Bug5427: Added JavaDoc for OfOverlay rendeder (flow description)
[groupbasedpolicy.git] / renderers / ofoverlay / src / main / java / org / opendaylight / groupbasedpolicy / renderer / ofoverlay / flow / DestinationMapper.java
old mode 100644 (file)
new mode 100755 (executable)
index 039bd42..1e8fa2a
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
@@ -8,12 +8,12 @@
 
 package org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.ARP;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.IPv4;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.IPv6;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.addNxRegMatch;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.applyActionIns;
-import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.createNodePath;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.decNwTtlAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.ethernetMatch;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.getOfPortNum;
@@ -25,13 +25,14 @@ import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtil
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadArpSpaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadRegAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadTunIPv4Action;
+import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadTunIdAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveArpShaToArpThaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveArpSpaToArpTpaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveEthSrcToEthDstAction;
-import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveRegTunIdAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.outputAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.setDlDstAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.setDlSrcAction;
+import static org.opendaylight.groupbasedpolicy.util.DataStoreHelper.readFromDs;
 
 import java.math.BigInteger;
 import java.util.ArrayList;
@@ -46,93 +47,176 @@ import java.util.Objects;
 import java.util.Set;
 
 import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
-import org.opendaylight.controller.md.sal.binding.api.ReadTransaction;
 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
-import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
-import org.opendaylight.groupbasedpolicy.endpoint.EpKey;
+import org.opendaylight.groupbasedpolicy.dto.EgKey;
+import org.opendaylight.groupbasedpolicy.dto.EpKey;
+import org.opendaylight.groupbasedpolicy.dto.IndexedTenant;
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OfContext;
-import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.PolicyManager.FlowMap;
+import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OfWriter;
+import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.endpoint.EndpointManager;
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.RegMatch;
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.OrdinalFactory.EndpointFwdCtxOrdinals;
-import org.opendaylight.groupbasedpolicy.resolver.EgKey;
-import org.opendaylight.groupbasedpolicy.resolver.PolicyInfo;
-import org.opendaylight.groupbasedpolicy.resolver.TenantUtils;
+import org.opendaylight.groupbasedpolicy.util.IidFactory;
+import org.opendaylight.groupbasedpolicy.util.TenantUtils;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Prefix;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv6Prefix;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev100924.MacAddress;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.action.Action;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNode;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.Flow;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.FlowBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.InstructionsBuilder;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.Match;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.MatchBuilder;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.instruction.go.to.table._case.GoToTable;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.Instruction;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.InstructionBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.Group;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.EndpointGroupId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.NetworkDomainId;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.SubnetId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.TenantId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.Endpoints;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoint.fields.L3Address;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoint.l3.prefix.fields.EndpointL3Gateways;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.Endpoint;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.EndpointL3;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.EndpointL3Key;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.ofoverlay.rev140528.EndpointLocation.LocationType;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.EndpointL3Prefix;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.ofoverlay.rev140528.OfOverlayContext;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.Tenant;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L3Context;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.Subnet;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.ForwardingContext;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.forwarding.context.L3Context;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.forwarding.context.Subnet;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeConnectorId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.ethernet.match.fields.EthernetDestinationBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.EthernetMatchBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.Layer3Match;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.ArpMatchBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.Ipv4MatchBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.Ipv6MatchBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg0;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.action.action.dec.nw.ttl._case.DecNwTtl;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg2;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg3;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg4;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg5;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg6;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg7;
-import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.overlay.rev150105.TunnelTypeVxlan;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import com.google.common.base.Optional;
+import com.google.common.base.Strings;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.SetMultimap;
 import com.google.common.collect.Sets;
-import com.google.common.util.concurrent.CheckedFuture;
 
 /**
- * Manage the table that maps the destination address to the next hop for the
- * path as well as applies any relevant routing transformations.
+ * <h1>Manage the table that maps the destination address to the next hop for the
+ * path as well as applies any relevant routing transformations (table=3)</h1>
  *
+ * Sync Ep flows, every endpoint pair creates L2 and L3 flow<br>
+ * <ul><li>Flow is external, when any {@link Endpoint} is external</li>
+ * <li>Flow is local, when src and dst endpoint {@link EndpointFwdCtxOrdinals} are the same</li>
+ * <li>Flow is local, when src and dst endpoint ordinals are not the same and {@link OfOverlayContext} is missing</li></ul>
+ * Also applies to L3
+ * <p>
+ * L2 Flows:
+ * <p>
+ * <i>External, local and remote L2 flows</i><br>
+ * Priority = 50<br>
+ * Matches:<br>
+ *      - dl_dst mac address {@link MacAddress}<br>
+ *      - loadReg4 {@link NxmNxReg4}<br>
+ * Actions:<br>
+ *      - load tunnel Ipv4 (local and remote only)<br>
+ *      - loadReg2 {@link NxmNxReg2}<br>
+ *      - loadReg3 {@link NxmNxReg3}<br>
+ *      - loadReg7 (next hop) {@link NxmNxReg7}<br>
+ *      - {@link GoToTable} POLICY ENFORCER table<br>
+ * <p>
+ * L3 flows:
+ * <p>
+ * <i>External, local and remote L3 routed flows:</i><br>
+ * Priority = 50<br>
+ * Matches:<br>
+ *      - ip (ethertype)
+ *      - dl_dst mac address {@link MacAddress}<br>
+ *      - setReg6 {@link NxmNxReg6}<br>
+ * Actions:<br>
+ *      - loadReg2 {@link NxmNxReg2}<br>
+ *      - loadReg3 {@link NxmNxReg3}<br>
+ *      - loadReg4 (tunnel destination) {@link NxmNxReg4} (remote only)<br>
+ *      - loadReg7 (next hop) {@link NxmNxReg7}<br>
+ *      - set dst mac to eth_dst {@link MacAddress}<br>
+ *      - dec_ttl {@link DecNwTtl} (local only)<br>
+ *      - {@link GoToTable} POLICY ENFORCER table
+ * <p>
+ * If virtual router ip is present in subnet, and subnet contains L3 context, arp flow is created<br>
+ * <p>
+ * <i>Router Arp flow</i><br>
+ * Priority = 150<br>
+ * Matches:<br>
+ *      - arp (ethertype)<br>
+ *      - arp target transport address<br>
+ *      - setReg6 {@link NxmNxReg6}<br>
+ * Actions:<br>
+ *      - move eth_src = eth_dst<br>
+ *      - set dl_src {@link MacAddress}<br>
+ *      - load arp_op<br>
+ *      - move arp_sha = arp_tha<br>
+ *      - load arp_sha<br>
+ *      - move arp_spa = arp_tpa<br>
+ *      - load arp_spa<br>
+ *      - output:port {@link NodeConnectorId}<br>
+ * <p>
+ * <i>Broadcast flow (per flood domain)</i>
+ * Priority = 140<br>
+ * Matches:<br>
+ *      - ethernet destination {@link MacAddress}
+ *      - setReg5 {@link NxmNxReg5}<br>
+ * Actions:<br>
+ *      - load tunnel ID<br>
+ *      - group action<br>
+ * <p>
+ * <i>L3 Prefix flow</i><br>
+ * Priority = 140<br>
+ * Matches:<br>
+ *      - ethernet destination {@link MacAddress}
+ *      - setReg5 {@link NxmNxReg5}<br>
+ * Actions:<br>
+ *      - dl_dst {@link MacAddress}<br>
+ *      - dec_ttl<br>
+ *      - loadReg2 {@link NxmNxReg2}<br>
+ *      - loadReg3 {@link NxmNxReg3}<br>
+ *      - loadReg4 (next hop) {@link NxmNxReg4}<br>
+ *      - loadReg7 (if internal, port_num == {@link NodeConnectorId of L2 EP} ) {@link NxmNxReg7}<br>
+ *      - loadReg7 (if external, port_num = external port) {@link NxmNxReg7}<br>
+ *      - {@link GoToTable} POLICY ENFORCER table
  */
 public class DestinationMapper extends FlowTable {
-    protected static final Logger LOG =
-            LoggerFactory.getLogger(DestinationMapper.class);
+
+    protected static final Logger LOG = LoggerFactory.getLogger(DestinationMapper.class);
 
     // TODO Li alagalah: Improve UT coverage for this class.
 
