says to include widearea physnodes, with the types set to those listed
in the node_auxtypes table. Those types will include the last mile
types that a vnode on a pnode can take on. The :count value for the
types is set to the min of the number of *free* vnodes on the pnode,
and the virtnode_capacity in the node_types table. Obviously, if all
the vnodes are allocated, the physnode will not appear in the ptop
file. For plab, virtnode_capacity will get set to one in the
node_types table, thereby preventing "revisitation" of a plab physnode
in an experiment.