Secure access
Send data to a secured remote node
Digi XBee® 3 802.15.4 RF Module User Guide
56
4. Send remote AT Commands to the remote server using the
with bit 4 of the Command Options field set. Bit 4 indicates the AT command
should be sent securely.
Note
If you are using 802.15.4 firmware you must send secured packets using the device's 64 bit
address. To do so, set
to
0xFFFF
.
Send data to a secured remote node
The process to send secured data is very similar to remotely configuring a node. The following steps
show how a client node can authenticate with a server node and send data securely.
1. Send a
Secure Session Control frame - 0x2E
to the client node with:
n
The server's 64-bit address.
n
The desired timeout.
n
The options field set to
0x00
for fixed timeout login or to
0x04
for inter-packet timeout
refresh login.
n
The password of the server node.
2. Wait for the
Secure Session Response frame - 0xAE
to determine if the the authentication was
successful.
3. Data can now be sent securely with
and
provided that:
n
Bit 4 in the transmit options field is set to indicate that the data should be sent
encrypted.
4. The returned
and
Explicit Rx Indicator frame - 0x91
receive
options fields should also have bit 4 set.
Note
The maximum payload per transmission size is reduced by four bytes due to the additional
encryption overhead.
NP (Maximum Packet Payload Bytes)
will not reflect this change when the
session is going on.
Note
If you use 802.15.4 firmware you must use 64-bit addressing to send secured packets. To do so,
set
to
0xFFFF
.
A node can be secured against emitting data out the serial port that was received insecurely via the
SA
command. This means that a remote node will not emit any serial data if it was received insecurely
(
bit 4 was not set). This includes any data in Transparent mode,
0x80
,
0x90
and
0x91
frames.
Note
When a device rejects a data transmission (0x80, 0x90, 0x91, or Transparent data) because of its
SA
configuration, it does not send an error back to the sender. This means that data transmissions to
a device give a success status even if they are rejected.
End a session from a server
If bit 3 of
is set, the server emits an extended modem status (whenever a
client establishes a session with it) that includes the 64-bit address of the client. Using these statuses
the MCU connected to the server can keep track of sessions established with the server. To end a
session from the server do the following:
