For a graph G, letG?(G?) denote an orientation ofG having maximum (minimum respectively) finite diameter. We show that the length of the longest path in any 2-edge connected (undirected) graph G is precisely diam(G?). LetK(m l ,m 2,...,m n) be the completen-partite graph with parts of cardinalitiesm 1 m2, ?,m n . We prove that ifm 1 = m2 = ? =m n = m,n ? 3, then diam(K?(m1,m2,...,mn)) = 2, unless m=1 andn = 4.