In 1/N_c expansion, analyticity and crossing lead to crossing even and odd (C = +/-1) vacuum exchanges for diffractive scattering at high-energy. We discuss how, using String/Gauge duality, these can be identified with a reggeized Graviton and the anti-symmetric Kalb-Ramond fields in AdS background. With confinement, these Regge singularities interpolate with glueball states. We also discuss unitarization based on eikonal sum in AdS. Extension of this formalism for diffractive Higgs production at LHC will also be discussed.