Zigbee pro: sending a multicast involving fragmentation

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 us开发者_如何学运维e 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

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.