diff --git a/TODO.md b/TODO.md
index 81c30cc..8119d0d 100644
--- a/TODO.md
+++ b/TODO.md
@@ -4,6 +4,21 @@ Zentrale Sammlung aller TODO-Markierungen im Repository (Stand: 13. Februar 2026
 
 Hinweis: Die Eintraege sind direkt aus den Quelldateien aggregiert.
 
+## Arbeitsnotizen (16. Februar 2026)
+
+- [x] API-Basis umgesetzt: `app/api/connections.php`, `app/api/device_type_ports.php`, `app/api/upload.php` auf aktuelles Schema gebracht (Auth, Validierung, Existenzpruefungen, Fehlerantworten).
+- [x] Bootstrap/Auth/Config/Routing umgesetzt: `app/config.php`, `app/bootstrap.php`, `app/lib/_sql.php`, `app/lib/auth.php`, `app/index.php`.
+- [x] Frontend-Grundlagen aktualisiert: `app/assets/js/app.js`, `app/assets/js/dashboard.js`, `app/assets/js/svg-editor.js`, `app/assets/js/network-view.js`.
+- [x] Delete-Flow fuer zentrale Module umgesetzt: `buildings`, `floors`, `racks`, `device_types`, `floor_infrastructure`.
+- [x] Legacy-Mock ersetzt: `app/modules/device_types/ports.php` lauffaehig gemacht (anzeigen, hinzufuegen, loeschen).
+- [x] TODO-Reste in `header.php`, `footer.php`, `layout.php`, `floor_infrastructure/edit.php` entfernt.
+
+Offene Blocker / naechste Punkte:
+- [ ] `app/modules/connections/list.php`: Detailbereich fuer ausgewaehlte Verbindung sowie Bearbeiten/Loeschen im UI fehlen noch.
+- [ ] `app/modules/dashboard/list.php`: grosse zoombare Gesamt-Topologie-Wand (fachlich/grafisch groesseres Feature).
+- [ ] `app/lib/helpers.php`: generischer Sammel-TODO ohne konkreten Scope.
+- [ ] Vollstaendiger End-to-End-Test aktuell nicht moeglich, da in dieser Shell kein `php` CLI verfuegbar ist.
+
 ## app\api\connections.php
 
 - [ ] L15: // TODO: Single-User-Auth prüfen
diff --git a/app/api/connections.php b/app/api/connections.php
index ffeba17..d05631b 100644
--- a/app/api/connections.php
+++ b/app/api/connections.php
@@ -1,194 +1,273 @@
 <?php
 /**
  * app/api/connections.php
- *
- * API für Netzwerkverbindungen (Port ↔ Port)
- * - Laden der Topologie
- * - Anlegen / Bearbeiten / Löschen von Verbindungen
- * - Unterstützt freie Verbindungstypen (Kupfer, LWL, BNC, Token Ring, etc.)
  */
 
 require_once __DIR__ . '/../bootstrap.php';
+requireAuth();
 
 header('Content-Type: application/json');
 
-// TODO: Single-User-Auth prüfen
-// if (!$_SESSION['user']) { http_response_code(403); exit; }
-
 $action = $_GET['action'] ?? 'load';
 
-/* =========================
- * Router
- * ========================= */
-
 switch ($action) {
-
     case 'load':
         loadConnections($sql);
         break;
-
     case 'save':
         saveConnection($sql);
         break;
-
     case 'delete':
         deleteConnection($sql);
         break;
-
     default:
-        http_response_code(400);
-        echo json_encode(['error' => 'Unbekannte Aktion']);
-        break;
+        jsonError('Unbekannte Aktion', 400);
 }
 
-/* =========================
- * Aktionen
- * ========================= */
-
-/**
- * Lädt alle Geräte + Ports + Verbindungen für eine Netzwerkansicht
- */
-function loadConnections($sql)
+function jsonError(string $message, int $status = 400): void
 {
-    $contextId = $_GET['context_id'] ?? null;
+    http_response_code($status);
+    echo json_encode(['error' => $message]);
+    exit;
+}
 
-    if (!$contextId) {
-        http_response_code(400);
-        echo json_encode(['error' => 'context_id fehlt']);
-        return;
+function normalizeEndpointType(string $type): ?string
+{
+    $map = [
+        'device' => 'device',
+        'device_ports' => 'device',
+        'module' => 'module',
+        'module_ports' => 'module',
+        'outlet' => 'outlet',
+        'network_outlet_ports' => 'outlet',
+        'patchpanel' => 'patchpanel',
+        'floor_patchpanel_ports' => 'patchpanel',
+    ];
+
+    $key = strtolower(trim($type));
+    return $map[$key] ?? null;
+}
+
+function endpointExists($sql, string $type, int $id): bool
+{
+    if ($id <= 0) {
+        return false;
     }
 
-    // TODO: Kontext definieren (Standort, Rack, Floor, gesamtes Netz)
+    if ($type === 'device') {
+        $row = $sql->single('SELECT id FROM device_ports WHERE id = ?', 'i', [$id]);
+        return !empty($row);
+    }
+
+    if ($type === 'module') {
+        $row = $sql->single('SELECT id FROM module_ports WHERE id = ?', 'i', [$id]);
+        return !empty($row);
+    }
+
+    if ($type === 'outlet') {
+        $row = $sql->single('SELECT id FROM network_outlet_ports WHERE id = ?', 'i', [$id]);
+        return !empty($row);
+    }
+
+    if ($type === 'patchpanel') {
+        $row = $sql->single('SELECT id FROM floor_patchpanel_ports WHERE id = ?', 'i', [$id]);
+        return !empty($row);
+    }
+
+    return false;
+}
+
+function loadConnections($sql): void
+{
+    $contextType = strtolower(trim((string)($_GET['context_type'] ?? 'all')));
+    $contextId = isset($_GET['context_id']) ? (int)$_GET['context_id'] : 0;
+
+    $where = '';
+    $bindType = '';
+    $bindValues = [];
+
+    if ($contextType !== 'all') {
+        if ($contextId <= 0) {
+            jsonError('context_id fehlt oder ist ungueltig', 400);
+        }
+
+        if ($contextType === 'location') {
+            $where = ' WHERE b.location_id = ?';
+            $bindType = 'i';
+            $bindValues = [$contextId];
+        } elseif ($contextType === 'building') {
+            $where = ' WHERE f.building_id = ?';
+            $bindType = 'i';
+            $bindValues = [$contextId];
+        } elseif ($contextType === 'floor') {
+            $where = ' WHERE r.floor_id = ?';
+            $bindType = 'i';
+            $bindValues = [$contextId];
+        } elseif ($contextType === 'rack') {
+            $where = ' WHERE d.rack_id = ?';
+            $bindType = 'i';
+            $bindValues = [$contextId];
+        } else {
+            jsonError('Ungueltiger Kontext. Erlaubt: all, location, building, floor, rack', 400);
+        }
+    }
 
-    /* ---------- Geräte ---------- */
     $devices = $sql->get(
-        "SELECT id, name, device_type_id, pos_x, pos_y
-         FROM devices
-         WHERE context_id = ?",
-        "i",
-        [$contextId]
+        "SELECT d.id, d.name, d.device_type_id, d.rack_id, 0 AS pos_x, 0 AS pos_y
+         FROM devices d
+         LEFT JOIN racks r ON r.id = d.rack_id
+         LEFT JOIN floors f ON f.id = r.floor_id
+         LEFT JOIN buildings b ON b.id = f.building_id" . $where,
+        $bindType,
+        $bindValues
     );
 
-    /* ---------- Ports ---------- */
     $ports = $sql->get(
-        "SELECT p.id, p.device_id, p.name, p.port_type_id
-         FROM ports p
-         JOIN devices d ON d.id = p.device_id
-         WHERE d.context_id = ?",
-        "i",
-        [$contextId]
+        "SELECT dp.id, dp.device_id, dp.name, dp.port_type_id
+         FROM device_ports dp
+         JOIN devices d ON d.id = dp.device_id
+         LEFT JOIN racks r ON r.id = d.rack_id
+         LEFT JOIN floors f ON f.id = r.floor_id
+         LEFT JOIN buildings b ON b.id = f.building_id" . $where,
+        $bindType,
+        $bindValues
     );
 
-    /* ---------- Verbindungen ---------- */
     $connections = $sql->get(
-        "SELECT
-            c.id,
-            c.connection_type_id,
-            c.port_a_id,
-            c.port_b_id,
-            c.vlan,
-            c.mode,
-            c.comment
-         FROM connections c",
-        "",
+        "SELECT id, connection_type_id, port_a_type, port_a_id, port_b_type, port_b_id, vlan_config, mode, comment
+         FROM connections",
+        '',
         []
     );
 
     echo json_encode([
-        'devices' => $devices,
-        'ports' => $ports,
-        'connections' => $connections
+        'devices' => $devices ?: [],
+        'ports' => $ports ?: [],
+        'connections' => $connections ?: []
     ]);
 }
 
-/**
- * Speichert eine Verbindung (neu oder Update)
- */
-function saveConnection($sql)
+function resolveConnectionTypeId($sql, array $data): int
 {
-    $data = json_decode(file_get_contents('php://input'), true);
-
-    if (!$data) {
-        http_response_code(400);
-        echo json_encode(['error' => 'Ungültige JSON-Daten']);
-        return;
+    if (!empty($data['connection_type_id'])) {
+        $requestedId = (int)$data['connection_type_id'];
+        $exists = $sql->single('SELECT id FROM connection_types WHERE id = ?', 'i', [$requestedId]);
+        if (!$exists) {
+            jsonError('connection_type_id existiert nicht', 400);
+        }
+        return $requestedId;
     }
 
-    // TODO: Validierung
-    // - port_a_id vorhanden
-    // - port_b_id vorhanden
-    // - Verbindungstyp erlaubt
+    $defaultType = $sql->single('SELECT id FROM connection_types ORDER BY id ASC LIMIT 1');
+    if (!$defaultType) {
+        jsonError('Kein Verbindungstyp vorhanden', 400);
+    }
+
+    return (int)$defaultType['id'];
+}
+
+function saveConnection($sql): void
+{
+    if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+        jsonError('Methode nicht erlaubt', 405);
+    }
+
+    $data = json_decode(file_get_contents('php://input'), true);
+    if (!is_array($data)) {
+        jsonError('Ungueltige JSON-Daten', 400);
+    }
+
+    $portAType = normalizeEndpointType((string)($data['port_a_type'] ?? ''));
+    $portBType = normalizeEndpointType((string)($data['port_b_type'] ?? ''));
+    $portAId = (int)($data['port_a_id'] ?? 0);
+    $portBId = (int)($data['port_b_id'] ?? 0);
+
+    if ($portAType === null || $portBType === null) {
+        jsonError('port_a_type/port_b_type ungueltig', 400);
+    }
+
+    if ($portAId <= 0 || $portBId <= 0) {
+        jsonError('port_a_id und port_b_id sind erforderlich', 400);
+    }
+
+    if ($portAType === $portBType && $portAId === $portBId) {
+        jsonError('Port A und Port B duerfen nicht identisch sein', 400);
+    }
+
+    if (!endpointExists($sql, $portAType, $portAId) || !endpointExists($sql, $portBType, $portBId)) {
+        jsonError('Mindestens ein Endpunkt existiert nicht', 400);
+    }
+
+    $connectionTypeId = resolveConnectionTypeId($sql, $data);
+
+    $vlanConfig = $data['vlan_config'] ?? null;
+    if (is_array($vlanConfig)) {
+        $vlanConfig = json_encode($vlanConfig);
+    } elseif (!is_string($vlanConfig) && $vlanConfig !== null) {
+        jsonError('vlan_config muss String, Array oder null sein', 400);
+    }
+
+    $mode = isset($data['mode']) ? (string)$data['mode'] : null;
+    $comment = isset($data['comment']) ? (string)$data['comment'] : null;
 
     if (!empty($data['id'])) {
-        // UPDATE
+        $id = (int)$data['id'];
+        $existing = $sql->single('SELECT id FROM connections WHERE id = ?', 'i', [$id]);
+        if (!$existing) {
+            jsonError('Verbindung existiert nicht', 404);
+        }
+
         $rows = $sql->set(
-            "UPDATE connections
-             SET connection_type_id = ?, port_a_id = ?, port_b_id = ?, vlan = ?, mode = ?, comment = ?
-             WHERE id = ?",
-            "iiiissi",
-            [
-                $data['connection_type_id'],
-                $data['port_a_id'],
-                $data['port_b_id'],
-                $data['vlan'],
-                $data['mode'],
-                $data['comment'],
-                $data['id']
-            ]
+            'UPDATE connections
+             SET connection_type_id = ?, port_a_type = ?, port_a_id = ?, port_b_type = ?, port_b_id = ?, vlan_config = ?, mode = ?, comment = ?
+             WHERE id = ?',
+            'isisisssi',
+            [$connectionTypeId, $portAType, $portAId, $portBType, $portBId, $vlanConfig, $mode, $comment, $id]
         );
 
-        echo json_encode([
-            'status' => 'updated',
-            'rows' => $rows
-        ]);
-    } else {
-        // INSERT
-        $id = $sql->set(
-            "INSERT INTO connections
-                (connection_type_id, port_a_id, port_b_id, vlan, mode, comment)
-             VALUES (?, ?, ?, ?, ?, ?)",
-            "iiiiss",
-            [
-                $data['connection_type_id'],
-                $data['port_a_id'],
-                $data['port_b_id'],
-                $data['vlan'],
-                $data['mode'],
-                $data['comment']
-            ],
-            true
-        );
+        if ($rows === false) {
+            jsonError('Update fehlgeschlagen', 500);
+        }
 
-        echo json_encode([
-            'status' => 'created',
-            'id' => $id
-        ]);
-    }
-}
-
-/**
- * Löscht eine Verbindung
- */
-function deleteConnection($sql)
-{
-    $id = $_GET['id'] ?? null;
-
-    if (!$id) {
-        http_response_code(400);
-        echo json_encode(['error' => 'ID fehlt']);
+        echo json_encode(['status' => 'updated', 'rows' => $rows]);
         return;
     }
 
-    // TODO: Prüfen, ob Verbindung existiert
-
-    $rows = $sql->set(
-        "DELETE FROM connections WHERE id = ?",
-        "i",
-        [$id]
+    $id = $sql->set(
+        'INSERT INTO connections (connection_type_id, port_a_type, port_a_id, port_b_type, port_b_id, vlan_config, mode, comment)
+         VALUES (?, ?, ?, ?, ?, ?, ?, ?)',
+        'isisisss',
+        [$connectionTypeId, $portAType, $portAId, $portBType, $portBId, $vlanConfig, $mode, $comment],
+        true
     );
 
-    echo json_encode([
-        'status' => 'deleted',
-        'rows' => $rows
-    ]);
+    if ($id === false) {
+        jsonError('Insert fehlgeschlagen', 500);
+    }
+
+    echo json_encode(['status' => 'created', 'id' => $id]);
+}
+
+function deleteConnection($sql): void
+{
+    if ($_SERVER['REQUEST_METHOD'] !== 'POST' && $_SERVER['REQUEST_METHOD'] !== 'DELETE') {
+        jsonError('Methode nicht erlaubt', 405);
+    }
+
+    $id = isset($_GET['id']) ? (int)$_GET['id'] : 0;
+    if ($id <= 0) {
+        jsonError('ID fehlt', 400);
+    }
+
+    $existing = $sql->single('SELECT id FROM connections WHERE id = ?', 'i', [$id]);
+    if (!$existing) {
+        jsonError('Verbindung existiert nicht', 404);
+    }
+
+    $rows = $sql->set('DELETE FROM connections WHERE id = ?', 'i', [$id]);
+    if ($rows === false) {
+        jsonError('Loeschen fehlgeschlagen', 500);
+    }
+
+    echo json_encode(['status' => 'deleted', 'rows' => $rows]);
 }
diff --git a/app/api/device_type_ports.php b/app/api/device_type_ports.php
index deeaf1d..8bfb1bc 100644
--- a/app/api/device_type_ports.php
+++ b/app/api/device_type_ports.php
@@ -1,175 +1,199 @@
 <?php
 /**
  * app/api/device_type_ports.php
- *
- * API für Ports von Gerätetypen
- * - Laden der Port-Definitionen (SVG-Port-Editor)
- * - Speichern (Position, Typ, Name)
- * - Löschen einzelner Ports
  */
 
 require_once __DIR__ . '/../bootstrap.php';
+requireAuth();
 
 header('Content-Type: application/json');
 
-// TODO: Single-User-Auth prüfen
-// if (!$_SESSION['user']) { http_response_code(403); exit; }
-
 $action = $_GET['action'] ?? 'load';
 
-/* =========================
- * Router
- * ========================= */
-
 switch ($action) {
-
     case 'load':
         loadPorts($sql);
         break;
-
     case 'save':
         savePorts($sql);
         break;
-
     case 'delete':
         deletePort($sql);
         break;
-
     default:
-        http_response_code(400);
-        echo json_encode(['error' => 'Unbekannte Aktion']);
-        break;
+        jsonError('Unbekannte Aktion', 400);
 }
 
-/* =========================
- * Aktionen
- * ========================= */
-
-/**
- * Lädt alle Ports eines Gerätetyps
- */
-function loadPorts($sql)
+function jsonError(string $message, int $status = 400): void
 {
-    $deviceTypeId = $_GET['device_type_id'] ?? null;
+    http_response_code($status);
+    echo json_encode(['error' => $message]);
+    exit;
+}
 
-    if (!$deviceTypeId) {
-        http_response_code(400);
-        echo json_encode(['error' => 'device_type_id fehlt']);
-        return;
+function loadPorts($sql): void
+{
+    $deviceTypeId = isset($_GET['device_type_id']) ? (int)$_GET['device_type_id'] : 0;
+    if ($deviceTypeId <= 0) {
+        jsonError('device_type_id fehlt', 400);
     }
 
     $ports = $sql->get(
-        "SELECT
-            id,
-            name,
-            port_type_id,
-            pos_x,
-            pos_y,
-            comment
+        'SELECT id, name, port_type_id, x, y, metadata
          FROM device_type_ports
          WHERE device_type_id = ?
-         ORDER BY id ASC",
-        "i",
+         ORDER BY id ASC',
+        'i',
         [$deviceTypeId]
     );
 
-    echo json_encode($ports);
+    echo json_encode($ports ?: []);
 }
 
-/**
- * Speichert alle Ports eines Gerätetyps
- * (Bulk-Save aus dem SVG-Editor)
- */
-function savePorts($sql)
+function validatePortTypeId($sql, $portTypeId): ?int
 {
-    $data = json_decode(file_get_contents('php://input'), true);
-
-    if (!$data || empty($data['device_type_id']) || !is_array($data['ports'])) {
-        http_response_code(400);
-        echo json_encode(['error' => 'Ungültige Daten']);
-        return;
+    if ($portTypeId === null || $portTypeId === '' || (int)$portTypeId <= 0) {
+        return null;
     }
 
-    $deviceTypeId = $data['device_type_id'];
-    $ports = $data['ports'];
+    $value = (int)$portTypeId;
+    $exists = $sql->single('SELECT id FROM port_types WHERE id = ?', 'i', [$value]);
+    if (!$exists) {
+        jsonError('port_type_id ist ungueltig', 400);
+    }
 
-    // TODO: Transaktion starten (falls SQL-Klasse das unterstützt)
+    return $value;
+}
 
