What's the purpose of ip_route_output_flow()?

Hi,
  Would you please tell me what the purpose of
ip_route_output_flow() is? and What the differences
between it and ip_route_output_key() are?

  Thank you.


=====
Best Regards,
Park Lee

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com