How get Zend_Controller_Dispatcher_Token from index.php

Hi all,
I'm new of Zend Framework..

I need your help. I need to know how can i now what Zend_Controller_Dispatcher_Token i'm going to dispatch in my Index.php.

I need to know this because i'm developing an authentication system that will make the following:
$controller = Zend_Controller_Front::getInstance();
//AuthenticationController is my authentication class
$auth = AuthenticationController::factory($db,$session,$controller);

// if i have to authenticate:
$username = trim($post->noTags('username'));

if ($username!='') {
    $password= trim($post->noTags('password'));
    $auth->login($username, $password);
}

// i control from my class if the $token need authentication
// when the user is authenticated .. authRequired return false.


if ($auth->authRequired($token) == true) {
  // I store in Session where i was going..
  $session->__set('token',$token);
                 // I go to /login/login for display a form and put username and password...
                       $dispacher = new Zend_Controller_Dispatcher();
                $token = new Zend_Controller_Dispatcher_Token ("Login","login");
                $dispacher->setControllerDirectory('../app/controllers');
                $dispacher->dispatch($token);
}


....

I need to know the  Zend_Controller_Dispatcher_Token where i was going ...

I hope someone can help me with this issue..

Regards.

Mauro Casula