-    foreach ($ports as $port) {
+function savePorts($sql): void
+{
+    if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+        jsonError('Methode nicht erlaubt', 405);
+    }
 
-        // TODO: Validierung:
-        // - name nicht leer
-        // - pos_x / pos_y numerisch
-        // - port_type_id erlaubt
+    $data = json_decode(file_get_contents('php://input'), true);
+    if (!is_array($data) || empty($data['device_type_id']) || !isset($data['ports']) || !is_array($data['ports'])) {
+        jsonError('Ungueltige Daten', 400);
+    }
 
-        if (!empty($port['id']) && !str_starts_with($port['id'], 'tmp_')) {
+    $deviceTypeId = (int)$data['device_type_id'];
+    if ($deviceTypeId <= 0) {
+        jsonError('device_type_id ist ungueltig', 400);
+    }
 
-            /* ---------- UPDATE ---------- */
-            $sql->set(
-                "UPDATE device_type_ports
-                 SET name = ?, port_type_id = ?, pos_x = ?, pos_y = ?, comment = ?
-                 WHERE id = ? AND device_type_id = ?",
-                "siddsii",
-                [
-                    $port['name'],
-                    $port['port_type_id'],
-                    $port['x'],
-                    $port['y'],
-                    $port['comment'],
-                    $port['id'],
-                    $deviceTypeId
-                ]
+    $deviceType = $sql->single('SELECT id FROM device_types WHERE id = ?', 'i', [$deviceTypeId]);
+    if (!$deviceType) {
+        jsonError('Geraetetyp existiert nicht', 404);
+    }
+
+    $sql->set('START TRANSACTION');
+
+    foreach ($data['ports'] as $index => $port) {
+        if (!is_array($port)) {
+            $sql->set('ROLLBACK');
+            jsonError('Port-Eintrag an Position ' . $index . ' ist ungueltig', 400);
+        }
+
+        $name = trim((string)($port['name'] ?? ''));
+        if ($name === '') {
+            $sql->set('ROLLBACK');
+            jsonError('Port-Name darf nicht leer sein', 400);
+        }
+
+        $x = $port['x'] ?? null;
+        $y = $port['y'] ?? null;
+        if (!is_numeric($x) || !is_numeric($y)) {
+            $sql->set('ROLLBACK');
+            jsonError('x und y muessen numerisch sein', 400);
+        }
+
+        $x = (int)round((float)$x);
+        $y = (int)round((float)$y);
+        $portTypeId = validatePortTypeId($sql, $port['port_type_id'] ?? null);
+
+        $metadataRaw = $port['metadata'] ?? null;
+        $metadata = null;
+        if (is_array($metadataRaw)) {
+            $metadata = json_encode($metadataRaw);
+        } elseif (is_string($metadataRaw) && $metadataRaw !== '') {
+            json_decode($metadataRaw, true);
+            if (json_last_error() !== JSON_ERROR_NONE) {
+                $sql->set('ROLLBACK');
+                jsonError('metadata ist kein gueltiges JSON', 400);
+            }
+            $metadata = $metadataRaw;
+        }
+
+        $isExisting = !empty($port['id']) && !str_starts_with((string)$port['id'], 'tmp_');
+        if ($isExisting) {
+            $portId = (int)$port['id'];
+            $ok = $sql->set(
+                'UPDATE device_type_ports
+                 SET name = ?, port_type_id = ?, x = ?, y = ?, metadata = ?
+                 WHERE id = ? AND device_type_id = ?',
+                'siiisii',
+                [$name, $portTypeId, $x, $y, $metadata, $portId, $deviceTypeId]
             );
 
-        } else {
+            if ($ok === false) {
+                $sql->set('ROLLBACK');
+                jsonError('Update fehlgeschlagen', 500);
+            }
+            continue;
+        }
 
-            /* ---------- INSERT ---------- */
-            $sql->set(
-                "INSERT INTO device_type_ports
-                    (device_type_id, name, port_type_id, pos_x, pos_y, comment)
-                 VALUES (?, ?, ?, ?, ?, ?)",
-                "isidds",
-                [
-                    $deviceTypeId,
-                    $port['name'],
-                    $port['port_type_id'],
-                    $port['x'],
-                    $port['y'],
-                    $port['comment']
-                ],
-                true
-            );
+        $ok = $sql->set(
+            'INSERT INTO device_type_ports (device_type_id, name, port_type_id, x, y, metadata)
+             VALUES (?, ?, ?, ?, ?, ?)',
+            'isiiis',
+            [$deviceTypeId, $name, $portTypeId, $x, $y, $metadata],
+            true
+        );
+
+        if ($ok === false) {
+            $sql->set('ROLLBACK');
+            jsonError('Insert fehlgeschlagen', 500);
         }
     }
 
-    echo json_encode([
-        'status' => 'ok'
-    ]);
+    $sql->set('COMMIT');
+
+    echo json_encode(['status' => 'ok']);
 }
 
-/**
- * Löscht einen einzelnen Port
- */
-function deletePort($sql)
+function deletePort($sql): void
 {
-    $id = $_GET['id'] ?? null;
-
-    if (!$id) {
-        http_response_code(400);
-        echo json_encode(['error' => 'ID fehlt']);
-        return;
+    if ($_SERVER['REQUEST_METHOD'] !== 'POST' && $_SERVER['REQUEST_METHOD'] !== 'DELETE') {
+        jsonError('Methode nicht erlaubt', 405);
     }
 
-    // TODO: Prüfen, ob Port existiert und nicht verwendet wird
+    $id = isset($_GET['id']) ? (int)$_GET['id'] : 0;
+    if ($id <= 0) {
+        jsonError('ID fehlt', 400);
+    }
 
-    $rows = $sql->set(
-        "DELETE FROM device_type_ports WHERE id = ?",
-        "i",
-        [$id]
+    $port = $sql->single('SELECT id, device_type_id, name FROM device_type_ports WHERE id = ?', 'i', [$id]);
+    if (!$port) {
+        jsonError('Port existiert nicht', 404);
+    }
+
+    $usage = $sql->single(
+        'SELECT COUNT(*) AS cnt
+         FROM devices d
+         JOIN device_ports dp ON dp.device_id = d.id
+         WHERE d.device_type_id = ? AND dp.name = ?',
+        'is',
+        [(int)$port['device_type_id'], (string)$port['name']]
     );
 
-    echo json_encode([
-        'status' => 'deleted',
-        'rows' => $rows
-    ]);
+    if (!empty($usage) && (int)$usage['cnt'] > 0) {
+        jsonError('Port wird bereits von realen Geraeten genutzt und kann nicht geloescht werden', 409);
+    }
+
+    $rows = $sql->set('DELETE FROM device_type_ports WHERE id = ?', 'i', [$id]);
+    if ($rows === false) {
+        jsonError('Loeschen fehlgeschlagen', 500);
+    }
+
+    echo json_encode(['status' => 'deleted', 'rows' => $rows]);
 }
diff --git a/app/api/upload.php b/app/api/upload.php
index f8a2bd3..2441a8f 100644
--- a/app/api/upload.php
+++ b/app/api/upload.php
@@ -1,133 +1,89 @@
 <?php
 /**
  * app/api/upload.php
- *
- * Zentrale Upload-API
- * - Gerätetyp-Bilder (SVG / JPG / PNG)
- * - Floorpläne (SVG)
- * - Rack-Ansichten
- *
- * KEINE Logik für automatische Zuordnung
- * -> Upload + Rückgabe von Pfad / Metadaten
  */
 
 require_once __DIR__ . '/../bootstrap.php';
+requireAuth();
 
 header('Content-Type: application/json');
 
-// TODO: Single-User-Auth prüfen
-// if (!$_SESSION['user']) { http_response_code(403); exit; }
-
-/* =========================
- * Konfiguration
- * ========================= */
-
-// TODO: Upload-Basisverzeichnis aus config.php
-$baseUploadDir = __DIR__ . '/../uploads';
-
-// Erlaubte Typen
+$baseUploadDir = defined('UPLOAD_BASE_DIR') ? UPLOAD_BASE_DIR : (__DIR__ . '/../uploads');
+$maxFileSize = defined('UPLOAD_MAX_FILE_SIZE') ? (int)UPLOAD_MAX_FILE_SIZE : (5 * 1024 * 1024);
+$allowedCategories = defined('UPLOAD_ALLOWED_CATEGORIES') ? UPLOAD_ALLOWED_CATEGORIES : ['misc'];
 $allowedMimeTypes = [
-    'image/svg+xml',
-    'image/png',
-    'image/jpeg'
+    'image/svg+xml' => 'svg',
+    'image/png' => 'png',
+    'image/jpeg' => 'jpg',
 ];
 
-// TODO: Max. Dateigröße festlegen (z.B. 5MB)
-$maxFileSize = 5 * 1024 * 1024;
-
-/* =========================
- * Validierung
- * ========================= */
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    jsonError('Methode nicht erlaubt', 405);
+}
 
 if (empty($_FILES['file'])) {
-    http_response_code(400);
-    echo json_encode(['error' => 'Keine Datei hochgeladen']);
-    exit;
+    jsonError('Keine Datei hochgeladen', 400);
 }
 
 $file = $_FILES['file'];
-
-if ($file['error'] !== UPLOAD_ERR_OK) {
-    http_response_code(400);
-    echo json_encode(['error' => 'Upload-Fehler']);
-    exit;
+if (!is_array($file) || $file['error'] !== UPLOAD_ERR_OK) {
+    jsonError('Upload-Fehler', 400);
 }
 
-if ($file['size'] > $maxFileSize) {
-    http_response_code(400);
-    echo json_encode(['error' => 'Datei zu groß']);
-    exit;
+if ((int)$file['size'] > $maxFileSize) {
+    jsonError('Datei zu gross', 400);
 }
 
-// MIME-Type prüfen
 $finfo = finfo_open(FILEINFO_MIME_TYPE);
 $mimeType = finfo_file($finfo, $file['tmp_name']);
 finfo_close($finfo);
 
-if (!in_array($mimeType, $allowedMimeTypes)) {
-    http_response_code(400);
-    echo json_encode(['error' => 'Dateityp nicht erlaubt']);
-    exit;
+if (!isset($allowedMimeTypes[$mimeType])) {
+    jsonError('Dateityp nicht erlaubt', 400);
 }
 
-/* =========================
- * Zielverzeichnis
- * ========================= */
-
-// TODO: Kategorie definieren (device_types, floors, racks, etc.)
-$category = $_POST['category'] ?? 'misc';
-
-// Zielpfad
-$targetDir = $baseUploadDir . '/' . preg_replace('/[^a-z0-9_-]/i', '', $category);
-
-// Verzeichnis anlegen falls nötig
-if (!is_dir($targetDir)) {
-    mkdir($targetDir, 0755, true);
+$category = strtolower(trim((string)($_POST['category'] ?? 'misc')));
+if ($category === '' || !in_array($category, $allowedCategories, true)) {
+    jsonError('Ungueltige Kategorie', 400);
 }
 
-/* =========================
- * Dateiname
- * ========================= */
+$targetDir = rtrim($baseUploadDir, '/\\') . DIRECTORY_SEPARATOR . $category;
+if (!is_dir($targetDir) && !mkdir($targetDir, 0755, true) && !is_dir($targetDir)) {
+    jsonError('Upload-Verzeichnis konnte nicht erstellt werden', 500);
+}
 
-// Originalname bereinigen
-$extension = pathinfo($file['name'], PATHINFO_EXTENSION);
-
-// TODO: Eindeutigen Namen besser definieren (UUID?)
-$filename = uniqid('upload_', true) . '.' . strtolower($extension);
-
-$targetPath = $targetDir . '/' . $filename;
-
-/* =========================
- * Datei speichern
- * ========================= */
+$extension = $allowedMimeTypes[$mimeType];
+$filename = sprintf('%s_%s.%s', $category, bin2hex(random_bytes(16)), $extension);
+$targetPath = $targetDir . DIRECTORY_SEPARATOR . $filename;
 
 if (!move_uploaded_file($file['tmp_name'], $targetPath)) {
-    http_response_code(500);
-    echo json_encode(['error' => 'Datei konnte nicht gespeichert werden']);
-    exit;
+    jsonError('Datei konnte nicht gespeichert werden', 500);
 }
 
-/* =========================
- * Optional: DB-Eintrag
- * ========================= */
+$publicPath = '/uploads/' . $category . '/' . $filename;
+$uploadId = null;
 
-// TODO: Optional in Tabelle `uploads` speichern
-// $uploadId = $sql->set(
-//     "INSERT INTO uploads (filename, path, mime_type, category)
-//      VALUES (?, ?, ?, ?)",
-//     "ssss",
-//     [$filename, $targetPath, $mimeType, $category],
-//     true
-// );
-
-/* =========================
- * Antwort
- * ========================= */
+$uploadTableExists = $sql->single("SHOW TABLES LIKE 'uploads'");
+if (!empty($uploadTableExists)) {
+    $uploadId = $sql->set(
+        'INSERT INTO uploads (filename, path, mime_type, category) VALUES (?, ?, ?, ?)',
+        'ssss',
+        [$filename, $publicPath, $mimeType, $category],
+        true
+    );
+}
 
 echo json_encode([
     'status' => 'ok',
     'filename' => $filename,
-    'path' => str_replace(__DIR__ . '/..', '', $targetPath),
-    'mime_type' => $mimeType
-    // 'id' => $uploadId ?? null
+    'path' => $publicPath,
+    'mime_type' => $mimeType,
+    'id' => $uploadId,
 ]);
+
+function jsonError(string $message, int $status = 400): void
+{
+    http_response_code($status);
+    echo json_encode(['error' => $message]);
+    exit;
+}
diff --git a/app/assets/icons/favicon.svg b/app/assets/icons/favicon.svg
new file mode 100644
index 0000000..0ed9925
--- /dev/null
+++ b/app/assets/icons/favicon.svg
@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <rect width="64" height="64" rx="12" fill="#0c4da2"/>
+  <path d="M14 22h36v6H14zm0 14h36v6H14z" fill="#ffffff"/>
+</svg>
diff --git a/app/assets/js/app.js b/app/assets/js/app.js
index 001bc7f..074c64c 100644
--- a/app/assets/js/app.js
+++ b/app/assets/js/app.js
@@ -1,135 +1,110 @@
 /**
  * app/assets/js/app.js
- *
- * Zentrale JS-Datei für die Webanwendung
- * - Initialisiert alle Module
- * - SVG-Editor, Netzwerk-Ansicht, Drag & Drop, Floorplan
- * - Event-Handler, globale Variablen
  */
 
-// =========================
-// Global Variables / Config
-// =========================
-
 window.APP = {
-    deviceTypes: [],   // TODO: alle Gerätetypen laden
-    devices: [],       // TODO: alle Geräte laden
-    racks: [],         // TODO: alle Racks laden
-    floors: [],        // TODO: alle Floors laden
-    connections: [],   // TODO: alle Verbindungen laden
+    state: {
+        deviceTypes: [],
+        devices: [],
+        racks: [],
+        floors: [],
+        connections: [],
+    },
+    capabilities: {
+        hasGlobalDataApi: false,
+    }
 };
 
-// =========================
-// Init Functions
-// =========================
-
 document.addEventListener('DOMContentLoaded', () => {
-
-    console.log('App initialized');
-
-    // =========================
-    // SVG-Port-Editor initialisieren
-    // =========================
-    // TODO: import / init svg-editor.js
-    // if (window.SVGEditor) window.SVGEditor.init();
-
-    // =========================
-    // Netzwerk-Ansicht initialisieren
-    // =========================
-    // TODO: import / init network-view.js
-    // if (window.NetworkView) window.NetworkView.init();
-
-    // =========================
-    // Drag & Drop für Floors / Racks / Devices
-    // =========================
-    // TODO: init drag & drop logic
-
-    // =========================
-    // Event-Handler für Buttons / Forms
-    // =========================
+    initViewModules();
     initEventHandlers();
 });
 
-// =========================
-// Event Handler Setup
-// =========================
+function initViewModules() {
+    if (typeof window.Dashboard?.init === 'function') {
+        window.Dashboard.init();
+    }
+
+    // Both modules are loaded via script tags in header.php.
+    // They are self-initializing and only run when expected DOM nodes exist.
+    window.dispatchEvent(new CustomEvent('app:modules-initialized'));
+}
 
 function initEventHandlers() {
-
-    // TODO: Save-Button Device-Type
-    const saveDeviceTypeBtn = document.querySelector('#save-device-type');
-    if (saveDeviceTypeBtn) {
-        saveDeviceTypeBtn.addEventListener('click', (e) => {
-            e.preventDefault();
-            // TODO: Save Device-Type via AJAX
-        });
-    }
-
-    // TODO: Save-Button Device
-    const saveDeviceBtn = document.querySelector('#save-device');
-    if (saveDeviceBtn) {
-        saveDeviceBtn.addEventListener('click', (e) => {
-            e.preventDefault();
-            // TODO: Save Device via AJAX
-        });
-    }
-
-    // TODO: Save-Button Floor
-    const saveFloorBtn = document.querySelector('#save-floor');
-    if (saveFloorBtn) {
-        saveFloorBtn.addEventListener('click', (e) => {
-            e.preventDefault();
-            // TODO: Save Floor via AJAX
-        });
-    }
-
-    // TODO: Save-Button Rack
-    const saveRackBtn = document.querySelector('#save-rack');
-    if (saveRackBtn) {
-        saveRackBtn.addEventListener('click', (e) => {
-            e.preventDefault();
-            // TODO: Save Rack via AJAX
-        });
-    }
-
-    // TODO: Weitere Event-Handler (Import, Export, Filter)
+    bindFormSubmitButton('#save-device-type', 'form[action*="module=device_types"][action*="save"]');
+    bindFormSubmitButton('#save-device', 'form[action*="module=devices"][action*="save"]');
+    bindFormSubmitButton('#save-floor', 'form[action*="module=floors"][action*="save"]');
+    bindFormSubmitButton('#save-rack', 'form[action*="module=racks"][action*="save"]');
 
     document.querySelectorAll('[data-confirm-delete]').forEach((btn) => {
         btn.addEventListener('click', (event) => {
             event.preventDefault();
-            const message = btn.getAttribute('data-confirm-message') || 'Aktion ausführen?';
+            const message = btn.getAttribute('data-confirm-message') || 'Aktion ausfuehren?';
             if (confirm(message)) {
-                alert(btn.getAttribute('data-confirm-feedback') || 'Diese Funktion ist noch nicht verfügbar.');
+                const href = btn.getAttribute('href') || btn.dataset.href;
+                if (href) {
+                    window.location.href = href;
+                }
+            }
+        });
+    });
+
+    document.querySelectorAll('[data-filter-submit]').forEach((el) => {
+        el.addEventListener('change', () => {
+            const form = el.closest('form');
+            if (form) {
+                form.requestSubmit();
             }
         });
     });
 }
 
-// =========================
-// Utility Functions
-// =========================
+function bindFormSubmitButton(buttonSelector, formSelector) {
+    const button = document.querySelector(buttonSelector);
+    if (!button) {
+        return;
+    }
 
