diff --git a/core/store/dist/src/main/java/org/onosproject/store/link/impl/CoreConfig.java b/core/store/dist/src/main/java/org/onosproject/store/link/impl/CoreConfig.java
new file mode 100644
index 0000000..dba3106
--- /dev/null
+++ b/core/store/dist/src/main/java/org/onosproject/store/link/impl/CoreConfig.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.link.impl;
+
+import org.onosproject.core.ApplicationId;
+import org.onosproject.net.config.Config;
+
+public class CoreConfig extends Config<ApplicationId> {
+
+    private static final String LINK_DISCOVERY_MODE = "linkDiscoveryMode";
+
+    protected static final String DEFAULT_LINK_DISCOVERY_MODE = "PERMISSIVE";
+
+    /**
+     * Returns the link discovery mode.
+     *
+     * @return link discovery mode
+     */
+    public ECLinkStore.LinkDiscoveryMode linkDiscoveryMode() {
+        return ECLinkStore.LinkDiscoveryMode
+                .valueOf(get(LINK_DISCOVERY_MODE, DEFAULT_LINK_DISCOVERY_MODE));
+    }
+}
+
diff --git a/core/store/dist/src/main/java/org/onosproject/store/link/impl/ECLinkStore.java b/core/store/dist/src/main/java/org/onosproject/store/link/impl/ECLinkStore.java
index 8e77ac8..845518e 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/link/impl/ECLinkStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/link/impl/ECLinkStore.java
@@ -15,21 +15,6 @@
  */
 package org.onosproject.store.link.impl;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-import static org.onosproject.net.DefaultAnnotations.merge;
-import static org.onosproject.net.DefaultAnnotations.union;
-import static org.onosproject.net.Link.State.ACTIVE;
-import static org.onosproject.net.Link.State.INACTIVE;
-import static org.onosproject.net.Link.Type.DIRECT;
-import static org.onosproject.net.Link.Type.INDIRECT;
-import static org.onosproject.net.LinkKey.linkKey;
-import static org.onosproject.net.link.LinkEvent.Type.LINK_ADDED;
-import static org.onosproject.net.link.LinkEvent.Type.LINK_REMOVED;
-import static org.onosproject.net.link.LinkEvent.Type.LINK_UPDATED;
-import static org.onosproject.store.service.EventuallyConsistentMapEvent.Type.PUT;
-import static org.onosproject.store.service.EventuallyConsistentMapEvent.Type.REMOVE;
-import static org.slf4j.LoggerFactory.getLogger;
-
 import java.util.Collection;
 import java.util.Map;
 import java.util.Objects;
@@ -48,6 +33,8 @@
 import org.onlab.util.SharedExecutors;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.NodeId;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
 import org.onosproject.mastership.MastershipService;
 import org.onosproject.net.AnnotationKeys;
 import org.onosproject.net.AnnotationsUtil;
@@ -56,8 +43,12 @@
 import org.onosproject.net.DefaultLink;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.Link;
-import org.onosproject.net.LinkKey;
 import org.onosproject.net.Link.Type;
+import org.onosproject.net.LinkKey;
+import org.onosproject.net.config.ConfigFactory;
+import org.onosproject.net.config.NetworkConfigEvent;
+import org.onosproject.net.config.NetworkConfigListener;
+import org.onosproject.net.config.NetworkConfigRegistry;
 import org.onosproject.net.device.DeviceClockService;
 import org.onosproject.net.link.DefaultLinkDescription;
 import org.onosproject.net.link.LinkDescription;
@@ -82,6 +73,22 @@
 import com.google.common.collect.Maps;
 import com.google.common.util.concurrent.Futures;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onosproject.net.DefaultAnnotations.merge;
+import static org.onosproject.net.DefaultAnnotations.union;
+import static org.onosproject.net.Link.State.ACTIVE;
+import static org.onosproject.net.Link.State.INACTIVE;
+import static org.onosproject.net.Link.Type.DIRECT;
+import static org.onosproject.net.Link.Type.INDIRECT;
+import static org.onosproject.net.LinkKey.linkKey;
+import static org.onosproject.net.config.basics.SubjectFactories.APP_SUBJECT_FACTORY;
+import static org.onosproject.net.link.LinkEvent.Type.LINK_ADDED;
+import static org.onosproject.net.link.LinkEvent.Type.LINK_REMOVED;
+import static org.onosproject.net.link.LinkEvent.Type.LINK_UPDATED;
+import static org.onosproject.store.service.EventuallyConsistentMapEvent.Type.PUT;
+import static org.onosproject.store.service.EventuallyConsistentMapEvent.Type.REMOVE;
+import static org.slf4j.LoggerFactory.getLogger;
+
 /**
  * Manages the inventory of links using a {@code EventuallyConsistentMap}.
  */
@@ -91,11 +98,29 @@
     extends AbstractStore<LinkEvent, LinkStoreDelegate>
     implements LinkStore {
 
