Envisalink 2DS/3 closing connection

[ksakhamuri]

I have an envisalink attached to my DSC. And I'm writing a python script that would connect to the Envisalink and check for status updates. However, every 20 mins or so, I'm seeing Envisalink sending a socket close to my client and I'm not sure what's causing this. Here is the sequence I'm seeing repeat about every 20 mins:
EVL [FIN, PSH, ACK], Client [FIN, ACK], EVL [ ACK]

Not sure why this is happening. Wondering if anyone can tell me what I could be doing wrong or if this is normal behavior.

Thanks,
Kalyan

[K-Man]

It sounds like you are blocking communications with the Envisacor reporintg servers and not POLLing the Envisalink in the interim. The modules are programmed to reboot every 20 minutes if they cannot connect to their home server or see traffic from a local TPI client. It is assumed there is something wrong with network stack.

If you are actively firewalling the Envisalink then you need to provide some sort of query every 10 minutes or so to keep the TPI connection alive.