Oriented network design problem

Given a set of n nodes, each node wants a connection of size 1 to every other node.

Between two nodes can be installed oriented capacities. A capacity of size c costs ca, where a is a real between 0 and 1.

1 - Some asymptotical examples.

Complete oriented graph



For example, the cost of the complete graph Kn with shortest path routing S(Kn) is

Cost(K n,S(K n))=n(n-1).


Oriented Ring



The cost of the ring Rn with shortest path routing S(R n) is

Cost(R n,S(R n))=n[n(n-1)/2]a.


Star graph



Finally the cost of the star graph Sn with shortest path routing S(Sn) is

Cost(Sn ,S(Sn ))=2(n-1)a+1 .

2 - Open problem

For a given n, let On be a graph that achieves the minimal cost and ROn its associated routing. We denote

Optimal(n)=Cost(On,RO n).

What is the value of Optimal(n) ? We know for sure that

(n-1)1+a <= Optimal(n) <= 2(n-1) 1+a,

but not much more. For more details, see our report.

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