RE: [soa-rm] Identity

["George Ntinolazos" <georgios.ntinolazos@stratasoftware.com>]

To understand better the concept of identity, I think we need to make a
distinction between design-time and runtime. 

A service definition/specification defines the service Type
(design/development time). It defines an encapsulated piece of software that
offers its functionality through well defined end-points. 

At runtime we should also consider the existence of state associated with
the service (NOTE: state here refers to the information that the service is
managing at runtime, not the requester-provider conversation state). 

To use an example, image a bookTicket service. This service has a service
definition expressed as a service contract (syntax, semantics etc). We can
deploy this same service (definition + implementation) and configure it to
manage different set of data. One service to manage the US tickets and one
to manage Europe/Asia. Looking at just the service description these
services seem to be equivalent.  

While the service description is important, so is the information/data
managed by the service at runtime. The key difference between development
time and runtime is that the runtime service has state. Since we can refer
to the service and the state together, we could call the runtime service, a
service object or service instance. It is these service objects that
actually have an identity.

George

-----Original Message-----
From: Duane Nickull [mailto:dnickull@adobe.com] 
Sent: 10 May 2005 16:17
Cc: SOA-RM
Subject: Re: [soa-rm] Identity

What about from the Service providers point of view?  I definitely think 
that identifying service consumers is not required in all cases, however 
service providers have some form of implied identity.

The expedia example however does raise the question of would you use the 
site to book a trip if you could not identify it was Expedia's site? If 
just before you were going to give them your credit card, it jumped to a 
different domain name?   Identity is implied by the URL resolution 
process, which in itself places a great deal of security requirements on 
the entire DNS process.

I am not thinking so much in terms of a service consumer as I am the 
service provider.  Ajay made the point in his presentation that it would 
be mandatory to be able to ascertain to some degree that the service you 
are going to use is the one you want to use.

I would at least like to mention it in the RM as an aspect (perhaps just 
in passing).  To me, the Service description is probably where a service 
provider could make a statement of claim regarding their identity and 
perhaps supply a token, even as simple as a URI, to provide proof.

anyone else?

Duane

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