| What's Next?What's Next?
				In the real world, intra-domain Internet routing uses either
				link-state (for larger domains) or distance vector (for smaller
				domains) approaches. Inter-domain routing involves issues like
				policy routing (eg: restrictions on the paths which can
				be used by certain subsets of nodes, what they pay to use it, and what
				quality of service they get, etc.), which invalidates metric
				assumptions in both distance-vector and link-state routing. This is a
				tough problem being tackled by researchers today.
				 
				Topology design is another area of networking which is graph-theoretic
				in nature.  Such a problem includes specifications of
				connectivity, network cost, routing
				stability and flexibility, reliability and
				availability.  A network topology adhering to given parameters
				is best modeled and analyzed in terms of graph theory.
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