diff --git a/web/gui/src/main/webapp/_sdh/trie-test.html b/web/gui/src/main/webapp/_sdh/trie-test.html
new file mode 100644
index 0000000..2d6517a
--- /dev/null
+++ b/web/gui/src/main/webapp/_sdh/trie-test.html
@@ -0,0 +1,64 @@
+<!DOCTYPE html>
+<!--
+  ~  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.
+  -->
+
+<!--
+  ONOS -- Sample use of trie functions in fn.js
+  -->
+
+<html>
+<head lang="en">
+    <meta charset="UTF-8">
+    <title>Test Trie Functions</title>
+
+    <script type="text/javascript" src="../tp/angular.js"></script>
+    <script type="text/javascript" src="../tp/angular-route.js"></script>
+
+    <script type="text/javascript" src="../tp/d3.js"></script>
+
+    <script type="text/javascript" src="../app/fw/util/util.js"></script>
+    <script type="text/javascript" src="../app/fw/util/fn.js"></script>
+
+    <script type="text/javascript" src="trie-test.js"></script>
+
+    <link rel="stylesheet" href="../app/common.css">
+
+    <style>
+        html,
+        body {
+            background-color: #ddf;
+            font-family: Arial, Helvetica, sans-serif;
+            font-size: 9pt;
+        }
+
+        h2 {
+            color: darkred;
+        }
+
+        #output div {
+            font-family: monospace;
+            white-space: pre;
+        }
+    </style>
+
+</head>
+
+<!-- outline for using a controller in Angular -->
+<body class="light" ng-app="trie" ng-controller="OvTrieTest as ctrl">
+    <h2>Testing the Trie Functions</h2>
+    <div id="output"></div>
+</body>
+</html>
\ No newline at end of file
diff --git a/web/gui/src/main/webapp/_sdh/trie-test.js b/web/gui/src/main/webapp/_sdh/trie-test.js
new file mode 100644
index 0000000..2c8716c
--- /dev/null
+++ b/web/gui/src/main/webapp/_sdh/trie-test.js
@@ -0,0 +1,116 @@
+/*
+ *  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.
+ */
+
+/*
+ ONOS GUI -- Test code illustrating use of trie functions
+ */
+
+(function () {
+    'use strict';
+
+    // injected refs
+    var $log, fs;
+
+    // internal state
+    var out,
+        trie = {},
+        counter = 5000;
+
+    function write(string) {
+        out.append('div').text(string);
+    }
+
+    function lookup(word) {
+        var result = fs.trieLookup(trie, word),
+            f = fs.isF(result),
+            show = f ? '{function}' : result;
+
+
+        write('------> ' + word + ' ==> ' + show);
+
+        f && f();
+    }
+
+    function add(word, data) {
+        var result = fs.addToTrie(trie, word, data);
+        write('   ADD> ' + word + ' [' + data + '] ==> ' + result);
+    }
+
+    function remove(word) {
+        var result = fs.removeFromTrie(trie, word);
+        write('REMOVE> ' + word + ' ==> ' + result);
+    }
+
+    function func1() {
+        counter++;
+        write('** function call **  ' + counter);
+    }
+
+    function func2() {
+        counter += 11;
+        write('** alternate call **  ' + counter);
+    }
+
+    function runTests() {
+        lookup('cat');
+
+        add('cat', 101);
+
+        lookup('ca');
+        lookup('cat');
+        lookup('cats');
+
+        add('cab', 103);
+        add('cog', 105);
+
+        lookup('cut');
+        lookup('cab');
+
+        remove('cab');
+
+        lookup('cab');
+        lookup('cat');
+
+        add('fun', func1);
+
+        lookup('fun');
+        lookup('fun');
+        lookup('fun');
+        lookup('cat');
+        lookup('fun');
+
+        add('fun', func2);
+
+        lookup('fun');
+        lookup('fun');
+        lookup('fun');
+
+        remove('fun');
+
+        lookup('fun');
+    }
+
+    angular.module('trie', ['onosUtil'])
+    .controller('OvTrieTest', ['$log', 'FnService',
+
+        function (_$log_, _fs_) {
+            $log = _$log_;
+            fs = _fs_;
+            out = d3.select('#output');
+
+            runTests();
+        }]);
+}());
diff --git a/web/gui/src/main/webapp/app/fw/util/fn.js b/web/gui/src/main/webapp/app/fw/util/fn.js
index d60ed2e..b0506fa 100644
--- a/web/gui/src/main/webapp/app/fw/util/fn.js
+++ b/web/gui/src/main/webapp/app/fw/util/fn.js
@@ -287,11 +287,16 @@
         }
     }
 
