php - Symfony2 Routing parameters -

i new symfony2 , mvc in general. going through documentation symfony , in chapter on routing.

i getting confused annotation

/**  * @route("/blog/{slug}", name="blog_show")  */ public function showaction($slug) {     // ... }

i understand if user visits blog/xxx, showaction called. not understand why there name="blog_show" after comma in @route.

could please describe why use it?

is alias route

this name 1 have call example twig

<a href="{{ path('blog_show', {'slug': my-blog-post}) }}" ...

it call /blog/my-blog-post

or if want redirect address

return new redirectresponse($this->generateurl('blog_show'), array('slug' => 'my-blog-post'));

or generate url

$url = $this->generateurl('blog_show', array('slug' => 'my-blog-post'));

here have documentation

WIKI