RSTP and a loop caused by an unmanaged switch

[ludacris]

hi,

does anyone know what the RSTP's RFC indicate about loop detected on a port caused by an unmanaged switch with a loop on it.

meaning

port1 is connected to the unmanaged switch which has loop on it.

how will port 1 behave?

will it block the port or not detect a loop?

i've encountered those 2 behaviors on 2 different vendor's switches, and i am looking to know what is the normal behavior.

thanks.