+    /**
+     * Modes for dealing with newly discovered links.
+     */
+    protected enum LinkDiscoveryMode {
+        /**
+         * Permissive mode - all newly discovered links are valid.
+         */
+        PERMISSIVE,
+
+        /**
+         * Strict mode - all newly discovered links must be defined in
+         * the network config.
+         */
+        STRICT
+    }
+
     private final Logger log = getLogger(getClass());
 
     private final Map<LinkKey, Link> links = Maps.newConcurrentMap();
     private EventuallyConsistentMap<Provided<LinkKey>, LinkDescription> linkDescriptions;
 
+    private ApplicationId appId;
+
     private static final MessageSubject LINK_INJECT_MESSAGE = new MessageSubject("inject-link-request");
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
@@ -113,9 +138,20 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClusterService clusterService;
 
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected NetworkConfigRegistry netCfgService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CoreService coreService;
+
     private EventuallyConsistentMapListener<Provided<LinkKey>, LinkDescription> linkTracker =
             new InternalLinkTracker();
 
+    // Listener for config changes
+    private final InternalConfigListener cfgListener = new InternalConfigListener();
+
+    protected LinkDiscoveryMode linkDiscoveryMode = LinkDiscoveryMode.STRICT;
+
     protected static final KryoSerializer SERIALIZER = new KryoSerializer() {
         @Override
         protected void setupKryoPool() {
@@ -129,6 +165,12 @@
 
     @Activate
     public void activate() {
+        appId = coreService.registerApplication("org.onosproject.core");
+        netCfgService.registerConfigFactory(factory);
+        netCfgService.addListener(cfgListener);
+
+        cfgListener.reconfigure(netCfgService.getConfig(appId, CoreConfig.class));
+
         KryoNamespace.Builder serializer = KryoNamespace.newBuilder()
                 .register(KryoNamespaces.API)
                 .register(MastershipBasedTimestamp.class)
@@ -162,6 +204,8 @@
         linkDescriptions.destroy();
         links.clear();
         clusterCommunicator.removeSubscriber(LINK_INJECT_MESSAGE);
+        netCfgService.removeListener(cfgListener);
+        netCfgService.unregisterConfigFactory(factory);
 
         log.info("Stopped");
     }
@@ -255,6 +299,7 @@
                         current.src(),
                         current.dst(),
                         current.type() == DIRECT ? DIRECT : updated.type(),
+                        current.isExpected(),
                         union(current.annotations(), updated.annotations()));
         }
         return updated;
@@ -268,6 +313,7 @@
                 eventType.set(LINK_ADDED);
                 return newLink;
             } else if (existingLink.state() != newLink.state() ||
+                       existingLink.isExpected() != newLink.isExpected() ||
                         (existingLink.type() == INDIRECT && newLink.type() == DIRECT) ||
                         !AnnotationsUtil.isEqual(existingLink.annotations(), newLink.annotations())) {
                     eventType.set(LINK_UPDATED);
@@ -316,14 +362,28 @@
                                                           linkDescriptions.get(key).annotations()));
         });
 
-        boolean isDurable = Objects.equals(annotations.get().value(AnnotationKeys.DURABLE), "true");
+        Link.State initialLinkState;
+
+        boolean isExpected;
+        if (linkDiscoveryMode == LinkDiscoveryMode.PERMISSIVE) {
+            initialLinkState = ACTIVE;
+            isExpected =
+                    Objects.equals(annotations.get().value(AnnotationKeys.DURABLE), "true");
+        } else {
+            initialLinkState = base.isExpected() ? ACTIVE : INACTIVE;
+            isExpected = base.isExpected();
+        }
+
+
+
+
         return DefaultLink.builder()
                 .providerId(baseProviderId)
                 .src(src)
                 .dst(dst)
                 .type(type)
-                .state(ACTIVE)
-                .isExpected(isDurable)
+                .state(initialLinkState)
+                .isExpected(isExpected)
                 .annotations(annotations.get())
                 .build();
     }
@@ -350,7 +410,7 @@
             return null;
         }
 
