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Subject: Re: [ws-rx] Issue 050


Tom Rutt wrote:

typo I corrected it below

the sentence should read:

A sender may not be willing to have its  messages  experience the delay 
associated with reliable ordered delivery for some operation types
(subsuequent successfully received messages must be buffered by RMD for 
delivery after the missing prios message is received and delivered)..

> Jacques Durand wrote:
>
>> Duane:
>>
>> None of what you say seems to invalidate my points which only state 
>> very precise facts :
>>
>>  
>>
>>    1. The DAs as described in our charter are not only different from
>>       those defined in WS-RM spec, but at least 2 of them are
>>       meaningless given the vagueness of "transferred".  This confirms
>>       my opinion that a charter is good at scoping the work but is no
>>       substitute for definitions that belong to a detailed spec. Now
>>       if we are to remove any other mention of DA beside those in the
>>       charter, then allow me a naïve question: "what is it that our
>>       protocol is trying to support exactly?"
>>    2. InOrder (as defined in WS-RM spec) requires two conditions in
>>       addition to the use of the protocol: (a) messages are numbered
>>       by RMS in same order they are submitted ("sent"), (b) messages
>>       are delivered by RMD in same order as they are numbered. Just
>>       saying this, no more no less. You can make of (a) an invariant
>>       of RMS behavior if you like, so that the Source side does not
>>       have to be aware of this DA - fine. But if that is not stated as
>>       part of the "protocol" spec, then RMS must be made aware of 
>> this DA.
>>
> As I stated in my last email, in response to Duane, while the source 
> does not have to be aware of the DA for the protocol to work if we 
> give it enough global invariants, it may still care that a particular 
> DA is in use, since it impacts the end to end behavour of the message 
> exchange.
>
> a sender may not be willing to have its  messages  experience the 
> delay associated with reliable ordered delivery (subsuequent 
> successfully received messages must be buffered by RMD for delivery 
> after the missing prios message is received and delivered).
>
> Tom
>
>>   1.
>>
>>
>>  
>>
>> Jacques
>>
>>  
>>
>> ------------------------------------------------------------------------
>>
>> *From:* Duane Nickull [mailto:dnickull@adobe.com]
>> *Sent:* Wednesday, November 09, 2005 1:49 PM
>> *To:* wsrx
>> *Subject:* RE: [ws-rx] Issue 050
>>
>>  
>>
>> Jacques:
>>
>>  
>>
>> My $0.02 worth on this topic is that all we can really do in this 
>> spec is to ensure that the RMS's understanding of the ordering of 
>> messages (as intended by the AS) is conveyed to the RMD.  Anything 
>> else is either out of scope or worse, violates opacity, one of the 
>> core tenets of SOA and WS.  There are several assumptions that have 
>> to be made in this, but the mechanics of which cannot be placed in 
>> the spec.
>>
>>  
>>
>>    1. That the AS will accurately convey the proper information to the
>>       RMS.  We should not attempt to specify any messages or
>>       mechanisms to do that.
>>
>>  
>>
>>    2. The RMD will receive and be able to reconstruct the streams as
>>       they left the RMS or in the alternative, throw a fault.  This
>>       must be fail proof. Due to the semantics described in our spec,
>>       the RMD will be able to understand the ordering/delivery
>>       intentions of the RMS (which we must assume is in alignment with
>>       the AS).  The RMD does not see or care about the RMS- AS
>>       relationship.
>>
>>  
>>
>>    3. The RMD is able to convey the "ordering intentions" of the RMS
>>       to the AD (based on the fact that we have a mechanism in the
>>       WS-RX protocol to convey it).  We should not specify any
>>       mechanics/encodings for this including whether or not messages
>>       are delivered in order (our charter forbids this).  What really
>>       matters is that the AD has access to the intentions.   If we
>>       word this as "messages are transferred in order..", that IS a
>>       mechanism from RMD to AD and violates our charter.
>>  
>>
>> Accordingly, a runtime DA is not really needed.   Chris Ferris and I 
>> (and others) have been trying to explain this, perhaps poorly.  We 
>> have to assume that both the AS-RMS and RMD-AD relationships are 
>> sound but not try to assume any specific details.  It really doesn't 
>> matter since if the intentions of the service as a whole are not met, 
>> the invocation should fail.
>>
>>  
>>
>> Chris states:
>>
>>  
>>
>> "As I have tried, apparently unsuccessfully, in the past to 
>> explain... regardless of the DA
>> in force, in effect or observed at the RMD, the source CAN ONLY know 
>> which messages have
>> been received. It can make NO assumptions (unless it wants to succumb 
>> to the Felix Unger
>> ass-u-me adage) as to which messages have been or ever will be 
>> "delivered" to the AD."
>>
>>  
>>
>> Any wording such as "...Messages are "transferred" in order..." 
>> specifies an assumption of a specific mechanism behind a service 
>> boundary, something which I do not like.  We should not constrain all 
