librenms-librenms/includes/discovery/mempools/nos.inc.php

<?php

if ($device['os'] == "nos") {
    echo("nos: ");

    $used   = snmp_get($device, "1.3.6.1.4.1.1588.2.1.1.1.26.6.0", "-Ovq");
    $total  = "100";
    $free       = ($total - $used);

    $percent    = $used;

    if (is_numeric($used)) {
        discover_mempool($valid_mempool, $device, 0, "nos", "Memory", "1", null, null);
    }
}