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Subject: Re: [wsrm] What about this tradeoff solution for the persistenceissue?
Paolo Romano wrote: > > >>I don't understand why we should specify >>the crash tolerance level in a message. >> >>My understanding is that WS-RM relys on message parsistance to achieve >>the three functionalities (i.e., guaranteed delivery, duplicate elimination, and >> >> >message > > >>ordering). If it is true, the specification "mustpersist=false" does not make >> >> >sense > > >>since, without message persistance, WS-RM does not provide any reliability. >> >> > >As Sunil pointed out we exstensively discussed about this point in F2F, but I do >not think we reached an agreement. In fact, also when the protocol state (i.e. >the information concerning the exchanged messages) is stored in a non persistent >way, some additional reliability guarantees are still provided by ws-rm, when >compared to classic TCP based protocols: that is, applications relying on ws-rm >are guaranteed that their messages will be delivered in face of communication >channel failures. This use case is common in wireless environments, and was >originally presented by Nokia members. > >Even when you choose to persist, in fact, ws-rm still can fail to provide >reliable messaging, simply because, whatever redundancy you can imagine, you >still cannot exclude a priori the event of persistent storage failures. >In other words, since ws-rm is not a stateless protocol, it can not be crash >tolerant in case of persistance storage failures. > > It is my understanding that in these cases the protocol will fail, but the user will not get a positive ack in such cases. I do not recal us agreeing on sending persistence level as a message parameter. If fact the way we defined persistence, and the decision not to define Persistent storage, was done to avoid such a new level parameter. Tom Rutt Fujitsu trutt@fsw.fujitsu.com
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