     // TODO Li alagalah: Use EndpointL3 for L3 flows, Endpoint for L2 flows
     // This ensures we have the appropriate network-containment'
 
-    public static final short TABLE_ID = 2;
+    public static short TABLE_ID;
     /**
      * This is the MAC address of the magical router in the sky
      */
-    public static final MacAddress ROUTER_MAC =
-            new MacAddress("88:f0:31:b5:12:b5");
-    public static final MacAddress MULTICAST_MAC =
-            new MacAddress("01:00:00:00:00:00");
+    public static final MacAddress ROUTER_MAC = new MacAddress("88:f0:31:b5:12:b5");
+    public static final MacAddress MULTICAST_MAC = new MacAddress("01:00:00:00:00:00");
+    public static final Integer BASE_L3_PRIORITY = 100;
 
-    public DestinationMapper(OfContext ctx) {
+    public DestinationMapper(OfContext ctx, short tableId) {
         super(ctx);
+        this.TABLE_ID = tableId;
     }
 
     Map<TenantId, HashSet<Subnet>> subnetsByTenant = new HashMap<TenantId, HashSet<Subnet>>();
@@ -143,108 +227,284 @@ public class DestinationMapper extends FlowTable {
     }
 
     @Override
-    public void sync(NodeId nodeId, PolicyInfo policyInfo, FlowMap flowMap)
-            throws Exception {
-
-        TenantId currentTenant;
-
-        flowMap.writeFlow(nodeId, TABLE_ID, dropFlow(Integer.valueOf(1), null));
-
-        Set<EpKey> visitedEps = new HashSet<>();
-        Set<Integer> fdIds = new HashSet<>();
+    public void sync(NodeId nodeId, OfWriter ofWriter) throws Exception {
+
+        TenantId currentTenant = null;
+
+        ofWriter.writeFlow(nodeId, TABLE_ID, dropFlow(Integer.valueOf(1), null, TABLE_ID));
+
+        SetMultimap<EpKey, EpKey> visitedEps = HashMultimap.create();
+        Set<EndpointFwdCtxOrdinals> epOrdSet = new HashSet<>();
+
+        for (Endpoint srcEp : ctx.getEndpointManager().getEndpointsForNode(nodeId)) {
+            Set<EndpointGroupId> srcEpgIds = new HashSet<>();
+            if (srcEp.getEndpointGroup() != null)
+                srcEpgIds.add(srcEp.getEndpointGroup());
+            if (srcEp.getEndpointGroups() != null)
+                srcEpgIds.addAll(srcEp.getEndpointGroups());
+
+            for (EndpointGroupId epgId : srcEpgIds) {
+                EgKey epg = new EgKey(srcEp.getTenant(), epgId);
+                Set<EgKey> peers = Sets.union(Collections.singleton(epg), ctx.getCurrentPolicy().getPeers(epg));
+                for (EgKey peer : peers) {
+                    Collection<Endpoint> endpointsForGroup = new HashSet<>();
+                    endpointsForGroup.addAll(ctx.getEndpointManager().getEndpointsForGroup(peer));
+                    endpointsForGroup.addAll(ctx.getEndpointManager().getExtEpsNoLocForGroup(peer));
+                    for (Endpoint peerEp : endpointsForGroup) {
+                        currentTenant = peerEp.getTenant();
+                        subnetsByTenant.put(currentTenant, getSubnets(currentTenant));
+                        EpKey srcEpKey = new EpKey(srcEp.getL2Context(), srcEp.getMacAddress());
+                        EpKey peerEpKey = new EpKey(peerEp.getL2Context(), peerEp.getMacAddress());
+
+                        if (visitedEps.get(srcEpKey) != null && visitedEps.get(srcEpKey).contains(peerEpKey)) {
+                            continue;
+                        }
+                        syncEP(ofWriter, nodeId, srcEp, peerEp);
+                        visitedEps.put(srcEpKey, peerEpKey);
+
+                        // Process subnets and flood-domains for epPeer
+                        EndpointFwdCtxOrdinals epOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx,
+                                peerEp);
+                        if (epOrds == null) {
+                            LOG.debug("getEndpointFwdCtxOrdinals is null for EP {}", peerEp);
+                            continue;
+                        }
 
-        for (EgKey epg : ctx.getEndpointManager().getGroupsForNode(nodeId)) {
-            Set<EgKey> peers = Sets.union(Collections.singleton(epg),
-                    policyInfo.getPeers(epg));
-            for (EgKey peer : peers) {
-                for (Endpoint epPeer : ctx.getEndpointManager().getEndpointsForGroup(peer)) {
-                    currentTenant = epPeer.getTenant();
-                    subnetsByTenant.put(currentTenant, getSubnets(currentTenant));
-                    syncEP(flowMap, nodeId, policyInfo, epPeer, visitedEps);
-                    // Process subnets and flood-domains for epPeer
-                    EndpointFwdCtxOrdinals epOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, epPeer);
-                    fdIds.add(epOrds.getFdId());
+                        epOrdSet.add(epOrds);
+                    }
                 }
             }
         }
 
         for (Entry<TenantId, HashSet<Subnet>> subnetEntry : subnetsByTenant.entrySet()) {
-            if(subnetEntry.getValue() == null ) {
-                LOG.trace("Tenant: {} has empty subnet entry.",subnetEntry.getKey());
+            if (subnetEntry.getValue() == null) {
+                LOG.trace("Tenant: {} has empty subnet entry.", subnetEntry.getKey());
                 continue;
             }
-            currentTenant=subnetEntry.getKey();
+            currentTenant = subnetEntry.getKey();
             for (Subnet sn : subnetEntry.getValue()) {
-                L3Context l3c = getL3ContextForSubnet(currentTenant,sn);
+                L3Context l3c = getL3ContextForSubnet(currentTenant, sn);
                 Flow arpFlow = createRouterArpFlow(currentTenant, nodeId, sn,
                         OrdinalFactory.getContextOrdinal(currentTenant, l3c.getId()));
                 if (arpFlow != null) {
-                    flowMap.writeFlow(nodeId, TABLE_ID, arpFlow);
+                    ofWriter.writeFlow(nodeId, TABLE_ID, arpFlow);
                 } else {
-                    LOG.debug("ARP flow is not created, because virtual router IP has not been set for subnet {} .",
+                    LOG.debug(
+                            "Gateway ARP flow is not created, because virtual router IP has not been set for subnet {} .",
                             sn.getIpPrefix().getValue());
                 }
             }
         }
 
         // Write broadcast flows per flood domain.
-        for (Integer fdId : fdIds) {
-            if (groupExists(nodeId, fdId)) {
-                flowMap.writeFlow(nodeId, TABLE_ID, createBroadcastFlow(fdId));
+        for (EndpointFwdCtxOrdinals epOrd : epOrdSet) {
+            if (ofWriter.groupExists(nodeId, Integer.valueOf(epOrd.getFdId()).longValue())) {
+                ofWriter.writeFlow(nodeId, TABLE_ID, createBroadcastFlow(epOrd));
+            }
+        }
+
+        // L3 Prefix Endpoint handling
+        Collection<EndpointL3Prefix> prefixEps = ctx.getEndpointManager().getEndpointsL3PrefixForTenant(currentTenant);
+        if (prefixEps != null) {
+            LOG.trace("DestinationMapper - Processing L3PrefixEndpoints");
+            for (EndpointL3Prefix prefixEp : prefixEps) {
+                List<Subnet> localSubnets = getLocalSubnets(nodeId);
+                if (localSubnets == null) {
+                    continue;
+                }
+                for (Subnet localSubnet: localSubnets) {
+                    Flow prefixFlow = createL3PrefixFlow(prefixEp, nodeId, localSubnet);
+                    if (prefixFlow != null) {
+                        ofWriter.writeFlow(nodeId, TABLE_ID, prefixFlow);
+                        LOG.trace("Wrote L3Prefix flow");
+                    }
+                }
             }
         }
     }
 
+
+
     // set up next-hop destinations for all the endpoints in the endpoint
     // group on the node
 
