Conversational Service Interactions
written by gunther gerlach-2009
Internet commerce has created newer forms of service interactions than traditional marketplace transactions. Amazon/UKOnline, single-consumer-to-service transactions – e.g., making customer listings, doing basic look-ups and verification checks, and purchasing goods – are giving way to more distributed, pull-oriented and data streaming modes of interaction on the web. Marketplace auctions, voting, and subscription-based RSS feeds are enhancing wider spans of participants and semistructured, audio and video data in conventional transactional forms.
In larger environments with long-running transactions in supply/production chains, process-based web services orchestration techniques are utilized. WS-BPEL is a developing standard with support in various commercial tools such as Oracle BPEL, Microsoft BizTalk, and SAP’s ccBPM tool. It allows the ordering of web service interactions to be captured through single-party process models. External interactions are captured through outgoing and incoming messaging operations in the model. In addition, support for multi-party collaborations through global model definitions has received attention in the context of W3C’s Web Services Choreography Description Language (WS-CDL) initiative.
Despite the fact that web service ecosystems are garnering large-scale and diverse exposure of services, executable modeling languages like WS-BPEL, ebXML/BPSS, WSCL, WSCI, and the more recently developing WS-CDL, have not as yet been exploited in these environments. Greater flexibility and productivity are available for service providers to enrich services in collaboration with other services providers through graphical service compositions. Even more radical, graphical tools could foster personalized, end-user composition of web services.
As the value of process composition filters out to the “dotcom” world, certain challenges will have to be overcome in order to harness orchestrated and choreographed service interactions with marketplace-style transactions. Does the single point of payment still hold for long-running processes? Will one-off authentication still hold? It is doubtful, considering that different paths with different service provisions can be taken through branching in processes. Different payment points – indeed, pay-as-you-go – should be expected. Such transactions could not be expected to cover single sessions, and more systematic ways of handling authentication and access control need to be factored. From a security perspective, longevity of process leads to the issues of trust chains and delegated access. How critical security considerations can sit seamlessly with BPM is still the subject of ongoing research.
The issue of assimilating process composition into “dotcom” transactions provides a touchstone in further considerations symbiotic with the web. The first generation of service provision on the web has seen a stove piping between service interactions and information search. Information relevant to services, as they are being utilized, is dispersed on the web. The bridge yet to be crossed for service ecosystems is how information ecosystems can be tapped to filter out timely and relevant information associated with a running service.
In general, increased efforts to harmonize different realms on the web can be expected. Google has signaled its pursuit of bringing greater coherence of information, service, geospatial and temporal sensitivity, and desktop/office. At the same time, initiatives like Digital City are expanding the service and information ecosystem reach to material interaction. Motivating applications include vehicle guidance, remote access to public instruments, and home devices (electricity meter readings) from utility service providers.
Published by. BPTrends November 2005
