FAQ suggestion

[Keith Swenson <KSwenson@fsw.fujitsu.com>]

Title: FAQ suggestion

I have just recently become aware of WSDM another OASIS TC on the subject of Web Services Distributed Management.  This came up when I mentioned that ASAP would 'start and monitor services'.  It seems clear to me that ASAP is dealing with 'service instances' which is different from underlying service (aka service-type or service-definition).  But there is a lot of overlap in the terminology; there is a lot of potential for people to misunderstand ASAP as being a 'management' API.  We need to be clear.

I believe we need a FAQ entry explain how ASAP is different from WSDM.

Actually, we need a FAQ.  We have none yet.  I don't know the mechanism of getting the FAQ on the web site.  But since I opened my mouth about the missing FAQ, let me submit the following proposal for a FAQ (hopefully this is correct?):

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How does ASAP differ from WSDM?

WSDM is an OASIS working group for "Web Services Distributed Management".  This group is working on management from a systems management perspective.  Web services manageability is defined as "a set of capabilities for discovering the existence, availability, health, performance, and usage, as well as the control and configuration of a Web service within the Web services architecture."  This would clearly be used by a person who has priveledged access to the services.  The performance, health, and usage statistics is information that would be interesting only to a person responsible for the physical implementation of the system. One would not want to open up this information for average end users.

ASAP on the other hand is a technique for creating "service instances" in order to perform a task for the requesting user.  This is not a priveledged access to internal information, but rather the way to access the main functionality of the web service designed to be used by programs that represent end users.  ASAP is oriented toward monitoring an instance of a service, not the overall health of the service.

While the terminology and some of the concepts of WSDM and ASAP overlap, the goals and the usage of the two different protocols is different.  We hope the two group will work in a concerted manager to coordinate as much as possible these two separate specifications.

How is WS-CAF related to ASAP?

The Web Services Composite Application Framework is another OASIS working group started recently to standardize certain types of web service interactions. WS-CAF is aimed to handle the problem of how to contact multiple web services, and to coordinate these interactions.  In essence, it is to allow multiple web services to act as if they were part of a single composite application.  Their layered approach includes, in the top level, support for transactional consistency between the web services.

ASAP is answering the need to be able to start a service at one point in time, and then come back later to check on the status.  ASAP also includes a way for the initiator to leave an address for the service to send a notification message back to to tell it that it is completed.  In this nomenclature an "Asynchronous Web Service" is Web Service that implementes standard operations to support starting and monitoring of a task which is expect to take a long time to complete.

The purpose of these two standards efforts are orthogonal to each other.  If you wanted to use ASAP in order to start two different asynchronous services in a coordinated manner, you would use WS-CAF tags in the header of the requests to make sure that either both services are start or neither are started.  This could not be accomplished using ASAP alone.  While WS-CAF allows (different) web services to coordinated, it does not say anything about the actual request that is being made.  ASAP specifies the actual request that must be made to achieve a particular outcome.

The goal then in both groups is to coordinate their efforts to be sure that implementors can use both standards at the same time.

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Keith D Swenson, kswenson@fsw.fujitsu.com
Fujitsu Software Corporation
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