-    private Flow createBroadcastFlow(int fdId) {
-        FlowId flowId = new FlowId(new StringBuilder()
-                .append("broadcast|")
-                .append(fdId).toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(new EthernetMatchBuilder()
-                        .setEthernetDestination(new EthernetDestinationBuilder()
-                                .setAddress(MULTICAST_MAC)
-                                .setMask(MULTICAST_MAC)
-                                .build())
-                        .build());
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg5.class, Long.valueOf(fdId)));
+    private Flow createL3PrefixFlow(EndpointL3Prefix prefixEp, NodeId nodeId, Subnet subnet) throws Exception {
+        /*
+         * Priority: 100+lengthprefix
+         * Match: prefix, l3c, "mac address of router" ?
+         * Action:
+         * - set Reg2, Reg3 for L3Ep by L2Ep ?
+         * - if external,
+         * - Reg7: use switch location external port else punt for now
+         * - if internal
+         * - Reg7: grab L2Ep from L3Ep and use its location info
+         * - goto_table: POLENF (will check there for external on EP)
+         */
 
-        FlowBuilder flowb = base()
-                .setPriority(Integer.valueOf(140))
-                .setId(flowId)
-                .setMatch(mb.build())
-                .setInstructions(instructions(applyActionIns(nxMoveRegTunIdAction(NxmNxReg0.class, false),
-                        groupAction(Long.valueOf(fdId)))));
-        return flowb.build();
-    }
+        ReadOnlyTransaction rTx = ctx.getDataBroker().newReadOnlyTransaction();
+        // TODO Bug #3440 Target: Be - should support for more than first gateway.
+        EndpointL3Gateways l3Gateway = prefixEp.getEndpointL3Gateways().get(0);
+        Optional<EndpointL3> optL3Ep = readFromDs(LogicalDatastoreType.OPERATIONAL,
+                IidFactory.l3EndpointIid(l3Gateway.getL3Context(), l3Gateway.getIpAddress()), rTx);
+        if (!optL3Ep.isPresent()) {
+            LOG.error("createL3PrefixFlow - L3Endpoint gateway {} for L3Prefix {} not found.", l3Gateway, prefixEp);
+            return null;
+        }
+        EndpointL3 l3Ep = optL3Ep.get();
+        if (l3Ep.getL2Context() == null || l3Ep.getMacAddress() == null) {
+            LOG.debug("L3 endpoint representing L3 gateway does not contain L2-context or MAC address. {}", l3Ep);
+            return null;
+        }
+        Optional<Endpoint> optL2Ep = readFromDs(LogicalDatastoreType.OPERATIONAL,
+                IidFactory.endpointIid(l3Ep.getL2Context(), l3Ep.getMacAddress()), rTx);
+        if (!optL2Ep.isPresent()) {
+            LOG.error("createL3PrefixFlow - L2Endpoint for L3Gateway {} not found.", l3Ep);
+            return null;
+        }
+        Endpoint l2Ep = optL2Ep.get();
+        EndpointFwdCtxOrdinals epFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, l2Ep);
+        if (epFwdCtxOrds == null) {
+            LOG.debug("getEndpointFwdCtxOrdinals is null for EP {}", l2Ep);
+            return null;
+        }
 
-    private boolean groupExists(NodeId nodeId, Integer fdId) throws Exception {
-        // Fetch existing GroupTables
-        if (ctx.getDataBroker() == null) {
-            return false;
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(l2Ep);
+
+        MacAddress epDestMac = l2Ep.getMacAddress();
+        MacAddress destSubnetGatewayMac = l2Ep.getMacAddress();
+        L3Context destL3c = getL3ContextForSubnet(prefixEp.getTenant(), subnet);
+        if (destL3c == null || destL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", subnet.getId());
+            return null;
         }
 
-        ReadOnlyTransaction t = ctx.getDataBroker().newReadOnlyTransaction();
-        InstanceIdentifier<Node> niid = createNodePath(nodeId);
-        Optional<Node> r =
-                t.read(LogicalDatastoreType.CONFIGURATION, niid).get();
-        if (!r.isPresent())
-            return false;
-        FlowCapableNode fcn = r.get().getAugmentation(FlowCapableNode.class);
-        if (fcn == null)
-            return false;
-
-        if (fcn.getGroup() != null) {
-            for (Group g : fcn.getGroup()) {
-                if (g.getGroupId().getValue().equals(Long.valueOf(fdId))) { // Group
-                                                                            // Exists.
-                    return true;
+        MacAddress matcherMac = routerPortMac(destL3c, subnet.getVirtualRouterIp());
+
+        ArrayList<Instruction> l3instructions = new ArrayList<>();
+        List<Action> applyActions = new ArrayList<>();
+        List<Action> l3ApplyActions = new ArrayList<>();
+
+        int order = 0;
+
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setNextHop;
+        String nextHop=null;
+
+        OfOverlayContext ofc = l2Ep.getAugmentation(OfOverlayContext.class);
+
+        long portNum = -1;
+        if (EndpointManager.isInternal(l2Ep, ctx.getTenant(l2Ep.getTenant()).getExternalImplicitGroups())) {
+            checkNotNull(ofc.getNodeConnectorId());
+            nextHop = ofc.getNodeConnectorId().getValue();
+            try {
+                portNum = getOfPortNum(ofc.getNodeConnectorId());
+            } catch (NumberFormatException ex) {
+                LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
+                return null;
+            }
+
+        } else {
+            // External
+            Set<NodeConnectorId> externalPorts = ctx.getSwitchManager().getExternalPorts(nodeId);
+            checkNotNull(externalPorts);
+            for (NodeConnectorId externalPort : externalPorts) {
+                // TODO Bug #3440 Target: Be - should support for more than first external port.
+                //TODO Bug 3546 - Difficult: External port is unrelated to Tenant, L3C, L2BD..
+                nextHop = externalPort.getValue();
+                try {
+                    portNum = getOfPortNum(externalPort);
+                } catch (NumberFormatException ex) {
+                    LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
+                    return null;
                 }
+                continue;
             }
         }
-        return false;
+
+        if (Strings.isNullOrEmpty(nextHop)
+                || portNum == -1) {
+            LOG.error("createL3Prefix - Cannot find nodeConnectorId for {} for Prefix: ", l2Ep, prefixEp);
+            return null;
+        }
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
+
+        Action setDlDst = setDlDstAction(epDestMac);
+        l3ApplyActions.add(setDlDst);
+
+        Action decTtl = decNwTtlAction();
+        l3ApplyActions.add(decTtl);
+
+        order += 1;
+        applyActions.add(setdEPG);
+        applyActions.add(setdCG);
+        applyActions.add(setNextHop);
+
+        applyActions.addAll(l3ApplyActions);
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
+
+        l3instructions.add(applyActionsIns);
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
+        l3instructions.add(gotoTable);
+
+        Layer3Match m = null;
+        Long etherType = null;
+        String ikey = null;
+        Integer prefixLength=0;
+        if (prefixEp.getIpPrefix().getIpv4Prefix() != null) {
+            ikey = prefixEp.getIpPrefix().getIpv4Prefix().getValue();
+            etherType = IPv4;
+            prefixLength=Integer.valueOf(prefixEp.getIpPrefix().getIpv4Prefix().getValue().split("/")[1]);
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
+        } else if (prefixEp.getIpPrefix().getIpv6Prefix() != null) {
+            ikey = prefixEp.getIpPrefix().getIpv6Prefix().getValue();
+            etherType = IPv6;
+            /*
+             *  This will result in flows with priority between 100-228, but since its matching on IPv6 prefix as well
+             *  this shouldn't pose and issue, as the priority is more important within the address space of the matcher,
+             *  even though technically flows are processed in priority order.
+             */
+
+            prefixLength=Integer.valueOf(prefixEp.getIpPrefix().getIpv6Prefix().getValue().split("/")[1]);
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
+        } else {
+            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", prefixEp);
+            return null;
+        }
+
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType));
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(epFwdCtxOrds.getL3Id())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "L3prefix", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(BASE_L3_PRIORITY+prefixLength))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
+        return flowb.build();
+    }
+
+    private Flow createBroadcastFlow(EndpointFwdCtxOrdinals epOrd) {
+        MatchBuilder mb = new MatchBuilder()
+                .setEthernetMatch(new EthernetMatchBuilder().setEthernetDestination(
+                        new EthernetDestinationBuilder().setAddress(MULTICAST_MAC)
+                                .setMask(MULTICAST_MAC)
+                                .build()).build());
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg5.class, Long.valueOf(epOrd.getFdId())));
+
+        Match match = mb.build();
+        FlowId flowId = FlowIdUtils.newFlowId(TABLE_ID, "broadcast", match);
+        FlowBuilder flowb = base().setPriority(Integer.valueOf(140))
+            .setId(flowId)
+            .setMatch(match)
+            .setInstructions(
+                    instructions(applyActionIns(nxLoadTunIdAction(BigInteger.valueOf(epOrd.getFdId()), false),
+                            groupAction(Long.valueOf(epOrd.getFdId())))));
+
+        return flowb.build();
     }
 
     private MacAddress routerPortMac(L3Context l3c, IpAddress ipAddress) {
@@ -256,9 +516,9 @@ public class DestinationMapper extends FlowTable {
         MacAddress defaultMacAddress = ROUTER_MAC;
 
