Li and Wu proposed Rule 2, a localized approximation algorithm that attempts
to find a small connected dominating set in a graph. Here we study the
asymptotic performance of Rule 2 on random unit disk graphs formed from n
random points in an s_n by s_n square region of the plane. If s_n is below the
threshold for connectivity, then Rule 2 produces a dominating set whose
expected size is O(n/(loglog n)^{3/2}). We conjecture that this bound is not
optimal.