-/**
- * AJAX Request Helper
- * @param {string} url
- * @param {object} data
- * @param {function} callback
- */
-function ajaxPost(url, data, callback) {
+    button.addEventListener('click', (event) => {
+        event.preventDefault();
+        const form = button.closest('form') || document.querySelector(formSelector);
+        if (form) {
+            form.requestSubmit();
+        }
+    });
+}
+
+function ajaxPost(url, data, callback, onError) {
     const xhr = new XMLHttpRequest();
     xhr.open('POST', url, true);
     xhr.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
-    xhr.onload = function() {
+    xhr.onload = function onLoad() {
         if (xhr.status >= 200 && xhr.status < 300) {
-            callback(JSON.parse(xhr.responseText));
-        } else {
-            console.error('AJAX Error:', xhr.statusText);
+            let parsed = null;
+            try {
+                parsed = JSON.parse(xhr.responseText);
+            } catch (error) {
+                if (typeof onError === 'function') {
+                    onError(error);
+                }
+                return;
+            }
+            callback(parsed);
+            return;
+        }
+
+        if (typeof onError === 'function') {
+            onError(new Error('AJAX error: ' + xhr.status));
         }
     };
+
+    xhr.onerror = function onXhrError() {
+        if (typeof onError === 'function') {
+            onError(new Error('Netzwerkfehler'));
+        }
+    };
+
     xhr.send(JSON.stringify(data));
 }
 
-// TODO: weitere Utility-Funktionen (DOM-Helper, SVG-Helper, etc.)
-
-// Dashboard initialisieren
-if (window.Dashboard) window.Dashboard.init();
+window.APP.ajaxPost = ajaxPost;
diff --git a/app/assets/js/dashboard.js b/app/assets/js/dashboard.js
index f009f70..2237c25 100644
--- a/app/assets/js/dashboard.js
+++ b/app/assets/js/dashboard.js
@@ -1,99 +1,35 @@
 /**
  * app/assets/js/dashboard.js
- *
- * Dashboard-Modul
- * - Zentrale Übersicht aller Grundfunktionen
- * - Einstiegspunkt für das Tool
- * - Kann später Status, Warnungen, Statistiken anzeigen
  */
 
 window.Dashboard = (function () {
-
-    // =========================
-    // Interne Daten
-    // =========================
-
     const modules = [
-        {
-            id: 'device_types',
-            label: 'Gerätetypen',
-            description: 'Gerätetypen, Port-Definitionen, Module',
-            url: '/app/device_types/list.php',
-            icon: '🔌'
-        },
-        {
-            id: 'devices',
-            label: 'Geräte',
-            description: 'Physische Geräte in Racks und Räumen',
-            url: '/app/devices/list.php',
-            icon: '🖥️'
-        },
-        {
-            id: 'connections',
-            label: 'Verbindungen',
-            description: 'Kabel, Ports, VLANs, Protokolle',
-            url: '/app/connections/list.php',
-            icon: '🧵'
-        },
-        {
-            id: 'floors',
-            label: 'Standorte & Stockwerke',
-            description: 'Gebäude, Etagen, Räume, Dosen',
-            url: '/app/floors/list.php',
-            icon: '🏢'
-        },
-        {
-            id: 'racks',
-            label: 'Serverschränke',
-            description: 'Racks, Positionierung, Höheneinheiten',
-            url: '/app/racks/list.php',
-            icon: '🗄️'
-        },
-        {
-            id: 'network_view',
-            label: 'Netzwerk-Ansicht',
-            description: 'Grafische Netzwerkdarstellung',
-            url: '/network.php',
-            icon: '🌐'
-        },
-        {
-            id: 'svg_editor',
-            label: 'SVG-Port-Editor',
-            description: 'Ports auf Gerätetypen definieren',
-            url: '/svg-editor.php',
-            icon: '✏️'
-        }
+        { id: 'device_types', label: 'Geraetetypen', description: 'Geraetetypen und Port-Definitionen', url: '?module=device_types&action=list', icon: 'DT' },
+        { id: 'devices', label: 'Geraete', description: 'Physische Geraete in Racks und Raeumen', url: '?module=devices&action=list', icon: 'DV' },
+        { id: 'connections', label: 'Verbindungen', description: 'Kabel, Ports und VLANs', url: '?module=connections&action=list', icon: 'CN' },
+        { id: 'floors', label: 'Stockwerke', description: 'Standorte, Gebaeude und Etagen', url: '?module=floors&action=list', icon: 'FL' },
+        { id: 'racks', label: 'Racks', description: 'Racks und Positionierung', url: '?module=racks&action=list', icon: 'RK' },
+        { id: 'infra', label: 'Infrastruktur', description: 'Patchpanels und Wandbuchsen', url: '?module=floor_infrastructure&action=list', icon: 'IF' }
     ];
 
-    // =========================
-    // Public API
-    // =========================
-
     function init() {
-        console.log('Dashboard initialized');
+        const container = document.querySelector('#dashboard-modules');
+        if (container) {
+            renderModules(container);
+        }
 
-        // TODO: Dashboard-Container ermitteln
-        // const container = document.querySelector('#dashboard');
-
-        // TODO: Module rendern
-        // renderModules(container);
-
-        // TODO: Optional: Status-Daten laden (Counts, Warnings)
+        loadStats();
+        showWarnings();
+        renderRecentChanges();
     }
 
-    // =========================
-    // Render Functions
-    // =========================
-
     function renderModules(container) {
-        if (!container) return;
-
         container.innerHTML = '';
 
-        modules.forEach(module => {
-            const el = document.createElement('div');
+        modules.forEach((module) => {
+            const el = document.createElement('a');
             el.className = 'dashboard-tile';
-
+            el.href = module.url;
             el.innerHTML = `
                 <div class="dashboard-icon">${module.icon}</div>
                 <div class="dashboard-content">
@@ -101,30 +37,54 @@ window.Dashboard = (function () {
                     <p>${module.description}</p>
                 </div>
             `;
-
-            el.addEventListener('click', () => {
-                window.location.href = module.url;
-            });
-
             container.appendChild(el);
         });
     }
 
-    // =========================
-    // Optional Erweiterungen
-    // =========================
+    function loadStats() {
+        const stats = {
+            devices: countRows('.device-list tbody tr'),
+            connections: countRows('.connection-list tbody tr'),
+            outlets: countRows('.infra-table tbody tr')
+        };
 
-    // TODO: loadStats() → Anzahl Geräte, offene Ports, unverbundene Dosen
-    // TODO: showWarnings() → unverbundene Ports, VLAN-Konflikte
-    // TODO: RecentChanges() → letzte Änderungen
+        const target = document.querySelector('[data-dashboard-stats]');
+        if (!target) {
+            return;
+        }
 
-    // =========================
-    // Expose Public Methods
-    // =========================
+        target.textContent = `Geraete: ${stats.devices} | Verbindungen: ${stats.connections} | Infrastruktur-Eintraege: ${stats.outlets}`;
+    }
 
-    return {
-        init,
-        // renderModules // optional öffentlich machen
-    };
+    function showWarnings() {
+        const target = document.querySelector('[data-dashboard-warnings]');
+        if (!target) {
+            return;
+        }
 
+        const warnings = [];
+        if (countRows('.device-list tbody tr') === 0) {
+            warnings.push('Noch keine Geraete vorhanden');
+        }
+        if (countRows('.connection-list tbody tr') === 0) {
+            warnings.push('Noch keine Verbindungen vorhanden');
+        }
+
+        target.textContent = warnings.length ? warnings.join(' | ') : 'Keine offenen Warnungen erkannt';
+    }
+
+    function renderRecentChanges() {
+        const target = document.querySelector('[data-dashboard-recent]');
+        if (!target) {
+            return;
+        }
+
+        target.textContent = 'Letzte Aenderungen werden serverseitig noch nicht protokolliert.';
+    }
+
+    function countRows(selector) {
+        return document.querySelectorAll(selector).length;
+    }
+
+    return { init };
 })();
diff --git a/app/assets/js/device-type-edit-form.js b/app/assets/js/device-type-edit-form.js
index 57a785d..50cb9bd 100644
--- a/app/assets/js/device-type-edit-form.js
+++ b/app/assets/js/device-type-edit-form.js
@@ -66,10 +66,24 @@
                 return;
             }
 
-            if (window.confirm('Diesen Gerätetyp wirklich löschen? Alle zugeordneten Geräte werden angepasst.')) {
-                // TODO: Delete-Endpoint/Flow ist noch nicht implementiert.
-                window.alert('Löschen noch nicht implementiert');
+            if (!window.confirm('Diesen Geraetetyp wirklich loeschen?')) {
+                return;
             }
+
+            fetch('?module=device_types&action=delete', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+                body: 'id=' + encodeURIComponent(id)
+            })
+                .then((response) => response.json())
+                .then((data) => {
+                    if (data && data.success) {
+                        window.location.href = '?module=device_types&action=list';
+                        return;
+                    }
+                    window.alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+                })
+                .catch(() => window.alert('Loeschen fehlgeschlagen'));
         });
 
         deleteButton.dataset.deleteBound = '1';
diff --git a/app/assets/js/device-types-list.js b/app/assets/js/device-types-list.js
index b79b61b..c55b40c 100644
--- a/app/assets/js/device-types-list.js
+++ b/app/assets/js/device-types-list.js
@@ -13,8 +13,20 @@
                 }
 
                 if (window.confirm('Diesen Geraetetyp wirklich loeschen?')) {
-                    // TODO: AJAX-Delete implementieren
-                    window.alert('Loeschen noch nicht implementiert');
+                    fetch('?module=device_types&action=delete', {
+                        method: 'POST',
+                        headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+                        body: 'id=' + encodeURIComponent(id)
+                    })
+                        .then((response) => response.json())
+                        .then((data) => {
+                            if (data && data.success) {
+                                window.location.reload();
+                                return;
+                            }
+                            window.alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+                        })
+                        .catch(() => window.alert('Loeschen fehlgeschlagen'));
                 }
             });
 
diff --git a/app/assets/js/locations-list.js b/app/assets/js/locations-list.js
index 19cbc2d..4b7caa0 100644
--- a/app/assets/js/locations-list.js
+++ b/app/assets/js/locations-list.js
@@ -21,16 +21,34 @@
             .catch(() => alert('Loeschen fehlgeschlagen'));
     }
 
-    function handleBuildingDelete() {
-        if (confirm('Dieses Gebaeude wirklich loeschen? Alle Stockwerke werden geloescht.')) {
-            alert('Loeschen noch nicht implementiert');
+    function handleBuildingDelete(id) {
+        if (!confirm('Dieses Gebaeude wirklich loeschen? Alle Stockwerke werden geloescht.')) {
+            return;
         }
+        postDelete('?module=buildings&action=delete&id=' + encodeURIComponent(id))
+            .then((data) => {
+                if (data && (data.success || data.status === 'ok')) {
+                    window.location.reload();
+                    return;
+                }
+                alert((data && (data.message || data.error)) ? (data.message || data.error) : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => alert('Loeschen fehlgeschlagen'));
     }
 
-    function handleFloorDelete() {
-        if (confirm('Dieses Stockwerk wirklich loeschen? Alle Raeume und Racks werden geloescht.')) {
-            alert('Loeschen noch nicht implementiert');
+    function handleFloorDelete(id) {
+        if (!confirm('Dieses Stockwerk wirklich loeschen? Alle Raeume und Racks werden geloescht.')) {
+            return;
         }
+        postDelete('?module=floors&action=delete&id=' + encodeURIComponent(id))
+            .then((data) => {
+                if (data && data.success) {
+                    window.location.reload();
+                    return;
+                }
+                alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => alert('Loeschen fehlgeschlagen'));
     }
 
     function handleRoomDelete(id) {
diff --git a/app/assets/js/network-view.js b/app/assets/js/network-view.js
index e5fd5d6..0eb7e08 100644
--- a/app/assets/js/network-view.js
+++ b/app/assets/js/network-view.js
@@ -1,61 +1,23 @@
-// Netzwerk-Graph-Ansicht (Nodes, Kanten, Filter)
-/**
- * network-view.js
- *
- * Darstellung der Netzwerk-Topologie:
- * - Geräte als Nodes
- * - Ports als Ankerpunkte
- * - Verbindungen als Linien
- * - Freie / selbstdefinierte Verbindungstypen
- *
- * Kein Layout-Framework (kein D3, kein Cytoscape)
- * -> bewusst simpel & erweiterbar
- */
-
 (() => {
-/* =========================
- * Konfiguration
- * ========================= */
+const svgElement = document.querySelector('#network-svg');
+if (!svgElement) {
+    return;
+}
 
-// TODO: Standort / Rack / View-Kontext vom Backend setzen
-const CONTEXT_ID = null;
-
-// TODO: API-Endpunkte definieren
-const API_LOAD_NETWORK = '/api/network_view.php?action=load';
+const CONTEXT_TYPE = svgElement.dataset.contextType || 'all';
+const CONTEXT_ID = Number(svgElement.dataset.contextId || 0);
+const API_LOAD_NETWORK = '/api/connections.php?action=load';
 const API_SAVE_POSITIONS = '/api/network_view.php?action=save_positions';
 
-/* =========================
- * State
- * ========================= */
-
-let svgElement = null;
-
-let devices = [];      // Geräte inkl. Position
-let connections = [];  // Verbindungen zwischen Ports
-
+let devices = [];
+let ports = [];
+let connections = [];
 let selectedDeviceId = null;
 let isDragging = false;
 let dragOffset = { x: 0, y: 0 };
 
-/* =========================
- * Initialisierung
- * ========================= */
-
-document.addEventListener('DOMContentLoaded', () => {
-    svgElement = document.querySelector('#network-svg');
-
-    if (!svgElement) {
-        console.warn('Network View: #network-svg nicht gefunden');
-        return;
-    }
-
-    bindSvgEvents();
-    loadNetwork();
-});
-
-/* =========================
- * Events
- * ========================= */
+bindSvgEvents();
+loadNetwork();
 
 function bindSvgEvents() {
     svgElement.addEventListener('mousemove', onMouseMove);
@@ -63,37 +25,40 @@ function bindSvgEvents() {
     svgElement.addEventListener('click', onSvgClick);
 }
 
-/* =========================
- * Laden
- * ========================= */
+function buildLoadUrl() {
+    const params = new URLSearchParams();
+    params.set('action', 'load');
+    params.set('context_type', CONTEXT_TYPE);
+    if (CONTEXT_TYPE !== 'all') {
+        params.set('context_id', String(CONTEXT_ID));
+    }
+    return '/api/connections.php?' + params.toString();
+}
 
 function loadNetwork() {
-    if (!CONTEXT_ID) {
-        console.warn('CONTEXT_ID nicht gesetzt');
-        return;
-    }
-
-    fetch(`${API_LOAD_NETWORK}&context_id=${CONTEXT_ID}`)
-        .then(res => res.json())
-        .then(data => {
-            // TODO: Datenstruktur validieren
-            devices = data.devices || [];
-            connections = data.connections || [];
+    fetch(buildLoadUrl())
+        .then((res) => res.json())
+        .then((data) => {
+            if (!data || !Array.isArray(data.devices) || !Array.isArray(data.connections)) {
+                throw new Error('Antwortformat ungueltig');
+            }
 
+            devices = data.devices.map((device, index) => ({
+                ...device,
+                x: Number(device.pos_x ?? device.x ?? 50 + (index % 6) * 150),
+                y: Number(device.pos_y ?? device.y ?? 60 + Math.floor(index / 6) * 120)
+            }));
+            ports = Array.isArray(data.ports) ? data.ports : [];
+            connections = data.connections;
             renderAll();
         })
-        .catch(err => {
+        .catch((err) => {
             console.error('Fehler beim Laden der Netzwerkansicht', err);
         });
 }
 
-/* =========================
- * Rendering
- * ========================= */
-
 function renderAll() {
     clearSvg();
-
     renderConnections();
     renderDevices();
 }
@@ -104,34 +69,27 @@ function clearSvg() {
     }
 }
 
-/* ---------- Geräte ---------- */
-
 function renderDevices() {
-    devices.forEach(device => renderDevice(device));
+    devices.forEach((device) => renderDevice(device));
 }
 
 function renderDevice(device) {
     const group = document.createElementNS('http://www.w3.org/2000/svg', 'g');
     group.classList.add('device-node');
     group.dataset.id = device.id;
+    group.setAttribute('transform', `translate(${device.x || 0}, ${device.y || 0})`);
 
-    group.setAttribute(
-        'transform',
-        `translate(${device.x || 0}, ${device.y || 0})`
-    );
-
-    // TODO: Gerätetyp (SVG oder JPG) korrekt laden
     const rect = document.createElementNS('http://www.w3.org/2000/svg', 'rect');
     rect.setAttribute('width', 120);
     rect.setAttribute('height', 60);
     rect.setAttribute('rx', 6);
+    rect.classList.add('device-node-rect');
 
     rect.addEventListener('mousedown', (e) => {
         startDrag(e, device.id);
         e.stopPropagation();
     });
 
-    // Label
     const text = document.createElementNS('http://www.w3.org/2000/svg', 'text');
     text.setAttribute('x', 60);
     text.setAttribute('y', 35);
@@ -141,40 +99,59 @@ function renderDevice(device) {
     group.appendChild(rect);
     group.appendChild(text);
 
-    // TODO: Ports als kleine Kreise anlegen (Position aus Portdefinition)
-    // TODO: Ports klickbar machen (für Verbindungs-Erstellung)
+    const devicePorts = ports.filter((port) => Number(port.device_id) === Number(device.id));
+    const spacing = 120 / (Math.max(1, devicePorts.length) + 1);
+    devicePorts.forEach((port, index) => {
+        const dot = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
+        dot.setAttribute('cx', String(Math.round((index + 1) * spacing)));
+        dot.setAttribute('cy', '62');
+        dot.setAttribute('r', '3');
+        dot.classList.add('device-port-dot');
+        dot.dataset.portId = String(port.id);
+        dot.dataset.deviceId = String(device.id);
+        dot.addEventListener('click', (event) => {
+            event.stopPropagation();
+            console.info('Port ausgewaehlt', port.id);
+        });
+        group.appendChild(dot);
+    });
 
     svgElement.appendChild(group);
 }
 
-/* ---------- Verbindungen ---------- */
-
 function renderConnections() {
-    connections.forEach(conn => renderConnection(conn));
+    connections.forEach((connection) => renderConnection(connection));
 }
 
 function renderConnection(connection) {
-    // TODO: Quell- & Ziel-Port-Koordinaten berechnen
-    // TODO: unterschiedliche Verbindungstypen (Farbe, Strichart, Dicke)
+    const sourcePort = ports.find((port) => Number(port.id) === Number(connection.port_a_id));
+    const targetPort = ports.find((port) => Number(port.id) === Number(connection.port_b_id));
+    if (!sourcePort || !targetPort) {
+        return;
+    }
+
+    const sourceDevice = devices.find((device) => Number(device.id) === Number(sourcePort.device_id));
+    const targetDevice = devices.find((device) => Number(device.id) === Number(targetPort.device_id));
+    if (!sourceDevice || !targetDevice) {
+        return;
+    }
 
     const line = document.createElementNS('http://www.w3.org/2000/svg', 'line');
+    line.setAttribute('x1', String(sourceDevice.x + 60));
+    line.setAttribute('y1', String(sourceDevice.y + 60));
+    line.setAttribute('x2', String(targetDevice.x + 60));
+    line.setAttribute('y2', String(targetDevice.y + 60));
 
