Re: Protocol independence and application protocols

and also for excessively, in fact obscenely, large values of N!

Christopher Ferris
Architect, Emerging e-business Industry Architecture
email: chrisfer@us.ibm.com
phone: +1 508 234 3624

www-ws-request@w3.org wrote on 04/16/2003 12:50:46 PM:

> 
> +N, for large values of N....
> 
> On Tuesday, April 15, 2003, at 08:42  AM, Mike Champion wrote:
> [...]
> I could live with: Although from the underlying protocol's perspective 
> Web services messages might appear to have different meanings depending 
> on which operation is used to move the message body from one network 
> node to another, the WSA takes the point of view that a Web services 
> message has the same meaning irrespective of the mechanism by which it 
> is delivered. This approach, often referred to as "tunneling" one 
> protocol over another, is controversial, and should be undertaken in a 
> specific application only after considering the advantages and 
> disadvantages:
> >
> > Advantages: Messages can be more easily bridged from one underlying 
> > protocol to another in a heterogenous environment .... Development 
> > tools, Web services, and application components can be written to the 
> > XML Infoset and SOAP processing model and abstracting away support for 

> > the underlying protocol(s) ....
> >
> > Disadvantages:  .... [you suggest some, Mark]
> >
> >
> >> it simply does not possess the properties necessary to succeed on the
> >> Internet.
> >
> > Remind me of what those are .... statelessness, visiblity, uniform 
> > interfaces?
> >
> > FWIW, I personally could easily live with the conclusion that 
> > stateful, limited-visibility, heterogenous interface services are most 

> > appropriate for enterprise-scale rather than Internet-scale 
> > deployment.  But since that's where Web services are actually being 
> > deployed today, that's not a problem if the advantages outweigh the 
> > disadvantages.
> >
> > Also, new generations of infrastructure are continually evolving to 
> > mitigate the disadvantages.  For example, application servers evolved 
> > to manage the disconnect between the stateless HTTP servers and the 
> > stateful applications that people wanted to access over the Web; 
> > SOAP/XML-aware firewalls are coming online that exploit the visibility 

> > that XML allows whereas Fielding (AFAIK) assumes that message bodies 
> > are opaque to intermediaries, and WSDL (and potentially RDF-based 
> > description languages) make heterogenous interfaces dynamically 
> > "understandable" [to a limited extent, of course] by both client side 
> > and service-side components.
> >
>