         EndpointL3Key l3Key = new EndpointL3Key(ipAddress, l3c.getId());
-        InstanceIdentifier<EndpointL3> endpointsIid =
-                InstanceIdentifier.builder(Endpoints.class)
-                        .child(EndpointL3.class, l3Key).build();
+        InstanceIdentifier<EndpointL3> endpointsIid = InstanceIdentifier.builder(Endpoints.class)
+            .child(EndpointL3.class, l3Key)
+            .build();
         ReadOnlyTransaction t = ctx.getDataBroker().newReadOnlyTransaction();
 
         Optional<EndpointL3> r;
@@ -279,7 +539,12 @@ public class DestinationMapper extends FlowTable {
     }
 
     private L3Context getL3ContextForSubnet(TenantId tenantId, Subnet sn) {
-        L3Context l3c = ctx.getPolicyResolver().getTenant(tenantId).resolveL3Context(sn.getId());
+        IndexedTenant indexedTenant = ctx.getTenant(tenantId);
+        if (indexedTenant == null) {
+            LOG.debug("Tenant {} is null, cannot get L3 context", tenantId);
+            return null;
+        }
+        L3Context l3c = indexedTenant.resolveL3Context(sn.getId());
         return l3c;
     }
 
@@ -308,39 +573,27 @@ public class DestinationMapper extends FlowTable {
 
             BigInteger intRouterMac = new BigInteger(1, bytesFromHexString(routerMac.getValue()));
 
-            FlowId flowId = new FlowId(new StringBuffer()
-                    .append("routerarp|")
-                    .append(sn.getId().getValue())
-                    .append("|")
-                    .append(ikey)
-                    .append("|")
-                    .append(l3Id)
-                    .toString());
-            MatchBuilder mb = new MatchBuilder()
-                    .setEthernetMatch(ethernetMatch(null, null, ARP))
-                    .setLayer3Match(new ArpMatchBuilder()
-                            .setArpOp(Integer.valueOf(1))
-                            .setArpTargetTransportAddress(new Ipv4Prefix(ikey + "/32"))
-                            .build());
-            addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                    Long.valueOf(l3Id)));
-
-            FlowBuilder flowb = base()
-                    .setPriority(150)
-                    .setId(flowId)
-                    .setMatch(mb.build())
-                    .setInstructions(instructions(applyActionIns(nxMoveEthSrcToEthDstAction(),
-                            setDlSrcAction(routerMac),
-                            nxLoadArpOpAction(BigInteger.valueOf(2L)),
-                            nxMoveArpShaToArpThaAction(),
-                            nxLoadArpShaAction(intRouterMac),
-                            nxMoveArpSpaToArpTpaAction(),
-                            nxLoadArpSpaAction(ikey),
-                            outputAction(new NodeConnectorId(nodeId.getValue() + ":INPORT")))));
+            MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, null, ARP)).setLayer3Match(
+                    new ArpMatchBuilder().setArpOp(Integer.valueOf(1))
+                        .setArpTargetTransportAddress(new Ipv4Prefix(ikey + "/32"))
+                        .build());
+            addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(l3Id)));
+
+            Match match = mb.build();
+            FlowId flowId = FlowIdUtils.newFlowId(TABLE_ID, "routerarp", match);
+            FlowBuilder flowb = base().setPriority(150)
+                .setId(flowId)
+                .setMatch(match)
+                .setInstructions(
+                        instructions(applyActionIns(nxMoveEthSrcToEthDstAction(), setDlSrcAction(routerMac),
+                                nxLoadArpOpAction(BigInteger.valueOf(2L)), nxMoveArpShaToArpThaAction(),
+                                nxLoadArpShaAction(intRouterMac), nxMoveArpSpaToArpTpaAction(),
+                                nxLoadArpSpaAction(ikey), outputAction(new NodeConnectorId(nodeId.getValue()
+                                        + ":INPORT")))));
             return flowb.build();
         } else {
-            LOG.warn("IPv6 virtual router {} for subnet {} not supported",
-                    sn.getVirtualRouterIp(), sn.getId().getValue());
+            LOG.warn("IPv6 virtual router {} for subnet {} not supported", sn.getVirtualRouterIp(), sn.getId()
+                .getValue());
             return null;
         }
 
@@ -354,10 +607,8 @@ public class DestinationMapper extends FlowTable {
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
@@ -368,13 +619,11 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(ofc.getNodeConnectorId());
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
 
         // END L2 LOCAL
 
@@ -382,70 +631,56 @@ public class DestinationMapper extends FlowTable {
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
         instructions.add(applyActionsIns);
 
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
         instructions.add(gotoTable);
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(epFwdCtxOrds.getBdId())
-                .append("|l2|")
-                .append(ep.getMacAddress().getValue())
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ep.getMacAddress(),
-                        null));
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, ep.getMacAddress(), null));
         addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(epFwdCtxOrds.getBdId())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(50))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(instructions)
-                        .build());
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "localL2", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(50))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(instructions).build());
         return flowb.build();
     }
 
-    private void syncEP(FlowMap flowMap,
-            NodeId nodeId, PolicyInfo policyInfo,
-            Endpoint epPeer, Set<EpKey> visitedEps)
+    private void syncEP(OfWriter ofWriter, NodeId nodeId, Endpoint srcEp, Endpoint destEp)
             throws Exception {
 
-        EpKey epPeerKey = new EpKey(epPeer.getL2Context(), epPeer.getMacAddress());
-
-        if (visitedEps.contains(epPeerKey)) {
+        if (ctx.getTenant(srcEp.getTenant()) == null
+                || ctx.getTenant(destEp.getTenant()) == null) {
+            LOG.debug("Source or destination EP references empty tenant srcEp:{} destEp:{}", srcEp, destEp);
             return;
         }
-        visitedEps.add(epPeerKey);
 
         // TODO: Conditions messed up, but for now, send policyInfo until this
         // is fixed.
-        EndpointFwdCtxOrdinals epFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, epPeer);
-
-        if (epPeer.getTenant() == null || (epPeer.getEndpointGroup() == null && epPeer.getEndpointGroups() == null)) {
-            LOG.trace("Didn't process endpoint due to either tenant, or EPG(s) being null", epPeer.getKey());
+        EndpointFwdCtxOrdinals destEpFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, destEp);
+        if (destEpFwdCtxOrds == null) {
+            LOG.debug("getEndpointFwdCtxOrdinals is null for EP {}", destEp);
+            return;
+        }
+        EndpointFwdCtxOrdinals srcEpFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, srcEp);
+        if (srcEpFwdCtxOrds == null) {
+            LOG.debug("getEndpointFwdCtxOrdinals is null for EP {}", srcEp);
             return;
         }
-        OfOverlayContext ofc = epPeer.getAugmentation(OfOverlayContext.class);
 
-        // ////////////////////////////////////////////////////////////////////////////////////////
-        /*
-         * NOT HANDLING EXTERNALS
-         */
-        if (LocationType.External.equals(ofc.getLocationType())) {
-            // XXX - TODO - perform NAT and send to the external network
-            // TODO: Use case neutron gateway interface
-            LOG.warn("External endpoints not yet supported");
+
+        if (destEp.getTenant() == null || (destEp.getEndpointGroup() == null && destEp.getEndpointGroups() == null)) {
+            if (destEp.getTenant() == null) {
+                LOG.debug("Didn't process endpoint {} due to tenant being null", destEp.getKey());
+            } else {
+                LOG.debug("Didn't process endpoint {} due to EPG(s) being null", destEp.getKey());
+            }
             return;
         }
 
