Web Service Atomic Transaction is an OASIS standard. To achieve all-or-nothing property for a group of services, it defines three protocols ('i.e.', completion, volatile two-phase commit, and durable two-phase commit), and a set of services. These protocols and services together ensure automatic activation, registration, propagation and atomic termination of Web Services.
Following the standard, a distributed transaction has a coordinator, an initiator, and one or more participants.