneBy(sc);
     }
 
diff --git a/server/src/main/java/com/cloud/alert/AlertManagerImpl.java b/server/src/main/java/com/cloud/alert/AlertManagerImpl.java
index ed777486a12..3eab3fbfeb1 100644
--- a/server/src/main/java/com/cloud/alert/AlertManagerImpl.java
+++ b/server/src/main/java/com/cloud/alert/AlertManagerImpl.java
@@ -313,13 +313,8 @@ public class AlertManagerImpl extends ManagerBase implements AlertManager, Confi
                 Math.min(CapacityManager.CapacityCalculateWorkers.value(), hostIds.size())));
         for (Long hostId : hostIds) {
             futures.put(hostId, executorService.submit(() -> {
-                Transaction.execute(new TransactionCallbackNoReturn() {
-                    @Override
-                    public void doInTransactionWithoutResult(TransactionStatus status) {
-                        final HostVO host = hostDao.findById(hostId);
-                        _capacityMgr.updateCapacityForHost(host);
-                    }
-                });
+                final HostVO host = hostDao.findById(hostId);
+                _capacityMgr.updateCapacityForHost(host);
                 return null;
             }));
         }
diff --git a/server/src/main/java/com/cloud/network/IpAddressManagerImpl.java b/server/src/main/java/com/cloud/network/IpAddressManagerImpl.java
index b99a2f553c4..8d179735a4d 100644
--- a/server/src/main/java/com/cloud/network/IpAddressManagerImpl.java
+++ b/server/src/main/java/com/cloud/network/IpAddressManagerImpl.java
@@ -2409,7 +2409,7 @@ public class IpAddressManagerImpl extends ManagerBase implements IpAddressManage
                             nic.setBroadcastUri(BroadcastDomainType.Vlan.toUri(ip.getVlanTag()));
                         nic.setFormat(AddressFormat.Ip4);
                         nic.setReservationId(String.valueOf(ip.getVlanTag()));
-                        if(nic.getMacAddress() == null) {
+                        if (nic.getMacAddress() == null) {
                             nic.setMacAddress(ip.getMacAddress());
                         }
                     }
@@ -2460,7 +2460,7 @@ public class IpAddressManagerImpl extends ManagerBase implements IpAddressManage
 
                         nic.setBroadcastUri(network.getBroadcastUri());
                         nic.setFormat(AddressFormat.Ip4);
-                        if(nic.getMacAddress() == null) {
+                        if (nic.getMacAddress() == null || !_networkModel.isMACUnique(nic.getMacAddress(), network.getId())) {
                             nic.setMacAddress(_networkModel.getNextAvailableMacAddressInNetwork(network.getId()));
                         }
                     }
diff --git a/server/src/main/java/com/cloud/network/Ipv6AddressManagerImpl.java b/server/src/main/java/com/cloud/network/Ipv6AddressManagerImpl.java
index d4c293ecf88..d096b09ec0d 100644
--- a/server/src/main/java/com/cloud/network/Ipv6AddressManagerImpl.java
+++ b/server/src/main/java/com/cloud/network/Ipv6AddressManagerImpl.java
@@ -241,7 +241,7 @@ public class Ipv6AddressManagerImpl extends ManagerBase implements Ipv6AddressMa
         if (nic.getBroadCastUri() == null) {
             nic.setBroadcastUri(network.getBroadcastUri());
         }
-        if (nic.getMacAddress() == null) {
+        if (nic.getMacAddress() == null || !_networkModel.isMACUnique(nic.getMacAddress(), network.getId())) {
             nic.setMacAddress(_networkModel.getNextAvailableMacAddressInNetwork(network.getId()));
         }
     }
diff --git a/server/src/main/java/com/cloud/network/NetworkModelImpl.java b/server/src/main/java/com/cloud/network/NetworkModelImpl.java
index 6fd41d2cdc5..22d987a951f 100644
--- a/server/src/main/java/com/cloud/network/NetworkModelImpl.java
+++ b/server/src/main/java/com/cloud/network/NetworkModelImpl.java
@@ -594,22 +594,34 @@ public class NetworkModelImpl extends ManagerBase implements NetworkModel, Confi
     @Override
     public String getNextAvailableMacAddressInNetwork(long networkId) throws InsufficientAddressCapacityException {
         NetworkVO network = _networksDao.findById(networkId);
-        Integer zoneIdentifier = MACIdentifier.value();
-        if (zoneIdentifier.intValue() == 0) {
-            zoneIdentifier = Long.valueOf(network.getDataCenterId()).intValue();
+        if (network == null) {
+            throw new CloudRuntimeException("Could not find network with id " + networkId);
         }
+
+        Integer zoneMacIdentifier = Long.valueOf(getMacIdentifier(network.getDataCenterId())).intValue();
         String mac;
         do {
-            mac = _networksDao.getNextAvailableMacAddress(networkId, zoneIdentifier);
+            mac = _networksDao.getNextAvailableMacAddress(networkId, zoneMacIdentifier);
             if (mac == null) {
                 throw new InsufficientAddressCapacityException("Unable to create another mac address", Network.class, networkId);
             }
-        } while(! isMACUnique(mac));
+        } while (!isMACUnique(mac, networkId));
         return mac;
     }
 
