Subject: RE: SDL-News: Modelling of unreliable transmission medium in Tau SDT
michael.andersson#telelogic.com
Date: Tue Dec 09 2003 - 17:56:45 GMT
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-----From michael.andersson#telelogic.com to sdlnews -----
Hi Allan,
try
Options1 / State Space: Input Port Length...
or the textual command
Define-Max-Input-Port-Length
it is by default set to three.
Command : help define-max-input-port-length
Define-Max-Input-Port-Length <Number>
Define the maximum length of the input port queues. If this length
is exceeded during state space exploration a report will be generated.
Another thing you might want to try out is to continue the exploration after
a problem/report.
For example: if you want to see how the system behaves after a signal is
lost (because of a full input port) you have to set:
Define-Report-Continue MaxQueueLength
Otherwise the Validator will prune the execution at the point where the
report is generated.
Another way to model the packet-loss situation would be to only use your
packet signals (and not model the unreliability with spontaneous
transitions). To be able to feed signals "faster than the system expects"
yuo would have to model the sender side in the SDL system as well. Then you
could take advantage of using a limited input port in order to achieve
packet loss. In this case you would have to define that the Validator should
continue after the MaxQueueLength report in order to reach behaviour beyond
this point.
regards
Michael
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> -----Original Message-----
> From: Allan Weber [mailto:awmi00#control.auc.dk]
> Sent: den 9 december 2003 17:20
> To: sdlnews#sdl-forum.org
> Subject: SDL-news: Modelling of unreliable transmission
> medium in Tau SDT
>
>
> Become an SDL Forum Society member
> <http://www.sdl-forum.org/Society/members.htm>
> The originator of this message is responsible for its
> content. -----From Allan Weber <awmi00#control.auc.dk> to
> sdlnews -----
>
> Hi.
>
> We are trying to model an unreliable medium in Tau SDT in
> order to to see how our protocol handles packetloss. However,
> we are facing some problems. We have tried to use both
> "none"-input and signals from the environment to issue a
> packetloss in our model of the medium. Both methods dont seem
> to fullfill our needs. If the priorities of environment and
> none signals are at their default values in the validator, a
> packetloss is only issued if the queue is empty, which is not
> desireable. If we set all priorities to the same value, the
> validator generates reports saying that the max queue length
> has been exceeded.
>
> Is there any way to avoid the max queue length exceeded
> "error", or possible som better way to model out medium??
>
> Best regards,
>
> Allan Weber
>
> --End text from Allan Weber <awmi00#control.auc.dk> to
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