Remote control commands with a response time of within 10 seconds
Each node controls a motor after receiving a downlink command.
After executing the command successfully, the node sends an acknowledgment (ACK) back to the server.
I understand that Class C devices can receive downlink messages almost at any time, but I am concerned about the gateway’s downlink capacity when supporting around 500 devices.
My questions are:
Is a single RAK7289V2 (16-channel) sufficient for approximately 500 Class C devices?
Will downlink capacity become the main bottleneck in this scenario?
Can this architecture reliably support command-and-response communication with a response time of less than 10 seconds?
Is ChirpStack suitable for this type of deployment, or are there any recommended configurations or optimizations?
Are there any limitations or best practices specific to the KR920 region that I should be aware of?
If anyone has experience deploying a similar system, I would greatly appreciate your advice.
hi @song
A single RAK7289V2 can support around 500 Class C devices, but the limiting factor is the downlink traffic, not the number of registered nodes.
If commands are sent occasionally or to a small number of devices at a time, a sub-10-second response is generally achievable. However, if many devices need to receive individual commands simultaneously, downlink scheduling will become the bottleneck.
ChirpStack is a good choice for this type of deployment. We recommend keeping payloads small, enabling ADR where appropriate, and validating the expected command rate with field testing.
If multiple devices receive the same command, you may also want to consider ChirpStack multicast, which can significantly reduce downlink usage. If every device requires a unique command and ACK, then unicast downlinks are required, and the achievable performance will depend on the command frequency and traffic pattern.
Overall, the proposed architecture is feasible, but the key factor is how many downlink commands you expect to send within a given time period, rather than simply having 500 devices.
To clarify our application, we do not need to send commands to many devices at the same time.
Our server sends a command to one device at a time , waits for the ACK from that device, and then proceeds to the next device. In other words, communication is performed sequentially, not simultaneously.
For example, the server communicates with Node 1, then Node 2, then Node 3, and so on, up to Node 500.
Do you think a single RAK7289V2 with ChirpStack is suitable for this sequential command-and-response workflow? Are there any recommended command rate limits or best practices for this type of operation?
