Large　cascading　failures　are　present　in　most　of　infrastructure　networks.　This　paper　reviews　the　problem　of　cascades　of　overload　failures　on　nodes　in　the　security　of　complex　networks.　Here　we　propose　a　nonlinear　load-capacity　model　for　cascading　failures　based　on　the　dynamical　redistribution　of　the　flow　on　the　network.　The　simulation　was　executed　on　the　weighted　scale-free　network　and　Internet　AS　level　network.　We　show　that　the　entire　network　may　collapse　for　the　breakdown　of　a　single　node　of　the　entire　network　if　the　node　is　among　the　ones　with　highest　loads.　This　is　important　for　real-world　networks　such　as　the　Internet,　which　has　a　highly　heterogeneous　distribution　of　loads.　©　2013　IEEE.