diff --git a/apps/t3/app/src/main/java/org/onosproject/t3/api/RouteNib.java b/apps/t3/app/src/main/java/org/onosproject/t3/api/RouteNib.java
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+/*
+ * Copyright 2020-present Open Networking Foundation
+ *
+ * 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.t3.api;
+
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
+import org.onosproject.routeservice.ResolvedRoute;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Represents Network Information Base (NIB) for routes
+ * and supports alternative functions to
+ * {@link org.onosproject.routeservice.RouteService} for offline data.
+ */
+public class RouteNib {
+
+    // TODO with method optimization, store into subdivided structures at the first load
+    // unresolved Route is treated as ResolvedRoute with nextHopMac null
+    Set<ResolvedRoute> routes;
+
+    // use the singleton helper to create the instance
+    protected RouteNib() {
+    }
+
+    /**
+     * Sets a set of routes.
+     *
+     * @param routes route set
+     */
+    public void setRoutes(Set<ResolvedRoute> routes) {
+        this.routes = routes;
+    }
+
+    /**
+     * Returns the set of routes.
+     *
+     * @return route set
+     */
+    public Set<ResolvedRoute> getRoutes() {
+        return routes;
+    }
+
+    /**
+     * Performs a longest prefix lookup on the given IP address.
+     *
+     * @param ip IP address to look up
+     * @return most specific matching route, if one exists
+     */
+    public Optional<ResolvedRoute> longestPrefixLookup(IpAddress ip) {
+        return routes.stream()
+                .filter(r -> r.prefix().contains(ip))
+                .max(Comparator.comparing(r -> r.prefix().prefixLength()));
+    }
+
+    /**
+     * Returns all resolved routes stored for the given prefix, including the
+     * best selected route.
+     *
+     * @param prefix IP prefix to look up routes for
+     * @return all stored resolved routes for this prefix
+     */
+    public Collection<ResolvedRoute> getAllResolvedRoutes(IpPrefix prefix) {
+        return routes.stream()
+                .filter(r -> r.prefix().contains(prefix)
+                        && r.nextHopMac() != null
+                        && r.nextHopVlan() != null)
+                .collect(Collectors.toCollection(ArrayList::new));
+    }
+
+    /**
+     * Returns the singleton instance of multicast routes NIB.
+     *
+     * @return instance of multicast routes NIB
+     */
+    public static RouteNib getInstance() {
+        return RouteNib.SingletonHelper.INSTANCE;
+    }
+
+    private static class SingletonHelper {
+        private static final RouteNib INSTANCE = new RouteNib();
+    }
+
+}