Hi Paul,
Does what you explained about CC2420 depend on the TinyOS version or used interfaces to achieve ACK messages? I mean, I am not using PacketAcknowledgements interface but I am using SendMsg interface in TinyOS 1.x with Telosb (CC2420 module) , do you mean that when the sender send an unicast message, sendDone event is launched if an ACK message is received from the recipient node? Do I have to activate or use any special interface to achieve this? Thank you in advance David De: [email protected] [mailto:[email protected]] En nombre de Paul Johnson Enviado el: martes, 08 de diciembre de 2009 17:08 Para: Vikram vik76 CC: tinyos-help Asunto: Re: [Tinyos-help] MAC acknowledgments Vikram, It's probably best to look at the code yourself to determine if your platform turns on acks by default or not. In general it is radio hardware specific, for example the CC1000 doesn't perform MAC level acks. Other hardware such as the CC2420 have mac acks enabled by default for unicast packets and disabled on broadcast packets. As for your first question, normally acks are only enabled for unicast packets.(If they were enabled for broadcast packets, all the acks from multiple receiving nodes would likely collide) For your second question the requestAck() function sets a field in the packet header that indicates the sender requests an ack for this packet. In general only when the intended node receives a packet with this field set, will it send an ACK. Once the sender receives an ack for this packet(with the ACK field set), only then will the sendDone function be called. -Paul On Mon, Dec 7, 2009 at 9:53 PM, Vikram vik76 <[email protected]> wrote: Hello, I would like to understand better the working of acknowledgments in tinyos. First, Is MAC level acknowledgment implemented by default? for Unicast or Broadcast? I also used the PacketAcknowledgements interface. When I use call PacketAcknowledgements.requestAck(&pkt) does it explicitly request the receivers to send an acknowledgement, or it just captures the acknowledgement that is sent by default by the receiver to the sender? Thanks Vikram _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
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