OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

ebsoa message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: Re: [ebsoa] Does SOA Require Registry-Based Dynamic Discovery?


No it does not IMO.

The SOA Manifesto

When we elected to pursue the SOA reference model, we started analyzing 
architectures that claim to be SOA and looked at the abstract elements 
that are present in 100% of all SOA's. There is a concept of service 
advertisement - a concept of advertising the service description 
(including contract) to the community of potential service consumers. 
This could be implemented as a registry but that limits the wire format 
to a push or pull mechanism. If we want to support multi-cast and 
broad-cast (think how Blue tooth components advertise to each other) 
then a registry or directory may not be the ideal mechanism. A P2P 
broadcast protocol does have advantages in certain implementations.

Now - that is the reference model answer. If you ask the question in the 
context of web services or ebXML, then the answer may be different. 
ebXML does require a registry currently, according to the architecture. 
This in itself may be wrong and not applicable to all ebXML 
implementations. It is possible to have a CPP on a file server somewhere 
rather than a full blown architecture including a registry. IMO - the 
current architecture should be updated to reflect this.

Also - web services do not require the use of a UDDI directory. You can 
simply analyze WSDL instance files to determine binding parameters to 
invoke/consume a service.

There are 5 basic components of SOA that we have identified at this 
time, although at an abstract level, there may only be 4 since the 
contract details may be deemed part of the service specification 

What are the elements of the SOA RM?

· Services

· Advertisement & Discovery Mechanism

· Specification of services (including security parameters & 
constraints, reusability & repurpose-ability).

· Specification of associated data model.

(optionally) an explicit contract offer

Q: What is the SOA Reference Model?

A: The SOA reference model is a framework for understanding significant 
relationships among the entities in a service oriented environment, and 
for the development of consistent standards or specifications supporting 
that environment. The SOA reference model is based on a small number of 
unifying concepts and may be used as a basis for education and 
explaining standards to a non-specialist.

Q: How does the SOA RM relate to the pattern concept?


Q: How does “infrastructure” fit into the reference model?

A: The reference model’s purpose is to act as a guide for those 
designing an SOA infrastructure.

Q: Does the SOA reference model require definition of core infrastructure?

A: No.

Q: What is a service?

A: A service is a contractually defined behavior that can be implemented 
and provided by a component for use by any component solely based on the 

Q: What is advertising?

A: Service must somehow communicate its service descriptions in a manner 
that is accessible to potential consumers.

Q: What is discovery?

A: A potential consumer obtains information about the existence of a 
service and its applicable parameters / terms. Discovery does not 
constitute authorization to execute against the service.

Q: What does specification of services mean?

<>A: Technical parameters, constraints, policies that come together to 
define terms of invocation.

The latter may also include the contract so we still have lots of 
analytical work to do.

Duane Nickull

Senior Standards Strategist - Adobe Systems, Inc. - http://www.adobe.com
Vice Chair - UN/CEFACT Bureau Plenary - http://www.unece.org/cefact/
Chair - OASIS eb SOA TC - http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ebsoa

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]