that an experiment prefers to use modelnet for traffic shaping.
       At some future time maybe we can mix modelnet with delay nodes,
       but please do not hold your breath waiting.

	alter table experiments add usemodelnet tinyint(1) NOT NULL \
		default '0' after useprepass;

       Add modelnet_cores and modelnet_edges variables to hold user
       tunable number of physical core nodes and edge nodes to throw
       at a virtual topology.

	alter table experiments add modelnet_cores tinyint(4) unsigned \
		NOT NULL default '0' after usemodelnet;
        alter table experiments add modelnet_edges tinyint(4) unsigned \
		NOT NULL default '0' after modelnet_cores;

       Add ismodelnet and isphantom slots to node_types table. ismodelnet
       is set for modelnet nodes (which are also going to be isvirt).  Add
       isphantom to mark nodes that do no get underlying physical nodes;
       there will be an entry in the reserved table but no entries in the
       nodes table. Initially, modelnet virtual nodes will all be phantoms.
       Will possibly change later.

	alter table node_types add ismodelnet tinyint(1) NOT NULL \
		default '0' after isvirtnode;
	alter table node_types add isphantom tinyint(1) NOT NULL \
		default '0' after ismodelnet;

       Not sure that isphantom is going to work cause of the number of
       queries that join reserved with the nodes table. I might end up
       making nodes dynamic instead, creating and detroying them on the
       fly. I would prefer that isphantom works, but I am willing to live
       with isdynamic since we can use that for all of our virtual nodes.

	alter table node_types add isdynamic tinyint(1) NOT NULL \
		default '0' after isphantom;