1. A computer implemented method for modeling and evaluating impact on service components, comprising: annotating a Unified Modeling Language (UML) sequence diagram using attributes in a distinct layer associated with the UML sequence diagram, wherein the UML sequence diagram describes a plurality of service components and flow of transactions between the service components, wherein annotating is separate from creating the UML sequence diagram; deriving a plurality of input parameters to a Markov model from the annotated UML sequence diagram for determining an impact on one or more of the plurality of service components, wherein the step of deriving includes deriving a plurality of states and state transition probabilities representing the flow of transactions between the service components; reducing the plurality of states; reverse engineering the Markov model; and generating a new UML sequence diagram.