XBee‐PRO®900HP/XBee‐PRO®XSCRFModules
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XBee-PRO 900HP Network Link Establishment and Maintenance
Building Aggregate Routes
In many applications it is necessary for many or all of the nodes in the network to transmit data to a central
aggregator node. In a new DigiMesh network the overhead of these nodes discovering routes to the
aggregator node can be extensive and taxing on the network. To eliminate this overhead the AG command can
be used to automatically build routes to an aggregate node in a DigiMesh network.
To send a unicast, modules configured for transparent mode (AP=0) must set their DH/DL registers to the
MAC address of the node to which they need to transmit to. In networks of transparent mode modules which
transmit to an aggregator node it is necessary to set every module's DH/DL registers to the MAC address of
the aggregator node. This can be a tedious process. The AG command can be used to set the DH/DL registers
of all the nodes in a DigiMesh network to that of the aggregator node in a simple and effective method.
Upon deploying a DigiMesh network the AG command can be issued on the desired aggregator node to cause
all nodes in the network to build routes to the aggregator node. The command can optionally be used to
automatically update the DH/DL registers to match the MAC address of the aggregator node. The AG
command requires a 64-bit parameter. The parameter indicates the current value of the DH/DL registers on a
module which should be replaced by the 64-bit address of the node sending the AG broadcast. If it is not
desirable to update the DH/DL of the module receiving the AG broadcast then the invalid address of 0xFFFE
can be used. API enabled modules will output an Aggregator Update API frame if they update their DH/DL
address (see the API section of this manual for a description of the frame). All modules which receive an AG
broadcast will update their routing table information to build a route to the sending module, regardless of
whether or not their DH/DL address is updated. This routing information will be used for future transmissions
of DigiMesh unicasts.
Example 1: To update the DH/DL registers of all modules in the network to be equal to the MAC address of an
aggregator node with a MAC address of 0x0013a2004052c507 after network deployment the following
technique could be employed:
1. Deploy all modules in the network with the default DH/DL of 0xFFFF.
2. Issue an ATAGFFFF command on the aggregator node.
Following the preceding sequence would result in all of the nodes in the network which received the AG
broadcast to have a DH of 0x0013a200 and a DL of 0x4052c507. These nodes would have automatically built
a route to the aggregator.
Example 2: To cause all nodes in the network to build routes to an aggregator node with a MAC address of
0x0013a2004052c507 without affecting the DH/DL of any nodes in the network the ATAGFFFE command
should be issued on the aggregator node. This will cause an AG broadcast to be sent to all nodes in the
network. All of the nodes will update their internal routing table information to contain a route to the
aggregator node. None of the nodes will update their DH/DL registers (because none of the registers are set
to an address of 0xFFFE).
Node Replacement
The AG command can also be used to update the routing table and DH/DL registers in the network after a
module is replaced. The DH/DL registers of nodes in the network can also be updated. To update only the
routing table information without affecting the DH/DL registers then the process of Example 2 above can be
used. To update the DH/DL registers of the network then the method of Example 3 below can be used.
Example 3: The module with serial number 0x0013a2004052c507 was being used as a network aggregator.
It was replaced with a module with serial number 0x0013a200f5e4d3b2. The AG0013a2004052c507
command should be issued on the new module. This will cause all modules which had a DH/DL register setting
of 0x0013a2004052c507 to update their DH/DL register setting to the MAC address of the sending module
(0x0013a200f5e4d3b2).
XBee-PRO 900HP Device Placement
For a network installation to be successful, the installer must be able to determine where to place individual
XBee devices to establish reliable links throughout the network.
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