When the BPEL process service component is on the client side of this transaction, it needs a scope activity containing an invoke activity to send the request, and a receive activity to accept the reply. The onAlarm handler of the scope activity has a time limit and instructions on what to do when the timer expires. For example, wait 30 minutes, then send a warning indicating that the process is taking longer than expected. As with all partner activities, the WSDL file defines the interaction.