diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyDatastore.java b/src/main/java/net/onrc/onos/core/topology/TopologyDatastore.java
new file mode 100644
index 0000000..5067666
--- /dev/null
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyDatastore.java
@@ -0,0 +1,206 @@
+package net.onrc.onos.core.topology;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import net.onrc.onos.core.datastore.DataStoreClient;
+import net.onrc.onos.core.datastore.IKVClient;
+import net.onrc.onos.core.datastore.topology.KVDevice;
+import net.onrc.onos.core.datastore.topology.KVLink;
+import net.onrc.onos.core.datastore.topology.KVPort;
+import net.onrc.onos.core.datastore.topology.KVPort.STATUS;
+import net.onrc.onos.core.datastore.topology.KVSwitch;
+import net.onrc.onos.core.datastore.utils.KVObject;
+import net.onrc.onos.core.datastore.utils.KVObject.WriteOp;
+import net.onrc.onos.core.topology.PortEvent.SwitchPort;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Contains methods which write topology events into the key-value data store.
+ */
+public class TopologyDatastore {
+    private static final Logger log = LoggerFactory.getLogger(TopologyDatastore.class);
+
+    /**
+     * Add a switch to the database.
+     *
+     * @param sw         the switch to add.
+     * @param portEvents the corresponding switch ports to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addSwitch(SwitchEvent sw,
+                             Collection<PortEvent> portEvents) {
+        log.debug("Adding switch {}", sw);
+        ArrayList<WriteOp> groupOp = new ArrayList<>();
+
+        KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
+        rcSwitch.setStatus(KVSwitch.STATUS.ACTIVE);
+
+        IKVClient client = DataStoreClient.getClient();
+
+        // XXX Is ForceCreating Switch on DB OK here?
+        // If ForceCreating, who ever is calling this method needs
+        // to assure that DPID is unique cluster-wide, etc.
+        groupOp.add(rcSwitch.forceCreateOp(client));
+
+        for (PortEvent portEvent : portEvents) {
+            KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
+            rcPort.setStatus(KVPort.STATUS.ACTIVE);
+
+            groupOp.add(rcPort.forceCreateOp(client));
+        }
+
+        boolean failed = KVObject.multiWrite(groupOp);
+
+        if (failed) {
+            log.error("Adding Switch {} and its ports failed.", sw.getDpid());
+            for (WriteOp op : groupOp) {
+                log.debug("Operation:{} for {} - Result:{}", op.getOperation(), op.getObject(), op.getStatus());
+
+                // If we changed the operation from ForceCreate to
+                // Conditional operation (Create/Update) then we should retry here.
+            }
+        }
+        return !failed;
+    }
+
+    /**
+     * Update a switch as inactive in the database.
+     *
+     * @param sw         the switch to update.
+     * @param portEvents the corresponding switch ports to update.
+     * @return true on success, otherwise false.
+     */
+    public boolean deactivateSwitch(SwitchEvent sw,
+                                    Collection<PortEvent> portEvents) {
+        log.debug("Deactivating switch {}", sw);
+        KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
+
+        IKVClient client = DataStoreClient.getClient();
+
+        List<WriteOp> groupOp = new ArrayList<>();
+        rcSwitch.setStatus(KVSwitch.STATUS.INACTIVE);
+
+        groupOp.add(rcSwitch.forceCreateOp(client));
+
+        for (PortEvent portEvent : portEvents) {
+            KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
+            rcPort.setStatus(KVPort.STATUS.INACTIVE);
+
+            groupOp.add(rcPort.forceCreateOp(client));
+        }
+
+        boolean failed = KVObject.multiWrite(groupOp);
+
+        return !failed;
+    }
+
+    /**
+     * Add a port to the database.
+     *
+     * @param port the port to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addPort(PortEvent port) {
+        log.debug("Adding port {}", port);
+
+        KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
+        rcPort.setStatus(KVPort.STATUS.ACTIVE);
+        rcPort.forceCreate();
+        // TODO add description into KVPort
+        //rcPort.setDescription(port.getDescription());
+
+        return true;
+    }
+
+    /**
+     * Update a port as inactive in the database.
+     *
+     * @param port the port to update.
+     * @return true on success, otherwise false.
+     */
+    public boolean deactivatePort(PortEvent port) {
+        log.debug("Deactivating port {}", port);
+
+        KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
+        rcPort.setStatus(STATUS.INACTIVE);
+
+        rcPort.forceCreate();
+
+        return true;
+    }
+
+    /**
+     * Add a link to the database.
+     *
+     * @param link the link to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addLink(LinkEvent link) {
+        log.debug("Adding link {}", link);
+
+        KVLink rcLink = new KVLink(link.getSrc().getDpid(),
+                link.getSrc().getNumber(),
+                link.getDst().getDpid(),
+                link.getDst().getNumber());
+
+        // XXX This method is called only by discovery,
+        // which means what we are trying to write currently is the truth
+        // so we can force write here
+        //
+        // TODO: We need to check for errors
+        rcLink.setStatus(KVLink.STATUS.ACTIVE);
+        rcLink.forceCreate();
+
+        return true;                    // Success
+    }
+
+    public boolean removeLink(LinkEvent linkEvent) {
+        log.debug("Removing link {}", linkEvent);
+
+        KVLink rcLink = new KVLink(linkEvent.getSrc().getDpid(), linkEvent.getSrc().getNumber(),
+                linkEvent.getDst().getDpid(), linkEvent.getDst().getNumber());
+        rcLink.forceDelete();
+
+        return true;
+    }
+
+    /**
+     * Add a device to the database.
+     *
+     * @param device the device to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addDevice(DeviceEvent device) {
+        log.debug("Adding device into DB. mac {}", device.getMac());
+
+        KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
+
+        for (SwitchPort sp : device.getAttachmentPoints()) {
+            byte[] portId = KVPort.getPortID(sp.getDpid(), sp.getNumber());
+            rcDevice.addPortId(portId);
+        }
+
+        rcDevice.forceCreate();
+
+        return true;
+    }
+
+    /**
+     * Remove a device from the database.
+     *
+     * @param device the device to remove.
+     * @return true on success, otherwise false.
+     */
+    public boolean removeDevice(DeviceEvent device) {
+        log.debug("Removing device into DB. mac {}", device.getMac());
+
+        KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
+        rcDevice.forceDelete();
+
+        return true;
+    }
+}