import psutil

def get_system_metrics():
    cpu_percent = psutil.cpu_percent(interval=1)
    memory = psutil.virtual_memory().percent
    disk = psutil.disk_usage('/').percent
    net_io = psutil.net_io_counters()

    stats = {
        'cpu_percent': cpu_percent,
        'memory': memory,
        'disk': disk,
        'network': {
            'bytes_sent': net_io.bytes_sent,
            'bytes_recv': net_io.bytes_recv,
            'packets_sent': net_io.packets_sent,
            'packets_recv': net_io.packets_recv
        }
    }

    return stats