-    private boolean isMACUnique(String mac) {
-        return (_nicDao.findByMacAddress(mac) == null);
+    @Override
+    public String getUniqueMacAddress(long macAddress, long networkId, long datacenterId) throws InsufficientAddressCapacityException {
+        String macAddressStr = NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(macAddress, getMacIdentifier(datacenterId)));
+        if (!isMACUnique(macAddressStr, networkId)) {
+            macAddressStr = getNextAvailableMacAddressInNetwork(networkId);
+        }
+        return macAddressStr;
+    }
+
+    @Override
+    public boolean isMACUnique(String mac, long networkId) {
+        return (_nicDao.findByMacAddress(mac, networkId) == null);
+
     }
 
     @Override
@@ -2818,4 +2830,18 @@ public class NetworkModelImpl extends ManagerBase implements NetworkModel, Confi
         }
         return false;
     }
+
+    @Override
+    public long getMacIdentifier(Long dataCenterId) {
+        long macAddress = 0;
+        if (dataCenterId == null) {
+            macAddress = NetworkModel.MACIdentifier.value();
+        } else {
+            macAddress = NetworkModel.MACIdentifier.valueIn(dataCenterId);
+            if (macAddress == 0) {
+                macAddress = dataCenterId;
+            }
+        }
+        return macAddress;
+    }
 }
diff --git a/server/src/main/java/com/cloud/network/guru/DirectNetworkGuru.java b/server/src/main/java/com/cloud/network/guru/DirectNetworkGuru.java
index 0cb698e9682..5c0c4eed7fc 100644
--- a/server/src/main/java/com/cloud/network/guru/DirectNetworkGuru.java
+++ b/server/src/main/java/com/cloud/network/guru/DirectNetworkGuru.java
@@ -293,7 +293,7 @@ public class DirectNetworkGuru extends AdapterBase implements NetworkGuru {
         allocateDirectIp(nic, network, vm, dc, nic.getRequestedIPv4(), nic.getRequestedIPv6());
         nic.setReservationStrategy(ReservationStrategy.Create);
 
-        if (nic.getMacAddress() == null) {
+        if (nic.getMacAddress() == null || !_networkModel.isMACUnique(nic.getMacAddress(), network.getId())) {
             nic.setMacAddress(_networkModel.getNextAvailableMacAddressInNetwork(network.getId()));
             if (nic.getMacAddress() == null) {
                 throw new InsufficientAddressCapacityException("Unable to allocate more mac addresses", Network.class, network.getId());
diff --git a/server/src/main/java/com/cloud/network/guru/PodBasedNetworkGuru.java b/server/src/main/java/com/cloud/network/guru/PodBasedNetworkGuru.java
index 5dafa60f1c7..15faec46589 100644
--- a/server/src/main/java/com/cloud/network/guru/PodBasedNetworkGuru.java
+++ b/server/src/main/java/com/cloud/network/guru/PodBasedNetworkGuru.java
@@ -53,6 +53,8 @@ public class PodBasedNetworkGuru extends AdapterBase implements NetworkGuru {
     DataCenterDao _dcDao;
     @Inject
     StorageNetworkManager _sNwMgr;
+    @Inject
+    NetworkModel _networkModel;
 
     Random _rand = new Random(System.currentTimeMillis());
 
