Zigbee coordinator as router

[MtnDrew]

Hello All,

I am brand new to ZigBee so I apologize for my ignorance.  I am developing a product that will use the nRF5340 for the coordinator, router and end devices (but we are actually using the Fanstel DK).  I have successfully built and tested the ncs Zigbee network_coordinator, light_switch and light_bulb samples.  Of course, the functionality of the coordinator, router and end device are split into their respective sample projects.  Our network will be a simple one to one relationship. That is, a single end device.  So, what I'm wondering, is it possible or even practical to pull the functionality of the light_switch sample (the router) into the network_coordinator?  Can the network coordinator also handle the router esponsibilities?

Thank you,

Drew

[Amanda Hsieh]

Hi, 

Sure, there shouldn't be any problem for a light switch also to be a coordinator.

Regards,
Amanda H.

[MtnDrew]

Thank you Amanda.  I'm going through the sample code line by line now.  My thoughts are to pull the light switch functionality onto the network coordinator as a starting point to move forward.  I will update my post after I've given it a shot.

Drew

[MtnDrew]

Hi Amanda,

I'm really spinning on this.  After a deeper dive, i now see that the light switch example is actually configured as a sleepy end device while the light bulb example is configured as the router.  So, what I'd really want is for the network coordinator to communicate directly with the sleepy end device (light switch) to control the LED's on the network coordinator board. Essentially what I'm asking, can the network be configured without a router? Any hints or insight would be greatly appreciated. 

Thank You,

Drew

[Amanda Hsieh]

Hi, 

The router acts as a relay point for the end devices, storing messages for the end device.

The Coordinator in a Zigbee network also has all the functionalities of a router. Therefore, theoretically, a network could function with just a Coordinator and an End Device, without an additional router. However, this would limit the network's range and capacity, as the Coordinator would need to manage all communications directly. See Zigbee topology in this guide. 

Regards,
Amanda H.

[MtnDrew]

Thank You Amanda,

I see that is possible for the ZED to communicate directly with the ZC, bypassing the router. I don't believe range and capacity will be an issue for us. There will only ever be a ZC and ZED in our network. So, my goal would then be to put the light bulb functionality on to the network coordinator board. I don't yet know what conflicts I might encounter doing that.

One issue I'm having with the sample (as configured for all three devices) is when I take the coordinator out of the network, at least momentarily, I get a warning on the debug console of the router (light bulb sample) "Parent is unreachable".  Adding the ZC back, and rebooting the router and end device, both successfully join the network, the bulb is found and the end device controls the LED on the router device. But I continue getting the "Parent is unreachable" warning. 

I'm not even sure what or why that is generated or how to fix it. Pressing Button 4 on the router board (`factory reset of the device <Resetting to factory defaults_>`) the router board rejoins the network but the end device does not. Nothing I've tried allows both devices to successfully rejoin the network short of reflashing the router and end device.

I believe there must be some network configurations cached in NVRAM because I have to erase and recover the boards before reflashing.  I'm really confused. Perhaps eliminating the router from the network would overcome these issues but I can't move forward until I understand what's happening.

Thanks,

Drew