-    // generate a trie structure from the given array of strings
-    // if ignoreCase is true, all words are converted to uppercase first
-    // note: each letter in each string must be valid as an object property key
-    function createTrie(words, ignoreCase) {
-        var trie = {};
+    // trie operation
+    function _trieOp(op, trie, word, data) {
+        var p = trie,
+            w = word.toUpperCase(),
+            s = w.split(''),
+            c = { p: p, s: s },
+            t = [],
+            x = 0,
+            f1 = op === '+' ? add : probe,
+            f2 = op === '+' ? insert : remove;
 
         function add(c) {
             var q = c.s.shift(),
@@ -300,31 +305,87 @@
             if (!np) {
                 c.p[q] = {};
                 np = c.p[q];
+                x = 1;
             }
-
-            return {
-                p: np,
-                s: c.s
-            }
+            return { p: np, s: c.s }
         }
 
-        words.forEach(function (word) {
-            var p = trie,
-                w = ignoreCase ? word.toUpperCase() : word,
-                s = w.split(''),
-                c = {
-                    p: p,
-                    s: s
-                };
+        function probe(c) {
+            var q = c.s.shift(),
+                k = Object.keys(c.p).length,
+                np = c.p[q];
 
-            while (c.s.length) {
-                c = add(c);
+            t.push({ q:q, k:k, p:c.p });
+            if (!np) {
+                t = [];
+                return { s: [] };
             }
-        });
+            return { p: np, s: c.s }
+        }
 
-        return trie;
+        function insert() {
+            c.p._data = data;
+            return x ? 'added' : 'updated';
+        }
+
+        function remove() {
+            if (t.length) {
+                t = t.reverse();
+                while (t.length) {
+                    c = t.shift();
+                    delete c.p[c.q];
+                    if (c.k > 1) {
+                        t = [];
+                    }
+                }
+                return 'removed';
+            }
+            return 'absent';
+        }
+
+        while (c.s.length) {
+            c = f1(c);
+        }
+        return f2();
     }
 
+    // add word to trie (word will be converted to uppercase)
+    // data associated with the word
+    // returns 'added' or 'updated'
+    function addToTrie(trie, word, data) {
+        return _trieOp('+', trie, word, data);
+    }
+
+    // remove word from trie (word will be converted to uppercase)
+    // returns 'removed' or 'absent'
+    function removeFromTrie(trie, word) {
+        return _trieOp('-', trie, word);
+    }
+
+    // lookup word (converted to uppercase) in trie
+    // returns:
+    //    undefined if the word is not in the trie
+    //    -1 for a partial match (word is a prefix to an existing word)
+    //    data for the word for an exact match
+    function trieLookup(trie, word) {
+        var s = word.toUpperCase().split(''),
+            p = trie,
+            n;
+
+        while (s.length) {
+            n = s.shift();
+            p = p[n];
+            if (!p) {
+                return undefined;
+            }
+        }
+        if (p._data) {
+            return p._data;
+        }
+        return -1;
+    }
+
+
     angular.module('onosUtil')
         .factory('FnService',
         ['$window', '$location', '$log', function (_$window_, $loc, _$log_) {
@@ -360,7 +421,9 @@
                 noPxStyle: noPxStyle,
                 endsWith: endsWith,
                 parseBitRate: parseBitRate,
-                createTrie: createTrie
+                addToTrie: addToTrie,
+                removeFromTrie: removeFromTrie,
+                trieLookup: trieLookup
             };
     }]);