

RE: requirements summary

From: Ricky Ho <riho@cisco.com>
Date: Tue, 25 Mar 2003 09:57:41 -0800
Message-Id: <>
To: "Jean-Jacques Dubray" <jjd@eigner.com>
Cc: <public-ws-chor@w3.org>

JJ, comments inline

>A binary collaboration can easily be used as part of an agreement, as
>well as to configure run-time engine that "monitor" the choreography
>(firewall concept).

I think the "monitor" doesn't restricted to binary collaboration.  It 
applies to multi-party as well.

>In the case of a multi-party, we might want to ask whether the goal is
>simply to represent what is going to happen such that each party can
>infer what they need to do. Hence decompose the multi-party into
>bilateral behavior (which will itself be decomposed in unilateral

Decomposing multi-party into bi-party may lost some information about 
dependencies (see the doctor/patient use case) and is not always possible.
I'm not sure I understand "unilateral behavior", sounds like it is a 
private implementation.

>Is there a need to establish multi-party agreements based on a
>multi-party choreography definition?

I guess a multi-party choreography is only useful when all defined roles 
agree to conform to.  So this is a multi-party agreement.

>At the run-time engine level, things gets far more complicated because
>unless there is a party that touches all the "bilateral choreographies",
>it is impossible without special run-time to "monitor" the multi-party
>choreography. So the question arise, is the goal of a multi-party
>choreography specification to allow configuration of run-time engines?

I think it is possible to monitoring all traffic pattern of a single party 
conforms to a multi-party choreography.  (you still need to have 
multi-party definition to do that).  If every party agrees to put a 
monitor, then you certainly can get the whole picture.  But even monitor 
one party can provide high value.

>In think in the light of this, we should not conclude that binary is a
>special case of multi-party. They may well have both distinct features
>(control flow?) and applications.

Does multi-party covers the case when N = 2 ?  Is so, then bi-party is a 
special case of multi-party.  But I agree that bi-party may have some extra 
properties (such as a simpler role binding model) that we should take a 
serious look at.

>I am also wondering if the group wants to keep as a requirement that
>says that in the choreography specification there is no distinction
>between the choreography involving "internal" services as opposed to
>external services. A separate layer of the specification should allow
>for annotating that this particular message exchange is external and may
>have more qualifiers. However, at the pure choreography specification
>level, the choreographies should not be distinguished.

If choreography is only meaningful to specify a contract between multiple 
"domain of control", then it should only focus in the message exchange 
across the boundary, which means external services ?  Right ?

Rgds, Ricky
Received on Tuesday, 25 March 2003 12:58:22 GMT
