RE: MSC-News: Incomplete messages


Subject: RE: MSC-News: Incomplete messages
From: Dmitry Zhukov (dmjr#ispras.ru)
Date: Thu Aug 20 1998 - 10:41:24 GMT


The originator of this message is responsible for its content.
-----From Dmitry Zhukov <dmjr#ispras.ru> to mscnews -----

Dear Jan,

On Thu, 20 Aug 1998, Jan Docekal wrote:

> It is correct.
>
> Possible interpreatations follows:
>
> Instance A sends message M to instance B. After M is sent, but before M
> is recieved, B is (inexpectedly) terminated. Message B still knows that
> it was on its way to B, but can no longer find it.
>
> I think that the possibility to specify the reciever of the lost
> messages is most useful when making a trace of a system execution,
> rather than when specifying system behaviour.

I agree with you that specifying the receiver of lost messages
is often useful. It is unclear to me, why an *input event* is
specified for the lost message. I think that if both output and
input events are known for a message it is better to use a general
message rather then a lost.

Best regards,
Dmitry.

> > I have a question of incomplete message events in MSC'96.
> > Consider the following example from Recommendation Z.120,
> > section 6.6:
> >
> > msc failure; inst Initiator, Responder;
> > instance Initiator;
> > condition Disconnected shared all;
> > in ICONreq from env;
> > set T;
> > out ICON to lost Responder; /* output event */
> > condition Wait_For_Resp shared all;
> > timeout T;
> > out IDISinf to env;
> > condition Disconnected shared all;
> > endinstance;
> >
> > instance Responder;
> > condition Disconnected shared all;
> > in ICON from Initiator; /* input event */
> > condition Wait_For_Responder shared all;
> > condition Disconnected shared all;
> > endinstance;
> > endmsc;
> >
> > As described in section 4.3,
> >
> > An incomplete message is a message which is either an output
> > (where the input is lost) or an input (where the output is
> > unknown)
> >
> > But in the example above the input is specified for the
> > lost message ICON. How should one understand this example ?
> > Is it correct ?

-----End text from Dmitry Zhukov <dmjr#ispras.ru> to mscnews -----
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