@@ -131,7 +133,8 @@ public class PodBasedNetworkGuru extends AdapterBase implements NetworkGuru {
         Integer vlan = result.getVlan();
 
         nic.setIPv4Address(result.getIpAddress());
-        nic.setMacAddress(NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(result.getMacAddress(), NetworkModel.MACIdentifier.value())));
+        String macAddress = _networkModel.getUniqueMacAddress(result.getMacAddress(), config.getId(), dest.getDataCenter().getId());
+        nic.setMacAddress(macAddress);
         nic.setIPv4Gateway(pod.getGateway());
         nic.setFormat(AddressFormat.Ip4);
         String netmask = NetUtils.getCidrNetmask(pod.getCidrSize());
diff --git a/server/src/main/java/com/cloud/network/guru/PrivateNetworkGuru.java b/server/src/main/java/com/cloud/network/guru/PrivateNetworkGuru.java
index 9fa8e2f26de..4c22dc16f82 100644
--- a/server/src/main/java/com/cloud/network/guru/PrivateNetworkGuru.java
+++ b/server/src/main/java/com/cloud/network/guru/PrivateNetworkGuru.java
@@ -189,8 +189,12 @@ public class PrivateNetworkGuru extends AdapterBase implements NetworkGuru {
             PrivateIpVO ipVO = _privateIpDao.allocateIpAddress(network.getDataCenterId(), network.getId(), null);
             String vlanTag = BroadcastDomainType.getValue(network.getBroadcastUri());
             String netmask = NetUtils.getCidrNetmask(network.getCidr());
+            String macAddress = NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(ipVO.getMacAddress(), networkModel.getMacIdentifier(network.getDataCenterId())));
+            if (!networkModel.isMACUnique(macAddress, network.getId())) {
+                macAddress = networkModel.getNextAvailableMacAddressInNetwork(network.getId());
+            }
             PrivateIpAddress ip =
-                new PrivateIpAddress(ipVO, vlanTag, network.getGateway(), netmask, NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(ipVO.getMacAddress(), NetworkModel.MACIdentifier.value())));
+                new PrivateIpAddress(ipVO, vlanTag, network.getGateway(), netmask, macAddress);
 
             nic.setIPv4Address(ip.getIpAddress());
             nic.setIPv4Gateway(ip.getGateway());
diff --git a/server/src/main/java/com/cloud/network/guru/StorageNetworkGuru.java b/server/src/main/java/com/cloud/network/guru/StorageNetworkGuru.java
index 221661fea12..4d2d582c9ff 100644
--- a/server/src/main/java/com/cloud/network/guru/StorageNetworkGuru.java
+++ b/server/src/main/java/com/cloud/network/guru/StorageNetworkGuru.java
@@ -37,7 +37,6 @@ import com.cloud.network.dao.NetworkDao;
 import com.cloud.network.dao.NetworkVO;
 import com.cloud.offering.NetworkOffering;
 import com.cloud.user.Account;
-import com.cloud.utils.net.NetUtils;
 import com.cloud.vm.Nic.ReservationStrategy;
 import com.cloud.vm.NicProfile;
 import com.cloud.vm.ReservationContext;
@@ -47,6 +46,8 @@ public class StorageNetworkGuru extends PodBasedNetworkGuru implements NetworkGu
     @Inject
     StorageNetworkManager _sNwMgr;
     @Inject
+    NetworkModel _networkModel;
+    @Inject
     NetworkDao _nwDao;
 
     protected StorageNetworkGuru() {
@@ -130,7 +131,8 @@ public class StorageNetworkGuru extends PodBasedNetworkGuru implements NetworkGu
 
         vlan = ip.getVlan();
         nic.setIPv4Address(ip.getIpAddress());
-        nic.setMacAddress(NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(ip.getMac(), NetworkModel.MACIdentifier.value())));
+        String macAddress = _networkModel.getUniqueMacAddress(ip.getMac(), network.getId(), dest.getDataCenter().getId());
+        nic.setMacAddress(macAddress);
         nic.setFormat(AddressFormat.Ip4);
         nic.setIPv4Netmask(ip.getNetmask());
         nic.setBroadcastType(BroadcastDomainType.Storage);
diff --git a/server/src/main/java/com/cloud/network/router/NicProfileHelper.java b/server/src/main/java/com/cloud/network/router/NicProfileHelper.java
index 832d77f9e40..b1ad2ef950b 100644
--- a/server/src/main/java/com/cloud/network/router/NicProfileHelper.java
+++ b/server/src/main/java/com/cloud/network/router/NicProfileHelper.java
@@ -16,6 +16,7 @@
 // under the License.
 package com.cloud.network.router;
 
