Tài liệu the PCI Bus demystified phần 8

Once configured, the primary job of a PCI-to-PCI bridge is to
act as an address filter, accepting transactions directed at agents
downstream of it and ignoring transactions that fall outside of its
address windows.
Bridges are allowed to prefetch read data and post write data
provided they observe rules to prevent deadlocks and avoid reading
stale data. Write posting can create a problem for interrupts because
the interrupt may arrive at the host processor before the associated