Re: [ws-rx] PR issue 09

[Christopher B Ferris <chrisfer@us.ibm.com>]

+1

Christopher Ferris
STSM, Software Group Standards Strategy
email: chrisfer@us.ibm.com
blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
phone: +1 508 377 9295

Paul Fremantle <paul@wso2.com> wrote on 10/31/2006
02:04:24 AM:

> Jacques
> 
> Let us take a concrete example. Suppose there was a third-party defined
> an extension to CreateSequence that specified InOrderExactlyOnce.
> 
> If the RMD specifies this, as we know from extensive discussion, there
> is no change to the wire protocol. Therefore there cannot be interop
> problems even if the client doesn't understand the extension.
> 
> If the specifier wants the RMS to be able to force this, then they
need 
> to specify the extension correctly. In general we do not have 
> client-side policies, so the extension would need to be specified
so 
> that the RMD responded to say it had accepted that model. If the RMD
> didn't understand the extension, it won't respond.
> 
> At one point we discussed making any extensions of CS mustUnderstand.
> Would that help allay the concerns of this group?
> 
> Paul
> 
> Durand, Jacques R. wrote:
> > Paul:
> >
> > Let me reword one of the concerns I see in the eAC comment:
> >
> > - because DAs are not specified - although often expected, as
our
> > charter recognizes - some WS-RM implementers may be led to establish
a
> > proprietary way to do it that requires use of extensibility points
in
> > the RM protocol, for signaling these DAs or parameters of these
DAs.
> > This way could become a de-facto standard for a significant part
of the
> > market (just an hypothesis, but quite possible).
> >
> > - if this happens, there would be interop issues with other RM
endpoints
> > that may not support these extensions, when you look at the bigger
> > picture (RM protocol + DAs) even though you may still have
> > interoperability at RM protocol level alone, since an RMD/RMS
may ignore
> > any extension. In case these other implementations want to align
with
> > the practice, besides the trouble in upgrading already deployed
> > products, there might be unexpected IP issues.
> >
> > So the worst interoperability scenario for those who need to
communicate
> > DA data, would be if sometime later this comes to affect implementations
> > of the lower protocol layer - RMS/RMD.
> >
> > Short of specifying DAs somewhere (and the way to communicate
them) I
> > see no good solution for preventing this scenario except getting
rid of
> > extensibility points... 
> >
> > Jacques
> >
> >
> >
> > -----Original Message-----
> > From: Paul Fremantle [mailto:paul@wso2.com] 
> > Sent: Thursday, October 26, 2006 4:23 PM
> > To: Durand, Jacques R.; ws-rx@lists.oasis-open.org
> > Subject: Re: [ws-rx] PR issue 09
> >
> > Jacques
> >
> > I understand what you are saying. I'm trying to understand how
we would 
> > prove something so obvious :-)
> >
> > Our protocol ensures that the messages are correctly transmitted
to the 
> > RMD together with a message number, which increases by one.
> >
> > So even if we did define this in our specification, the text
would sound
> >
> > pretty lame:
> >
> > i.e.
> > "To achieve the "ordered delivery" delivery assurance,
the RMD must 
> > deliver the messages in the order of the MessageNumbers."
> > "To achieve the AtMostOnce delivery assurance, the RMD must
only deliver
> >
> > one message with a given MessageNumber"
> > "To achieve the AtLeastOnce delivery assurance, the RMD
must ensure that
> >
> > it delivers each transmitted message with a given MessageNumber."
> >
> > As regards your second point, I have some sympathy for that.
> >
> > Paul
> >
> >
> > Durand, Jacques R. wrote:
> >   
> >> I think the issue is not so much "how can I implement
my DAs on top of
> >>     
> >
> >   
> >> this protocol" . Many folks in eAC are quite experimented
with RM and 
> >> have known sequence numbers way before WS-RX started.
> >>
> >> But without going as far as bringing back the DAs, at a minimum
it 
> >> would be helpful to demonstrate the following, either in
the spec 
> >> (appendix) or in a companion doc:
> >>
> >> - whatever DAs (among most popular ones) are defined on top
of this 
> >> protocol, and assuming both sides are aware of which DA is
being used 
> >> (communicated out of band), then the protocol as defined
is sufficient
> >>     
> >
> >   
> >> to *enable* the DAs and does not need additional interoperability
> >> tightening or extensions when actual DAs are implemented.
Were it 
> >> otherwise, it would mean that proprietary extensions to the
protocol 
> >> are needed that would introduce both interop and IP issues.
> >>
> >> Now that probably isn't enough to make everyone happy. Standard
DAs to
> >>     
> >
> >   
> >> choose from, along with their parameters, are still expected
from some
> >>     
> >
> >   
> >> users and are considered as part of the interop equation.
But wherever
> >>     
> >
> >   
> >> these are defined - either wsrmp or elsewhere - it is important
to 
> >> show first that this has no bearing on the wsrm protocol
layer and its
> >>     
> >
> >   
> >> implementations, i.e. this layer can be considered stable.
> >>
> >> -Jacques
> >>
> >>     
> >
> >   
> 
> -- 
> Paul Fremantle
> VP/Technology and Partnerships, WSO2 
> OASIS WS-RX TC Co-chair
> 
> http://bloglines.com/blog/paulfremantle
> paul@wso2.com
> (646) 290 8050
> 
> "Oxygenating the Web Service Platform", www.wso2.com
> 
>