diff --git a/core/api/src/main/java/org/onosproject/ui/model/topo/UiTopology.java b/core/api/src/main/java/org/onosproject/ui/model/topo/UiTopology.java
index a8b5b06..3a11fcf 100644
--- a/core/api/src/main/java/org/onosproject/ui/model/topo/UiTopology.java
+++ b/core/api/src/main/java/org/onosproject/ui/model/topo/UiTopology.java
@@ -17,27 +17,54 @@
 package org.onosproject.ui.model.topo;
 
 import org.onosproject.cluster.NodeId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.HostId;
+import org.onosproject.net.region.RegionId;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
-import java.util.TreeSet;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
 
 /**
  * Represents the overall network topology.
  */
 public class UiTopology extends UiElement {
 
+    private static final String E_UNMAPPED =
+            "Attempting to retrieve unmapped {}: {}";
+
     private static final String DEFAULT_TOPOLOGY_ID = "TOPOLOGY-0";
 
     private static final Logger log = LoggerFactory.getLogger(UiTopology.class);
 
-    private final UiCluster uiCluster = new UiCluster();
-    private final Set<UiRegion> uiRegions = new TreeSet<>();
+
+    // top level mappings of topology elements by ID
+    private final Map<NodeId, UiClusterMember> cnodeLookup = new HashMap<>();
+    private final Map<RegionId, UiRegion> regionLookup = new HashMap<>();
+    private final Map<DeviceId, UiDevice> deviceLookup = new HashMap<>();
+    private final Map<HostId, UiHost> hostLookup = new HashMap<>();
+    private final Map<UiLinkId, UiLink> linkLookup = new HashMap<>();
+
 
     @Override
     public String toString() {
-        return "Topology: " + uiCluster + ", " + uiRegions.size() + " regions";
+        return toStringHelper(this)
+                .add("#cnodes", clusterMemberCount())
+                .add("#regions", regionCount())
+                .add("#devices", deviceLookup.size())
+                .add("#hosts", hostLookup.size())
+                .add("#links", linkLookup.size())
+                .toString();
+    }
+
+    @Override
+    public String idAsString() {
+        return DEFAULT_TOPOLOGY_ID;
     }
 
     /**
@@ -46,19 +73,22 @@
      */
     public void clear() {
         log.debug("clearing topology model");
-        uiRegions.clear();
-        uiCluster.clear();
+        cnodeLookup.clear();
+        regionLookup.clear();
+        deviceLookup.clear();
+        hostLookup.clear();
+        linkLookup.clear();
     }
 
     /**
      * Returns the cluster member with the given identifier, or null if no
-     * such member.
+     * such member exists.
      *
      * @param id cluster node identifier
-     * @return the cluster member with that identifier
+     * @return corresponding UI cluster member
      */
     public UiClusterMember findClusterMember(NodeId id) {
-        return uiCluster.find(id);
+        return cnodeLookup.get(id);
     }
 
     /**
@@ -67,7 +97,7 @@
      * @param member cluster member to add
      */
     public void add(UiClusterMember member) {
-        uiCluster.add(member);
+        cnodeLookup.put(member.id(), member);
     }
 
     /**
@@ -76,7 +106,10 @@
      * @param member cluster member to remove
      */
     public void remove(UiClusterMember member) {
-        uiCluster.remove(member);
+        UiClusterMember m = cnodeLookup.remove(member.id());
+        if (m != null) {
+            m.destroy();
+        }
     }
 
     /**
@@ -85,7 +118,18 @@
      * @return number of cluster members
      */
     public int clusterMemberCount() {
-        return uiCluster.size();
+        return cnodeLookup.size();
+    }
+
+    /**
+     * Returns the region with the specified identifier, or null if
+     * no such region exists.
+     *
+     * @param id region identifier
+     * @return corresponding UI region
+     */
+    public UiRegion findRegion(RegionId id) {
+        return regionLookup.get(id);
     }
 
     /**
@@ -94,11 +138,182 @@
      * @return number of regions
      */
     public int regionCount() {
-        return uiRegions.size();
+        return regionLookup.size();
     }
 
