PCI arbiter doubt

Hi all,

 I have some basic doubts on PCI arbiter.

 1)how is the framen controlled -- i guess it is a shared resource on
the PCI bus wher all the devices  sitting on the PCI bus have access to
it.

 2)If a request is received from a device on PCI bus ,should the grant
be issued immediately or should the PCI arbiter wait until the framen
is dropped (asserted).

  3)If a request is received from a device on PCI bus , but the framen
is not dropped at all.how should the PCI arbiter react to this
condition.

Regards,
Praveen