Specifications
XBee®/XBee‐PRO®SERFModules
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The response will be the ZigBee Register Joining Device Status (0xA4) API frame which will
indicate success or failure.
This is the preferred method, because it limits access to the network to pre-approved MAC
addresses.
Second Method
Configure the joining device with the Trust Center Link Key. This is done by using the KY command
on the joining device to match the Trust Center Link Key. This is risky, as it discloses an address
and link key which are unique to a particular Smart Energy network. Anyone else who gets access
to that address and link key will be able to join that network, which would compromise the security
of that particular network.
Enable Joining
Before the new device can join the network, the network must be commanded to temporarily drop
its guard, and permit joining for a time. Standard ZigBee networks may optionally permit joining
at any time. But the Smart Energy Profile, to maintain a higher level of security, requires that
permit joining should not be left on permanently, which would be the same as leaving the front
door unlocked.
There are three methods by which one may enable "permit joining" on the network. All three may
only be done by a node which is already joined to the network. Typically this will be done by the
utility--sending a command to the ESP through its non-ZigBee backhaul interface.
Commissioning button
Two presses of the commissioning button (pin 20) on any node which is already joined to the
network will cause a broadcast of the Permit-Join message. The NJ register setting determines the
permit join time interval in units of one second. A zero value setting indicates the time interval
should be one minute.
CB2
An AT command "CB" with a parameter value of 2 is equivalent in effect to two presses of the
Commissioning button. The AT Command (0x08) API frame can be used to do this. The permit join
time is set similar to the commissioning button example.
Broadcast of a ZDO Permit-join
The Explicit Addressing ZigBee Command Frame (0x11) can be used to broadcast a ZDO Permit-
Join message ([4], 2.4.3.3.7). To use the frame, set the field values as follows:
64 bit Destination Address = 0x0000 0000 0000 FFFF
16 bit Destination Address = 0xFFFE
Source Endpoint = 0
Destination Endpoint = 0
Cluster = 0x36
Profile Id = 0x0000
Data Payload =
1 byte sequence number,
1 byte time (seconds),
1 byte Trust Center significance
0x00 = no effect on Trust Center
0x01 = Trust Center authentication policy is affected, if addressed to the T.C.