Re: [ws-rx-implement] Queries on interop doc

[Matthew Lovett <MLOVETT@uk.ibm.com>]

Hi all,

I think that Dan raised some interesting
points here. Any of the other implementors care to comment? My comments
are inline....

Daniel Millwood/UK/IBM@IBMGB wrote on 06/02/2006
16:53:27:

> 
> 
> 
> 
> Hi all,
> 
> A couple of queries on the interop doc.
> 
> In scenario 2.1, it states that when the service has sent all of the
> replies and received all of the acknowledgements for those replies
it will
> send a TerminateSequence to the client.  Given that the client
can send a
> varying number of requests (between 1 and 3 messages) to the service,
how
> is the service supposed to know when it can terminate the offered
sequence?
> Is it really expected to compare the number of inbound requests with
the
> number of outbound responses?  This requires a relationship between
the two
> sequences that is not defined.

+1: The terminate from service to client seems to
rely on the assumption that the sequences are linked, which contradicts
the main spec. This raises questions about managing the lifetime of offered
sequences, and how we should handle them in an interoperable way.

Perhaps one option would be for the client to inform
the server that the sequence was now closed (e.g. send a sequence closed
fault), and then terminate it (send a sequence terminated fault). Of course,
if the service were using the sequence to carry some other messages to
the client then the close operation could lead to the service needing to
allocate some messages back into a new sequence... but it will work fine
for most real-world cases.

> 
> The clients terminateSequence message example is also missing from
this
> scenario.

+1

> 
> Secondly,
> 
> As the resolution of issue i090 on offered sequences has not been
resolved
> yet, I wanted to highlight the way in which offered sequences are
used in
> the proposed scenarios.
> 
> Ive used the following notation to differentiate the client at the
RMS and
> the server at the RMD.
> 
> RMS  ------------ outbound sequence   ------> RMD
> RRMD <-------  offered sequence   ------------ RRMS
> 
> In scenario 2.1, where offer is used, the ReplyTo EPR in the CS message
> from the RMS is http://client-machine/RMreplies.  The application
replies
> need to be sent to http://client-machine/replies.  So in this
case, the
> offered sequence cannot be correlated against any EPR from the CS
message,
> so either a relationship is assumed between the outbound and offered
> sequences or some out-of-band exchange is required so the RRMS knows
which
> sequence to use.
> 

This seems to be a symptom of offered sequences being
underspecified. I hope that we get to discuss this on the interop call,
as discussion of this specific case could lead into the issue discussion
for i090 during the main TC call.

> In scenario 2.2 where there is no offer, the
CS message from the RRMS to
> the RRMD is sent to the ReplyTo from the EchoString
> http://client-machine/replies.  Application messages are sent
to the same
> address.
> 
> In scenario 2.3, where the offer is rejected, the CS message from
the RRMS
> to the RRMD is sent to the ReplyTo from the application message
> http://client-machine/replies.  Application messages are sent
to the same
> address.
> 
> Thoughts?
> 
> Thanks,  Dan
> 
> WS-Reliable Messaging Architect and Team Lead
> IBM WebSphere Messaging Design and Development
> MP 211
> Hursley
> Tel. Internal 248617
> Tel. External +44 1962 818617
> Email. millwood@uk.ibm.com
> 
> 
> 
>                    
                     
                     
           
>              Matthew    
                     
                     
      
>              Lovett/UK/IBM@IBM
                     
                     
>              GB      
                     
                     
      To 
>                    
                   ws-rx-implement@lists.oasis-open.or
>              06/02/2006 14:34  
       g            
                     
>                    
                     
                     
        cc 
>                    
                     
                     
           
>                    
                     
                     
   Subject 
>                    
                   [ws-rx-implement]
Updated scenarios 
>                    
                   doc
                     
          
>                    
                     
                     
           
>                    
                     
                     
           
>                    
                     
                     
           
>                    
                     
                     
           
>                    
                     
                     
           
>                    
                     
                     
           
> 
> 
> 
> 
> 
> Hi all,
> 
> I have made the updates to Scenario 2.2, and added Scenario 2.3. The
new
> doc is attached - please let me know if I should be uploading it somewhere.
> 
> 
> 
> 
> Thanks
> 
> Matt
> [attachment "InteropScenarios.doc" deleted by Daniel Millwood/UK/IBM]
>