diff --git a/includes/polling/port-adsl.inc.php b/includes/polling/port-adsl.inc.php
index e3567e26b5..901fb6d0b9 100644
--- a/includes/polling/port-adsl.inc.php
+++ b/includes/polling/port-adsl.inc.php
@@ -39,9 +39,9 @@
 // adslAturPerfESs.1 = 0 seconds
 // adslAturPerfValidIntervals.1 = 0
 // adslAturPerfInvalidIntervals.1 = 0
-if (isset($port_stats[$port_id]['adslLineCoding'])) {
+if (isset($port_stats[$ifIndex]['adslLineCoding'])) {
     // Check to make sure Port data is cached.
-    $this_port = &$port_stats[$port_id];
+    $this_port = &$port_stats[$ifIndex];
 
     $rrdfile = get_port_rrdfile_path ($device['hostname'], $port_id, 'adsl');
 
diff --git a/includes/polling/port-etherlike.inc.php b/includes/polling/port-etherlike.inc.php
index bf947b92db..ea8b044c2a 100644
--- a/includes/polling/port-etherlike.inc.php
+++ b/includes/polling/port-etherlike.inc.php
@@ -1,10 +1,10 @@
 <?php
 
-if ($port_stats[$port_id] &&
+if ($port_stats[$ifIndex] &&
     $port['ifType'] == 'ethernetCsmacd' &&
-    isset($port_stats[$port_id]['dot3StatsIndex'])) {
+    isset($port_stats[$ifIndex]['dot3StatsIndex'])) {
     // Check to make sure Port data is cached.
-    $this_port = &$port_stats[$port_id];
+    $this_port = &$port_stats[$ifIndex];
 
     // TODO: remove legacy check?
     $old_rrdfile = $config['rrd_dir'].'/'.$device['hostname'].'/'.safename('etherlike-'.$port['ifIndex'].'.rrd');
diff --git a/includes/polling/port-poe.inc.php b/includes/polling/port-poe.inc.php
index 7b598a6b81..08642d232c 100644
--- a/includes/polling/port-poe.inc.php
+++ b/includes/polling/port-poe.inc.php
@@ -35,11 +35,11 @@ $peth_oids = array(
     'pethMainPseConsumptionPower',
 );
 
-if ($port_stats[$port_id]
+if ($port_stats[$ifIndex]
     && $port['ifType'] == 'ethernetCsmacd'
-    && isset($port_stats[$port_id]['dot3StatsIndex'])) {
+    && isset($port_stats[$ifIndex]['dot3StatsIndex'])) {
     // Check to make sure Port data is cached.
-    $this_port = &$port_stats[$port_id];
+    $this_port = &$port_stats[$ifIndex];
 
     $rrdfile = get_port_rrdfile_path ($device['hostname'], $port_id, 'poe');
     if (!file_exists($rrdfile)) {
diff --git a/includes/polling/ports.inc.php b/includes/polling/ports.inc.php
index 03bf4693da..6a46068614 100644
--- a/includes/polling/ports.inc.php
+++ b/includes/polling/ports.inc.php
@@ -280,9 +280,15 @@ foreach ($port_stats as $ifIndex => $port) {
             dbInsert(array('port_id' => $port_id), 'ports_statistics');
         }
 
-        // Assure stable mapping
-        $port_stats[$ifIndex]['port_id'] = $port_id;
+        /** Assure stable bidirectional port mapping between DB and polled data
+          *
+          * Store the *current* ifIndex in the port info array containing all port information
+          * fetched from the database, as this is the only means we have to map ports_stats we
+          * just polled from the device to a port in $ports. All code below an includeed below
+          * will and has to map a port using it's ifIndex.
+          */
         $ports[$port_id]['ifIndex'] = $ifIndex;
+        $port_stats[$ifIndex]['port_id'] = $port_id;
     }
 
     // Port vanished (mark as deleted)
@@ -299,11 +305,12 @@ echo "\n";
 // Loop ports in the DB and update where necessary
 foreach ($ports as $port) {
     $port_id = $port['port_id'];
+    $ifIndex = $port['ifIndex'];
 
-    echo 'Port ' . $port['ifName'] . ': ' . $port['ifDescr'] . '(' . $port['ifIndex'] . ') ';
-    if ($port_stats[$port['ifIndex']] && $port['disabled'] != '1') {
+    echo 'Port ' . $port['ifName'] . ': ' . $port['ifDescr'] . '(' . $ifIndex . ') ';
+    if ($port_stats[$ifIndex] && $port['disabled'] != '1') {
         // Check to make sure Port data is cached.
-        $this_port = &$port_stats[$port['ifIndex']];
+        $this_port = &$port_stats[$ifIndex];
 
         if ($device['os'] == 'vmware' && preg_match('/Device ([a-z0-9]+) at .*/', $this_port['ifDescr'], $matches)) {
             $this_port['ifDescr'] = $matches[1];