@@ -461,29 +696,65 @@ public class DestinationMapper extends FlowTable {
             return;
         }
 
-        if (Objects.equals(ofc.getNodeId(), nodeId)) {
+        OfOverlayContext ofc = destEp.getAugmentation(OfOverlayContext.class);
+
+        // forwarding outside of internal domain should be done when dest EP or GW is external.
+        Subnet srcSubnet = ctx.getTenant(srcEp.getTenant()).resolveSubnet(new SubnetId(srcEp.getNetworkContainment()));
+        Endpoint l2Gw = this.getL2EndpointOfSubnetGateway(srcEp.getTenant(), srcSubnet);
+        boolean destEpIsExternal = destEp.getNetworkContainment() != null
+                && EndpointManager.isExternal(destEp, ctx.getTenant(destEp.getTenant()).getExternalImplicitGroups());
+        boolean subnetGwIsExternal = l2Gw != null
+                && EndpointManager.isExternal(l2Gw, ctx.getTenant(l2Gw.getTenant()).getExternalImplicitGroups());
+        if (destEpIsExternal || subnetGwIsExternal) {
+            if (ofc == null && destEp.getNetworkContainment().equals(srcEp.getNetworkContainment())) {
+                Flow flow = createExternalL2Flow(destEp, destEpFwdCtxOrds, nodeId);
+                if (flow != null) {
+                    ofWriter.writeFlow(nodeId, TABLE_ID, flow);
+                }
+            } else if (l2Gw != null && EndpointManager.isExternal(l2Gw, ctx.getTenant(l2Gw.getTenant()).getExternalImplicitGroups())
+                    && !destEp.getNetworkContainment().equals(srcEp.getNetworkContainment())) {
+                for (L3Address l3a : destEp.getL3Address()) {
+                    if (l3a.getIpAddress() == null || l3a.getL3Context() == null) {
+                        LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",
+                                destEp.getL3Address());
+                        continue;
+                    }
+                    for (Subnet localSubnet : localSubnets) {
+                        Flow extL3Flow = createExternalL3RoutedFlow(destEp, l3a, destEpFwdCtxOrds, localSubnet, nodeId);
+                        if (extL3Flow != null) {
+                            ofWriter.writeFlow(nodeId, TABLE_ID, extL3Flow);
+                        } else {
+                            LOG.trace("Did not write remote L3 flow for endpoint {} and subnet {}", l3a.getIpAddress(),
+                                    localSubnet.getIpPrefix().getValue());
+                        }
+                    }
+                }
+            }
+        }
+        else if (ofc != null && Objects.equals(ofc.getNodeId(), nodeId)) {
             // this is a local endpoint; send to the approppriate local
             // port
 
-            flowMap.writeFlow(nodeId, TABLE_ID, createLocalL2Flow(epPeer, epFwdCtxOrds, ofc));
-
+            if (srcEpFwdCtxOrds.getBdId() == destEpFwdCtxOrds.getBdId()) {
+                ofWriter.writeFlow(nodeId, TABLE_ID, createLocalL2Flow(destEp, destEpFwdCtxOrds, ofc));
+            }
             // TODO Li alagalah: Need to move to EndpointL3 for L3 processing.
             // The Endpoint conflation must end!
-            if (epPeer.getL3Address() == null) {
-                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", epPeer.getKey());
+            if (destEp.getL3Address() == null) {
+                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", destEp.getKey());
                 return;
             }
 
-            for (L3Address l3a : epPeer.getL3Address()) {
+            for (L3Address l3a : destEp.getL3Address()) {
                 if (l3a.getIpAddress() == null || l3a.getL3Context() == null) {
                     LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",
-                            epPeer.getL3Address());
+                            destEp.getL3Address());
                     continue;
                 } else {
                     for (Subnet localSubnet : localSubnets) {
-                        Flow flow = createLocalL3Flow(epPeer, l3a, epFwdCtxOrds, ofc, localSubnet);
+                        Flow flow = createLocalL3RoutedFlow(destEp, l3a, destEpFwdCtxOrds, ofc, localSubnet);
                         if (flow != null) {
-                            flowMap.writeFlow(nodeId, TABLE_ID, flow);
+                            ofWriter.writeFlow(nodeId, TABLE_ID, flow);
                         } else {
                             LOG.trace("Did not write remote L3 flow for endpoint {} and subnet {}", l3a.getIpAddress(),
                                     localSubnet.getIpPrefix().getValue());
@@ -491,31 +762,36 @@ public class DestinationMapper extends FlowTable {
                     }
                 }
             }
-        } else {
+        } else if(ofc!= null) {
             // this endpoint is on a different switch; send to the
             // appropriate tunnel
-
-            Flow remoteL2Flow = createRemoteL2Flow(epPeer, nodeId, epFwdCtxOrds, ofc);
-            if (remoteL2Flow != null) {
-                flowMap.writeFlow(nodeId, TABLE_ID, remoteL2Flow);
+            if (srcEpFwdCtxOrds.getBdId() == destEpFwdCtxOrds.getBdId()) {
+                Flow remoteL2Flow = createRemoteL2Flow(destEp, nodeId, srcEpFwdCtxOrds, destEpFwdCtxOrds, ofc);
+                if (remoteL2Flow != null) {
+                    ofWriter.writeFlow(nodeId, TABLE_ID, remoteL2Flow);
+                }
+            } else {
+                LOG.trace("DestinationMapper: RemoteL2Flow: not created, in different BDs src: {} dst: {}",
+                        srcEpFwdCtxOrds.getBdId(), destEpFwdCtxOrds.getBdId());
             }
 
             // TODO Li alagalah: Need to move to EndpointL3 for L3 processing.
             // The Endpoint conflation must end!
-            if (epPeer.getL3Address() == null) {
-                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", epPeer.getKey());
+            if (destEp.getL3Address() == null) {
+                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", destEp.getKey());
                 return;
             }
-            for (L3Address l3a : epPeer.getL3Address()) {
+            for (L3Address l3a : destEp.getL3Address()) {
                 if (l3a.getIpAddress() == null || l3a.getL3Context() == null) {
                     LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",
-                            epPeer.getL3Address());
+                            destEp.getL3Address());
                     continue;
                 } else {
                     for (Subnet localSubnet : localSubnets) {
-                        Flow remoteL3Flow = createRemoteL3Flow(epPeer, l3a, nodeId, epFwdCtxOrds, ofc, localSubnet);
+                        Flow remoteL3Flow = createRemoteL3RoutedFlow(destEp, l3a, nodeId, srcEpFwdCtxOrds,
+                                destEpFwdCtxOrds, ofc, localSubnet);
                         if (remoteL3Flow != null) {
-                            flowMap.writeFlow(nodeId, TABLE_ID, remoteL3Flow);
+                            ofWriter.writeFlow(nodeId, TABLE_ID, remoteL3Flow);
                         } else {
                             LOG.trace("Did not write remote L3 flow for endpoint {} and subnet {}", l3a.getIpAddress(),
                                     localSubnet.getIpPrefix().getValue());
@@ -533,7 +809,7 @@ public class DestinationMapper extends FlowTable {
      * ################################## DestMapper Flow methods
      * ##################################
      */
-    private Flow createLocalL3Flow(Endpoint destEp, L3Address destL3Address, EndpointFwdCtxOrdinals epFwdCtxOrds,
+    private Flow createLocalL3RoutedFlow(Endpoint destEp, L3Address destL3Address, EndpointFwdCtxOrdinals epFwdCtxOrds,
             OfOverlayContext ofc, Subnet srcSubnet) {
 
         // TODO Li alagalah - refactor common code but keep simple method
@@ -541,10 +817,10 @@ public class DestinationMapper extends FlowTable {
         Subnet destSubnet = null;
         HashSet<Subnet> subnets = getSubnets(destEp.getTenant());
         if (subnets == null) {
-            LOG.trace("No subnets in tenant {}", destL3Address.getIpAddress());
+            LOG.trace("No subnets in tenant {}", destEp.getTenant());
             return null;
         }
-        NetworkDomainId epNetworkContainment= getEPNetworkContainment(destEp);
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(destEp);
         for (Subnet subnet : subnets) {
             // TODO Li alagalah add IPv6 support
             if (subnet.getId().getValue().equals(epNetworkContainment.getValue())) {
@@ -580,19 +856,17 @@ public class DestinationMapper extends FlowTable {
 
         if (!(srcL3c.getId().getValue().equals(destL3c.getId().getValue()))) {
             LOG.trace("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
-                    .getValue(), destL3c.getId().getValue());
+                .getValue(), destL3c.getId().getValue());
             return null;
         }
 
