I have a Node-RED instance running on a Windows Server 2012 that it is listening to GPRS devices from a TCP-IN node. I have noticed that sometimes the incoming messages contain 2 or 3 messages concatenated from different devices. These devices are scheduled to communicate at the same time. I am confused if the problem is on Node-RED, Windows or even the Network provider. It appears that these devices are deployed in the same location and with the SIM cards from the same network provider (90% confidence). How can I check if the problem is not on Node-RED neither on Windows.
The problem was that these devices are actually communicating to another Node-RED instance I have, and that instance is forwarding to the main Node-RED instance using the "tcp request node". This node was configured to keep the connection open and I presume that was causing this problem. I set this node to return "immediately - don't wait for reply" but the concatenation still happening once in a while. Will the "link-out node" with "Close connection after each message is sent" fix this?? (Note that I am using the "tcp request node" because it allows me to configure the endpoint on the message, while with "link-out node" doesn't seem to be possible)
When communicating between node-red instances you should consider using MQTT. It is often by far the easiest way of doing it.
In fact, if you run mosquitto on both devices then you can mirror topics between the two instances using MQTT Bridging, so the individual node red servers do not even need to connect to the other device's broker.