Case have published a white paper on Web Services External (WS-X): their AS4 Implementation. From the Introduction:
Modern economy compels business organizations to optimize their operations. For such optimization, an organization often specializes in certain core areas, and may outsource non-core activities to other organizations. Such outsourcing results in complex inter-organizational business processes. The participant organizations employ diverse industry standards based on proprietary and Internet protocols to implement these processes.
In the recent times, web services have gained prominence as a protocol for exchanging business data for B2B interactions due to the ease of use, and ubiquitous availability of tools and skills. W3C has developed several standards such as SOAP, SwA, MTOM, WS-Security, WS Reliability, and WSReliableMessaging to enable the necessary quality of service required to support business transactions over web services. ebMS 3.0 [4] is the leading standard that aggregates these web services standards [6] to provide the necessary transactional features. It standardizes exception handling by defining acknowledgement receipts and errors messages, and supports message choreographies. ebMS supports a broad set of features not all of which are required by typical integration scenarios. Therefore, OASIS developed a lightweight ebMS profile, known as AS4 [3], with a core set of features.
Cloud Computing is gaining popularity as a computing trend in today’s IT environment. Organizations are adopting it to solve many problems, and provide new services faster and simpler than ever before. There is a growing need for standards that would enable the cloud-based services to interoperate.AS4 is a standard that can achieve such interoperability in the cloud.
This white-paper (a) summarizes AS4 profile, (b) describes the motivation and the architecture of Cisco’s AS4 framework, Web Services External (WS-X), (c) describes couple use cases of this framework, and (d) describes how AS4 addresses the challenge of cloud interoperability.
References:
http://ebxml.xml.org/resource/web-services-external-ws-x-an-as4-implementation-at-cisco
http://www.oagi.org/oagi/Website/Case_Studies/OAGIS_AS4Cisco-final-1.pdf