[GRAAP-WG] Modification to the wiki Page on Renegotiating an established Agreement

[parkinm at cs.man.ac.uk]

Dominic,

Sorry, I missed a step so I withdraw one of my questions below...

On Aug 28 2007, parkinm at cs.man.ac.uk wrote:
 
> On Aug 27 2007, Dominic Battre wrote:
>  
> > Thank you very much, Karl, for giving a lot of insight what is behind
> > WS-Agreement.
> > 
> > > Furthermore, 2PC can be synthesized with two WS-Agreement round-trips
> > > and an appropriate domain-specific agreement semantics. So, either
> > > advance reservation, combined with the right cost/penalty model, or
> > > the underlying invitation system can both look like 2PC in practice:
> > 
> > I tried to digest that and this is what I came up with:
> > 
> > https://cit-server.cit.tu-berlin.de/trac/negmgr/wiki/TwoPhaseCommit
> 
> Between step 5 and 6 of this protocol, how long does the provier wait 
> for a response? As there is no facility for the user reject an offer in 
> this protocol and let the provider know it doesn't want the advance 
> reservation - the provider must specify a time limit to the offer, no? As 
> was said in an earlier email - you can't assume agreement is going to 
> happen...


Sorry, please ignore this comment - I just saw the "User can cancel advance 
reservation offer for cheap fee" step.


> Also, what happens if between step 5 and 6 another user wants to reserve 
> the same resources? What does the provider do then?
> 
> As I mentioned in a previous email, the provider cannot offer those 
> resources to the second user because if the first user accepts and the 
> second user acccepts too, there is a problem of overcommitment of 
> resources.
> 
> 
> > (I used my wiki because it supports tables)
> > 
> > It would be great, if you could have a brief look at it and tell me
> > whether this is what you had in mind.
> > 
> > 
> > If some people want to contribute, I'd be interested in starting to
> > write a "Best Practices in WS-Agreement" / "Design Patterns in
> > WS-Agreement" / "WS-Agreement cookbook" / ... document.
> 
> Yes, I am interested.
>  
> > This issue of 2PC for example would be a good candidate for such a
> > document. I think it would really help if we find a place to collect
> > examples, approaches of modeling something, approaches of implementing
> > something, ...
> > 
> > I could easily contribute lots of questions but maybe some answers as 
> > well.
> 
> Thanks,
> 
> Michael.
>