Multitech Network Server + TTN Packet Forwarder

(Tom Iotexperts) #1


I have a concept/design question here.

Is it possible to run a network server on the multitech gateway, in order to decode the packets and to run a node-red flow on the value. While also to use TTN packet forwarder and to use the gateway with the TTN network server ?

It is a requirement for our project that the gateway will act upon incoming packets when there is no connectivity with the network server.

for example,
Class A LoRaWAN device communicates sensor data periodically, if the value reaches a certain threshold, the GW sends a command to a Class B device to turn on/off the irrigation valve. The data is also sent/managed by the TTN network server.

Can this be done?

I am referring to an architecture of running Edge logic and Edge analytics on the GW level.

Hopefully I am clear enough,

(Jac Kersing) #2

Yes and no. The AEP models run a network server. However that network server will not have the keys required to decode the data or TTN will not have the keys. Also you will need a packet forwarder that sends data to multiple destinations. Both (old) poly_pkt_fwd and mp_pkt_fwd can do this but the installer does not support it and will disable the local lorawan software upon installation. This is because two network servers directing one packet forwarder is bound to introduce issues if you are not very knowledgeable. (If you are you can install things by hand)

Also, keep in mind LoRaWAN is not a reliable protocol so packets will be lost. (It is not a matter of ‘packets might be lost’, just a matter how many will be lost) Is that a good base for your process control??

Class B is currently not supported by TTN (and will not be in the near future), I am not sure the MultiTech network server supports it.

(Tom Iotexperts) #3

Hi @kersing thanks for the detailed reply,

So running a local network server, and a packet forwarder is possible, if we do it manually, correct?

Any other suggestion on how to achieve near-real-time logic on the gateway, and have it function when connection to the internet is down?

One method I can thinking about is: If my end-device then has 2 packets it sends under certain alerts, one with the TTN network settings it got doing OTA, and the other preset, to work with the local network server?

I did hear that TTN is working on a Pico-cell network server install, that one might sync with the main ttn network server ? No release date on that that’ve heard.


(Jac Kersing) #4

Yes, if you install it manually.

Managing two sets of keys and counters on a node can probably be done, but requires detailed knowledge of the LoRaWAN stack on the node and is error prone. I’m not saying it can’t be done, however it is not a solution I would choose.

LoRaWAN and near-real-time feels like a contradiction in terms for me. Class C devices are the only ones even approaching real-time and are not supported by TTN. There might be network servers you can run yourself that support it.
For other options for network servers, please search the forum and the internet. The answers are not exactly hiding. However as those are not TTN based I’ll not go into it on this forum (for free).


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