-    @Override
-    public String idAsString() {
-        return DEFAULT_TOPOLOGY_ID;
+    /**
+     * Adds the given region to the topology model.
+     *
+     * @param uiRegion region to add
+     */
+    public void add(UiRegion uiRegion) {
+        regionLookup.put(uiRegion.id(), uiRegion);
     }
+
+    /**
+     * Removes the given region from the topology model.
+     *
+     * @param uiRegion region to remove
+     */
+    public void remove(UiRegion uiRegion) {
+        regionLookup.remove(uiRegion.id());
+    }
+
+    /**
+     * Returns the device with the specified identifier, or null if
+     * no such device exists.
+     *
+     * @param id device identifier
+     * @return corresponding UI device
+     */
+    public UiDevice findDevice(DeviceId id) {
+        return deviceLookup.get(id);
+    }
+
+    /**
+     * Adds the given device to the topology model.
+     *
+     * @param uiDevice device to add
+     */
+    public void add(UiDevice uiDevice) {
+        deviceLookup.put(uiDevice.id(), uiDevice);
+    }
+
+    /**
+     * Removes the given device from the topology model.
+     *
+     * @param uiDevice device to remove
+     */
+    public void remove(UiDevice uiDevice) {
+        UiDevice d = deviceLookup.remove(uiDevice.id());
+        if (d != null) {
+            d.destroy();
+        }
+    }
+
+    /**
+     * Returns the link with the specified identifier, or null if no such
+     * link exists.
+     *
+     * @param id the canonicalized link identifier
+     * @return corresponding UI link
+     */
+    public UiLink findLink(UiLinkId id) {
+        return linkLookup.get(id);
+    }
+
+    /**
+     * Adds the given UI link to the topology model.
+     *
+     * @param uiLink link to add
+     */
+    public void add(UiLink uiLink) {
+        linkLookup.put(uiLink.id(), uiLink);
+    }
+
+    /**
+     * Removes the given UI link from the model.
+     *
+     * @param uiLink link to remove
+     */
+    public void remove(UiLink uiLink) {
+        UiLink link = linkLookup.get(uiLink.id());
+        if (link != null) {
+            link.destroy();
+        }
+    }
+
+    /**
+     * Returns the host with the specified identifier, or null if no such
+     * host exists.
+     *
+     * @param id host identifier
+     * @return corresponding UI host
+     */
+    public UiHost findHost(HostId id) {
+        return hostLookup.get(id);
+    }
+
+    /**
+     * Adds the given host to the topology model.
+     *
+     * @param uiHost host to add
+     */
+    public void add(UiHost uiHost) {
+        hostLookup.put(uiHost.id(), uiHost);
+    }
+
+    /**
+     * Removes the given host from the topology model.
+     *
+     * @param uiHost host to remove
+     */
+    public void remove(UiHost uiHost) {
+        UiHost h = hostLookup.remove(uiHost.id());
+        if (h != null) {
+            h.destroy();
+        }
+    }
+
+    // ==
+    // package private methods for supporting linkage amongst topology entities
+    // ==
+
+    /**
+     * Returns the set of UI devices with the given identifiers.
+     *
+     * @param deviceIds device identifiers
+     * @return set of matching UI device instances
+     */
+    Set<UiDevice> deviceSet(Set<DeviceId> deviceIds) {
+        Set<UiDevice> uiDevices = new HashSet<>();
+        for (DeviceId id : deviceIds) {
+            UiDevice d = deviceLookup.get(id);
+            if (d != null) {
+                uiDevices.add(d);
+            } else {
+                log.warn(E_UNMAPPED, "device", id);
+            }
+        }
+        return uiDevices;
+    }
+
+    /**
+     * Returns the set of UI hosts with the given identifiers.
+     *
+     * @param hostIds host identifiers
+     * @return set of matching UI host instances
+     */
+    Set<UiHost> hostSet(Set<HostId> hostIds) {
+        Set<UiHost> uiHosts = new HashSet<>();
+        for (HostId id : hostIds) {
+            UiHost h = hostLookup.get(id);
+            if (h != null) {
+                uiHosts.add(h);
+            } else {
+                log.warn(E_UNMAPPED, "host", id);
+            }
+        }
+        return uiHosts;
+    }
+
+    /**
+     * Returns the set of UI links with the given identifiers.
+     *
+     * @param uiLinkIds link identifiers
+     * @return set of matching UI link instances
+     */
+    Set<UiLink> linkSet(Set<UiLinkId> uiLinkIds) {
+        Set<UiLink> uiLinks = new HashSet<>();
+        for (UiLinkId id : uiLinkIds) {
+            UiLink link = linkLookup.get(id);
+            if (link != null) {
+                uiLinks.add(link);
+            } else {
+                log.warn(E_UNMAPPED, "link", id);
+            }
+        }
+        return uiLinks;
+    }
+
 }