+import com.cloud.exception.InsufficientAddressCapacityException;
 import org.apache.cloudstack.network.router.deployment.RouterDeploymentDefinition;
 
 import com.cloud.network.Network;
@@ -24,7 +25,7 @@ import com.cloud.vm.NicProfile;
 
 public interface NicProfileHelper {
 
-    public abstract NicProfile createPrivateNicProfileForGateway(final VpcGateway privateGateway, final VirtualRouter router);
+    public abstract NicProfile createPrivateNicProfileForGateway(final VpcGateway privateGateway, final VirtualRouter router) throws InsufficientAddressCapacityException;
 
     public abstract NicProfile createGuestNicProfileForVpcRouter(final RouterDeploymentDefinition vpcRouterDeploymentDefinition,
             Network guestNetwork);
diff --git a/server/src/main/java/com/cloud/network/router/NicProfileHelperImpl.java b/server/src/main/java/com/cloud/network/router/NicProfileHelperImpl.java
index 649689d8d77..b6dce4312b8 100644
--- a/server/src/main/java/com/cloud/network/router/NicProfileHelperImpl.java
+++ b/server/src/main/java/com/cloud/network/router/NicProfileHelperImpl.java
@@ -21,6 +21,7 @@ import java.net.URI;
 
 import javax.inject.Inject;
 
+import com.cloud.exception.InsufficientAddressCapacityException;
 import com.cloud.vm.NicVO;
 import com.cloud.vm.VirtualMachine;
 import org.apache.cloudstack.network.router.deployment.RouterDeploymentDefinition;
@@ -61,7 +62,7 @@ public class NicProfileHelperImpl implements NicProfileHelper {
 
     @Override
     @DB
-    public NicProfile createPrivateNicProfileForGateway(final VpcGateway privateGateway, final VirtualRouter router) {
+    public NicProfile createPrivateNicProfileForGateway(final VpcGateway privateGateway, final VirtualRouter router) throws InsufficientAddressCapacityException {
         final Network privateNetwork = _networkModel.getNetwork(privateGateway.getNetworkId());
 
         PrivateIpVO ipVO = _privateIpDao.allocateIpAddress(privateNetwork.getDataCenterId(), privateNetwork.getId(), privateGateway.getIp4Address());
@@ -90,14 +91,14 @@ public class NicProfileHelperImpl implements NicProfileHelper {
             privateNicProfile.setDeviceId(null);
 
             if (router.getIsRedundantRouter()) {
-              String newMacAddress = NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(ipVO.getMacAddress(), NetworkModel.MACIdentifier.value()));
-              privateNicProfile.setMacAddress(newMacAddress);
+                String newMacAddress = _networkModel.getUniqueMacAddress(ipVO.getMacAddress(), privateNetwork.getId(), privateNetwork.getDataCenterId());
+                privateNicProfile.setMacAddress(newMacAddress);
             }
         } else {
             final String netmask = NetUtils.getCidrNetmask(privateNetwork.getCidr());
+            String newMacAddress = _networkModel.getUniqueMacAddress(ipVO.getMacAddress(), privateNetwork.getId(), privateNetwork.getDataCenterId());
             final PrivateIpAddress ip =
-                    new PrivateIpAddress(ipVO, privateNetwork.getBroadcastUri().toString(), privateNetwork.getGateway(), netmask,
-                            NetUtils.long2Mac(NetUtils.createSequenceBasedMacAddress(ipVO.getMacAddress(), NetworkModel.MACIdentifier.value())));
+                    new PrivateIpAddress(ipVO, privateNetwork.getBroadcastUri().toString(), privateNetwork.getGateway(), netmask, newMacAddress);
 
             final URI netUri = BroadcastDomainType.fromString(ip.getBroadcastUri());
             privateNicProfile.setIPv4Address(ip.getIpAddress());
diff --git a/server/src/test/java/com/cloud/network/Ipv6AddressManagerTest.java b/server/src/test/java/com/cloud/network/Ipv6AddressManagerTest.java
index 0b8e7f43137..68a0fa8052d 100644
--- a/server/src/test/java/com/cloud/network/Ipv6AddressManagerTest.java
+++ b/server/src/test/java/com/cloud/network/Ipv6AddressManagerTest.java
@@ -246,8 +246,10 @@ public class Ipv6AddressManagerTest {
 
