Merge pull request #2919 from awlx/add_description_to_mibbases_polling

Add description to mibbases polling

doc/Extensions/MIB-based-polling.md

@@ -144,6 +144,38 @@ graph.
     can follow the above process, then use the resultant data collected by
     LibreNMS in the RRD files or the database tables `device_oids`
 
+## Configuration
+### Main Configuration
+In `/opt/librenms/config.php` add `$config['poller_modules']['mib'] = 1;`
+
+### Discovery
+
+You need to add your desired MIBs to `/opt/librenms/mibs` folder. Afterwards you need to register your MIBs to the discovery function. 
+
+#### Example
+`/opt/librenms/includes/discovery/os/f5.inc.php`
+
+```
+<?php
+if (!$os || $os === 'linux') {
+    $f5_sys_parent = '1.3.6.1.4.1.3375.2.1';
+    if (strpos($sysObjectId, $f5_sys_parent)) {
+        $os = 'f5';
+   }
+
+}
+
+### MIB definition as an array 
+$f5_mibs = array(
+                "ltmVirtualServStatEntry" => "F5-BIGIP-LOCAL-MIB",
+        );
+
+### Actual registering of the MIB
+register_mibs($device, $f5_mibs, "includes/discovery/os/f5.inc.php");
+
+```
+
+The important thing is the array $f5_mibs where you define which parts (ltmVirtualServStatEntry) of the MIB (F5-BIGIP-LOCAL-MIB) you are going to add. The registering is also important, otherwise poller cannot make use of the MIB.
 
 ## TODO ##