{HEAD ~ Methods} and systems for a topology service providing {TAIL ~ an interface} for specifying a topology and answering queries regarding the topology 
{ HEAD ~ Methods } and systems for a topology service providing { TAIL ~ an interface } for specifying a topology and answering queries regarding the topology
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH