Diameter 2 Cayley Graphs of Dihedral Groups
  We consider the degree-diameter problem for Cayley graphs of dihedral groups. We find upper and lower bounds on the maximum number of vertices of such a graph with diameter 2 and degree $d$. We completely determine the asymptotic behaviour of this class of graphs by showing that both limits are asymptotically $d^2/2$. 
Grahame Erskine
math.CO