Juan Pablo Carvallo Juan Pablo Carvallo Universidad Del Pac Universidad Del Pac í í fico fico Cuenca, Ecuador Cuenca, Ecuador Xavier Franch Xavier Franch Universitat Polit Universitat Polit è è cnica de Catalunya cnica de Catalunya Barcelona, Spain Barcelona, Spain RE RE ’ ’ 11, Trento (Italy) 11, Trento (Italy) – – August, 2011 August, 2011 Requirements Negotiation for Requirements Negotiation for Multilayer System Components Multilayer System Components