-        MacAddress destMacAddress = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
-        MacAddress srcMacAddress = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
+        MacAddress matcherMac = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
+        MacAddress epDestMac = destEp.getMacAddress();
+        MacAddress destSubnetGatewayMac = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
 
-        // TODO Li alagalah: using gateway field instead of overloading
-        // virtual-router-ip will remove need for the && check.
-        if (srcMacAddress.getValue().equals(destMacAddress.getValue()) &&
-                !(srcMacAddress.getValue().equals(ROUTER_MAC.getValue()))) {
-            LOG.trace("Same source and destination MacAddress in createL3 Flow, this flow not needed as handled by ARP");
-            return null;
+        if (srcSubnet.getId().getValue().equals(destSubnet.getId().getValue())) {
+            // This is our final destination, so match on actual EP mac.
+            matcherMac = epDestMac;
         }
 
         ArrayList<Instruction> l3instructions = new ArrayList<>();
@@ -601,16 +875,11 @@ public class DestinationMapper extends FlowTable {
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
-        Action setDlSrc = setDlSrcAction(destMacAddress);
-        Action decTtl = decNwTtlAction();
-
         // BEGIN L3 LOCAL
         nextHop = ofc.getNodeConnectorId().getValue();
 
@@ -618,36 +887,175 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(ofc.getNodeConnectorId());
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
+        // END L3 LOCAL
 
-        Action setDlDst = setDlDstAction(destEp.getMacAddress());
+        // Lets not re-write the srcMac if its local.
+        if (!(matcherMac.getValue().equals(epDestMac.getValue()))) {
+            Action setDlSrc = setDlSrcAction(destSubnetGatewayMac);
+            l3ApplyActions.add(setDlSrc);
+        }
+
+        Action setDlDst = setDlDstAction(epDestMac);
         l3ApplyActions.add(setDlDst);
+
+        Action decTtl = decNwTtlAction();
+        l3ApplyActions.add(decTtl);
+
+        order += 1;
+        applyActions.add(setdEPG);
+        applyActions.add(setdCG);
+        applyActions.add(setNextHop);
+
+        applyActions.addAll(l3ApplyActions);
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
+
+        l3instructions.add(applyActionsIns);
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
+        l3instructions.add(gotoTable);
+        Layer3Match m = null;
+        Long etherType = null;
+        String ikey = null;
+        if (destL3Address.getIpAddress().getIpv4Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv4Address().getValue() + "/32";
+            etherType = IPv4;
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
+        } else if (destL3Address.getIpAddress().getIpv6Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv6Address().getValue() + "/128";
+            etherType = IPv6;
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
+        } else {
+            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", destL3Address.toString());
+            return null;
+        }
+
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType))
+            .setLayer3Match(m);
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(epFwdCtxOrds.getL3Id())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "localL3", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(132))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
+        return flowb.build();
+    }
+
+    private Flow createExternalL3RoutedFlow(Endpoint destEp, L3Address destL3Address, EndpointFwdCtxOrdinals epFwdCtxOrds,
+            Subnet srcSubnet, NodeId nodeId) {
+
+        Subnet destSubnet = null;
+        HashSet<Subnet> subnets = getSubnets(destEp.getTenant());
+        if (subnets == null) {
+            LOG.trace("No subnets in tenant {}", destEp.getTenant());
+            return null;
+        }
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(destEp);
+        for (Subnet subnet : subnets) {
+            // TODO Li alagalah add IPv6 support
+            if (subnet.getId().getValue().equals(epNetworkContainment.getValue())) {
+                destSubnet = subnet;
+                break;
+            }
+        }
+        if (destSubnet == null) {
+            LOG.trace("Destination IP address does not match any subnet in tenant {}", destL3Address.getIpAddress());
+            return null;
+        }
+
+        if (destSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Destination subnet {} for Endpoint {}.{} has no gateway IP", destSubnet.getIpPrefix(),
+                    destL3Address.getKey());
+            return null;
+        }
+
+        if (srcSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Local subnet {} has no gateway IP", srcSubnet.getIpPrefix());
+            return null;
+        }
+        L3Context destL3c = getL3ContextForSubnet(destEp.getTenant(), destSubnet);
+        if (destL3c == null || destL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", destSubnet.getId());
+            return null;
+        }
+        L3Context srcL3c = getL3ContextForSubnet(destEp.getTenant(), srcSubnet);
+        if (srcL3c == null || srcL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", srcSubnet.getId());
+            return null;
+        }
+
+        if (!(srcL3c.getId().getValue().equals(destL3c.getId().getValue()))) {
+            LOG.trace("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
+                .getValue(), destL3c.getId().getValue());
+            return null;
+        }
+
+        Endpoint l2Gw = getL2EndpointOfSubnetGateway(destEp.getTenant(), srcSubnet);
+        if(l2Gw == null) {
+            LOG.warn("The endpoint representing external gateway of subnet {} not found", srcSubnet);
+            return null;
+        }
+        MacAddress matcherMac = destEp.getMacAddress();
+        MacAddress destSubnetGatewayMac = l2Gw.getMacAddress();
+
+        ArrayList<Instruction> l3instructions = new ArrayList<>();
+        List<Action> applyActions = new ArrayList<>();
+        List<Action> l3ApplyActions = new ArrayList<>();
+
+        int order = 0;
+
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setNextHop;
+
+        Set<NodeConnectorId> extPorts = ctx.getSwitchManager().getExternalPorts(nodeId);
+        if (extPorts == null || !extPorts.iterator().hasNext()) {
+            LOG.warn("No external interface on node: {}. External Gateway {} is not reachable!", nodeId, l2Gw.getKey());
+            return null;
+        }
+        // only one external port is supported for now
+         NodeConnectorId extPort = extPorts.iterator().next();
+
+        long portNum;
+        try {
+            portNum = getOfPortNum(extPort);
+        } catch (NumberFormatException ex) {
+            LOG.warn("Could not parse port number {}", extPort, ex);
+            return null;
+        }
+
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
         // END L3 LOCAL
 
+
+        Action setDlSrc = setDlSrcAction(destSubnetGatewayMac);
         l3ApplyActions.add(setDlSrc);
-        l3ApplyActions.add(decTtl);
+
+        Action setDlDst = setDlDstAction(l2Gw.getMacAddress());
+        l3ApplyActions.add(setDlDst);
+
         order += 1;
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
 
         applyActions.addAll(l3ApplyActions);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
         l3instructions.add(applyActionsIns);
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
         l3instructions.add(gotoTable);
         Layer3Match m = null;
         Long etherType = null;
@@ -655,54 +1063,50 @@ public class DestinationMapper extends FlowTable {
         if (destL3Address.getIpAddress().getIpv4Address() != null) {
             ikey = destL3Address.getIpAddress().getIpv4Address().getValue() + "/32";
             etherType = IPv4;
-            m = new Ipv4MatchBuilder()
-                    .setIpv4Destination(new Ipv4Prefix(ikey))
-                    .build();
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
         } else if (destL3Address.getIpAddress().getIpv6Address() != null) {
             ikey = destL3Address.getIpAddress().getIpv6Address().getValue() + "/128";
             etherType = IPv6;
-            m = new Ipv6MatchBuilder()
-                    .setIpv6Destination(new Ipv6Prefix(ikey))
-                    .build();
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
         } else {
             LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", destL3Address.toString());
             return null;
         }
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(Integer.toString(epFwdCtxOrds.getL3Id()))
-                .append("|l3|")
-                .append(ikey)
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getEpgId()))
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getCgId()))
-                .append("|")
-                .append(srcMacAddress)
-                .append("|")
-                .append(destMacAddress)
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        srcMacAddress,
-                        etherType))
-                .setLayer3Match(m);
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                Long.valueOf(epFwdCtxOrds.getL3Id())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(132))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(l3instructions)
-                        .build());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType))
+            .setLayer3Match(m);
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(epFwdCtxOrds.getL3Id())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "externalL3", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(132))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
         return flowb.build();
     }
 
