According to the SOA Reference Model document itself, a reference model is an abstract framework for understanding significant relationships among the entities of some environment. It enables the development of specific reference or concrete architectures using consistent standards or specifications supporting that environment. A reference model consists of a minimal set of unifying concepts, axioms and relationships within a particular problem domain, and is independent of specific standards, technologies, implementations, or other concrete details.
The reference model defines SOA as:
Service Oriented Architecture (SOA) is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains.
Now SOA has a standardized reference model, thanks to the work of OASIS SOA-RM technical committee. According to an email sent to the OASIS Reference Model Technical Committee, Duane Nickull, chair of the TC notified the group's status on the standardization vote as follows:
The Ballot to advance the Reference Model for SOA to become a full OASIS Standard received 89 positive votes, the second highest number of positive votes anyone on the TC can recall being cast to support a standard. The single no vote came from Avaya Inc. The sole statement provided by a representative from that company was:
"Too vague and confusing, e.g. things which are not SOA can be mapped into this and claim they conform to this SOA model."
Despite this sole dissenting vote, the techical committee, after approaching Avaya with a formal letter and expressing an interest to resolve any issues with the spec, the Technical Committee decided to move ahead according to the OASIS rules and move to a standard with a final tally of 89 organizations supporting, one against.
The Reference Model can be downloaded here:
http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=soa-rm