Xbee, association to coordinator

HI.
I am using a network of Xbee/Uno. Few End Devices and 1 coordinator.
here is the setup i choose =

The Coordinator =

  • A2 is 6-110 (0 - ReassignPanID, 1 - ReassignChannel, 1 - AllowAssociate )
  • has a fix PANI ID.
  • has a specific NODE identifier (lets say "Master")
  • Key Encryption Enable (EE) is enabled
  • A 128 bit key (KY) is used

End DEvices =

  • A1 is 6-0110 (0 - ReassignPanID, 1 - ReassignChannel, 1 - AutoAssociate, 0 - PollCoordOnPinWake)
  • has a fix PANI ID.
  • has a specific NODE identifier (lets say "BOX #")
  • Key Encryption Enable (EE) is enabled
  • A 128 bit key (KY) is used

So ;
When switched on, the coordinator performe an Energy Scan and choose a channel to transmit. When switched on, end devices search for a coordinator and try to associate with it if it has the same PAN ID.
Once the association is done, they will communicate with each other only if the secure key (KY) is the same.
That's marvelous !!!!

but i have a question, trying to make the network the more secure possible.
If someone put a coordinator with the same PAN ID near my network, my End devices may choose to associate with it.
In my setup, is this possible to force all my End devices to associate with and only with the coordinator with a specific serial number ?

Maybe my all setup coordinator-End device is not the good choice ?
I just want a master device to communicate with end device (transmission and reception), Communication between end devices is not necessarry, and do it with the highest security possible.

do you have a suggestion ?

In my setup, is this possible to force all my End devices to associate with and only with the coordinator with a specific serial number ?

Not that I know of. But, since you are asking this question on an Arduino forum, is it safe to assume that the end devices are mounted on Arduinos?

If so, then the Arduino can ask the coordinator to supply a serial number. The Arduino that it is attached to can respond with some value.

Then, the end devices can choose whether to transmit data, or not, depending on the reply received from the coordinator.

HI.
Yes, you're right, i use an arduino, a Xbee/Uno like i said.
i am already doing something With ATDN function.
My end device send ATDNMASTER to the serial Port.
I get OK if the box has a Node Identifier that is "MASTER" (which is my coordinator)
I get ERROR if the NI is different.

If ATDN gives me ERROR, the 2 things i can do are :

  • use ATFR to reset the Xbee of the end device, and make it associate an other time
  • use ATDA to force the end device to re-associate.

But what if the end device keeps associate with the same coordinator, that is not mine ? (because it is closer, or has a stronger signal .. i don't know)

Maybe i search problems where there's not, but i think about every situation that may happen.

thx

Hi
I found something more ...
if my end Device associate with a coordinator with the same PAN ID than my coordinator (PAN ID = MASTER), The ATAI command on my end device gives me 0 = "Successful Completion - Coordinator successfully started or End Device association complete ".
But The ATDNMASTER command will give me OK only if the 128 bit key (KY) are the same on both Xbee. Otherwise : ERROR (maybe because there's no response, and time for answer is ended).