[Tinyos-help] sendDone() called before receive

[Bibudh Lahiri]

Hi Faisal,
   U can put some seqeunce number in the packet at the application layer,
but then, if MAC has to retransmit the packet because it gets lost in
collision, it will maintain the same application-layer sequence number, it
will not update ur sequence number, so at the receiver u'll receive the
packet with the same seq number as u put in the sender, so u won't even know
that there was a collision which resulted in a retransmission. So u'd never
know how much time was wasted for collisions and retransmissions. Anyway, if
u think that this time is negligible from ur application's point of view, u
can go for it.
                                                           Bibudh


Bibudh Lahiri
Graduate Research Assistant
Department of Electrical and Computer Engineering
Iowa State University
http://www.ece.iastate.edu/~bibudh/



On 4/2/07, Faisal Karim <shaikh_fk at yahoo.com> wrote:
>
>  Hi Bibudh
>
> 1) Thats true, I also dont know the answers yet :-) after these
> experiments I'll try them on real motes as well.
> 2) For second problem you are right and that was the reason I asked the
> question on list. And one interesting observation is the difference between
> receive() and sendDone() is always 31 seconds within single hop.
> I was thinking to start considering the timing from send() instead of
> sendDone() by this the processing time, queuing time etc will also be
> considered. One concern can be than may be the send() will not send
> packet(collisions etc), so to hack around im thinking to put some sort of
> sequence no. or identifier in packet at src than check that on receiver.
>
> Any suggestion
>
>  Regards
> Faisal
>
>
>
>
> ----- Original Message ----
> Date: Mon, 2 Apr 2007 14:04:34 -0500
> From: "Bibudh Lahiri" <bibudh at gmail.com>
> Subject: Re: [Tinyos-help] sendDone() called before receive
> To: tinyos-help at millennium.berkeley.edu
> Message-ID:
>     <e522914f0704021204k61a21422y48874c4e8b469f2a at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Faisal,
>      As an idea, it sounds OK, but I'd like to mention a thing or two:
>
> 1) I'm not sure how close this would be to the transmission delay that u'd
> obtain on real motes
> 2) If the problem of receive() being called in the receiver before
> sendDone() being called in the sender persists (as u reported), then u'll
> have a problem.
>
>
>
>
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