Web Service Description and stateful services

Dear WS-ARCH group members,

the Web Services description is currently defined in the latest Web 
Service Architecture document (1.5.3) as:

"The service description is a machine processable specification of the 
message formats, datatypes and protocols that should be used between the 
requester agent and the provider agent. It also specifies the network 
location of the provider agent, and may provide some information about 
the message exchange pattern that is expected"

In the research community, I've seen some attempt at representing the 
service state by using WSDL extensions, i.e. by extending the web 
service description with attributes that carry the information related 
to the current state of a service. This means that, for each service 
instance, a WSDL document should be created.

I would like to receive your point of view on the following issue. From 
the definition you give, I understand that the service state is a 
concept more related to the service representation (def. 2.2.29), while 
the service description (def. 2.2.32) should describe service interface 
and semantics.

Extending a WSDL document with service representation related data is 
somewhat merging service description with service representation. This 
solution might be handy when you want, for instance, advertise the 
quality related attributes in order to make a QoS based discovery.

 From a Web Service Architecture point of view, how do you deal with 
this issue and the above solution?

Any clarification is appreciated.

Thanks,

Sergio A.



-- 
Sergio Andreozzi

Istituto Nazionale di Fisica Nucleare - CNAF
Viale Berti Pichat, 6/2
40127 BOLOGNA
ITALY

E-mail : sergio.andreozzi@cnaf.infn.it
Website: www.cnaf.infn.it/~sergio

Received on Tuesday, 20 May 2003 07:03:30 UTC