network ack failure and address not found errors

I have a network of 40 xbee devices setup in API 2 mode. For the most part, these devices send packets to a base station (also a router). Sometimes I need to change the settings on these devices, so I send individual 0x10 requests to those devices that need settings updates.

Most of the time I get responses that the transmission is successful.

About 10% of the time I get a 0x21 status response, network ack failure. Resending the same information to the device has a success rate of 1 in 3, meaning I usually have to send at least 4 times to get a OK response.

About 5% of the time I get a 0x24 status response, address not found failure. Retrying the send one time typically results in success.

Where should I start looking for the root cause of these issues? I am assuming they are related, and likely due to some sort of network traffic issue, but I am not sure how I might go about fixing.

This is most likely do to Too much network traffic. Try getting an inexpensive zigbee sniffer to help you see where the bottleneck is occurring. You may simply find that you need to reduce the amount of data flowing for the size of the network.

Hi Mvut,

Thanks for the quick answer. Two follow up questions:

  1. I’ve found the following online: Atmel’s RZUB and Dresden’s deRFUSB. Any recommendation between the two? Recommendation on software?

  2. Do you have a recommendation on literature regarding the best practices of network design? I’d like to push this network to over 100 nodes that can send and receive, so want to read up on how I might accomplish this.

I would recommend reading over both and finding the one that best fits you. The one I am use to using is really a developmental tool and rather expensive.

As for the other, make sure that as you increase, use items such as Source Routing and decrease as much unnecessary traffic as you can.
Try to avoid issuing Broadcast packets.