Supporting Quality of Service properties in BPEL processes is essential to enable Web Service based production workflows.
In fact, when implementing a Web Service composition with a BPEL process, appropriate means are needed to express and enforce
various QoS properties such as security, reliable messaging, and transactions.
In this paper, we present a generic and non-proprietary approach to express QoS properties in BPEL processes using policies.
This approach uses XPath, WS-Policy, and the external policy attachment mechanism of WS-PolicyAttachment to enable a separate
and non-intrusive specification of both the messaging-level and process-level QoS requirements in BPEL processes. We also
present a prototype implementation on top of the Colombo BPEL engine, which supports the enforcement of policies that are
attached to BPEL activities.