-    private Flow createRemoteL2Flow(Endpoint ep, NodeId nodeId, EndpointFwdCtxOrdinals epFwdCtxOrds,
-            OfOverlayContext ofc) {
+    private Endpoint getL2EndpointOfSubnetGateway(TenantId tenantId, Subnet subnet) {
+        if (subnet != null && subnet.getVirtualRouterIp() != null) {
+            IpAddress gwIpAddress = subnet.getVirtualRouterIp();
+            Collection<EndpointL3Prefix> prefixEps = ctx.getEndpointManager().getEndpointsL3PrefixForTenant(tenantId);
+            if (prefixEps != null) {
+                for (EndpointL3Prefix prefixEp : prefixEps) {
+                    for (EndpointL3Gateways gw : prefixEp.getEndpointL3Gateways()) {
+                        EndpointL3 l3Ep = ctx.getEndpointManager().getL3Endpoint(gw.getL3Context(), gwIpAddress,
+                                prefixEp.getTenant());
+                        if (l3Ep != null && l3Ep.getL2Context() != null && l3Ep.getMacAddress() != null) {
+                            return ctx.getEndpointManager().getEndpoint(
+                                    new EpKey(l3Ep.getL2Context(), l3Ep.getMacAddress()));
+                        }
+                    }
+                }
+            }
+        }
+        return null;
+    }
+
+    private Flow createRemoteL2Flow(Endpoint ep, NodeId nodeId, EndpointFwdCtxOrdinals srcEpFwdCtxOrds,
+            EndpointFwdCtxOrdinals destEpFwdCtxOrds, OfOverlayContext ofc) {
 
         // TODO Li alagalah - refactor common code but keep simple method
 
@@ -714,18 +1118,14 @@ public class DestinationMapper extends FlowTable {
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(destEpFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(destEpFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
         // BEGIN TUNNEL HANDLING
-        IpAddress tunDst =
-                ctx.getSwitchManager().getTunnelIP(ofc.getNodeId());
-        NodeConnectorId tunPort =
-                ctx.getSwitchManager().getTunnelPort(nodeId);
+        IpAddress tunDst = ctx.getSwitchManager().getTunnelIP(ofc.getNodeId(), TunnelTypeVxlan.class);
+        NodeConnectorId tunPort = ctx.getSwitchManager().getTunnelPort(nodeId, TunnelTypeVxlan.class);
         if (tunDst == null) {
             LOG.warn("Failed to get Tunnel IP for NodeId {} with EP {}", nodeId, ep);
             return null;
@@ -742,8 +1142,7 @@ public class DestinationMapper extends FlowTable {
             tundstAction = nxLoadTunIPv4Action(nextHop, false);
         } else if (tunDst.getIpv6Address() != null) {
             // nextHop = tunDst.getIpv6Address().getValue();
-            LOG.error("IPv6 tunnel destination {} for {} not supported",
-                    tunDst.getIpv6Address().getValue(),
+            LOG.error("IPv6 tunnel destination {} for {} not supported", tunDst.getIpv6Address().getValue(),
                     ofc.getNodeId());
             return null;
         } else {
@@ -756,17 +1155,11 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(tunPort);
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
-        Action tunIdAction =
-                nxMoveRegTunIdAction(NxmNxReg0.class, false);
-
-        applyActions.add(tunIdAction);
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
         applyActions.add(tundstAction);
         // END TUNNEL
 
@@ -774,48 +1167,89 @@ public class DestinationMapper extends FlowTable {
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
         instructions.add(applyActionsIns);
 
-        applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
         instructions.add(gotoTable);
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(epFwdCtxOrds.getBdId())
-                .append("|l2|")
-                .append(ep.getMacAddress().getValue())
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ep.getMacAddress(),
-                        null));
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(epFwdCtxOrds.getBdId())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(50))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(instructions)
-                        .build());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, ep.getMacAddress(), null));
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(destEpFwdCtxOrds.getBdId())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "remoteL2", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(50))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(instructions).build());
 
         return flowb.build();
     }
 
-    private Flow createRemoteL3Flow(Endpoint destEp, L3Address destL3Address, NodeId nodeId,
-            EndpointFwdCtxOrdinals epFwdCtxOrds, OfOverlayContext ofc, Subnet srcSubnet) {
+    private Flow createExternalL2Flow(Endpoint ep, EndpointFwdCtxOrdinals epFwdCtxOrds,NodeId nodeId) {
+
+        ArrayList<Instruction> instructions = new ArrayList<>();
+        List<Action> applyActions = new ArrayList<>();
+
+        int order = 0;
+
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setNextHop;
+
+        // BEGIN L2 LOCAL
+        Set<NodeConnectorId> extPorts = ctx.getSwitchManager().getExternalPorts(nodeId);
+        if(extPorts == null || !extPorts.iterator().hasNext()) {
+            return null;
+        }
+        // Only one external port is currently supported.
+        NodeConnectorId extPort = extPorts.iterator().next();
+        long portNum;
+        try {
+            portNum = getOfPortNum(extPort);
+        } catch (NumberFormatException ex) {
+            LOG.warn("Could not parse port number {}", extPort, ex);
+            return null;
+        }
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
+
+        // END L2 LOCAL
+
+        order += 1;
+        applyActions.add(setdEPG);
+        applyActions.add(setdCG);
+        applyActions.add(setNextHop);
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
+        instructions.add(applyActionsIns);
+
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
+        instructions.add(gotoTable);
+
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, ep.getMacAddress(), null));
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(epFwdCtxOrds.getBdId())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "externalL2", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(50))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(instructions).build());
+        return flowb.build();
+    }
+
+    private Flow createRemoteL3RoutedFlow(Endpoint destEp, L3Address destL3Address, NodeId nodeId,
+            EndpointFwdCtxOrdinals srcEpFwdCtxOrds, EndpointFwdCtxOrdinals destEpFwdCtxOrds, OfOverlayContext ofc,
+            Subnet srcSubnet) {
 
         // TODO Li alagalah - refactor common code but keep simple method
 
@@ -824,10 +1258,10 @@ public class DestinationMapper extends FlowTable {
         Subnet destSubnet = null;
         HashSet<Subnet> subnets = getSubnets(destEp.getTenant());
         if (subnets == null) {
-            LOG.trace("No subnets in tenant {}", destL3Address.getIpAddress());
+            LOG.trace("No subnets in tenant {}", destEp.getTenant());
             return null;
         }
-        NetworkDomainId epNetworkContainment= getEPNetworkContainment(destEp);
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(destEp);
         for (Subnet subnet : subnets) {
             // TODO Li alagalah add IPv6 support
             if (subnet.getId().getValue().equals(epNetworkContainment.getValue())) {
@@ -850,55 +1284,44 @@ public class DestinationMapper extends FlowTable {
             LOG.trace("Local subnet {} has no gateway IP", srcSubnet.getIpPrefix());
             return null;
         }
-        L3Context destL3c = getL3ContextForSubnet(destEp.getTenant(),destSubnet);
+        L3Context destL3c = getL3ContextForSubnet(destEp.getTenant(), destSubnet);
         if (destL3c == null || destL3c.getId() == null) {
             LOG.error("No L3 Context found associated with subnet {}", destSubnet.getId());
             return null;
         }
-        L3Context srcL3c = getL3ContextForSubnet(destEp.getTenant(),srcSubnet);
+        L3Context srcL3c = getL3ContextForSubnet(destEp.getTenant(), srcSubnet);
         if (srcL3c == null || srcL3c.getId() == null) {
             LOG.error("No L3 Context found associated with subnet {}", srcSubnet.getId());
             return null;
         }
 
         if (!(srcL3c.getId().getValue().equals(destL3c.getId().getValue()))) {
-            LOG.info("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
-                    .getValue(), destL3c.getId().getValue());
+            LOG.trace("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
+                .getValue(), destL3c.getId().getValue());
             return null;
         }
 