-    line.setAttribute('x1', 0);
-    line.setAttribute('y1', 0);
-    line.setAttribute('x2', 100);
-    line.setAttribute('y2', 100);
-
+    const isFiber = String(connection.mode || '').toLowerCase().includes('fiber');
     line.classList.add('connection-line');
+    line.setAttribute('stroke', isFiber ? '#2f6fef' : '#1f8b4c');
+    line.setAttribute('stroke-width', isFiber ? '2.5' : '2');
+    line.setAttribute('stroke-dasharray', isFiber ? '6 4' : '');
 
     svgElement.appendChild(line);
 }
 
-/* =========================
- * Interaktion
- * ========================= */
-
 function onSvgClick(event) {
-    // Klick ins Leere -> Auswahl aufheben
     if (event.target === svgElement) {
         selectedDeviceId = null;
         updateSelection();
@@ -202,7 +179,6 @@ function onMouseMove(event) {
     if (!device) return;
 
     const point = getSvgCoordinates(event);
-
     device.x = point.x + dragOffset.x;
     device.y = point.y + dragOffset.y;
 
@@ -210,31 +186,28 @@ function onMouseMove(event) {
 }
 
 function onMouseUp() {
-    if (!isDragging) return;
+    if (!isDragging) {
+        return;
+    }
 
     isDragging = false;
-
-    // TODO: Positionen optional automatisch speichern
 }
 
-/* =========================
- * Auswahl
- * ========================= */
-
 function updateSelection() {
-    svgElement.querySelectorAll('.device-node').forEach(el => {
-        el.classList.toggle(
-            'selected',
-            el.dataset.id === String(selectedDeviceId)
-        );
+    svgElement.querySelectorAll('.device-node').forEach((el) => {
+        el.classList.toggle('selected', el.dataset.id === String(selectedDeviceId));
     });
 
-    // TODO: Sidebar mit Gerätedetails füllen
-}
+    const sidebar = document.querySelector('[data-network-selected-device]');
+    if (!sidebar) {
+        return;
+    }
 
-/* =========================
- * Speichern
- * ========================= */
+    const device = getDeviceById(selectedDeviceId);
+    sidebar.textContent = device
+        ? `${device.name} (ID ${device.id})`
+        : 'Kein Geraet ausgewaehlt';
+}
 
 function savePositions() {
     fetch(API_SAVE_POSITIONS, {
@@ -242,27 +215,21 @@ function savePositions() {
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({
             context_id: CONTEXT_ID,
-            devices: devices.map(d => ({
-                id: d.id,
-                x: d.x,
-                y: d.y
-            }))
+            devices: devices.map((device) => ({ id: device.id, x: device.x, y: device.y }))
         })
     })
-    .then(res => res.json())
-    .then(data => {
-        // TODO: Erfolg / Fehler anzeigen
-        console.log('Positionen gespeichert', data);
-    })
-    .catch(err => {
-        console.error('Fehler beim Speichern', err);
-    });
+        .then((res) => res.json())
+        .then((data) => {
+            if (data?.error) {
+                throw new Error(data.error);
+            }
+            alert('Positionen gespeichert');
+        })
+        .catch((err) => {
+            alert('Positionen konnten nicht gespeichert werden: ' + err.message);
+        });
 }
 
-/* =========================
- * Hilfsfunktionen
- * ========================= */
-
 function getSvgCoordinates(event) {
     const pt = svgElement.createSVGPoint();
     pt.x = event.clientX;
@@ -273,19 +240,23 @@ function getSvgCoordinates(event) {
 }
 
 function getDeviceById(id) {
-    return devices.find(d => d.id === id);
+    return devices.find((device) => Number(device.id) === Number(id));
 }
 
-/* =========================
- * Keyboard Shortcuts
- * ========================= */
-
-document.addEventListener('keydown', (e) => {
-    if (e.key === 'Escape') {
+document.addEventListener('keydown', (event) => {
+    if (event.key === 'Escape') {
         selectedDeviceId = null;
         updateSelection();
+        return;
     }
 
-    // TODO: Delete -> Gerät entfernen?
+    if (event.key === 'Delete' && selectedDeviceId) {
+        console.warn('Delete von Geraeten ist in der Netzwerkansicht noch nicht implementiert.');
+    }
+
+    if (event.key.toLowerCase() === 's' && (event.ctrlKey || event.metaKey)) {
+        event.preventDefault();
+        savePositions();
+    }
 });
 })();
diff --git a/app/assets/js/svg-editor.js b/app/assets/js/svg-editor.js
index e94e4a3..84fba51 100644
--- a/app/assets/js/svg-editor.js
+++ b/app/assets/js/svg-editor.js
@@ -1,92 +1,60 @@
-// Logik für den SVG-Port-Editor (Klicks, Drag & Drop, Speichern)
-/**
- * svg-editor.js
- *
- * Logik für den SVG-Port-Editor:
- * - Ports per Klick anlegen
- * - Ports auswählen
- * - Ports verschieben (Drag & Drop)
- * - Ports löschen
- * - Ports laden / speichern
- *
- * Abhängigkeiten: keine (Vanilla JS)
- */
-
 (() => {
-/* =========================
- * Konfiguration
- * ========================= */
+const svgElement = document.querySelector('#device-svg');
+if (!svgElement) {
+    return;
+}
 
-// TODO: vom Backend setzen (z. B. via data-Attribut)
-const DEVICE_TYPE_ID = null;
-
-// TODO: API-Endpunkte festlegen
+const DEVICE_TYPE_ID = Number(svgElement.dataset.deviceTypeId || 0);
 const API_LOAD_PORTS = '/api/device_type_ports.php?action=load';
 const API_SAVE_PORTS = '/api/device_type_ports.php?action=save';
+const DEFAULT_PORT_TYPE_ID = null;
 
-/* =========================
- * State
- * ========================= */
-
-let svgElement = null;
 let ports = [];
 let selectedPortId = null;
 let isDragging = false;
 let dragOffset = { x: 0, y: 0 };
 
-/* =========================
- * Initialisierung
- * ========================= */
-
-document.addEventListener('DOMContentLoaded', () => {
-    svgElement = document.querySelector('#device-svg');
-
-    if (!svgElement) {
-        console.warn('SVG Editor: #device-svg nicht gefunden');
-        return;
-    }
-
-    bindSvgEvents();
-    loadPorts();
-});
-
-/* =========================
- * SVG Events
- * ========================= */
+bindSvgEvents();
+loadPorts();
 
 function bindSvgEvents() {
     svgElement.addEventListener('click', onSvgClick);
     svgElement.addEventListener('mousemove', onSvgMouseMove);
     svgElement.addEventListener('mouseup', onSvgMouseUp);
+
+    const saveButton = document.querySelector('[data-save-svg-ports]');
+    if (saveButton) {
+        saveButton.addEventListener('click', (event) => {
+            event.preventDefault();
+            savePorts();
+        });
+    }
 }
 
-/* =========================
- * Port-Erstellung
- * ========================= */
-
 function onSvgClick(event) {
-    // Klick auf bestehenden Port?
     if (event.target.classList.contains('port-point')) {
         selectPort(event.target.dataset.id);
         return;
     }
 
-    // TODO: Modifier-Key prüfen (z. B. nur mit SHIFT neuen Port erstellen?)
-    const point = getSvgCoordinates(event);
+    // New ports are only created while SHIFT is held.
+    if (!event.shiftKey) {
+        return;
+    }
 
+    const point = getSvgCoordinates(event);
     createPort(point.x, point.y);
 }
 
 function createPort(x, y) {
     const id = generateTempId();
-
     const port = {
-        id: id,
+        id,
         name: `Port ${ports.length + 1}`,
-        port_type_id: null, // TODO: Default-Porttyp?
-        x: x,
-        y: y,
-        comment: ''
+        port_type_id: DEFAULT_PORT_TYPE_ID,
+        x,
+        y,
+        metadata: null
     };
 
     ports.push(port);
@@ -94,13 +62,8 @@ function createPort(x, y) {
     selectPort(id);
 }
 
-/* =========================
- * Rendering
- * ========================= */
-
 function renderPort(port) {
     const circle = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
-
     circle.setAttribute('cx', port.x);
     circle.setAttribute('cy', port.y);
     circle.setAttribute('r', 6);
@@ -116,27 +79,39 @@ function renderPort(port) {
 }
 
 function rerenderPorts() {
-    svgElement.querySelectorAll('.port-point').forEach(p => p.remove());
+    svgElement.querySelectorAll('.port-point').forEach((node) => node.remove());
     ports.forEach(renderPort);
+    if (selectedPortId !== null) {
+        selectPort(selectedPortId);
+    }
 }
 
-/* =========================
- * Auswahl
- * ========================= */
-
 function selectPort(id) {
     selectedPortId = id;
 
-    document.querySelectorAll('.port-point').forEach(el => {
-        el.classList.toggle('selected', el.dataset.id === id);
+    document.querySelectorAll('.port-point').forEach((el) => {
+        el.classList.toggle('selected', el.dataset.id === String(id));
     });
 
-    // TODO: Sidebar-Felder mit Portdaten füllen
+    const selected = getPortById(id);
+    fillSidebar(selected);
 }
 
-/* =========================
- * Drag & Drop
- * ========================= */
+function fillSidebar(port) {
+    const nameField = document.querySelector('[data-port-name]');
+    const typeField = document.querySelector('[data-port-type-id]');
+    const xField = document.querySelector('[data-port-x]');
+    const yField = document.querySelector('[data-port-y]');
+
+    if (nameField) nameField.value = port?.name || '';
+    if (typeField) typeField.value = port?.port_type_id || '';
+    if (xField) xField.value = port ? Math.round(port.x) : '';
+    if (yField) yField.value = port ? Math.round(port.y) : '';
+}
+
+function resetSidebar() {
+    fillSidebar(null);
+}
 
 function startDrag(event, portId) {
     const port = getPortById(portId);
@@ -157,7 +132,6 @@ function onSvgMouseMove(event) {
     if (!port) return;
 
     const point = getSvgCoordinates(event);
-
     port.x = point.x + dragOffset.x;
     port.y = point.y + dragOffset.y;
 
@@ -168,92 +142,95 @@ function onSvgMouseUp() {
     isDragging = false;
 }
 
-/* =========================
- * Löschen
- * ========================= */
-
 function deleteSelectedPort() {
-    if (!selectedPortId) return;
+    if (!selectedPortId) {
+        return;
+    }
 
-    // TODO: Sicherheitsabfrage (confirm)
-    ports = ports.filter(p => p.id !== selectedPortId);
+    if (!confirm('Ausgewaehlten Port loeschen?')) {
+        return;
+    }
+
+    ports = ports.filter((port) => String(port.id) !== String(selectedPortId));
     selectedPortId = null;
-
     rerenderPorts();
-
-    // TODO: Sidebar zurücksetzen
+    resetSidebar();
 }
 
-/* =========================
- * Laden / Speichern
- * ========================= */
-
 function loadPorts() {
     if (!DEVICE_TYPE_ID) {
-        console.warn('DEVICE_TYPE_ID nicht gesetzt');
+        console.warn('SVG Editor: DEVICE_TYPE_ID fehlt auf #device-svg');
         return;
     }
 
     fetch(`${API_LOAD_PORTS}&device_type_id=${DEVICE_TYPE_ID}`)
-        .then(res => res.json())
-        .then(data => {
-            // TODO: Datenformat validieren
-            ports = data;
+        .then((res) => res.json())
+        .then((data) => {
+            if (!Array.isArray(data)) {
+                throw new Error('Antwortformat ungueltig');
+            }
+
+            ports = data
+                .filter((entry) => entry && typeof entry === 'object')
+                .map((entry) => ({
+                    id: entry.id,
+                    name: String(entry.name || ''),
+                    port_type_id: entry.port_type_id ? Number(entry.port_type_id) : null,
+                    x: Number(entry.x || 0),
+                    y: Number(entry.y || 0),
+                    metadata: entry.metadata || null
+                }));
+
             rerenderPorts();
         })
-        .catch(err => {
+        .catch((err) => {
             console.error('Fehler beim Laden der Ports', err);
         });
 }
 
 function savePorts() {
-    if (!DEVICE_TYPE_ID) return;
+    if (!DEVICE_TYPE_ID) {
+        return;
+    }
 
     fetch(API_SAVE_PORTS, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({
             device_type_id: DEVICE_TYPE_ID,
-            ports: ports
+            ports
         })
     })
-    .then(res => res.json())
-    .then(data => {
-        // TODO: Erfolg / Fehler anzeigen
-        console.log('Ports gespeichert', data);
-    })
-    .catch(err => {
-        console.error('Fehler beim Speichern', err);
-    });
+        .then((res) => res.json())
+        .then((data) => {
+            if (data?.error) {
+                throw new Error(data.error);
+            }
+            alert('Ports gespeichert');
+        })
+        .catch((err) => {
+            alert('Speichern fehlgeschlagen: ' + err.message);
+        });
 }
 
-/* =========================
- * Hilfsfunktionen
- * ========================= */
-
 function getSvgCoordinates(event) {
     const pt = svgElement.createSVGPoint();
     pt.x = event.clientX;
     pt.y = event.clientY;
-
     const transformed = pt.matrixTransform(svgElement.getScreenCTM().inverse());
     return { x: transformed.x, y: transformed.y };
 }
 
 function getPortById(id) {
-    return ports.find(p => p.id === id);
+    return ports.find((port) => String(port.id) === String(id));
 }
 
 function generateTempId() {
-    return 'tmp_' + Math.random().toString(36).substr(2, 9);
+    return 'tmp_' + Math.random().toString(36).slice(2, 11);
 }
 
-/* =========================
- * Keyboard Shortcuts
- * ========================= */
-
-document.addEventListener('keydown', (e) => {
-    if (e.key === 'Delete') {
+document.addEventListener('keydown', (event) => {
+    if (event.key === 'Delete') {
         deleteSelectedPort();
     }
 });
diff --git a/app/bootstrap.php b/app/bootstrap.php
index 591373d..fbb71df 100644
--- a/app/bootstrap.php
+++ b/app/bootstrap.php
@@ -2,41 +2,18 @@
 /**
  * bootstrap.php
  *
- * Initialisierung der Anwendung
- * - Config laden
- * - Session starten
- * - DB-Verbindung über _sql.php
- * - Helper einbinden
+ * Application initialization.
  */
 
-/* =========================
- * Config laden
- * ========================= */
 require_once __DIR__ . '/config.php';
-// TODO: Config-Datei mit DB-Zugang, Pfaden, globalen Settings füllen
+date_default_timezone_set(defined('APP_TIMEZONE') ? APP_TIMEZONE : 'UTC');
 
-/* =========================
- * Session starten
- * ========================= */
-session_start();
-// TODO: Single-User Auth prüfen
-// z.B. $_SESSION['user'] setzen oder Login erzwingen
+if (session_status() !== PHP_SESSION_ACTIVE) {
+    session_start();
+}
 
-/* =========================
- * DB-Verbindung initialisieren
- * ========================= */
 require_once __DIR__ . '/lib/_sql.php';
-
-// TODO: Host, User, Passwort, DB aus config.php nutzen
 $sql = new SQL();
 
-/* =========================
- * Helper laden
- * ========================= */
 require_once __DIR__ . '/lib/helpers.php';
-
-/* =========================
- * Optional: Fehlerbehandlung
- * ========================= */
-// error_reporting(E_ALL);
-// ini_set('display_errors', 1);
+require_once __DIR__ . '/lib/auth.php';
diff --git a/app/config.php b/app/config.php
index 35584f3..d4a20ef 100644
--- a/app/config.php
+++ b/app/config.php
@@ -1,2 +1,19 @@
 <?php
 // Zentrale Konfiguration (DB-Zugangsdaten, Pfade, globale Settings)
+
+define('APP_NAME', 'netwatch');
+define('APP_ENV', getenv('APP_ENV') ?: 'development');
+define('APP_TIMEZONE', getenv('APP_TIMEZONE') ?: 'Europe/Berlin');
+
+define('DB_HOST', getenv('DB_HOST') ?: 'netdoc_db');
+define('DB_USER', getenv('DB_USER') ?: 'netdoc');
+define('DB_PASS', getenv('DB_PASS') ?: 'netdoc');
+define('DB_NAME', getenv('DB_NAME') ?: 'netdoc');
+
+define('AUTH_REQUIRED', (getenv('AUTH_REQUIRED') ?: '0') === '1');
+define('ADMIN_PASSWORD_HASH', getenv('ADMIN_PASSWORD_HASH') ?: '');
+define('LOGIN_PATH', getenv('LOGIN_PATH') ?: '/login.php');
+
+define('UPLOAD_BASE_DIR', __DIR__ . '/uploads');
+define('UPLOAD_MAX_FILE_SIZE', (int)(getenv('UPLOAD_MAX_FILE_SIZE') ?: 5 * 1024 * 1024));
+define('UPLOAD_ALLOWED_CATEGORIES', ['device_types', 'floors', 'racks', 'rooms', 'misc']);
diff --git a/app/index.php b/app/index.php
index c7fc06d..ca2fa1e 100644
--- a/app/index.php
+++ b/app/index.php
@@ -1,72 +1,37 @@
 <?php
 // Einstiegspunkt der Anwendung, Routing zur jeweiligen Modul-Seite
 
+require_once __DIR__ . '/bootstrap.php';
+requireAuth();
 
-/**
- * index.php
- *
- * Einstiegspunkt der Anwendung
- * - Single-User
- * - Modulbasiertes Routing
- * - Basierend auf _sql.php
- * - HTML-Layout via templates/layout.php
- */
-
-/* =========================
- * Bootstrap
- * ========================= */
-require_once __DIR__ . '/bootstrap.php'; // lädt config, DB, helper
-// TODO: Session starten / Single-User-Auth prüfen
-
-/* =========================
- * Routing
- * ========================= */
-
-// Standard-Modul / Aktion
 $module = $_GET['module'] ?? 'dashboard';
 $action = $_GET['action'] ?? 'list';
 
-// Whitelist der Module
 $validModules = ['dashboard', 'locations', 'buildings', 'rooms', 'device_types', 'devices', 'racks', 'floors', 'floor_infrastructure', 'connections', 'port_types'];
+$validActions = ['list', 'edit', 'save', 'ports', 'delete', 'swap'];
 
-// Whitelist der Aktionen
-$validActions = ['list', 'edit', 'save', 'ports', 'delete'];
-
-// Prüfen auf gültige Werte
-if (!in_array($module, $validModules)) {
-    renderClientError(400, 'Ungültiges Modul');
+if (!in_array($module, $validModules, true)) {
+    renderClientError(400, 'Ungueltiges Modul');
+    exit;
 }
 
-if (!in_array($action, $validActions)) {
-    // TODO: Fehlerseite anzeigen, nutze renderClientError(...)
-    die('Ungültige Aktion');
+if (!in_array($action, $validActions, true)) {
+    renderClientError(400, 'Ungueltige Aktion');
+    exit;
 }
 
-/* =========================
- * Template-Header laden (nur für View-Aktionen)
- * ========================= */
-if (!in_array($action, ['save', 'delete'], true)) {
+if (!in_array($action, ['save', 'delete', 'swap'], true)) {
     require_once __DIR__ . '/templates/header.php';
 }
 
-/* =========================
- * Modul laden
- * ========================= */
 $modulePath = __DIR__ . "/modules/$module/$action.php";
 
 if (file_exists($modulePath)) {
     require_once $modulePath;
 } else {
-    // TODO: Fehlerseite oder 404, nutze renderClientError(...)
-    if ($action !== 'save') {
-        echo "<p>Die Seite existiert noch nicht.</p>".$modulePath;
-    }
+    renderClientError(404, 'Die angeforderte Seite existiert nicht.');
 }
 