         Mockito.when(network.getIp6Cidr()).thenReturn("2001:db8:100::/64");
         Mockito.when(network.getIp6Gateway()).thenReturn("2001:db8:100::1");
+        Mockito.when(network.getId()).thenReturn(1L);
 
         Mockito.when(networkModel.getNetworkIp6Dns(network, dc)).thenReturn(new Pair<>("2001:db8::53:1", "2001:db8::53:2"));
+        Mockito.when(networkModel.isMACUnique("1e:00:b1:00:0a:f6", 1L)).thenReturn(true);
 
         String expected = "2001:db8:100:0:1c00:b1ff:fe00:af6";
 
diff --git a/server/src/test/java/com/cloud/network/MockNetworkModelImpl.java b/server/src/test/java/com/cloud/network/MockNetworkModelImpl.java
index a959553ed78..b5e081e043b 100644
--- a/server/src/test/java/com/cloud/network/MockNetworkModelImpl.java
+++ b/server/src/test/java/com/cloud/network/MockNetworkModelImpl.java
@@ -129,6 +129,24 @@ public class MockNetworkModelImpl extends ManagerBase implements NetworkModel {
         return null;
     }
 
+    /* (non-Javadoc)
+     * @see com.cloud.network.NetworkModel#getUniqueMacAddress(long, long, long)
+     */
+    @Override
+    public String getUniqueMacAddress(long macAddress, long networkId, long datacenterId) throws InsufficientAddressCapacityException {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    /* (non-Javadoc)
+     * @see com.cloud.network.NetworkModel#isMACUnique(String, long)
+     */
+    @Override
+    public boolean isMACUnique(String mac, long networkId) {
+        // TODO Auto-generated method stub
+        return true;
+    }
+
     /* (non-Javadoc)
      * @see com.cloud.network.NetworkModel#getPublicIpAddress(long)
      */
diff --git a/server/src/test/java/com/cloud/vpc/MockNetworkModelImpl.java b/server/src/test/java/com/cloud/vpc/MockNetworkModelImpl.java
index df100535c5b..b9423daaeeb 100644
--- a/server/src/test/java/com/cloud/vpc/MockNetworkModelImpl.java
+++ b/server/src/test/java/com/cloud/vpc/MockNetworkModelImpl.java
@@ -141,6 +141,24 @@ public class MockNetworkModelImpl extends ManagerBase implements NetworkModel {
         return null;
     }
 
+    /* (non-Javadoc)
+     * @see com.cloud.network.NetworkModel#getUniqueMacAddress(long, long, long)
+     */
+    @Override
+    public String getUniqueMacAddress(long macAddress, long networkId, long datacenterId) throws InsufficientAddressCapacityException {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    /* (non-Javadoc)
+     * @see com.cloud.network.NetworkModel#isMACUnique(String, long)
+     */
+    @Override
+    public boolean isMACUnique(String mac, long networkId) {
+        // TODO Auto-generated method stub
+        return true;
+    }
+
     /* (non-Javadoc)
      * @see com.cloud.network.NetworkModel#getPublicIpAddress(long)
      */
diff --git a/setup/bindir/cloud-sysvmadm.in b/setup/bindir/cloud-sysvmadm.in
index a262f6b710e..00b24806d07 100755
--- a/setup/bindir/cloud-sysvmadm.in
+++ b/setup/bindir/cloud-sysvmadm.in
@@ -184,49 +184,29 @@ stop_start_system() {
 stop_start_router() {
     prepare_ids_clause
     router=(`mysql -h $db --user=$user --password=$password --skip-column-names -U cloud -e "select uuid from vm_instance where state=\"Running\" and type=\"DomainRouter\"$zone$vmidsclause"`)
-    length_router=(${#router[@]})
+    length_router=${#router[@]}
 
     echo -e "\nStopping and starting $length_router running routing vm(s)$inzone$withids... "
     echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Stopping and starting $length_router running routing vm(s)$inzone$withids... " >>$LOGFILE
 