-        MacAddress destMacAddress = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
-        MacAddress srcMacAddress = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
-
-        // TODO Li alagalah: using gateway field instead of overloading
-        // virtual-router-ip will remove need for the && check.
-        if (srcMacAddress.getValue().equals(destMacAddress.getValue()) &&
-                !(srcMacAddress.getValue().equals(ROUTER_MAC.getValue()))) {
-            LOG.trace("Same source and destination MacAddress in createL3 Flow, this flow not needed as handled by ARP");
-            return null;
+        MacAddress matcherMac = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
+        MacAddress epDestMac = destEp.getMacAddress();
+        MacAddress destSubnetGatewayMac = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
+        if (srcSubnet.getId().getValue().equals(destSubnet.getId().getValue())) {
+            // This is our final destination, so match on actual EP mac.
+            matcherMac = epDestMac;
         }
-
         ArrayList<Instruction> l3instructions = new ArrayList<>();
         List<Action> applyActions = new ArrayList<>();
         List<Action> l3ApplyActions = new ArrayList<>();
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(destEpFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(destEpFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
-        Action setDlSrc = setDlSrcAction(srcMacAddress);
-        Action decTtl = decNwTtlAction();
-
         // BEGIN TUNNEL HANDLING
-        IpAddress tunDst =
-                ctx.getSwitchManager().getTunnelIP(ofc.getNodeId());
-        NodeConnectorId tunPort =
-                ctx.getSwitchManager().getTunnelPort(nodeId);
+        IpAddress tunDst = ctx.getSwitchManager().getTunnelIP(ofc.getNodeId(), TunnelTypeVxlan.class);
+        NodeConnectorId tunPort = ctx.getSwitchManager().getTunnelPort(nodeId, TunnelTypeVxlan.class);
         if (tunDst == null) {
             LOG.warn("Failed to get Tunnel IP for NodeId {} with L3Address {}", nodeId, destL3Address);
             return null;
@@ -915,8 +1338,7 @@ public class DestinationMapper extends FlowTable {
             tundstAction = nxLoadTunIPv4Action(nextHop, false);
         } else if (tunDst.getIpv6Address() != null) {
             // nextHop = tunDst.getIpv6Address().getValue();
-            LOG.error("IPv6 tunnel destination {} for {} not supported",
-                    tunDst.getIpv6Address().getValue(),
+            LOG.error("IPv6 tunnel destination {} for {} not supported", tunDst.getIpv6Address().getValue(),
                     ofc.getNodeId());
             return null;
         } else {
@@ -929,40 +1351,40 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(tunPort);
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
-        Action tunIdAction =
-                nxMoveRegTunIdAction(NxmNxReg0.class, false);
-
-        applyActions.add(tunIdAction);
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
         applyActions.add(tundstAction);
         // END TUNNEL
 
-        l3ApplyActions.add(setDlSrc);
-        l3ApplyActions.add(decTtl);
         order += 1;
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
-        l3ApplyActions.add(setDlSrc);
+
+        // Lets not re-write the srcMac if its local.
+        if (!(matcherMac.getValue().equals(epDestMac.getValue()))) {
+            Action setDlSrc = setDlSrcAction(destSubnetGatewayMac);
+            l3ApplyActions.add(setDlSrc);
+        }
+
+        Action setDlDst = setDlDstAction(epDestMac);
+        l3ApplyActions.add(setDlDst);
+
+        Action decTtl = decNwTtlAction();
         l3ApplyActions.add(decTtl);
 
         applyActions.addAll(l3ApplyActions);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
         l3instructions.add(applyActionsIns);
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns(ctx.getPolicyManager().getTABLEID_POLICY_ENFORCER()))
+            .build();
         l3instructions.add(gotoTable);
         Layer3Match m = null;
         Long etherType = null;
@@ -970,49 +1392,25 @@ public class DestinationMapper extends FlowTable {
         if (destL3Address.getIpAddress().getIpv4Address() != null) {
             ikey = destL3Address.getIpAddress().getIpv4Address().getValue() + "/32";
             etherType = IPv4;
-            m = new Ipv4MatchBuilder()
-                    .setIpv4Destination(new Ipv4Prefix(ikey))
-                    .build();
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
         } else if (destL3Address.getIpAddress().getIpv6Address() != null) {
             ikey = destL3Address.getIpAddress().getIpv6Address().getValue() + "/128";
             etherType = IPv6;
-            m = new Ipv6MatchBuilder()
-                    .setIpv6Destination(new Ipv6Prefix(ikey))
-                    .build();
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
         } else {
             LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", destL3Address.toString());
             return null;
         }
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(Integer.toString(epFwdCtxOrds.getL3Id()))
-                .append("|l3|")
-                .append(ikey)
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getEpgId()))
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getCgId()))
-                .append("|")
-                .append(srcMacAddress)
-                .append("|")
-                .append(destMacAddress)
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        destMacAddress,
-                        etherType))
-                .setLayer3Match(m);
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                Long.valueOf(epFwdCtxOrds.getL3Id())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(132))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(l3instructions)
-                        .build());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType))
+            .setLayer3Match(m);
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(destEpFwdCtxOrds.getL3Id())));
+        Match match = mb.build();
+        FlowId flowid = FlowIdUtils.newFlowId(TABLE_ID, "remoteL3", match);
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(132))
+            .setMatch(match)
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
         return flowb.build();
     }
 
@@ -1025,17 +1423,14 @@ public class DestinationMapper extends FlowTable {
              * which we can't do because of the backwards way endpoints were
              * "architected".
              */
-            return ctx.getPolicyResolver().getTenant(endpoint.getTenant())
-                    .getEndpointGroup(endpoint.getEndpointGroup()).getNetworkDomain();
+            return ctx.getTenant(endpoint.getTenant())
+                .getEndpointGroup(endpoint.getEndpointGroup())
+                .getNetworkDomain();
         }
     }
 
     private HashSet<Subnet> getSubnets(final TenantId tenantId) {
 
-        // if (subnetsByTenant.get(tenantId) != null) {
-        // return subnetsByTenant.get(tenantId);
-        // }
-
         if (ctx.getDataBroker() == null) {
             return null;
         }
@@ -1048,18 +1443,20 @@ public class DestinationMapper extends FlowTable {
         } catch (Exception e) {
             LOG.error("Could not read Tenant {}", tenantId, e);
             return null;
+        } finally {
+            t.close();
         }
 
-        HashSet<Subnet> subnets = new HashSet<Subnet>();
-
         if (!tenantInfo.isPresent()) {
             LOG.warn("Tenant {} not found", tenantId);
             return null;
         }
 
-        subnets.addAll(tenantInfo.get().getSubnet());
-        // subnetsByTenant.put(tenantId, subnets);
-        return subnets;
+        ForwardingContext fwCtx = tenantInfo.get().getForwardingContext();
+        if (fwCtx == null || fwCtx.getSubnet() == null) {
+            return new HashSet<>();
+        }
+        return new HashSet<>(fwCtx.getSubnet());
     }
 
     // Need a method to get subnets for EPs attached to the node locally
@@ -1072,10 +1469,10 @@ public class DestinationMapper extends FlowTable {
         for (Endpoint endpoint : endpointsForNode) {
             HashSet<Subnet> subnets = getSubnets(endpoint.getTenant());
             if (subnets == null) {
-                LOG.error("No local subnets.");
-                return null;
+                LOG.debug("No local subnets in tenant {} for EP {}.", endpoint.getTenant(), endpoint.getKey());
+                continue;
             }
-            NetworkDomainId epNetworkContainment= getEPNetworkContainment(endpoint);
+            NetworkDomainId epNetworkContainment = getEPNetworkContainment(endpoint);
             for (Subnet subnet : subnets) {
                 if (epNetworkContainment.getValue().equals(subnet.getId().getValue())) {
                     localSubnets.add(subnet);
@@ -1085,24 +1482,6 @@ public class DestinationMapper extends FlowTable {
         return localSubnets;
     }
 
-    /**
-     * Reads data from datastore as synchronous call.
-     *
-     * @return {@link Optional#isPresent()} is {@code true} if reading was
-     *         successful and data exists in datastore;
-     *         {@link Optional#isPresent()} is {@code false} otherwise
-     */
-    public static <T extends DataObject> Optional<T> readFromDs(LogicalDatastoreType store, InstanceIdentifier<T> path,
-            ReadTransaction rTx) {
-        CheckedFuture<Optional<T>, ReadFailedException> resultFuture = rTx.read(store, path);
-        try {
-            return resultFuture.checkedGet();
-        } catch (ReadFailedException e) {
-            LOG.warn("Read failed from DS.", e);
-            return Optional.absent();
-        }
-    }
-
     static byte[] bytesFromHexString(String values) {
         String target = "";
         if (values != null) {