diff --git a/apps/tvue/src/main/java/org/onlab/onos/tvue/TopologyResource.java b/apps/tvue/src/main/java/org/onlab/onos/tvue/TopologyResource.java
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+++ b/apps/tvue/src/main/java/org/onlab/onos/tvue/TopologyResource.java
@@ -0,0 +1,153 @@
+package org.onlab.onos.tvue;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.ElementId;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.device.DeviceService;
+import org.onlab.onos.net.host.HostService;
+import org.onlab.onos.net.link.LinkService;
+import org.onlab.onos.net.topology.Topology;
+import org.onlab.onos.net.topology.TopologyGraph;
+import org.onlab.onos.net.topology.TopologyService;
+import org.onlab.onos.net.topology.TopologyVertex;
+import org.onlab.rest.BaseResource;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.Response;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Topology viewer resource.
+ */
+@Path("topology")
+public class TopologyResource extends BaseResource {
+
+    @Path("/graph")
+    @GET
+    @Produces("application/json")
+    public Response graph() {
+        ObjectMapper mapper = new ObjectMapper();
+
+        // Fetch the services we'll be using.
+        DeviceService deviceService = get(DeviceService.class);
+        HostService hostService = get(HostService.class);
+        TopologyService topologyService = get(TopologyService.class);
+
+        // Fetch the current topology and its graph that we'll use to render.
+        Topology topo = topologyService.currentTopology();
+        TopologyGraph graph = topologyService.getGraph(topo);
+
+        // Build all interior vertexes, i.e. no end-station hosts yet
+        ArrayNode vertexesNode = mapper.createArrayNode();
+        for (TopologyVertex vertex : graph.getVertexes()) {
+            vertexesNode.add(json(mapper, vertex.deviceId(), 2,
+                                  deviceService.isAvailable(vertex.deviceId())));
+        }
+
+        // Now scan all links and count number of them between the same devices
+        // using a normalized link key.
+        Map<String, AggLink> linkRecords = aggregateLinks();
+
+        // Now build all interior edges using the aggregated links.
+        ArrayNode edgesNode = mapper.createArrayNode();
+        for (AggLink lr : linkRecords.values()) {
+            edgesNode.add(json(mapper, lr.links.size(), lr.link.src(), lr.link.dst()));
+        }
+
+        // Merge the exterior and interior vertexes and inject host links as
+        // the exterior edges.
+//        Iterator<Host> hosts = hostService.getHosts();
+//        while (hosts.hasNext()) {
+//            Host host = hosts.next();
+//            vertexesNode.add(json(mapper, host.id().ip().toString(), 3, true));
+//            edgesNode.add(json(mapper, 1, host.ip().toString(),
+//                               host.location().elementId().uri()));
+//        }
+
+        // Now put the vertexes and edges into a root node and ship them off
+        ObjectNode rootNode = mapper.createObjectNode();
+        rootNode.put("vertexes", vertexesNode);
+        rootNode.put("edges", edgesNode);
+        return Response.ok(rootNode.toString()).build();
+    }
+
+    // Scan all links and counts number of them between the same devices
+    // using a normalized link key.
+    private Map<String, AggLink> aggregateLinks() {
+        Map<String, AggLink> aggLinks = new HashMap<>();
+        LinkService linkService = get(LinkService.class);
+        for (Link link : linkService.getLinks()) {
+            String key = key(link);
+            AggLink lr = aggLinks.get(key);
+            if (lr == null) {
+                lr = new AggLink(key);
+                aggLinks.put(key, lr);
+            }
+            lr.addLink(link);
+        }
+        return aggLinks;
+    }
+
+    // Produces JSON for a graph vertex.
+    private ObjectNode json(ObjectMapper mapper, ElementId id, int group,
+                            boolean isOnline) {
+        return mapper.createObjectNode()
+                .put("name", id.uri().toString())
+                .put("group", group)
+                .put("online", isOnline);
+    }
+
+    // Produces JSON for a graph edge.
+    private ObjectNode json(ObjectMapper mapper, int count,
+                            ConnectPoint src, ConnectPoint dst) {
+        return json(mapper, count, id(src), id(dst));
+    }
+
+    // Produces JSON for a graph edge.
+    private ObjectNode json(ObjectMapper mapper, int count, String src, String dst) {
+        return mapper.createObjectNode()
+                .put("source", src).put("target", dst).put("value", count);
+    }
+
+    // Aggregate link of all links between the same devices regardless of
+    // their direction.
+    private class AggLink {
+        Link link; // representative links
+
+        final String key;
+        final Set<Link> links = new HashSet<>();
+
+        AggLink(String key) {
+            this.key = key;
+        }
+
+        void addLink(Link link) {
+            links.add(link);
+            if (this.link == null) {
+                this.link = link;
+            }
+        }
+    }
+
+    // Returns a canonical key for the specified link.
+    static String key(Link link) {
+        String s = id(link.src());
+        String d = id(link.dst());
+        return s.compareTo(d) > 0 ? d + s : s + d;
+    }
+
+    // Returns a formatted string for the element associated with the given
+    // connection point.
+    private static String id(ConnectPoint cp) {
+        return cp.elementId().uri().toString();
+    }
+
+}