I am using XBee3 Zigbee 3.0 with firmware version of 100D. There are one coordinator and quite a number of router xbee in my network (no end devices). I encountered a problem (data unable to send to coordinator) before when there are around 38 router devices. After some findings, I changed the routing approach to many-to-one routing and the problem gone. Currently, I have 1 coordinator with 44 routers connect to it. And seem likes the problem occurred again.
The answer is Roughly 65K routers. But the real issue is the overall throughput needed and the number of hops. The more hops, the lower the throughput.
Also has to do with the addressing used. If at all possible, try sending unicast packets instead of broadcast packets.
If I want to split my network into two for sharing workload by adding another coordinator. The channel and stack profile settings remain default but having same PAN ID with the first coordinator. Will it causing problems to my network? What I want to achieve is those router XBee will select and join one of the coordinators automatically based on signal strength (Join window is opened).