[Tinyos-help] [TinyOS-Help]:What is the usage of "DCC2420_NO_ACKNOWLEDGEMENTS"??

[Razvan Musaloiu-E.]

Hi!

On Thu, 25 Sep 2008, Renee Azhen wrote:

> thanks, Razvan Musaloiu-E,
> then what is the usage of CC2420_NO_ACKNOWLEDGEMENTS?

The CC2420_NO_ACKNOWLEDGEMENTS will disable the sending of ACKs. The other 
directive related to ACKs is CC2420_HW_ACKNOWLEDGEMENTS which will disable 
the software ACKs and enable the hardware ones.

> If a sender transmit a packet, then the receiver will reply with a ACK.

If a sender does not request for ACKs then the received will not ACK the 
packet. If the packet requests for an ACK and the receiver has disabled 
the ACKS then again the ACK will not be sent.

> So what interface the sender will use to receive the ACK?
> and how does the sender process the ACK message?
> Do you know some sample code about this flag? could you please share it with me?

Actually there is such a problem already in the tree in this place:
 	apps/tests/cc2420/TestAcks

All the best!
Razvan ME

> "Razvan Musaloiu-E." <razvanm at cs.jhu.edu> 写道： Hi!
>
> On Wed, 24 Sep 2008, Renee Azhen wrote:
>
>> Does this flag(CC2420_NO_ACKNOWLEDGEMENTS) is used by mac/link layer?
>> if the CC2420_NO_ACKNOWLEDGEMENTS was set, then no ack will be sent by
>> receiver, so the receive.Done event will always return true?
>
> You are talking about AMSend.sendDone? AMSend.sendDone will not return a
> fail even if the packet is not acked. To check for that you have to use
> the wasAcked from the PacketAcknowledgements interface
> (PacketAcknowledgements.nc from tos/interfaces). You also need to use the
> requestAck from it before doing a AMSend.send of the packet.
>
> --
> Razvan ME
>
>> Tony O'Donovan
>> When a sender tranmits a message to a receiver the receiver can send an
>> acknowledgment (ACK) message. The purpose of the ACK is to let the
>> sender know the message was successfully received. If the
>> CC2420_NO_ACKNOWLEDGEMENTS option is set the receiver does not send an
>> ACK when it receives a message.
>>
>>
>> --- Renee Azhen  wrote:
>>
>>> hi, all,
>>> I am using the collection protocol, and found that
>>> if I use:
>>> CFLAGS += -DCC2420_NO_ACKNOWLEDGEMENTS
>>> CFLAGS += -DCC2420_NO_ADDRESS_RECOGNITION
>>> in the app makfile, network almost failed, it can't
>>> deliver any packet.
>>>
>>> So is there anyone know what is the usage of that
>>> line in Makefile??
>>>
>>> thanks
>>> Sam
>>>
>>>
>
>
>
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