Relay command payload
The Relay command payload allows for executing one or multiple (pre-configured) commands on the gateway. The command payloads are encoded as TLV (like the event payloads), such that the command payloads can contain data for known and unknown (proprietary) command types.
Bytes:
| 1 byte | 4 bytes | 4 bytes | n bytes | 4 bytes |
|---|---|---|---|---|
| Command MHDR | Timestamp | Relay ID | TLV payload (encrypted) | MIC |
Command MHDR
Bits:
| 7..5 | 4..3 | 2..0 |
|---|---|---|
| MType | Payload type | Hop count |
- MType =
111(= Proprietary LoRaWAN MType) - Payload type =
11(= Relay command) - Hop count =
000= 1, ...111= 8
Note: The hop count is incremented each time the command payload is relayed by an other Relay Gateway. The MIC must be re-calculated on each relay.
Timestamp
Unix timestamp (seconds).
Relay ID
The Relay ID of the Relay Gateway that must execute the command(s).
TLV payload
Bytes:
| 1 byte | 1 byte | n bytes |
|---|---|---|
| Type | Length | Payload |
Please see the TLV payloads page for the known payload types.
Encryption
The TLV payload is encrypted using the same encryption scheme as the LoRaWAN FrmPayload (see section 4.3.3 of the LoRaWAN 1.0.4 specs). For the encryption the block Ai is defined as follow:
Octets:
| 1 | 4 | 1 | 4 | 4 | 1 | 1 |
|---|---|---|---|---|---|---|
| 0x01 | 4 x 0x00 | 0x01 | Relay ID | Timestamp | 0x00 | i |
MIC
Message integrity code, used by other Relay and Border gateways to check the data integrity of the packet. This is obtained by calculating the CMAC over the command payload (- MIC bytes), and using the first 4 bytes of the calculated CMAC as MIC. Note: The MIC must be calculated after encrypting the TLV payload!