Hi everyone,
I had created the mesh network using Xbee S2 modules, and i am trying to build a tree topology now.
Refer to the user guide,it seems that there is not different between setting mesh network.
I followed the guide, but i failed it.The network that i trying to build is very simple.Just connect those xbees far from coordinator by connecting one router to another router.
Did i miss something?
And advice will be appreciate 
Nope you didn’t. It is that simple. Just make sure that each node is in range of the node before it so they can communicate.
Thank you for your comment mvut!!
I am sure that each node is in range of the node,
But i still failed at third router.(always the third router or end device)
All my router are in same setting which is shown below
ID:1111
SC:22
JV:1
DH:0
DL:0
*other setting is default zigbee router AT
Any clues? 
What do you mean by Fail at the 3rd node? What constituents a failure? Is it not associating to the network? Are you not able to send data from that node to the Coordinator or receive data from the Coordinator? Or is it you are simply timing out?
i uploaded a sketch to link below
http://imageshack.com/a/img901/238/cRGG0k.png
The failure which i meant is 「failed to join the network」.
Maybe the reason which i kept failed at third router is at the hardware that i made.
I use a cell battery to power up these routers.But the first two router can join the network flawless with the same hardware.Hmmm…
The hardware i made:
http://imageshack.com/a/img673/6521/stb8Oz.jpg
Maybe the cell button current isn’t enough to maintain three xbee at one time?
What do you mean by three radios at once? Are you trying to power all three radios from the same battery?
> Are you trying to power all three radios from the same battery?
Of course not.
I have made three boards which same as the pic that i uploaded,then i power up each of them one by one after putting each of them at difference place(outdoor , the distance between each of them is about 40m).
If the last xbee( which is 120m far from cordinator xbee) is connect to the network successful, i will get a Node Join Notification.
Routers are suppose to be always on devices and should be mains powered. Only End devices should be powered via a battery.
Next, try making sure that the NH and BH values are at 3 or higher. Also make sure you are not trying to send data when you try to add the 3rd module.
Thanks for your reply mvut!!!
>Routers are suppose to be always on devices and should be mains powered.
>Next, try making sure that the NH and BH values are at 3 or higher.
I will update the result after i try this asap !!!