ipavailable

HelLo,
Could sb pls explain the command ipavailable?
BEst

which is explained here [opavailable].

Does it affect the nroftransportsin/out? I mean if you pull two items with this condition ipavailable, does it reserve the places for these items after pulling?

It returns true if the corresponding output port feeding the object's input port exists and is open and available (green port connection and no red bar) .