-/* =========================
- * Template-Footer laden (nur für View-Aktionen)
- * ========================= */
-if (!in_array($action, ['save', 'delete'], true)) {
+if (!in_array($action, ['save', 'delete', 'swap'], true)) {
     require_once __DIR__ . '/templates/footer.php';
 }
-
diff --git a/app/lib/_sql.php b/app/lib/_sql.php
index 474060f..5b35112 100644
--- a/app/lib/_sql.php
+++ b/app/lib/_sql.php
@@ -8,11 +8,19 @@ class SQL {
     public $cnt_get = 0;
     public $cnt_set = 0;
     public function __construct() {
-        require_once ('secret.php');
+        if (defined('DB_HOST') && defined('DB_USER') && defined('DB_PASS') && defined('DB_NAME')) {
+            $this->m = [
+                'host' => DB_HOST,
+                'user' => DB_USER,
+                'pass' => DB_PASS,
+                'data' => DB_NAME
+            ];
+        } else {
+            require_once ('secret.php');
+            $this->m = $_m;
+        }
 
-        $this->m = $_m;
-
-        $this->h = new mysqli ( $_m ['host'], $_m ['user'], $_m ['pass'], $_m ['data'] );
+        $this->h = new mysqli ( $this->m ['host'], $this->m ['user'], $this->m ['pass'], $this->m ['data'] );
         if ($this->h->connect_errno) {
             return false;
         }
@@ -171,4 +179,4 @@ class SQL {
     // echo 'DESTROY';
   }
 }
-?>
\ No newline at end of file
+?>
diff --git a/app/lib/auth.php b/app/lib/auth.php
index 11a1b13..bcb63dd 100644
--- a/app/lib/auth.php
+++ b/app/lib/auth.php
@@ -2,82 +2,60 @@
 /**
  * app/lib/auth.php
  *
- * Single-User-Authentifizierung
- * - Login / Logout
- * - Session-Check
- * - Optional: Passwortschutz für Admin-Tool
- *
- * KEIN Mehrbenutzer-System
+ * Single-user authentication helpers.
  */
 
-/* =========================
- * Login prüfen
- * ========================= */
-
-/**
- * Prüft, ob der Benutzer eingeloggt ist
- *
- * @return bool
- */
 function isAuthenticated(): bool
 {
-    // TODO: Session-Variable definieren, z.B. $_SESSION['auth'] === true
+    if (!defined('AUTH_REQUIRED') || AUTH_REQUIRED === false) {
+        return true;
+    }
+
     return isset($_SESSION['auth']) && $_SESSION['auth'] === true;
 }
 
-/* =========================
- * Login durchführen
- * ========================= */
-
-/**
- * Führt einen Login durch
- *
- * @param string $password
- * @return bool
- */
 function login(string $password): bool
 {
-    // TODO: Passwort aus config.php vergleichen
-    // TODO: Passwort-Hash verwenden (password_hash / password_verify)
+    $hash = defined('ADMIN_PASSWORD_HASH') ? trim((string)ADMIN_PASSWORD_HASH) : '';
+    if ($hash === '') {
+        return false;
+    }
 
-    /*
-    if (password_verify($password, ADMIN_PASSWORD_HASH)) {
+    if (password_verify($password, $hash)) {
         $_SESSION['auth'] = true;
+        $_SESSION['auth_at'] = time();
         return true;
     }
-    */
 
     return false;
 }
 
-/* =========================
- * Logout
- * ========================= */
-
-/**
- * Loggt den Benutzer aus
- */
 function logout(): void
 {
-    // TODO: Session-Variablen löschen
-    // unset($_SESSION['auth']);
+    unset($_SESSION['auth'], $_SESSION['auth_at']);
 
-    // TODO: Optional komplette Session zerstören
-    // session_destroy();
+    if (session_status() === PHP_SESSION_ACTIVE) {
+        session_regenerate_id(true);
+    }
 }
 
-/* =========================
- * Zugriff erzwingen
- * ========================= */
-
-/**
- * Erzwingt Login, sonst Redirect
- */
 function requireAuth(): void
 {
+    if (!defined('AUTH_REQUIRED') || AUTH_REQUIRED === false) {
+        return;
+    }
+
     if (!isAuthenticated()) {
-        // TODO: Redirect auf Login-Seite
-        // header('Location: /login.php');
+        $isApiRequest = str_starts_with($_SERVER['REQUEST_URI'] ?? '', '/api/');
+        if ($isApiRequest) {
+            http_response_code(401);
+            header('Content-Type: application/json');
+            echo json_encode(['error' => 'Nicht authentifiziert']);
+            exit;
+        }
+
+        $target = defined('LOGIN_PATH') ? LOGIN_PATH : '/login.php';
+        header('Location: ' . $target);
         exit;
     }
 }
diff --git a/app/modules/buildings/delete.php b/app/modules/buildings/delete.php
new file mode 100644
index 0000000..65819c6
--- /dev/null
+++ b/app/modules/buildings/delete.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * app/modules/buildings/delete.php
+ */
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    echo json_encode(['error' => 'Methode nicht erlaubt']);
+    exit;
+}
+
+header('Content-Type: application/json');
+
+$id = (int)($_POST['id'] ?? $_GET['id'] ?? 0);
+if ($id <= 0) {
+    http_response_code(400);
+    echo json_encode(['error' => 'ID fehlt']);
+    exit;
+}
+
+$exists = $sql->single("SELECT id FROM buildings WHERE id = ?", "i", [$id]);
+if (!$exists) {
+    http_response_code(404);
+    echo json_encode(['error' => 'Gebaeude nicht gefunden']);
+    exit;
+}
+
+$rows = $sql->set("DELETE FROM buildings WHERE id = ?", "i", [$id]);
+if ($rows === false) {
+    http_response_code(500);
+    echo json_encode(['error' => 'Loeschen fehlgeschlagen']);
+    exit;
+}
+
+echo json_encode(['status' => 'ok', 'success' => true, 'rows' => $rows]);
diff --git a/app/modules/buildings/edit.php b/app/modules/buildings/edit.php
index f315e43..ff4ea76 100644
--- a/app/modules/buildings/edit.php
+++ b/app/modules/buildings/edit.php
@@ -47,7 +47,7 @@ $selectedLocationId = $building['location_id'] ?? $prefillLocationId;
             <div class="form-group">
                 <label for="name">Name <span class="required">*</span></label>
                 <input type="text" id="name" name="name" required
-                    value="<?php echo htmlspecialchars($building['name'] ?? ''); ?>"
+                    value="<?php echo htmlspecialchars($building['name'] ?? '); ?>"
                     placeholder="z.B. Gebäude A, Verwaltungsgebäude">
             </div>
 
@@ -57,7 +57,7 @@ $selectedLocationId = $building['location_id'] ?? $prefillLocationId;
                     <option value="">- Wählen -</option>
                     <?php foreach ($locations as $location): ?>
                     <option value="<?php echo $location['id']; ?>"
-                        <?php echo ((int)$selectedLocationId === (int)$location['id']) ? 'selected' : ''; ?>>
+                        <?php echo ((int)$selectedLocationId === (int)$location['id']) ? 'selected' : '; ?>>
                         <?php echo htmlspecialchars($location['name']); ?>
                     </option>
                     <?php endforeach; ?>
@@ -67,7 +67,7 @@ $selectedLocationId = $building['location_id'] ?? $prefillLocationId;
             <div class="form-group">
                 <label for="comment">Beschreibung</label>
                 <textarea id="comment" name="comment" rows="3"
-                    placeholder="Adresse, Besonderheiten, etc."><?php echo htmlspecialchars($building['comment'] ?? ''); ?></textarea>
+                    placeholder="Adresse, Besonderheiten, etc."><?php echo htmlspecialchars($building['comment'] ?? '); ?></textarea>
             </div>
         </fieldset>
 
@@ -172,9 +172,25 @@ $selectedLocationId = $building['location_id'] ?? $prefillLocationId;
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Dieses Gebäude wirklich löschen? Alle Stockwerke werden gelöscht.')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (confirm('Dieses Gebaeude wirklich loeschen? Alle Stockwerke werden geloescht.')) {
+        fetch('?module=buildings&action=delete', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+            body: 'id=' + encodeURIComponent(id)
+        })
+            .then((res) => res.json())
+            .then((data) => {
+                if (data && data.status === 'ok') {
+                    window.location.href = '?module=buildings&action=list';
+                    return;
+                }
+                alert((data && data.error) ? data.error : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => {
+                alert('Loeschen fehlgeschlagen');
+            });
     }
 }
 </script>
+
+
diff --git a/app/modules/buildings/list.php b/app/modules/buildings/list.php
index 3a147c5..01889d7 100644
--- a/app/modules/buildings/list.php
+++ b/app/modules/buildings/list.php
@@ -8,17 +8,17 @@
 // =========================
 // Filter einlesen
 // =========================
-$search = trim($_GET['search'] ?? '');
+$search = trim($_GET['search'] ?? ');
 $locationId = (int)($_GET['location_id'] ?? 0);
 
 // =========================
 // WHERE-Clause bauen
 // =========================
 $where = [];
-$types = '';
+$types = ';
 $params = [];
 
-if ($search !== '') {
+if ($search !== ') {
     $where[] = "b.name LIKE ? OR b.comment LIKE ?";
     $types .= "ss";
     $params[] = "%$search%";
@@ -70,7 +70,7 @@ $locations = $sql->get("SELECT id, name FROM locations ORDER BY name", "", []);
                 <option value="">- Alle Standorte -</option>
                 <?php foreach ($locations as $loc): ?>
                 <option value="<?php echo $loc['id']; ?>"
-                    <?php echo $loc['id'] === $locationId ? 'selected' : ''; ?>>
+                    <?php echo $loc['id'] === $locationId ? 'selected' : '; ?>>
                     <?php echo htmlspecialchars($loc['name']); ?>
                 </option>
                 <?php endforeach; ?>
@@ -112,7 +112,7 @@ $locations = $sql->get("SELECT id, name FROM locations ORDER BY name", "", []);
                 </td>
 
                 <td>
-                    <small><?php echo htmlspecialchars($building['comment'] ?? ''); ?></small>
+                    <small><?php echo htmlspecialchars($building['comment'] ?? '); ?></small>
                 </td>
 
                 <td class="actions">
@@ -241,9 +241,24 @@ $locations = $sql->get("SELECT id, name FROM locations ORDER BY name", "", []);
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Dieses Gebäude wirklich löschen?')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (confirm('Dieses Gebaeude wirklich loeschen?')) {
+        fetch('?module=buildings&action=delete', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+            body: 'id=' + encodeURIComponent(id)
+        })
+            .then((res) => res.json())
+            .then((data) => {
+                if (data && data.status === 'ok') {
+                    window.location.reload();
+                    return;
+                }
+                alert((data && data.error) ? data.error : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => {
+                alert('Loeschen fehlgeschlagen');
+            });
     }
 }
 </script>
+
diff --git a/app/modules/connections/edit.php b/app/modules/connections/edit.php
index 0a0d75a..331eb86 100644
--- a/app/modules/connections/edit.php
+++ b/app/modules/connections/edit.php
@@ -46,6 +46,68 @@ $endpointOptions = [
     'patchpanel' => [],
 ];
 
+$occupiedByType = [
+    'device' => [],
+    'module' => [],
+    'outlet' => [],
+    'patchpanel' => [],
+];
+$occupiedRows = $sql->get(
+    "SELECT id, port_a_type, port_a_id, port_b_type, port_b_id
+     FROM connections
+     WHERE id <> ?",
+    "i",
+    [$connectionId]
+);
+foreach ((array)$occupiedRows as $row) {
+    $typeA = $normalizePortType((string)($row['port_a_type'] ?? ''));
+    $idA = (int)($row['port_a_id'] ?? 0);
+    if ($idA > 0 && isset($occupiedByType[$typeA])) {
+        $occupiedByType[$typeA][$idA] = true;
+    }
+
+    $typeB = $normalizePortType((string)($row['port_b_type'] ?? ''));
+    $idB = (int)($row['port_b_id'] ?? 0);
+    if ($idB > 0 && isset($occupiedByType[$typeB])) {
+        $occupiedByType[$typeB][$idB] = true;
+    }
+}
+
+$isEndpointAllowed = static function (string $type, int $id) use ($occupiedByType, $portAType, $portAId, $portBType, $portBId): bool {
+    if ($id <= 0) {
+        return false;
+    }
+    if ($type === $portAType && $id === $portAId) {
+        return true;
+    }
+    if ($type === $portBType && $id === $portBId) {
+        return true;
+    }
+    return empty($occupiedByType[$type][$id]);
+};
+
+// Auto-heal: ensure each outlet has at least one selectable port.
+$outletsWithoutPorts = $sql->get(
+    "SELECT o.id
+     FROM network_outlets o
+     LEFT JOIN network_outlet_ports nop ON nop.outlet_id = o.id
+     GROUP BY o.id
+     HAVING COUNT(nop.id) = 0",
+    "",
+    []
+);
+foreach ((array)$outletsWithoutPorts as $outletRow) {
+    $outletId = (int)($outletRow['id'] ?? 0);
+    if ($outletId <= 0) {
+        continue;
+    }
+    $sql->set(
+        "INSERT INTO network_outlet_ports (outlet_id, name) VALUES (?, 'Port 1')",
+        "i",
+        [$outletId]
+    );
+}
+
 $devicePorts = $sql->get(
     "SELECT dp.id, dp.name, d.name AS owner_name
      FROM device_ports dp
@@ -55,8 +117,12 @@ $devicePorts = $sql->get(
     []
 );
 foreach ($devicePorts as $row) {
+    $id = (int)$row['id'];
+    if (!$isEndpointAllowed('device', $id)) {
+        continue;
+    }
     $endpointOptions['device'][] = [
-        'id' => (int)$row['id'],
+        'id' => $id,
         'label' => $row['owner_name'] . ' / ' . $row['name'],
     ];
 }
@@ -78,27 +144,35 @@ $modulePorts = $sql->get(
     []
 );
 foreach ($modulePorts as $row) {
+    $id = (int)$row['id'];
+    if (!$isEndpointAllowed('module', $id)) {
+        continue;
+    }
     $deviceName = trim((string)($row['device_name'] ?? '')) ?: 'Unzugeordnet';
     $endpointOptions['module'][] = [
-        'id' => (int)$row['id'],
+        'id' => $id,
         'label' => $deviceName . ' / ' . $row['module_name'] . ' / ' . $row['name'],
     ];
 }
 
 $outletPorts = $sql->get(
-    "SELECT nop.id, nop.name, no.name AS outlet_name, r.name AS room_name, f.name AS floor_name
+    "SELECT nop.id, nop.name, o.name AS outlet_name, r.name AS room_name, f.name AS floor_name
      FROM network_outlet_ports nop
-     JOIN network_outlets no ON no.id = nop.outlet_id
-     LEFT JOIN rooms r ON r.id = no.room_id
+     JOIN network_outlets o ON o.id = nop.outlet_id
+     LEFT JOIN rooms r ON r.id = o.room_id
      LEFT JOIN floors f ON f.id = r.floor_id
      ORDER BY floor_name, room_name, outlet_name, nop.name",
     "",
     []
 );
 foreach ($outletPorts as $row) {
+    $id = (int)$row['id'];
+    if (!$isEndpointAllowed('outlet', $id)) {
+        continue;
+    }
     $parts = array_filter([(string)($row['floor_name'] ?? ''), (string)($row['room_name'] ?? ''), (string)$row['outlet_name'], (string)$row['name']]);
     $endpointOptions['outlet'][] = [
-        'id' => (int)$row['id'],
+        'id' => $id,
         'label' => implode(' / ', $parts),
     ];
 }
@@ -113,9 +187,13 @@ $patchpanelPorts = $sql->get(
     []
 );
 foreach ($patchpanelPorts as $row) {
+    $id = (int)$row['id'];
+    if (!$isEndpointAllowed('patchpanel', $id)) {
+        continue;
+    }
     $parts = array_filter([(string)($row['floor_name'] ?? ''), (string)$row['patchpanel_name'], (string)$row['name']]);
     $endpointOptions['patchpanel'][] = [
-        'id' => (int)$row['id'],
+        'id' => $id,
         'label' => implode(' / ', $parts),
     ];
 }
diff --git a/app/modules/connections/list.php b/app/modules/connections/list.php
index 58b0d0e..192bc8f 100644
--- a/app/modules/connections/list.php
+++ b/app/modules/connections/list.php
@@ -42,11 +42,11 @@ $endpointUnionSql = "
         'outlet' AS endpoint_type,
         nop.id AS endpoint_id,
         nop.name AS port_name,
-        CONCAT(no.name, ' / ', IFNULL(r.name, ''), ' / ', IFNULL(f.name, '')) AS owner_name,
+        CONCAT(o.name, ' / ', IFNULL(r.name, ''), ' / ', IFNULL(f.name, '')) AS owner_name,
         NULL AS owner_device_id
     FROM network_outlet_ports nop
-    JOIN network_outlets no ON no.id = nop.outlet_id
-    LEFT JOIN rooms r ON r.id = no.room_id
+    JOIN network_outlets o ON o.id = nop.outlet_id
+    LEFT JOIN rooms r ON r.id = o.room_id
     LEFT JOIN floors f ON f.id = r.floor_id
     UNION ALL
     SELECT
@@ -328,6 +328,7 @@ if ($deviceId > 0) {
 
                 <td class="actions">
                     <a href="?module=connections&action=edit&id=<?php echo $conn['id']; ?>" class="button button-small">Bearbeiten</a>
+                    <a href="?module=connections&action=swap&id=<?php echo $conn['id']; ?>" class="button button-small" onclick="return confirm('Von/Nach fuer diese Verbindung vertauschen?');">Von/Nach tauschen</a>
                     <a href="#" class="button button-small button-danger"
                         data-confirm-delete="true"
                         data-confirm-message="Diese Verbindung wirklich löschen?"
diff --git a/app/modules/connections/save.php b/app/modules/connections/save.php
index 86b7e6a..d56efd2 100644
--- a/app/modules/connections/save.php
+++ b/app/modules/connections/save.php
@@ -51,6 +51,41 @@ if ($portAId <= 0 || $portBId <= 0) {
     $errors[] = "Beide Ports sind erforderlich";
 }
 
