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Ok, we do some brainstorming on a future project involving Zigbee PRO and the protocol interface cluster. Something like tunnelling a protocol (bacnet) IN the zigbee network.

In bacnet, there is unicast (one target) and broadcast (many target) frame. Both frames travel on bacnet network and they will need to be tunnelled in the zigbee network.

bacnet unicast ==> zigbee unicast. bacnet broadcast ==> zigbee multicast.

When the bacnet payload > zigbee payload, Zigbee Fragmentation is involved according too the zigbee payload (the frame is broke in smaller frames).

But zigbee fragmentation can't be use on multicast frame (zigbee specification)...!

What is the best approach with that issue ? Can I bypass this by creating binding between all the zigbee device ?

Thanks

Reference: http://www.bacnet.org/Addenda/Add-135-2008q.pdf

Fred Alexandre
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So, what you are saying is that Zigbee provides fragmentation for unicast but not multicast. Therefore as you still require fragmentation you must implement framing above Zigbee.

Now you have a choice of implementing framing once and using for both unicast and multicast and ignoring what Zigbee provides for unicast, or only using it for multicast. The choice is dependent upon protocol limits and convenience, it might be more convenient to implement framing yourself and completely ignore Zigbee.

Steve-o
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  • Hi Steve-o, thanks for your input. I raise this possibility a few days before and the project need to be full compliant with Zigbee and BACnet, including compatible with 3rd party device. – Fred Alexandre Aug 25 '11 at 17:40
  • I need to look at zigbee bindings. Maybe a can build a giant binding with all device that I need to reach and send multiple unicast (point to point) instead of using one Multicast. – Fred Alexandre Aug 25 '11 at 17:45