RE: Intermediaries

Where do gateways fit into this?  Beyond the scope of intermediaries?
If so, what is the distinction that puts them outside the scope.

By "gateway" I have in mind, for example, a company that provides, as a
service, the collecting of purchase requests from client companies and
the sending of the required purchase request to vendors, handling  along
the way security, tracking, and so on.

-----Original Message-----
From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org] On
Behalf Of Champion, Mike
Sent: Friday, December 05, 2003 3:10 PM
To: www-ws-arch@w3.org
Subject: RE: Intermediaries



 

> -----Original Message-----
> From: Cutler, Roger (RogerCutler)
> [mailto:RogerCutler@chevrontexaco.com] 
> Sent: Friday, December 05, 2003 3:37 PM
> To: Ugo Corda; Francis McCabe
> Cc: www-ws-arch@w3.org
> Subject: RE: Intermediaries
> 
> 
> Yes -- is it possible that the issues that you are trying to
> raise with respect to intermediaries are beyond a reasonable 
> scope for the present effort, given the practical limitations 
> of time and personnel?

I for one am becoming less and less convinced that the idea of
"application defined equivalence" to distinguish intermediaries from
"regular" web services is productive.  

I think it would be desireable to identify the various senses in which
"intermediaries" is used in the web services context. As far as I can
tell, the only thing that distinguishes any kind of intermediary is that
it is both a message receiver and a message sender.  We have at least
the
following:

"Underlying protocol" [I fear to say "transport"] intermediaries that
help move bits around efficiently, e.g. TCP/IP routers, HTTP proxies and
caches.

"message intermediaries" that perform some MOM-level service such as
gateways between HTTP and MQ, routers that send a message to the
geographically appropriate destination,  or perhaps those that handle a
protocol such as WS-ReliableMessaging.  These make sure that SOAP
messages (as opposed to bits) are delivered to the correct ultimate
receiver node.

"service intermediaries" provide higher-level services such as policy
enforcement.  WS-Security aware Firewalls are an obvious example, as
would be the SOAP Primer example of an intermediary that quietly changes
business class reservation requests to coach class if an
application-level policy requires it.

Received on Friday, 5 December 2003 16:52:21 UTC