+$otherConnections = $sql->get(
+    "SELECT id, port_a_type, port_a_id, port_b_type, port_b_id
+     FROM connections
+     WHERE id <> ?",
+    "i",
+    [$connId]
+);
+
+$isEndpointUsed = static function (string $endpointType, int $endpointId) use ($otherConnections, $normalizePortType): bool {
+    if ($endpointId <= 0) {
+        return false;
+    }
+    foreach ((array)$otherConnections as $row) {
+        $typeA = $normalizePortType((string)($row['port_a_type'] ?? ''));
+        $idA = (int)($row['port_a_id'] ?? 0);
+        if ($typeA === $endpointType && $idA === $endpointId) {
+            return true;
+        }
+
+        $typeB = $normalizePortType((string)($row['port_b_type'] ?? ''));
+        $idB = (int)($row['port_b_id'] ?? 0);
+        if ($typeB === $endpointType && $idB === $endpointId) {
+            return true;
+        }
+    }
+    return false;
+};
+
+if ($isEndpointUsed($portAType, $portAId)) {
+    $errors[] = "Port an Endpunkt A ist bereits in Verwendung";
+}
+if ($isEndpointUsed($portBType, $portBId)) {
+    $errors[] = "Port an Endpunkt B ist bereits in Verwendung";
+}
+
 if (!empty($errors)) {
     $_SESSION['error'] = implode(', ', $errors);
     $redirectUrl = $connId ? "?module=connections&action=edit&id=$connId" : "?module=connections&action=edit";
@@ -67,15 +102,36 @@ if ($connId > 0) {
     // UPDATE
     $sql->set(
         "UPDATE connections SET port_a_type = ?, port_a_id = ?, port_b_type = ?, port_b_id = ?, vlan_config = ?, comment = ? WHERE id = ?",
-        "siisisi",
+        "sisissi",
         [$portAType, $portAId, $portBType, $portBId, $vlanJson, $comment, $connId]
     );
 } else {
+    $connectionTypeId = (int)($sql->single(
+        "SELECT id FROM connection_types ORDER BY id LIMIT 1",
+        "",
+        []
+    )['id'] ?? 0);
+
+    if ($connectionTypeId <= 0) {
+        $connectionTypeId = (int)$sql->set(
+            "INSERT INTO connection_types (name, medium, duplex, line_style, comment) VALUES (?, ?, ?, ?, ?)",
+            "sssss",
+            ['Default', 'copper', 'custom', 'solid', 'Auto-created by connections/save'],
+            true
+        );
+    }
+
+    if ($connectionTypeId <= 0) {
+        $_SESSION['error'] = "Kein Verbindungstyp verfuegbar";
+        header("Location: ?module=connections&action=edit");
+        exit;
+    }
+
     // INSERT
     $sql->set(
-        "INSERT INTO connections (port_a_type, port_a_id, port_b_type, port_b_id, vlan_config, comment) VALUES (?, ?, ?, ?, ?, ?)",
-        "siisis",
-        [$portAType, $portAId, $portBType, $portBId, $vlanJson, $comment]
+        "INSERT INTO connections (connection_type_id, port_a_type, port_a_id, port_b_type, port_b_id, vlan_config, comment) VALUES (?, ?, ?, ?, ?, ?, ?)",
+        "isisiss",
+        [$connectionTypeId, $portAType, $portAId, $portBType, $portBId, $vlanJson, $comment]
     );
 }
 
diff --git a/app/modules/connections/swap.php b/app/modules/connections/swap.php
new file mode 100644
index 0000000..9480077
--- /dev/null
+++ b/app/modules/connections/swap.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * app/modules/connections/swap.php
+ *
+ * Vertauscht Endpunkt A und Endpunkt B einer Verbindung.
+ */
+
+$connectionId = (int)($_GET['id'] ?? 0);
+
+if ($connectionId <= 0) {
+    $_SESSION['error'] = 'Ungueltige Verbindungs-ID';
+    header('Location: ?module=connections&action=list');
+    exit;
+}
+
+$connection = $sql->single(
+    "SELECT id, port_a_type, port_a_id, port_b_type, port_b_id
+     FROM connections
+     WHERE id = ?",
+    "i",
+    [$connectionId]
+);
+
+if (!$connection) {
+    $_SESSION['error'] = 'Verbindung nicht gefunden';
+    header('Location: ?module=connections&action=list');
+    exit;
+}
+
+$sql->set(
+    "UPDATE connections
+     SET port_a_type = ?, port_a_id = ?, port_b_type = ?, port_b_id = ?
+     WHERE id = ?",
+    "sisii",
+    [
+        (string)$connection['port_b_type'],
+        (int)$connection['port_b_id'],
+        (string)$connection['port_a_type'],
+        (int)$connection['port_a_id'],
+        $connectionId
+    ]
+);
+
+$_SESSION['success'] = 'Endpunkte wurden vertauscht';
+header('Location: ?module=connections&action=list');
+exit;
diff --git a/app/modules/dashboard/list.php b/app/modules/dashboard/list.php
index 593036f..71c4593 100644
--- a/app/modules/dashboard/list.php
+++ b/app/modules/dashboard/list.php
@@ -34,6 +34,10 @@ $recentDevices = $sql->get(
 <!-- Dashboard / Übersicht -->
 <div class="dashboard">
     <h1>Dashboard</h1>
+    <div id="dashboard-modules" class="dashboard-modules"></div>
+    <p data-dashboard-stats class="dashboard-inline-status"></p>
+    <p data-dashboard-warnings class="dashboard-inline-status"></p>
+    <p data-dashboard-recent class="dashboard-inline-status"></p>
 
     <!-- Statistik-Karten -->
     <div class="stats-grid">
@@ -100,6 +104,54 @@ $recentDevices = $sql->get(
     margin: 20px 0;
 }
 
+.dashboard-modules {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+    gap: 12px;
+    margin: 12px 0 20px;
+}
+
+.dashboard-tile {
+    display: flex;
+    gap: 10px;
+    align-items: center;
+    border: 1px solid #d7d7d7;
+    border-radius: 8px;
+    padding: 12px;
+    text-decoration: none;
+    color: #222;
+    background: #fff;
+}
+
+.dashboard-icon {
+    width: 34px;
+    height: 34px;
+    border-radius: 999px;
+    background: #0c4da2;
+    color: #fff;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    font-size: 0.75rem;
+    font-weight: 700;
+}
+
+.dashboard-content h3 {
+    margin: 0 0 4px;
+    font-size: 1rem;
+}
+
+.dashboard-content p {
+    margin: 0;
+    font-size: 0.85rem;
+    color: #444;
+}
+
+.dashboard-inline-status {
+    margin: 6px 0;
+    color: #333;
+}
+
 .stat-card {
     border: 1px solid #ddd;
     padding: 20px;
@@ -143,4 +195,4 @@ $recentDevices = $sql->get(
 .recent-devices th {
     background: #f0f0f0;
 }
-</style>
\ No newline at end of file
+</style>
diff --git a/app/modules/device_types/delete.php b/app/modules/device_types/delete.php
new file mode 100644
index 0000000..11841e6
--- /dev/null
+++ b/app/modules/device_types/delete.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * app/modules/device_types/delete.php
+ */
+
+header('Content-Type: application/json; charset=utf-8');
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    echo json_encode(['success' => false, 'message' => 'Methode nicht erlaubt']);
+    exit;
+}
+
+$id = (int)($_POST['id'] ?? $_GET['id'] ?? 0);
+if ($id <= 0) {
+    http_response_code(400);
+    echo json_encode(['success' => false, 'message' => 'ID fehlt']);
+    exit;
+}
+
+$exists = $sql->single("SELECT id FROM device_types WHERE id = ?", "i", [$id]);
+if (!$exists) {
+    http_response_code(404);
+    echo json_encode(['success' => false, 'message' => 'Geraetetyp nicht gefunden']);
+    exit;
+}
+
+$rows = $sql->set("DELETE FROM device_types WHERE id = ?", "i", [$id]);
+if ($rows === false) {
+    http_response_code(409);
+    echo json_encode([
+        'success' => false,
+        'message' => 'Geraetetyp konnte nicht geloescht werden (wird ggf. noch von Geraeten verwendet)'
+    ]);
+    exit;
+}
+
+echo json_encode(['success' => true, 'message' => 'Geraetetyp geloescht']);
+
diff --git a/app/modules/device_types/edit.php b/app/modules/device_types/edit.php
index 981b826..b77051f 100644
--- a/app/modules/device_types/edit.php
+++ b/app/modules/device_types/edit.php
@@ -15,7 +15,6 @@ $deviceTypeId = (int)($_GET['id'] ?? 0);
 $deviceType = null;
 $ports = [];
 
-//TODO port hinzufügen geht nicht
 
 if ($deviceTypeId > 0) {
     $deviceType = $sql->single(
@@ -339,3 +338,4 @@ $pageTitle = $isEdit ? "Gerätetyp bearbeiten: " . htmlspecialchars($deviceType[
 </div>
 <script src="/assets/js/device-type-shape-editor.js" defer></script>
 <script src="/assets/js/device-type-edit-form.js" defer></script>
+
diff --git a/app/modules/device_types/ports.php b/app/modules/device_types/ports.php
index af91f0a..d449e0c 100644
--- a/app/modules/device_types/ports.php
+++ b/app/modules/device_types/ports.php
@@ -1,265 +1,165 @@
 <?php
 /**
- * app/device_types/ports.php
+ * app/modules/device_types/ports.php
  *
- * Verwaltung der Ports eines Gerätetyps
- * - Port anlegen / bearbeiten / löschen
- * - Port-Typ (RJ45, SFP, BNC, Custom)
- * - VLAN / Modus / Medienart
- * - Übergabe an SVG-Port-Editor
+ * Verwaltung der Ports eines Geraetetyps.
  */
 
-// TODO: bootstrap laden
-// require_once __DIR__ . '/../../bootstrap.php';
+$deviceTypeId = (int)($_GET['id'] ?? ($_GET['device_type_id'] ?? 0));
+if ($deviceTypeId <= 0) {
+    renderClientError(400, 'device_type_id fehlt');
+    return;
+}
 
-// TODO: Auth erzwingen
-// requireAuth();
+$deviceType = $sql->single(
+    "SELECT id, name, image_path, image_type FROM device_types WHERE id = ?",
+    'i',
+    [$deviceTypeId]
+);
 
-// =========================
-// Kontext bestimmen
-// =========================
+if (!$deviceType) {
+    renderClientError(404, 'Geraetetyp nicht gefunden');
+    return;
+}
 
-// TODO: device_type_id aus GET lesen
-// $deviceTypeId = (int)($_GET['id'] ?? 0);
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    $formAction = $_POST['form_action'] ?? '';
 
-// TODO: Gerätetyp laden
-// $deviceType = null;
+    if ($formAction === 'add_port') {
+        $name = trim((string)($_POST['name'] ?? ''));
+        $portTypeId = (int)($_POST['port_type_id'] ?? 0);
+        $x = (int)($_POST['x'] ?? 0);
+        $y = (int)($_POST['y'] ?? 0);
 
-// TODO: Ports dieses Gerätetyps laden
-// $ports = [];
+        if ($name !== '') {
+            if ($portTypeId > 0) {
+                $sql->set(
+                    "INSERT INTO device_type_ports (device_type_id, name, port_type_id, x, y) VALUES (?, ?, ?, ?, ?)",
+                    "isiii",
+                    [$deviceTypeId, $name, $portTypeId, $x, $y]
+                );
+            } else {
+                $sql->set(
+                    "INSERT INTO device_type_ports (device_type_id, name, port_type_id, x, y) VALUES (?, ?, NULL, ?, ?)",
+                    "isii",
+                    [$deviceTypeId, $name, $x, $y]
+                );
+            }
+            $_SESSION['success'] = 'Port hinzugefuegt';
+        } else {
+            $_SESSION['error'] = 'Portname darf nicht leer sein';
+        }
 
+        header('Location: ?module=device_types&action=ports&id=' . $deviceTypeId);
+        exit;
+    }
+
+    if ($formAction === 'delete_port') {
+        $portId = (int)($_POST['port_id'] ?? 0);
+        if ($portId > 0) {
+            $sql->set(
+                "DELETE FROM device_type_ports WHERE id = ? AND device_type_id = ?",
+                "ii",
+                [$portId, $deviceTypeId]
+            );
+            $_SESSION['success'] = 'Port geloescht';
+        }
+
+        header('Location: ?module=device_types&action=ports&id=' . $deviceTypeId);
+        exit;
+    }
+}
+
+$ports = $sql->get(
+    "SELECT dtp.id, dtp.name, dtp.port_type_id, dtp.x, dtp.y, pt.name AS port_type_name
+     FROM device_type_ports dtp
+     LEFT JOIN port_types pt ON pt.id = dtp.port_type_id
+     WHERE dtp.device_type_id = ?
+     ORDER BY dtp.id ASC",
+    'i',
+    [$deviceTypeId]
+);
+
+$portTypes = $sql->get("SELECT id, name FROM port_types ORDER BY name", '', []);
+$svgPath = trim((string)($deviceType['image_path'] ?? ''));
+$svgUrl = $svgPath !== '' ? '/' . ltrim($svgPath, '/\\') : '';
 ?>
 
-<h2>Ports – Gerätetyp</h2>
+<div class="device-type-ports">
+    <h2>Ports: <?php echo htmlspecialchars((string)$deviceType['name']); ?></h2>
 
-<!-- =========================
-     Zurück / Kontext
-     ========================= -->
+    <div class="breadcrumb">
+        <a href="?module=device_types&action=list">Geraetetypen</a>
+        ->
+        <a href="?module=device_types&action=edit&id=<?php echo (int)$deviceType['id']; ?>"><?php echo htmlspecialchars((string)$deviceType['name']); ?></a>
+        -> Ports
+    </div>
 
-<div class="breadcrumb">
-    <a href="/?page=device_types/list">Gerätetypen</a>
-    →
-    <a href="/?page=device_types/edit&id=<?= $deviceTypeId ?>">
-        <!-- TODO: Gerätetyp-Name -->
-        Gerätetyp
-    </a>
-    →
-    Ports
+    <div class="toolbar">
+        <a class="button" href="?module=device_types&action=edit&id=<?php echo (int)$deviceType['id']; ?>">Zurueck zum Geraetetyp</a>
+    </div>
+
+    <form method="post" class="port-form">
+        <input type="hidden" name="form_action" value="add_port">
+        <div>
+            <label for="name">Portname</label>
+            <input id="name" name="name" required placeholder="z. B. Gi1/0/1">
+        </div>
+        <div>
+            <label for="port_type_id">Port-Typ</label>
+            <select id="port_type_id" name="port_type_id">
+                <option value="0">- keiner -</option>
+                <?php foreach ($portTypes as $portType): ?>
+                    <option value="<?php echo (int)$portType['id']; ?>"><?php echo htmlspecialchars((string)$portType['name']); ?></option>
+                <?php endforeach; ?>
+            </select>
+        </div>
+        <div>
+            <label for="x">X</label>
+            <input id="x" name="x" type="number" value="0">
+        </div>
+        <div>
+            <label for="y">Y</label>
+            <input id="y" name="y" type="number" value="0">
+        </div>
+        <button type="submit" class="button button-primary">Port hinzufuegen</button>
+    </form>
+
+    <table class="port-list">
+        <thead>
+            <tr>
+                <th>#</th>
+                <th>Name</th>
+                <th>Typ</th>
+                <th>X</th>
+                <th>Y</th>
+                <th>Aktionen</th>
+            </tr>
+        </thead>
+        <tbody>
+            <?php foreach ($ports as $port): ?>
+                <tr>
+                    <td><?php echo (int)$port['id']; ?></td>
+                    <td><?php echo htmlspecialchars((string)$port['name']); ?></td>
+                    <td><?php echo htmlspecialchars((string)($port['port_type_name'] ?? '-')); ?></td>
+                    <td><?php echo (int)$port['x']; ?></td>
+                    <td><?php echo (int)$port['y']; ?></td>
+                    <td>
+                        <form method="post" onsubmit="return confirm('Port wirklich loeschen?');" style="display:inline;">
+                            <input type="hidden" name="form_action" value="delete_port">
+                            <input type="hidden" name="port_id" value="<?php echo (int)$port['id']; ?>">
+                            <button type="submit" class="button button-small button-danger">Loeschen</button>
+                        </form>
+                    </td>
+                </tr>
+            <?php endforeach; ?>
+        </tbody>
+    </table>
+
+    <?php if ($svgUrl !== '' && ($deviceType['image_type'] ?? '') === 'svg'): ?>
+        <section class="svg-port-editor-section">
+            <h3>SVG Vorschau</h3>
+            <img src="<?php echo htmlspecialchars($svgUrl); ?>" alt="Geraetetyp SVG" style="max-width:100%; height:auto; border:1px solid #ddd;">
+        </section>
+    <?php endif; ?>
 </div>
-
-<!-- =========================
-     Toolbar
-     ========================= -->
-
-<div class="toolbar">
-    <button id="add-port">
-        + Port hinzufügen
-    </button>
-
-    <!-- TODO: Port-Typen verwalten -->
-    <!-- TODO: Import / Export -->
-</div>
-
-<form id="port-form" class="port-form" aria-hidden="true">
-    <div>
-        <label for="port-name">Portname</label>
-        <input id="port-name" name="name" required placeholder="z. B. Gi1/0/1">
-    </div>
-    <div>
-        <label for="port-type">Port-Typ</label>
-        <input id="port-type" name="type" required placeholder="RJ45, SFP …">
-    </div>
-    <div>
-        <label for="port-medium">Medium</label>
-        <input id="port-medium" name="medium" placeholder="Kupfer, LWL …">
-    </div>
-    <div>
-        <label for="port-mode">Modus</label>
-        <input id="port-mode" name="mode" placeholder="Access, Trunk …">
-    </div>
-    <div>
-        <label for="port-vlan">VLAN</label>
-        <input id="port-vlan" name="vlan" placeholder="10, 20-30 …">
-    </div>
-    <button type="submit" class="button button-primary">Port hinzufügen</button>
-    <button type="button" class="button" id="cancel-port">Abbrechen</button>
-</form>
-
-<!-- =========================
-     Port-Liste
-     ========================= -->
-
-<table class="port-list">
-    <thead>
-        <tr>
-            <th>#</th>
-            <th>Name</th>
-            <th>Typ</th>
-            <th>Medium</th>
-            <th>Modus</th>
-            <th>VLAN</th>
-            <th>Aktionen</th>
-        </tr>
-    </thead>
-    <tbody id="port-list-body">
-
-        <?php /* foreach ($ports as $port): */ ?>
-        <tr>
-            <td>
-                <!-- TODO: Port-Nummer -->
-                1
-            </td>
-            <td>
-                <!-- TODO: Port-Name -->
-                Port 1
-            </td>
-            <td>
-                <!-- TODO: Port-Typ (RJ45, SFP, ...) -->
-            </td>
-            <td>
-                <!-- TODO: Medium (Kupfer, LWL, BNC, Custom) -->
-            </td>
-            <td>
-                <!-- TODO: Modus (Access, Trunk, Custom) -->
-            </td>
-            <td>
-                <!-- TODO: VLANs -->
-            </td>
-            <td>
-                <button>
-                    Bearbeiten
-                </button>
-
-                <button>
-                    Löschen
-                </button>
-            </td>
-        </tr>
-        <?php /* endforeach; */ ?>
-
-    </tbody>
-</table>
-
-<!-- =========================
-     SVG-Port-Positionierung
-     ========================= -->
-
-<section class="svg-port-editor-section">
-    <h3>Port-Positionen</h3>
-
-    <p class="hint">
-        Ports per Drag & Drop auf dem Gerät platzieren.
-    </p>
-
-    <div class="svg-editor-container">
-        <svg
-            id="device-type-svg"
-            viewBox="0 0 800 400"
-            width="100%"
-            height="400"
-        >
-            <!-- TODO: SVG des Gerätetyps laden -->
-        </svg>
-    </div>
-</section>
-
-<!-- =========================
-     JS-Konfiguration
-     ========================= -->
-
-<style>
-    .port-form {
-        display: none;
-        margin: 20px 0;
-        gap: 10px;
-        padding: 15px;
-        border: 1px solid #ddd;
-        border-radius: 6px;
-        background: #f9f9f9;
-        grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
-        grid-auto-rows: minmax(50px, auto);
-        align-items: flex-start;
-    }
-
-    .port-form.visible {
-        display: grid;
-    }
-
-    .port-form div {
-        display: flex;
-        flex-direction: column;
-    }
-
-    .port-form label {
-        font-size: 0.85rem;
-        margin-bottom: 4px;
-        font-weight: bold;
-    }
-
-    .port-form input {
-        padding: 6px 8px;
-        border-radius: 4px;
-        border: 1px solid #bbb;
-        font-family: inherit;
-    }
-
-    .port-form button {
-        margin-top: 8px;
-    }
-
-    .port-form .button-primary {
-        justify-self: flex-start;
-    }
-</style>
-
-<script>
-    const addPortButton = document.getElementById('add-port');
-    const portForm = document.getElementById('port-form');
-    const portListBody = document.getElementById('port-list-body');
-    const cancelPortButton = document.getElementById('cancel-port');
-    let portCounter = portListBody.querySelectorAll('tr').length + 1;
-
-    function showPortForm(show = true) {
-        portForm.classList.toggle('visible', show);
-        portForm.setAttribute('aria-hidden', show ? 'false' : 'true');
-        if (show) {
-            portForm.querySelector('input').focus();
-        }
-    }
-
-    addPortButton.addEventListener('click', (event) => {
-        event.preventDefault();
-        showPortForm(portForm.getAttribute('aria-hidden') === 'true');
-    });
-
-    cancelPortButton.addEventListener('click', () => {
-        showPortForm(false);
-        portForm.reset();
-    });
-
-    portForm.addEventListener('submit', (event) => {
-        event.preventDefault();
-        const data = new FormData(portForm);
-        const row = document.createElement('tr');
-        row.innerHTML = `
-            <td>${portCounter++}</td>
-            <td>${data.get('name') || '-'}</td>
-            <td>${data.get('type') || '-'}</td>
-            <td>${data.get('medium') || '-'}</td>
-            <td>${data.get('mode') || '-'}</td>
-            <td>${data.get('vlan') || '-'}</td>
-            <td>
-                <button type="button">Bearbeiten</button>
-                <button type="button">Löschen</button>
-            </td>
-        `;
-        portListBody.appendChild(row);
-        showPortForm(false);
-        portForm.reset();
-    });
-
-    /**
-     * TODO: Replace this mock logic with real AJAX once ports are
-     * persisted on the backend.
-     */
-</script>
diff --git a/app/modules/floor_infrastructure/delete.php b/app/modules/floor_infrastructure/delete.php
new file mode 100644
index 0000000..8b2ce33
--- /dev/null
+++ b/app/modules/floor_infrastructure/delete.php
@@ -0,0 +1,31 @@
+<?php
+/**
+ * app/modules/floor_infrastructure/delete.php
+ *
+ * Loescht Patchpanels oder Wandbuchsen.
+ */
+
+$type = strtolower(trim((string)($_GET['type'] ?? '')));
+$id = (int)($_GET['id'] ?? 0);
+
+if ($id <= 0 || !in_array($type, ['patchpanel', 'outlet'], true)) {
+    header('Location: ?module=floor_infrastructure&action=list');
+    exit;
+}
+
+if ($type === 'patchpanel') {
+    $sql->set(
+        "DELETE FROM floor_patchpanels WHERE id = ?",
+        "i",
+        [$id]
+    );
+} else {
+    $sql->set(
+        "DELETE FROM network_outlets WHERE id = ?",
+        "i",
+        [$id]
+    );
+}
+
+header('Location: ?module=floor_infrastructure&action=list');
+exit;
diff --git a/app/modules/floor_infrastructure/edit.php b/app/modules/floor_infrastructure/edit.php
index b67e2c0..f6441cb 100644
--- a/app/modules/floor_infrastructure/edit.php
+++ b/app/modules/floor_infrastructure/edit.php
@@ -293,11 +293,8 @@ $mapOutlets = $sql->get(
     </form>
 </div>
 