>> applications to serial processing only based on message reception 
>> events.  Many, including myself, would probably prefer to architect 
>> serial processing of the message payloads, but not constrain that 
>> they have to be actually delivered in serial order.  This is a bad 
>> practice as it creates an unnecessary dependency on the base 
>> transport routing between RMD and AD and also adds a requirement for 
>> some form of RM behind the service to detect out of order messages.  
>> A far more elegant solution would be for the RMD to convey the 
>> ordering information to the AD, deliver the messages in whatever 
>> sequence it likes and let the AD use that information to do its' job 
>> or processing them correctly.  We should assume that people 
>> implementing this are not idiots and will take proper precautions in 
>> the manner they feel is best and not constrain behavior behind 
>> firewalls.
>>
>>  
>>
>> Duane
>>
>> ------------------------------------------------------------------------
>>
>> *From:* Jacques Durand [mailto:JDurand@us.fujitsu.com]
>> *Sent:* Tuesday, November 08, 2005 7:05 PM
>> *To:* Duane Nickull; Yalcinalp, Umit; wsrx
>> *Subject:* RE: [ws-rx] Issue 050
>>
>>  
>>
>> (assuming this is the right thread for this... can't say I am as lazy 
>> as some Canadians for an excuse ;-)
>>
>>  
>>
>> As far as I can tell, there are two proposals on the table for i050: 
>> both consist of removing DAs from "this" protocol specification, yet 
>> they are very different:
>>
>>  
>>
>> 1-       Proposal currently logged with the issue def: DAs are simply 
>> moved to another document(s):
>>
>>  
>>
>> (a)     Remove all references to delivery assurances from the WS-RM spec
>>
>> (b) Describe, in detail, DA's in the policy spec (since we're adding 
>> an Assurances element to that document anyway).
>>
>> (c ) Create a new deliverable for the TC; a profiles document. The 
>> profiles would describe how the protocol should be used to implement 
>> the various delivery assurances
>>
>>  
>>
>>  
>>
>> 2-       The one informally proposed in October discussions:
>>
>> That any mention of DAs be removed altogether from any doc produced 
>> by this TC (if I interpret well)
>>
>>                       
>> I would consider (2) only if I were convinced that the protocol 
>> specification **really** supports the DAs that we are after all 
>> chartered to support, and if these DAs were defined in an unambiguous 
>> way for a starter. Two examples of why I think it is premature to 
>> shut down any talk on DA at this stage:
>>
>>  
>>
>> - I note that InOrder is defined differently in our charter 
>> ("Messages are transferred in the order in which they are sent")  and 
>> in our draft ("..delivered in the order in which they are sent"). I 
>> do not consider a charter a precise-enough doc to look for an 
>> accurate definition of what we really are supposed to enable in a 
>> final spec. DAs have to be more accurately defined somewhere else.
>>
>>  
>>
>> - at this time I'm not convinced that InOrder will work if defined as 
>> purely an RMD/AD contract. For this to work out, more needs to be 
>> done, e.g. there must be a requirement (today absent) for the RMS to 
>> assign sequence numbers to messages in the order they have been 
>> submitted (sent), which is an obvious precondition for the order to 
>> be restored on destination side (hint: that looks to me like an 
>> AS/RMS contract...).
>>
>>  
>>
>>  
>>
>> Jacques
>>
>>  
>>
>> ------------------------------------------------------------------------
>>
>> *From:* Duane Nickull [mailto:dnickull@adobe.com]
>> *Sent:* Friday, November 04, 2005 4:48 PM
>> *To:* Yalcinalp, Umit; wsrx
>> *Subject:* RE: [ws-rx] Issue 050
>>
>>  
>>
>> Pure laziness.  Rather than make a new email I simply copied an 
>> existing one and replied.  While I changed the thread subject, I did 
>> neglect to delete the existing text in the body. It is gone now.
>>
>> Most Canadian are lazy.  I am no exception. What can I say ;-)
>>
>>  
>>
>> May I ask why you not support the first proposed resolution?  I would 
>> be interested in hearing a counter argument for keeping it.
>>
>>  
>>
>> Thanks
>>
>>  
>>
>> Duane
>>
>>  
>>
>>  
>>
>> ------------------------------------------------------------------------
>>
>> *From:* Yalcinalp, Umit [mailto:umit.yalcinalp@sap.com]
>> *Sent:* Friday, November 04, 2005 4:18 PM
>> *To:* Duane Nickull; wsrx
>> *Subject:* RE: [ws-rx] Issue 050
>>
>>  
>>
>>  I am not sure why this is put forward in this thread, but
>>
>>  
>>
>> A big -1.
>>
>>  
>>
>> --umit
>>
>>  
>>
>>     
>>     
>> ------------------------------------------------------------------------
>>
>>     *From:* Duane Nickull [mailto:dnickull@adobe.com]
>>     *Sent:* Friday, Nov 04, 2005 10:27 AM
>>     *To:* wsrx
>>     *Subject:* RE: [ws-rx] Issue 050
>>
>>     After more contemplation, I would like to suggest we accept Marc's
>>     proposal #1 WRT 050.  Remove all DA's from the spec.
>>
>>     
>>     Duane
>>
>
>


-- 
----------------------------------------------------
Tom Rutt	email: tom@coastin.com; trutt@us.fujitsu.com
Tel: +1 732 801 5744          Fax: +1 732 774 5133




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