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Re: Protocol independence and application protocols

From: Geoff Arnold <Geoff.Arnold@Sun.COM>
Date: Wed, 16 Apr 2003 12:50:46 -0400
To: Mike Champion <mc@xegesis.org>
Cc: www-ws@w3.org
Message-id: <921895F9-702B-11D7-BB69-000393C53568@sun.com>

+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.
>
Received on Wednesday, 16 April 2003 12:50:49 GMT

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