Business processes specified using BPEL will interact with their partners through operation invocations of web services. Web services are based on loosely coupled Service Oriented Architecture (SOA) . The communication between web services is done over Internet connections that may or may not be highly reliable. Web services could also raise faults due to logical errors and execution errors arising from defects in the infrastructure. Therefore, BPEL business processes will need to handle faults appropriately. BPEL processes may also need to signal faults themselves. Fault handling and signaling is an important aspect of business processes designed using BPEL.
Faults in BPEL can arise in various situations: