diff --git a/web/ons-demo/js/utils.js b/web/ons-demo/js/utils.js
index 4f6d0c1..d597507 100644
--- a/web/ons-demo/js/utils.js
+++ b/web/ons-demo/js/utils.js
@@ -1,3 +1,6 @@
+/***************************************************************************************************
+extract url parameters into a map
+***************************************************************************************************/
 function parseURLParameters() {
 	var parameters = {};
 
@@ -13,12 +16,72 @@
 	return parameters;
 }
 
-function findLink(model, dpid) {
-	var links = [];
-	model.links.forEach(function (link) {
-		if (link['src-switch'] == dpid || link['dst-switch'] == dpid) {
-			links.push(link);
-		}
-	});
-	return links;
-}
\ No newline at end of file
+/***************************************************************************************************
+convenience function for moving an SVG element to the front so that it draws on top
+***************************************************************************************************/
+d3.selection.prototype.moveToFront = function() {
+  return this.each(function(){
+    this.parentNode.appendChild(this);
+  });
+};
+
+/***************************************************************************************************
+standard function for generating the 'd' attribute for a path from an array of points
+***************************************************************************************************/
+var line = d3.svg.line()
+    .x(function(d) {
+    	return d.x;
+    })
+    .y(function(d) {
+    	return d.y;
+    });
+
+
+/***************************************************************************************************
+starts the "pending" animation
+***************************************************************************************************/
+function setPending(selection) {
+	selection.classed('pending', false);
+	setTimeout(function () {
+		selection.classed('pending', true);
+	}, 0);
+}
+
+/***************************************************************************************************
+convert angle in degrees to radians
+***************************************************************************************************/
+function toRadians (degrees) {
+  return degrees * (Math.PI / 180);
+}
+
+/***************************************************************************************************
+used to generate DOM element id for this link
+***************************************************************************************************/
+function makeLinkKey(link) {
+	return link['src-switch'] + '=>' + link['dst-switch'];
+}
+
+/***************************************************************************************************
+used to generate DOM element id for this flow in the topology view
+***************************************************************************************************/
+function makeFlowKey(flow) {
+	return flow.srcDpid + '=>' + flow.dstDpid;
+}
+
+/***************************************************************************************************
+used to generate DOM element id for this flow in the selected flows table
+***************************************************************************************************/
+function makeSelectedFlowKey(flow) {
+	return 'S' + makeFlowKey(flow);
+}
+
+/***************************************************************************************************
+update the app header using the current model
+***************************************************************************************************/
+function updateHeader() {
+	d3.select('#lastUpdate').text(new Date());
+	d3.select('#activeSwitches').text(model.edgeSwitches.length + model.aggregationSwitches.length + model.coreSwitches.length);
+	d3.select('#activeFlows').text(model.flows.length);
+}
+
+