Fastcgi protocol

Hi, I’m trying to understand fastcgi protocol. I’ve been studying
fastcgi
specification:

http://www.fastcgi.com/drupal/node/6?q=node/22

However I’m still unsure about some of the details. I would really
appreciate
if some of the developers could answer my questions.

  1. Fastcgi roles - Responder, Authorizer and Filter. I think Responder
    is
    supported by most web frameworks like php, perl, etc. Are there any
    frameworks
    that support Authorizer and Filter? How useful are these roles? How does
    a web
    server map different roles to fastcgi applications? Can a single fastcgi
    application support all 3 roles over a single TCP connections?

  2. Multiplexing request sessions over a single TCP connection. A request
    session consists of one of more fastcgi records, that have the same
    request
    ID. Is this at all supported by nginx or another web frameworks?

Thanks very much