Minimum spanning tree with hop restrictions

Let U = (uij)i,j=1n be a symmetric requirement matrix. Let d = (dij)i,j=1n be a cost metric. A spanning tree T = (V, ET) V = {1,2 ..... n} is feasible if for every pair of vertices v, w the v - w path in T contains at most uvw, edges. We explore the problem of finding a minimum cost feasible spanning tree, when uij ∈ {1,2, ∞}. We present a polynomial algorithm for the problem when the graph induced by the edges with uij < ∞ is 2-vertex-connected. We also present a polynomial algorithm with bounded performance guarantee for the general case.