Signaling parameters are passed between the application and the TUP task in the form of events. Events are fixed format structures consisting of one or more information elements (IEs). Information elements are fixed format structures consisting of a flag indicating their presence or absence from the corresponding TUP message, and one or more tokens, or fields.
The following illustration shows how event structures simplify applications by enabling them to operate on fixed format structures rather than the variable length and variable formats employed by the TUP protocol: