Open and closed string interpretation of SUSYCFT's on branes with boundaries

We consider certain supersymmetric configurations of intersecting branes an d branes ending on branes and analyze the duality between their open and cl osed string interpretation. The examples we study are chosen such that we h ave the lower dimensional brane realizing an n+1 dimensional conformal fiel d theory on its worldvolume and the higher dimensional one introducing a co nformal boundary. We also consider two CFTs, possibly with different centra l charges, interacting along a common conformal boundary. We show with a pr obe calculation that the dual closed string description is in terms of grav ity in an AdS(n+2) bulk with an AdS(n+1) defect or two different AdS(n+2) s paces joined along a defect. We also comment briefly on the expected back-r eaction.