W3C home > Mailing lists > Public > xml-dist-app@w3.org > February 2001

RE: Thoughts about path and intermediaries

From: Marc J. Hadley <marc@hadleynet.org>
Date: Wed, 14 Feb 2001 12:32:00 -0000
To: <xml-dist-app@w3.org>
Message-ID: <LMBBKHOODJHIHAMKNKMCOEEKCGAA.marc@hadleynet.org>
> >* There have been suggestions to move back to a single hop
> >protocol, putting all path-like notions at a higher level, and
> >Henrik suggests (I
> >think) to do about what SOAP does today.  My view:  if path is
> >application level, then I'm not sure why SOAP-ENV:actor isn't
> >as well.  Given that SOAP deals at the level of naming
> >intermediaries and targeting headers to them, that's very
> >close to the level at which you worry about getting to the
> >intermediaries in the wrong order.  It feels to me as if actor
> >and header-path come more or less together.
>
> SOAP takes the approach of defining targeting but not the path itself.
> This allows us to support all of the above message path models directly
> within the SOAP processing model but it doesn't actually require any of
> them to be used. This enables us to bound SOAP to as diverse protocols
> like HTTP, SMTP, TCP, UDP, etc.
>
I remain confused as to why a sender would want to include headers targeted
for a given intermediary without being able to specify a path to ensure that
the nodes hosting each intermediary are visited. If the sender doesn't
specify a path then it will need to have a-priori knowledge (or just faith)
that the initial intermediary will "do the right thing" with the message to
ensure that all headers targeted at intermediaries located on other nodes
are processed. If the sender doesn't know which intermediaries will be
visited beyond those located at the first node then why would it bother to
insert headers targeted at intermediaries not located there ?

I think what I'm trying to say is that targeting without path information is
fine for a single-hop based protocol, but not really enough for multi-hop
use.

Marc.

---
Marc Hadley <marc.hadley@uk.sun.com>
Received on Wednesday, 14 February 2001 07:35:41 GMT

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