-        if (link.isDurable()) {
+        if (linkDiscoveryMode == LinkDiscoveryMode.PERMISSIVE && link.isExpected()) {
             // FIXME: this will not sync link state!!!
             return link.state() == INACTIVE ? null :
                     updateLink(linkKey(link.src(), link.dst()), link,
@@ -421,4 +481,47 @@
             }
         }
     }
+
+    private class InternalConfigListener implements NetworkConfigListener {
+
+        void reconfigure(CoreConfig coreConfig) {
+            if (coreConfig == null) {
+                linkDiscoveryMode = LinkDiscoveryMode.PERMISSIVE;
+            } else {
+                linkDiscoveryMode = coreConfig.linkDiscoveryMode();
+            }
+            if (linkDiscoveryMode == LinkDiscoveryMode.STRICT) {
+                // Remove any previous links to force them to go through the strict
+                // discovery process
+                linkDescriptions.clear();
+                links.clear();
+            }
+            log.debug("config set link discovery mode to {}",
+                      linkDiscoveryMode.name());
+        }
+
+        @Override
+        public void event(NetworkConfigEvent event) {
+
+            if ((event.type() == NetworkConfigEvent.Type.CONFIG_ADDED ||
+                    event.type() == NetworkConfigEvent.Type.CONFIG_UPDATED) &&
+                    event.configClass().equals(CoreConfig.class)) {
+
+                CoreConfig cfg = netCfgService.getConfig(appId, CoreConfig.class);
+                reconfigure(cfg);
+                log.info("Reconfigured");
+            }
+        }
+    }
+
+    // Configuration properties factory
+    private final ConfigFactory factory =
+            new ConfigFactory<ApplicationId, CoreConfig>(APP_SUBJECT_FACTORY,
+                                                        CoreConfig.class,
+                                                        "core") {
+                @Override
+                public CoreConfig createConfig() {
+                    return new CoreConfig();
+                }
+            };
 }
diff --git a/core/store/dist/src/main/java/org/onosproject/store/link/impl/GossipLinkStore.java b/core/store/dist/src/main/java/org/onosproject/store/link/impl/GossipLinkStore.java
index cf46b15..551e731 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/link/impl/GossipLinkStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/link/impl/GossipLinkStore.java
@@ -15,12 +15,20 @@
  */
 package org.onosproject.store.link.impl;
 
-import com.google.common.base.Function;
-import com.google.common.collect.FluentIterable;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Multimaps;
-import com.google.common.collect.SetMultimap;
-import com.google.common.collect.Sets;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
 import org.apache.commons.lang3.RandomUtils;
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -32,7 +40,6 @@
 import org.onosproject.cluster.ControllerNode;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.mastership.MastershipService;
-import org.onosproject.net.AnnotationKeys;
 import org.onosproject.net.AnnotationsUtil;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.DefaultAnnotations;
@@ -60,20 +67,12 @@
 import org.onosproject.store.serializers.custom.DistributedStoreSerializers;
 import org.slf4j.Logger;
 
-import java.io.IOException;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.Objects;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentMap;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
+import com.google.common.base.Function;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Multimaps;
+import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Sets;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Predicates.notNull;
@@ -433,7 +432,9 @@
                     new DefaultLinkDescription(
                         linkDescription.value().src(),
                         linkDescription.value().dst(),
-                        newType, merged),
+                        newType,
+                        existingLinkDescription.value().isExpected(),
+                        merged),
                     linkDescription.timestamp());
         }
         return descs.put(providerId, newLinkDescription);
@@ -608,14 +609,17 @@
             annotations = merge(annotations, e.getValue().value().annotations());
         }
 
-        boolean isDurable = Objects.equals(annotations.value(AnnotationKeys.DURABLE), "true");
+        //boolean isDurable = Objects.equals(annotations.value(AnnotationKeys.DURABLE), "true");
+
+        // TEMP
+        Link.State initialLinkState = base.value().isExpected() ? ACTIVE : INACTIVE;
         return DefaultLink.builder()
                 .providerId(baseProviderId)
                 .src(src)
                 .dst(dst)
                 .type(type)
-                .state(ACTIVE)
-                .isExpected(isDurable)
+                .state(initialLinkState)
+                .isExpected(base.value().isExpected())
                 .annotations(annotations)
                 .build();
     }