     #Spawn reboot router in parallel - run commands in <n> chunks - number of threads is configurable
 
+    if [ $maxthreads -gt $length_router ]; then
+        maxthreads=$length_router
+    fi
     pids=()
     for d in "${router[@]}"; do
 
         reboot_router $d &
 
         pids=( "${pids[@]}" $! )
-
-        length_pids=(${#pids[@]})
-        unfinishedPids=(${#pids[@]})
-
-        if [ $maxthreads -gt $length_router ]; then
-          maxthreads=$length_router
-        fi
+        length_pids=${#pids[@]}
 
         if [ $length_pids -ge $maxthreads ]; then
-            while [ $unfinishedPids -gt 0 ]; do
-                sleep 10
-                count=0
-                for ((  i = 0 ;  i < $length_pids;  i++  )); do
-                    if ! ps ax | grep -v grep | grep ${pids[$i]} > /dev/null; then
-                        count=`expr $count + 1`
-                    fi
-                done
-
-                if [ $count -eq $unfinishedPids ]; then
-                  unfinishedPids=0
-                fi
-
-            done
-
-            #remove all elements from pids
-            if [ $unfinishedPids -eq 0 ]; then
-                pids=()
-                length_pids=(${#pids[@]})
-            fi
-
+            # Wait for $maxthreads number of processes to finish
+            wait
+            # Clear the pids array for the next batch
+            pids=()
         fi
 
     done
@@ -234,9 +214,8 @@ stop_start_router() {
     if [ "$length_router" == "0" ];then
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] No running router vms found \n" >>$LOGFILE
     else
-        while [ $unfinishedPids -gt 0 ]; do
-          sleep 10
-        done
+        # Wait for the remaining background processes to finish
+        wait
 
         echo -e "Done restarting router(s)$inzone$withids. \n"
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Done restarting router(s)$inzone$withids. \n" >>$LOGFILE
@@ -288,49 +267,29 @@ reboot_router(){
 restart_networks(){
     networks=(`mysql -h $db --user=$user --password=$password --skip-column-names -U cloud -e "select n.id
     from networks n, network_offerings no where n.network_offering_id = no.id and no.system_only = 0 and n.removed is null$zone"`)
-    length_networks=(${#networks[@]})
+    length_networks=${#networks[@]}
 
     echo -e "\nRestarting $length_networks networks$inzone... "
     echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Restarting $length_networks networks$inzone... " >>$LOGFILE
 
     #Spawn restart network in parallel - run commands in <n> chunks - number of threads is configurable
 
+    if [ $maxthreads -gt $length_networks ]; then
+        maxthreads=$length_networks
+    fi
     pids=()
     for d in "${networks[@]}"; do
 
         restart_network $d &
 
         pids=( "${pids[@]}" $! )
-
-        length_pids=(${#pids[@]})
-        unfinishedPids=(${#pids[@]})
-
-        if [ $maxthreads -gt $length_networks ]; then
-            maxthreads=$length_networks
-        fi
+        length_pids=${#pids[@]}
 
         if [ $length_pids -ge $maxthreads ]; then
-            while [ $unfinishedPids -gt 0 ]; do
-                sleep 10
-                count=0
-                for ((  i = 0 ;  i < $length_pids;  i++  )); do
-                    if ! ps ax | grep -v grep | grep ${pids[$i]} > /dev/null; then
-                        count=`expr $count + 1`
-                    fi
-                done
-
-                if [ $count -eq $unfinishedPids ]; then
-                    unfinishedPids=0
-                fi
-
-            done
-
-            #remove all elements from pids
-            if [ $unfinishedPids -eq 0 ]; then
-                pids=()
-                length_pids=(${#pids[@]})
-            fi
-
+            # Wait for $maxthreads number of processes to finish
+            wait
+            # Clear the pids array for the next batch
+            pids=()
         fi
 
     done
@@ -339,9 +298,8 @@ restart_networks(){
     if [ "$length_networks" == "0" ];then
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] No networks found \n" >>$LOGFILE
     else
-        while [ $unfinishedPids -gt 0 ]; do
-            sleep 10
-        done
+        # Wait for the remaining background processes to finish
+        wait
 
