[Tinyos-help] Retransmissions count... ACK?

Joe Polastre joe.polastre at gmail.com
Sat Mar 5 17:27:48 PST 2005


The CC2420 radio has built in address filtering (ADDR_DECODE and
AUTO_ACK).  See the CC2420 datasheet.


On Sat, 05 Mar 2005 17:02:11 -0800, Jeongyeup Paek <jpaek at usc.edu> wrote:
> 
> Hi Joe,
> 
> I want to ask whether the ACK is sent by the intended receiver or not.
> I'll put it in other words: Who sends the ACK?
> 
> (The setup is that I use MicaZ, and
> called 'enableAck()' provided by CC2420RadioC during the init phase.)
> 
> I read the code briefly (maybe I should read more thoroughly but..)
> and couldn't find the part that looks at the 'msg->addr',
> 
> which makes me suspect that the ACK is sent by all the nodes
> that receive the packet without looking at the 'msg->addr'
> even if that nodes is not the intended receiver.
> If so, then msg->ack will not guarantee the reception
> at the intended receiver.
> 
> Is this correct? Or did I miss some part of the code?
> 
> Thank you.
> 
> --
> 
> Jeongyeup Paek
> 
> Graduate Student
> Electrical Engineering Department
> University of Southern California /
> Embedded Networks Laboratory
> Computer Science Department
> University of Southern California
> 
> Joe Polastre wrote:
> > The link protocol is not responsible for retransmissions; it tells you
> > if an ack has been received and it is up to your protocol to decide
> > whether to retry or drop the packet.
> >
> >
> > On Sun, 06 Mar 2005 01:20:29 +0100, Emiliano <emi.mi at libero.it> wrote:
> >
> >>Hello everybody,
> >>
> >>I'd like to count how many time a packet is retransmitted because has been lost. I'm using mica2 with tiny-os 1.7. I expect that, once Ack is enabled, the packet is sent again up to a maximum number of times. I'm looking inside CC1000RadioIntM to figure where the retransmission of the packet takes place if the Ack is not received but I doesn't understand completely where is the code that invokes a retransmission after an Ack failure.
> >>
> >>Is there anybody that could give me some useful suggestions??
> >>
> >>Thanks a lot,
> >>Emiliano
> >>
> >>____________________________________________________________
> >>6X velocizzare la tua navigazione a 56k? 6X Web Accelerator di Libero!
> >>Scaricalo su INTERNET GRATIS 6X http://www.libero.it
> >>
> >>_______________________________________________
> >>Tinyos-help mailing list
> >>Tinyos-help at Millennium.Berkeley.EDU
> >>http://mail.Millennium.Berkeley.EDU/mailman/listinfo/tinyos-help
> >>
> >
> > _______________________________________________
> > Tinyos-help mailing list
> > Tinyos-help at Millennium.Berkeley.EDU
> > http://mail.Millennium.Berkeley.EDU/mailman/listinfo/tinyos-help
> 
>


More information about the Tinyos-help mailing list