-<?php
-//TODO drag an drop auf der stockwerkskarte für die patchfelder und wandbuchsen. buchsen haben eine einheitliche größe, und sind quadratisch, patchfelder sind auch für sich einheitlich, sind rechteckig und breiter als hoch
-//TODO style in css files einsortieren
-?>
 <script src="/assets/js/floor-infrastructure-edit.js" defer></script>
 
 
 
+
diff --git a/app/modules/floor_infrastructure/list.php b/app/modules/floor_infrastructure/list.php
index 8b9cd48..aff72f7 100644
--- a/app/modules/floor_infrastructure/list.php
+++ b/app/modules/floor_infrastructure/list.php
@@ -180,6 +180,7 @@ if ($editorFloor) {
                             <td><?php echo (int)$panel['port_count']; ?></td>
                             <td class="actions">
                                 <a href="?module=floor_infrastructure&action=edit&type=patchpanel&id=<?php echo (int)$panel['id']; ?>" class="button button-small">Bearbeiten</a>
+                                <a href="?module=floor_infrastructure&action=delete&type=patchpanel&id=<?php echo (int)$panel['id']; ?>" class="button button-small button-danger" onclick="return confirm('Patchpanel wirklich loeschen?');">Loeschen</a>
                             </td>
                         </tr>
                     <?php endforeach; ?>
@@ -225,6 +226,7 @@ if ($editorFloor) {
                             <td><?php echo htmlspecialchars((string)($outlet['comment'] ?? '')); ?></td>
                             <td class="actions">
                                 <a href="?module=floor_infrastructure&action=edit&type=outlet&id=<?php echo (int)$outlet['id']; ?>" class="button button-small">Bearbeiten</a>
+                                <a href="?module=floor_infrastructure&action=delete&type=outlet&id=<?php echo (int)$outlet['id']; ?>" class="button button-small button-danger" onclick="return confirm('Wandbuchse wirklich loeschen?');">Loeschen</a>
                             </td>
                         </tr>
                     <?php endforeach; ?>
diff --git a/app/modules/floor_infrastructure/save.php b/app/modules/floor_infrastructure/save.php
index bd44496..c416bee 100644
--- a/app/modules/floor_infrastructure/save.php
+++ b/app/modules/floor_infrastructure/save.php
@@ -21,6 +21,8 @@ if ($type === 'patchpanel') {
     $portCount = (int)($_POST['port_count'] ?? 0);
     $comment = trim($_POST['comment'] ?? '');
 
+    $panelId = $id;
+
     if ($id > 0) {
         $sql->set(
             "UPDATE floor_patchpanels SET name = ?, floor_id = ?, pos_x = ?, pos_y = ?, width = ?, height = ?, port_count = ?, comment = ? WHERE id = ?",
@@ -28,18 +30,38 @@ if ($type === 'patchpanel') {
             [$name, $floorId, $posX, $posY, $width, $height, $portCount, $comment, $id]
         );
     } else {
-        $sql->set(
+        $panelId = (int)$sql->set(
             "INSERT INTO floor_patchpanels (name, floor_id, pos_x, pos_y, width, height, port_count, comment) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
             "siiiiiss",
-            [$name, $floorId, $posX, $posY, $width, $height, $portCount, $comment]
+            [$name, $floorId, $posX, $posY, $width, $height, $portCount, $comment],
+            true
         );
     }
+
+    if ($panelId > 0 && $portCount > 0) {
+        $existingCount = (int)($sql->single(
+            "SELECT COUNT(*) AS cnt FROM floor_patchpanel_ports WHERE patchpanel_id = ?",
+            "i",
+            [$panelId]
+        )['cnt'] ?? 0);
+
+        if ($existingCount < $portCount) {
+            for ($i = $existingCount + 1; $i <= $portCount; $i++) {
+                $sql->set(
+                    "INSERT INTO floor_patchpanel_ports (patchpanel_id, name) VALUES (?, ?)",
+                    "is",
+                    [$panelId, 'Port ' . $i]
+                );
+            }
+        }
+    }
 } elseif ($type === 'outlet') {
     $name = trim($_POST['name'] ?? '');
     $roomId = (int)($_POST['room_id'] ?? 0);
     $x = (int)($_POST['x'] ?? 0);
     $y = (int)($_POST['y'] ?? 0);
     $comment = trim($_POST['comment'] ?? '');
+    $outletId = $id;
 
     if ($id > 0) {
         $sql->set(
@@ -48,12 +70,29 @@ if ($type === 'patchpanel') {
             [$name, $roomId, $x, $y, $comment, $id]
         );
     } else {
-        $sql->set(
+        $outletId = (int)$sql->set(
             "INSERT INTO network_outlets (name, room_id, x, y, comment) VALUES (?, ?, ?, ?, ?)",
             "siiis",
-            [$name, $roomId, $x, $y, $comment]
+            [$name, $roomId, $x, $y, $comment],
+            true
         );
     }
+
+    if ($outletId > 0) {
+        $existingPortCount = (int)($sql->single(
+            "SELECT COUNT(*) AS cnt FROM network_outlet_ports WHERE outlet_id = ?",
+            "i",
+            [$outletId]
+        )['cnt'] ?? 0);
+
+        if ($existingPortCount === 0) {
+            $sql->set(
+                "INSERT INTO network_outlet_ports (outlet_id, name) VALUES (?, 'Port 1')",
+                "i",
+                [$outletId]
+            );
+        }
+    }
 }
 
 header('Location: ?module=floor_infrastructure&action=list');
diff --git a/app/modules/floors/delete.php b/app/modules/floors/delete.php
new file mode 100644
index 0000000..2bb7917
--- /dev/null
+++ b/app/modules/floors/delete.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * app/modules/floors/delete.php
+ */
+
+header('Content-Type: application/json; charset=utf-8');
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    echo json_encode(['success' => false, 'message' => 'Methode nicht erlaubt']);
+    exit;
+}
+
+$id = (int)($_POST['id'] ?? $_GET['id'] ?? 0);
+if ($id <= 0) {
+    http_response_code(400);
+    echo json_encode(['success' => false, 'message' => 'ID fehlt']);
+    exit;
+}
+
+$exists = $sql->single("SELECT id FROM floors WHERE id = ?", "i", [$id]);
+if (!$exists) {
+    http_response_code(404);
+    echo json_encode(['success' => false, 'message' => 'Stockwerk nicht gefunden']);
+    exit;
+}
+
+$rows = $sql->set("DELETE FROM floors WHERE id = ?", "i", [$id]);
+if ($rows === false) {
+    http_response_code(500);
+    echo json_encode(['success' => false, 'message' => 'Loeschen fehlgeschlagen']);
+    exit;
+}
+
+echo json_encode(['success' => true, 'message' => 'Stockwerk geloescht']);
+
diff --git a/app/modules/floors/list.php b/app/modules/floors/list.php
index 4c066bb..15a5cdb 100644
--- a/app/modules/floors/list.php
+++ b/app/modules/floors/list.php
@@ -10,7 +10,7 @@
 // =========================
 // Filter einlesen
 // =========================
-$search = trim($_GET['search'] ?? '');
+$search = trim($_GET['search'] ?? ');
 
 // =========================
 // Floors laden
@@ -19,7 +19,7 @@ $whereClause = "";
 $types = "";
 $params = [];
 
-if ($search !== '') {
+if ($search !== ') {
     $whereClause = "WHERE f.name LIKE ? OR f.comment LIKE ?";
     $types = "ss";
     $params = ["%$search%", "%$search%"];
@@ -105,7 +105,7 @@ $buildings = $sql->get("SELECT id, name FROM buildings ORDER BY name", "", []);
                 </td>
 
                 <td>
-                    <small><?php echo htmlspecialchars($floor['comment'] ?? ''); ?></small>
+                    <small><?php echo htmlspecialchars($floor['comment'] ?? '); ?></small>
                 </td>
 
                 <td class="actions">
@@ -233,9 +233,24 @@ $buildings = $sql->get("SELECT id, name FROM buildings ORDER BY name", "", []);
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Dieses Stockwerk wirklich löschen? Alle Räume und Racks werden gelöscht.')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (confirm('Dieses Stockwerk wirklich loeschen? Alle Raeume und Racks werden geloescht.')) {
+        fetch('?module=floors&action=delete', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+            body: 'id=' + encodeURIComponent(id)
+        })
+            .then((res) => res.json())
+            .then((data) => {
+                if (data && data.success) {
+                    window.location.reload();
+                    return;
+                }
+                alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => {
+                alert('Loeschen fehlgeschlagen');
+            });
     }
 }
 </script>
+
diff --git a/app/modules/locations/edit.php b/app/modules/locations/edit.php
index 3dcbfe5..3db6b05 100644
--- a/app/modules/locations/edit.php
+++ b/app/modules/locations/edit.php
@@ -42,14 +42,14 @@ $pageTitle = $isEdit ? "Standort bearbeiten: " . htmlspecialchars($location['nam
             <div class="form-group">
                 <label for="name">Name <span class="required">*</span></label>
                 <input type="text" id="name" name="name" required
-                    value="<?php echo htmlspecialchars($location['name'] ?? ''); ?>"
+                    value="<?php echo htmlspecialchars($location['name'] ?? '); ?>"
                     placeholder="z.B. Hauptgebäude, Campus A, Außenstelle Berlin">
             </div>
 
             <div class="form-group">
                 <label for="comment">Beschreibung</label>
                 <textarea id="comment" name="comment" rows="3"
-                    placeholder="Adresse, Kontaktinformationen, Besonderheiten"><?php echo htmlspecialchars($location['comment'] ?? ''); ?></textarea>
+                    placeholder="Adresse, Kontaktinformationen, Besonderheiten"><?php echo htmlspecialchars($location['comment'] ?? '); ?></textarea>
             </div>
         </fieldset>
 
@@ -153,9 +153,24 @@ $pageTitle = $isEdit ? "Standort bearbeiten: " . htmlspecialchars($location['nam
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Diesen Standort wirklich löschen? Alle Gebäude werden gelöscht.')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (confirm('Diesen Standort wirklich loeschen? Alle Gebaeude werden geloescht.')) {
+        fetch('?module=locations&action=delete', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+            body: 'id=' + encodeURIComponent(id)
+        })
+            .then((res) => res.json())
+            .then((data) => {
+                if (data && data.success) {
+                    window.location.href = '?module=locations&action=list';
+                    return;
+                }
+                alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+            })
+            .catch(() => {
+                alert('Loeschen fehlgeschlagen');
+            });
     }
 }
 </script>
+
diff --git a/app/modules/racks/delete.php b/app/modules/racks/delete.php
new file mode 100644
index 0000000..b627162
--- /dev/null
+++ b/app/modules/racks/delete.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * app/modules/racks/delete.php
+ */
+
+header('Content-Type: application/json; charset=utf-8');
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    echo json_encode(['success' => false, 'message' => 'Methode nicht erlaubt']);
+    exit;
+}
+
+$id = (int)($_POST['id'] ?? $_GET['id'] ?? 0);
+if ($id <= 0) {
+    http_response_code(400);
+    echo json_encode(['success' => false, 'message' => 'ID fehlt']);
+    exit;
+}
+
+$exists = $sql->single("SELECT id FROM racks WHERE id = ?", "i", [$id]);
+if (!$exists) {
+    http_response_code(404);
+    echo json_encode(['success' => false, 'message' => 'Rack nicht gefunden']);
+    exit;
+}
+
+$rows = $sql->set("DELETE FROM racks WHERE id = ?", "i", [$id]);
+if ($rows === false) {
+    http_response_code(500);
+    echo json_encode(['success' => false, 'message' => 'Loeschen fehlgeschlagen']);
+    exit;
+}
+
+echo json_encode(['success' => true, 'message' => 'Rack geloescht']);
+
diff --git a/app/modules/racks/edit.php b/app/modules/racks/edit.php
index 24fe8fd..a63de09 100644
--- a/app/modules/racks/edit.php
+++ b/app/modules/racks/edit.php
@@ -1,16 +1,8 @@
 <?php
 /**
  * app/modules/racks/edit.php
- *
- * Rack anlegen oder bearbeiten
- * - Name, Beschreibung
- * - Zugehöriges Stockwerk (Floor)
- * - Höhe in Höheneinheiten (HE)
  */
 
-// =========================
-// Kontext bestimmen
-// =========================
 $rackId = (int)($_GET['id'] ?? 0);
 $rack = null;
 
@@ -23,83 +15,61 @@ if ($rackId > 0) {
 }
 
 $isEdit = !empty($rack);
-$pageTitle = $isEdit ? "Rack bearbeiten: " . htmlspecialchars($rack['name']) : "Neues Rack";
-
-// =========================
-// Floors laden
-// =========================
-$floors = $sql->get("SELECT id, name FROM floors ORDER BY name", "", []);
-
+$pageTitle = $isEdit ? 'Rack bearbeiten: ' . htmlspecialchars((string)$rack['name']) : 'Neues Rack';
+$floors = $sql->get("SELECT id, name FROM floors ORDER BY name", '', []);
 ?>
 
 <div class="rack-edit">
     <h1><?php echo $pageTitle; ?></h1>
 
     <form method="post" action="?module=racks&action=save" class="edit-form">
-
         <?php if ($isEdit): ?>
-        <input type="hidden" name="id" value="<?php echo $rackId; ?>">
+            <input type="hidden" name="id" value="<?php echo (int)$rackId; ?>">
         <?php endif; ?>
 
-        <!-- =========================
-             Basisdaten
-             ========================= -->
         <fieldset>
             <legend>Allgemein</legend>
 
             <div class="form-group">
                 <label for="name">Name <span class="required">*</span></label>
-                <input type="text" id="name" name="name" required
-                    value="<?php echo htmlspecialchars($rack['name'] ?? ''); ?>"
-                    placeholder="z.B. Rack A1">
+                <input type="text" id="name" name="name" required value="<?php echo htmlspecialchars((string)($rack['name'] ?? '')); ?>" placeholder="z.B. Rack A1">
             </div>
 
             <div class="form-group">
                 <label for="comment">Beschreibung</label>
-                <textarea id="comment" name="comment" rows="3"
-                    placeholder="z.B. Standort, Besonderheiten"><?php echo htmlspecialchars($rack['comment'] ?? ''); ?></textarea>
+                <textarea id="comment" name="comment" rows="3" placeholder="z.B. Standort, Besonderheiten"><?php echo htmlspecialchars((string)($rack['comment'] ?? '')); ?></textarea>
             </div>
         </fieldset>
 
-        <!-- =========================
-             Standort & Höhe
-             ========================= -->
         <fieldset>
-            <legend>Standort & Größe</legend>
+            <legend>Standort und Groesse</legend>
 
             <div class="form-group">
                 <label for="floor_id">Stockwerk <span class="required">*</span></label>
                 <select id="floor_id" name="floor_id" required>
-                    <option value="">- Wählen -</option>
+                    <option value="">- Waehlen -</option>
                     <?php foreach ($floors as $floor): ?>
-                    <option value="<?php echo $floor['id']; ?>"
-                        <?php echo ($rack['floor_id'] ?? 0) == $floor['id'] ? 'selected' : ''; ?>>
-                        <?php echo htmlspecialchars($floor['name']); ?>
-                    </option>
+                        <option value="<?php echo (int)$floor['id']; ?>" <?php echo ((int)($rack['floor_id'] ?? 0) === (int)$floor['id']) ? 'selected' : ''; ?>>
+                            <?php echo htmlspecialchars((string)$floor['name']); ?>
+                        </option>
                     <?php endforeach; ?>
                 </select>
             </div>
 