         echo -e "Done restarting networks$inzone. \n"
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Done restarting networks$inzone. \n" >>$LOGFILE
@@ -392,49 +350,29 @@ restart_vpc(){
 
 restart_vpcs(){
     vpcs=(`mysql -h $db --user=$user --password=$password --skip-column-names -U cloud -e "select uuid from vpc WHERE removed is null$zone"`)
-    length_vpcs=(${#vpcs[@]})
+    length_vpcs=${#vpcs[@]}
 
     echo -e "\nRestarting $length_vpcs vpcs... "
     echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Restarting $length_vpcs vpcs... " >>$LOGFILE
 
     #Spawn restart vpcs in parallel - run commands in <n> chunks - number of threads is configurable
 
+    if [ $maxthreads -gt $length_vpcs ]; then
+        maxthreads=$length_vpcs
+    fi
     pids=()
     for d in "${vpcs[@]}"; do
 
         restart_vpc $d &
 
         pids=( "${pids[@]}" $! )
-
-        length_pids=(${#pids[@]})
-        unfinishedPids=(${#pids[@]})
-
-        if [ $maxthreads -gt $length_vpcs ]; then
-            maxthreads=$length_vpcs
-        fi
+        length_pids=${#pids[@]}
 
         if [ $length_pids -ge $maxthreads ]; then
-            while [ $unfinishedPids -gt 0 ]; do
-                sleep 10
-                count=0
-                for ((  i = 0 ;  i < $length_pids;  i++  )); do
-                    if ! ps ax | grep -v grep | grep ${pids[$i]} > /dev/null; then
-                        count=`expr $count + 1`
-                    fi
-                done
-
-                if [ $count -eq $unfinishedPids ]; then
-                    unfinishedPids=0
-                fi
-
-            done
-
-            #remove all elements from pids
-            if [ $unfinishedPids -eq 0 ]; then
-                pids=()
-                length_pids=(${#pids[@]})
-            fi
-
+            # Wait for $maxthreads number of processes to finish
+            wait
+            # Clear the pids array for the next batch
+            pids=()
         fi
 
     done
@@ -443,9 +381,8 @@ restart_vpcs(){
     if [ "$length_vpcs" == "0" ];then
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] No vpcs found \n" >>$LOGFILE
     else
-        while [ $unfinishedPids -gt 0 ]; do
-            sleep 10
-        done
+        # Wait for the remaining background processes to finish
+        wait
 
         echo -e "Done restarting vpcs$inzone. \n"
         echo -e "[$(date "+%Y.%m.%d-%H.%M.%S")] Done restarting vpcs$inzone. \n" >>$LOGFILE
diff --git a/utils/src/main/java/com/cloud/utils/net/NetUtils.java b/utils/src/main/java/com/cloud/utils/net/NetUtils.java
index 782a5404cbb..65878e055e7 100644
--- a/utils/src/main/java/com/cloud/utils/net/NetUtils.java
+++ b/utils/src/main/java/com/cloud/utils/net/NetUtils.java
@@ -131,17 +131,17 @@ public class NetUtils {
         }
     }
 
-    public static long createSequenceBasedMacAddress(final long macAddress, long globalConfig) {
+    public static long createSequenceBasedMacAddress(final long macAddress, long macIdentifier) {
         /*
             Logic for generating MAC address:
             Mac = B1:B2:B3:B4:B5:B6 (Bx is a byte).
             B1 -> Presently controlled by prefix variable. The value should be such that the MAC is local and unicast.
-            B2 -> This will be configurable for each deployment/installation. Controlled by the global config MACIdentifier
+            B2 -> This will be configurable for each deployment/installation. Controlled by the 'mac.identifier' zone-level config
             B3 -> A randomly generated number between 0 - 255
             B4,5,6 -> These bytes are based on the unique DB identifier associated with the IP address for which MAC is generated (refer to mac_address field in user_ip_address table).
          */
 
-        return macAddress | prefix<<40 | globalConfig << 32 & 0x00ff00000000l | (long)s_rand.nextInt(255) << 24;
+        return macAddress | prefix << 40 | macIdentifier << 32 & 0x00ff00000000L | (long)s_rand.nextInt(255) << 24;
     }
 
     public static String getHostName() {