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I am studying the ZigBee standard and I have a basic doubt about the behavior of the communication. I know that ZigBee is the network layer and 802.15.4 the mac layer. So, if I send a message from node n1 to the base station bs through node n2. The ACK that I receive is a 802.15.4 packet, right? so that means that the ACK was generated by n2. So, can I get as well an ACK from the bs and then n1 would know for sure that the bs received the message?

Thanks in advance!

user3791422
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2 Answers2

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Yes this is known as an application layer acknowledgement (or APS Ack), it is different to MAC Ack's. Slide 34 of this may help http://processors.wiki.ti.com/images/8/8a/08_-_ZigBee_Stack.pdf.

Regards, TC.

t.c.
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To expand on TC's answer. If you are sending a message from n1 to bs that routes through n1 (aka n1 => n2 => bs). The following will happen

  1. n1 sends message to n2
  2. n2 MAC ACKs n1
  3. n2 forwards message to bs
  4. bs MAC ACKs n2
  5. bs sends APS ACK to n2
  6. n2 MAC ACKs bs
  7. n2 forwards APS ACK to n1
  8. n1 MAC ACKS n2

Now bs has received the original message and n1 has received an APS ACK indicating that bs has received its message.

kyork
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