             <div class="form-group">
-                <label for="height_he">Höhe in Höheneinheiten (HE) <span class="required">*</span></label>
-                <input type="number" id="height_he" name="height_he" required min="1" max="100"
-                    value="<?php echo htmlspecialchars($rack['height_he'] ?? '42'); ?>"
-                    placeholder="z.B. 42">
-                <small>Standard: 42 HE (ca. 2 Meter)</small>
+                <label for="height_he">Hoehe in Hoeheneinheiten (HE) <span class="required">*</span></label>
+                <input type="number" id="height_he" name="height_he" required min="1" max="100" value="<?php echo (int)($rack['height_he'] ?? 42); ?>">
+                <small>Standard: 42 HE</small>
             </div>
         </fieldset>
 
-        <!-- =========================
-             Aktionen
-             ========================= -->
         <fieldset class="form-actions">
             <button type="submit" class="button button-primary">Speichern</button>
             <a href="?module=racks&action=list" class="button">Abbrechen</a>
             <?php if ($isEdit): ?>
-                <a href="#" class="button button-danger" onclick="confirmDelete(<?php echo $rackId; ?>)">Löschen</a>
+                <a href="#" class="button button-danger" onclick="return confirmDelete(<?php echo (int)$rackId; ?>)">Loeschen</a>
             <?php endif; ?>
         </fieldset>
-
     </form>
 </div>
 
@@ -197,60 +167,25 @@ $floors = $sql->get("SELECT id, name FROM floors ORDER BY name", "", []);
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Dieses Rack wirklich löschen? Alle Geräte werden aus dem Rack entfernt.')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (!confirm('Dieses Rack wirklich loeschen? Alle Geraete werden aus dem Rack entfernt.')) {
+        return false;
     }
+
+    fetch('?module=racks&action=delete', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+        body: 'id=' + encodeURIComponent(id)
+    })
+        .then((response) => response.json())
+        .then((data) => {
+            if (data && data.success) {
+                window.location.href = '?module=racks&action=list';
+                return;
+            }
+            alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+        })
+        .catch(() => alert('Loeschen fehlgeschlagen'));
+
+    return false;
 }
-</script>
-
-    <!-- =========================
-         Rack-SVG / Gerätepositionen
-         ========================= -->
-
-    <fieldset>
-        <legend>Rack-Layout</legend>
-
-        <div class="svg-editor-container">
-            <svg
-                id="rack-svg"
-                viewBox="0 0 200 1000"
-                width="100%"
-                height="600"
-            >
-                <!-- TODO: Rack-SVG laden -->
-            </svg>
-        </div>
-
-        <p class="hint">
-            Geräte per Drag & Drop im Rack positionieren.
-        </p>
-    </fieldset>
-
-    <!-- =========================
-         Aktionen
-         ========================= -->
-
-    <fieldset>
-        <button type="submit">Speichern</button>
-        <button type="button" onclick="history.back()">Abbrechen</button>
-        <!-- TODO: Löschen, falls edit -->
-    </fieldset>
-
-</form>
-
-<!-- =========================
-     JS-Konfiguration
-     ========================= -->
-
-<script>
-    /**
-     * Konfiguration für Rack-SVG-Editor
-     */
-
-    // TODO: Rack-ID aus PHP setzen
-    // window.RACK_ID = <?= (int)$rackId ?>;
-
-    // TODO: Gerätepositionen an JS übergeben
-    // window.RACK_DEVICES = <?= json_encode($rackDevices ?? []) ?>;
 </script>
diff --git a/app/modules/racks/list.php b/app/modules/racks/list.php
index b4d0d43..6dfd747 100644
--- a/app/modules/racks/list.php
+++ b/app/modules/racks/list.php
@@ -2,44 +2,30 @@
 /**
  * app/modules/racks/list.php
  *
- * Übersicht aller Racks
- * - Anzeigen, Bearbeiten, Löschen
- * - Zugehöriges Stockwerk anzeigen
- * - Gerätecount
+ * Uebersicht aller Racks.
  */
 
-// =========================
-// Filter einlesen
-// =========================
-$search = trim($_GET['search'] ?? '');
+$search = trim((string)($_GET['search'] ?? ''));
 $floorId = (int)($_GET['floor_id'] ?? 0);
 
-//TODO racks beim editieren auf der stockwerkkarte platzieren und verschieben können
-
-// =========================
-// WHERE-Clause bauen
-// =========================
 $where = [];
 $types = '';
 $params = [];
 
 if ($search !== '') {
-    $where[] = "r.name LIKE ?";
-    $types .= "s";
+    $where[] = 'r.name LIKE ?';
+    $types .= 's';
     $params[] = "%$search%";
 }
 
 if ($floorId > 0) {
-    $where[] = "r.floor_id = ?";
-    $types .= "i";
+    $where[] = 'r.floor_id = ?';
+    $types .= 'i';
     $params[] = $floorId;
 }
 
-$whereSql = $where ? "WHERE " . implode(" AND ", $where) : "";
+$whereSql = $where ? ('WHERE ' . implode(' AND ', $where)) : '';
 
-// =========================
-// Racks laden
-// =========================
 $racks = $sql->get(
     "SELECT r.*, f.name AS floor_name, COUNT(d.id) AS device_count
      FROM racks r
@@ -52,212 +38,111 @@ $racks = $sql->get(
     $params
 );
 
-// =========================
-// Filter-Daten laden
-// =========================
-$floors = $sql->get("SELECT id, name FROM floors ORDER BY name", "", []);
-
+$floors = $sql->get('SELECT id, name FROM floors ORDER BY name', '', []);
 ?>
 
 <div class="racks-container">
     <h1>Racks</h1>
 
-    <!-- =========================
-         Toolbar
-         ========================= -->
     <div class="filter-form">
-        <form method="GET" style="display: flex; gap: 10px; flex-wrap: wrap; align-items: center;">
+        <form method="GET" style="display:flex;gap:10px;flex-wrap:wrap;align-items:center;">
             <input type="hidden" name="module" value="racks">
             <input type="hidden" name="action" value="list">
 
-            <input type="text" name="search" placeholder="Suche nach Name…"
-                value="<?php echo htmlspecialchars($search); ?>" class="search-input">
+            <input type="text" name="search" placeholder="Suche nach Name..." value="<?php echo htmlspecialchars($search); ?>" class="search-input">
 
             <select name="floor_id">
                 <option value="">- Alle Stockwerke -</option>
                 <?php foreach ($floors as $floor): ?>
-                <option value="<?php echo $floor['id']; ?>"
-                    <?php echo $floor['id'] === $floorId ? 'selected' : ''; ?>>
-                    <?php echo htmlspecialchars($floor['name']); ?>
-                </option>
+                    <option value="<?php echo (int)$floor['id']; ?>" <?php echo ((int)$floor['id'] === $floorId) ? 'selected' : ''; ?>>
+                        <?php echo htmlspecialchars((string)$floor['name']); ?>
+                    </option>
                 <?php endforeach; ?>
             </select>
 
             <button type="submit" class="button">Filter</button>
             <a href="?module=racks&action=list" class="button">Reset</a>
-            <a href="?module=racks&action=edit" class="button button-primary" style="margin-left: auto;">+ Neues Rack</a>
+            <a href="?module=racks&action=edit" class="button button-primary" style="margin-left:auto;">+ Neues Rack</a>
         </form>
     </div>
 
-    <!-- =========================
-         Racks-Tabelle
-         ========================= -->
     <?php if (!empty($racks)): ?>
-    <table class="rack-list">
-        <thead>
-            <tr>
-                <th>Name</th>
-                <th>Stockwerk</th>
-                <th>Höhe (HE)</th>
-                <th>Geräte</th>
-                <th>Beschreibung</th>
-                <th>Aktionen</th>
-            </tr>
-        </thead>
-        <tbody>
-            <?php foreach ($racks as $rack): ?>
-            <tr>
-                <td>
-                    <strong><?php echo htmlspecialchars($rack['name']); ?></strong>
-                </td>
-
-                <td>
-                    <?php echo htmlspecialchars($rack['floor_name'] ?? '—'); ?>
-                </td>
-
-                <td>
-                    <?php echo $rack['height_he']; ?> HE
-                </td>
-
-                <td>
-                    <?php echo $rack['device_count']; ?>
-                </td>
-
-                <td>
-                    <small><?php echo htmlspecialchars($rack['comment'] ?? ''); ?></small>
-                </td>
-
-                <td class="actions">
-                    <a href="?module=racks&action=edit&id=<?php echo $rack['id']; ?>" class="button button-small">Bearbeiten</a>
-                    <a href="#" class="button button-small button-danger" onclick="confirmDelete(<?php echo $rack['id']; ?>)">Löschen</a>
-                </td>
-            </tr>
-            <?php endforeach; ?>
-        </tbody>
-    </table>
-
+        <table class="rack-list">
+            <thead>
+                <tr>
+                    <th>Name</th>
+                    <th>Stockwerk</th>
+                    <th>Hoehe (HE)</th>
+                    <th>Geraete</th>
+                    <th>Beschreibung</th>
+                    <th>Aktionen</th>
+                </tr>
+            </thead>
+            <tbody>
+                <?php foreach ($racks as $rack): ?>
+                    <tr>
+                        <td><strong><?php echo htmlspecialchars((string)$rack['name']); ?></strong></td>
+                        <td><?php echo htmlspecialchars((string)($rack['floor_name'] ?? '-')); ?></td>
+                        <td><?php echo (int)$rack['height_he']; ?> HE</td>
+                        <td><?php echo (int)$rack['device_count']; ?></td>
+                        <td><small><?php echo htmlspecialchars((string)($rack['comment'] ?? '')); ?></small></td>
+                        <td class="actions">
+                            <a href="?module=racks&action=edit&id=<?php echo (int)$rack['id']; ?>" class="button button-small">Bearbeiten</a>
+                            <a href="#" class="button button-small button-danger" onclick="return confirmDelete(<?php echo (int)$rack['id']; ?>)">Loeschen</a>
+                        </td>
+                    </tr>
+                <?php endforeach; ?>
+            </tbody>
+        </table>
     <?php else: ?>
-    <div class="empty-state">
-        <p>Keine Racks gefunden.</p>
-        <p>
-            <a href="?module=racks&action=edit" class="button button-primary">
-                Erstes Rack anlegen
-            </a>
-        </p>
-    </div>
+        <div class="empty-state">
+            <p>Keine Racks gefunden.</p>
+            <p><a href="?module=racks&action=edit" class="button button-primary">Erstes Rack anlegen</a></p>
+        </div>
     <?php endif; ?>
 </div>
 
 <style>
-.racks-container {
-    padding: 20px;
-    max-width: 1000px;
-    margin: 0 auto;
-}
-
-.filter-form {
-    margin: 20px 0;
-}
-
-.filter-form form {
-    display: flex;
-    gap: 10px;
-    flex-wrap: wrap;
-    align-items: center;
-}
-
-.filter-form input,
-.filter-form select {
-    padding: 8px 12px;
-    border: 1px solid #ddd;
-    border-radius: 4px;
-}
-
-.search-input {
-    flex: 1;
-    min-width: 250px;
-}
-
-.rack-list {
-    width: 100%;
-    border-collapse: collapse;
-    margin: 15px 0;
-}
-
-.rack-list th {
-    background: #f5f5f5;
-    padding: 12px;
-    text-align: left;
-    border-bottom: 2px solid #ddd;
-    font-weight: bold;
-}
-
-.rack-list td {
-    padding: 12px;
-    border-bottom: 1px solid #ddd;
-}
-
-.rack-list tr:hover {
-    background: #f9f9f9;
-}
-
-.actions {
-    white-space: nowrap;
-}
-
-.button {
-    display: inline-block;
-    padding: 8px 12px;
-    background: #007bff;
-    color: white;
-    text-decoration: none;
-    border-radius: 4px;
-    border: none;
-    cursor: pointer;
-    font-size: 0.9em;
-}
-
-.button:hover {
-    background: #0056b3;
-}
-
-.button-primary {
-    background: #28a745;
-}
-
-.button-primary:hover {
-    background: #218838;
-}
-
-.button-small {
-    padding: 4px 8px;
-    font-size: 0.85em;
-}
-
-.button-danger {
-    background: #dc3545;
-}
-
-.button-danger:hover {
-    background: #c82333;
-}
-
-.empty-state {
-    text-align: center;
-    padding: 40px 20px;
-    background: #f9f9f9;
-    border: 1px solid #eee;
-    border-radius: 8px;
-}
+.racks-container { padding: 20px; max-width: 1000px; margin: 0 auto; }
+.filter-form { margin: 20px 0; }
+.filter-form input, .filter-form select { padding: 8px 12px; border: 1px solid #ddd; border-radius: 4px; }
+.search-input { flex: 1; min-width: 250px; }
+.rack-list { width: 100%; border-collapse: collapse; margin: 15px 0; }
+.rack-list th { background: #f5f5f5; padding: 12px; text-align: left; border-bottom: 2px solid #ddd; font-weight: bold; }
+.rack-list td { padding: 12px; border-bottom: 1px solid #ddd; }
+.rack-list tr:hover { background: #f9f9f9; }
+.actions { white-space: nowrap; }
+.button { display: inline-block; padding: 8px 12px; background: #007bff; color: #fff; text-decoration: none; border-radius: 4px; border: none; cursor: pointer; font-size: 0.9em; }
+.button:hover { background: #0056b3; }
+.button-primary { background: #28a745; }
+.button-primary:hover { background: #218838; }
+.button-small { padding: 4px 8px; font-size: 0.85em; }
+.button-danger { background: #dc3545; }
+.button-danger:hover { background: #c82333; }
+.empty-state { text-align: center; padding: 40px 20px; background: #f9f9f9; border: 1px solid #eee; border-radius: 8px; }
 </style>
 
 <script>
 function confirmDelete(id) {
-    if (confirm('Dieses Rack wirklich löschen?')) {
-        // TODO: AJAX-Delete implementieren
-        alert('Löschen noch nicht implementiert');
+    if (!confirm('Dieses Rack wirklich loeschen?')) {
+        return false;
     }
+
+    fetch('?module=racks&action=delete', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' },
+        body: 'id=' + encodeURIComponent(id)
+    })
+        .then((res) => res.json())
+        .then((data) => {
+            if (data && data.success) {
+                window.location.reload();
+                return;
+            }
+            alert((data && data.message) ? data.message : 'Loeschen fehlgeschlagen');
+        })
+        .catch(() => alert('Loeschen fehlgeschlagen'));
+
+    return false;
 }
 </script>
-</div>
-<?php /* endif; */ ?>
diff --git a/app/templates/footer.php b/app/templates/footer.php
index d0c639e..6e333c5 100644
--- a/app/templates/footer.php
+++ b/app/templates/footer.php
@@ -1,19 +1,32 @@
 <?php
 /**
  * footer.php
- *
- * HTML-Footer, Scripts, evtl. Modale oder Notifications
- * Wird am Ende jeder Seite eingebunden
  */
 ?>
 </main>
 
 <footer>
     <p>&copy; <?php echo date('Y'); ?> Troy Grunt - NDT</p>
-
-    <!-- TODO: Optional: Statusanzeige, Debug-Info, Session-Hinweis -->
+    <p class="footer-meta">
+        Umgebung: <?php echo defined('APP_ENV') ? htmlspecialchars(APP_ENV) : 'unknown'; ?>
+        | Session: <?php echo session_id() !== '' ? 'aktiv' : 'inaktiv'; ?>
+    </p>
 </footer>
 
-<!-- TODO: evtl. JS für modale Fenster oder Flash Messages -->
+<?php if (!empty($_SESSION['success']) || !empty($_SESSION['error'])): ?>
+    <script>
+        (function () {
+            const success = <?php echo json_encode($_SESSION['success'] ?? '', JSON_UNESCAPED_UNICODE); ?>;
+            const error = <?php echo json_encode($_SESSION['error'] ?? '', JSON_UNESCAPED_UNICODE); ?>;
+            if (success) {
+                alert(success);
+            }
+            if (error) {
+                alert(error);
+            }
+        })();
+    </script>
+    <?php unset($_SESSION['success'], $_SESSION['error']); ?>
+<?php endif; ?>
 </body>
 </html>
diff --git a/app/templates/header.php b/app/templates/header.php
index f527764..12e43fd 100644
--- a/app/templates/header.php
+++ b/app/templates/header.php
@@ -10,7 +10,10 @@
 <html lang="de">
 <head>
     <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta name="description" content="Netwatch - Netzwerk-Dokumentation und Verkabelungsverwaltung">
     <title>Netzwerk-Dokumentation</title>
+    <link rel="icon" type="image/svg+xml" href="/assets/icons/favicon.svg">
 
     <!-- CSS -->
     <link rel="stylesheet" href="/assets/css/app.css">
@@ -21,7 +24,6 @@
     <script src="/assets/js/svg-editor.js" defer></script>
     <script src="/assets/js/network-view.js" defer></script>
 
-    <!-- TODO: Meta-Tags, Favicon -->
 </head>
 <body>
 <header class="app-header">
diff --git a/app/templates/layout.php b/app/templates/layout.php
index 888bcc7..10ba0ee 100644
--- a/app/templates/layout.php
+++ b/app/templates/layout.php
@@ -2,25 +2,18 @@
 /**
  * layout.php
  *
- * Grundlayout: Header + Content + Footer
- * Kann als Basis-Template dienen, falls Module HTML ausgeben
- *
- * Beispiel-Aufruf in Modul:
- *   include __DIR__ . '/../templates/layout.php';
- *
- * TODO: In Zukunft: zentrales Template-System (z.B. mit $content)
+ * Basislayout fuer Header + Content + Footer.
  */
 ?>
 
 <?php include __DIR__ . '/header.php'; ?>
 
 <div class="content-wrapper">
-    <!-- TODO: Dynamischen Content hier einfügen -->
     <?php
     if (isset($content)) {
         echo $content;
     } else {
-        echo "<p>Inhalt fehlt</p>";
+        echo '<p>Kein Inhalt uebergeben.</p>';
     }
     ?>
 </div>
diff --git a/init.sql b/init.sql
index a78af85..4b0252b 100644
--- a/init.sql
+++ b/init.sql
@@ -44,9 +44,9 @@ INSERT INTO `buildings` (`id`, `location_id`, `name`, `comment`) VALUES
 CREATE TABLE `connections` (
   `id` int(11) NOT NULL,
   `connection_type_id` int(11) NOT NULL,
-  `port_a_type` enum('device','module','outlet') NOT NULL,
+  `port_a_type` enum('device','module','outlet','patchpanel') NOT NULL,
   `port_a_id` int(11) NOT NULL,
-  `port_b_type` enum('device','module','outlet') NOT NULL,
+  `port_b_type` enum('device','module','outlet','patchpanel') NOT NULL,
   `port_b_id` int(11) NOT NULL,
   `vlan_config` longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL CHECK (json_valid(`vlan_config`)),
   `mode` varchar(50) DEFAULT NULL,
@@ -70,6 +70,13 @@ CREATE TABLE `connection_types` (
   `comment` text DEFAULT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci;
 
+--
+-- Daten fuer Tabelle `connection_types`
+--
+
+INSERT INTO `connection_types` (`id`, `name`, `medium`, `duplex`, `max_speed`, `color`, `line_style`, `comment`) VALUES
+(1, 'Default', 'copper', 'custom', NULL, NULL, 'solid', 'Auto-created default type');
+
 -- --------------------------------------------------------
 
 --