title: Common varnish: difference between beresp & resp, bereq & req; req.ttl & beresp.ttl
body: <p>Tell me please, whats the difference between these concepts? I didn't found any answers in documentations of Varnish. They just operative these concepts, nothing more.</p>
  
  <p>And what is better to use for caching: beresp.ttl or max-age in Cache-control header?</p>
  
  <p>If you can do it with little examples - do it please :)</p>