Failed connection to EnvisaLink 4 - resolved

Information and support for EnvisaLink modules.

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Joined: Fri Jun 12, 2020 4:49 pm

Failed connection to EnvisaLink 4 - resolved

Postby jamesfpb » Fri Jun 12, 2020 5:06 pm

Purchased Envisalink 4 and have been struggling with intermittent connectivity, really slow local access, packet loss and firmware update failure.
Envisalink is directly connected to Ubiquiti switch with Ubiquiti USG providing DHCP.

For reasons that I still don't understand, situation was fully resolved by disabling STP (Spanning Tree Protocol) and LLDP Med for the switch port where my Envisalink 4 connected. From assessing packet loss, I believe both settings are affecting connectivity but it's possible that one or other of the 2 is much more important.

Real PITA to work this out so wanted to share for the benefit of others.
I am curious if anyone can explain why these settings matter.


Posts: 18
Joined: Wed Oct 18, 2017 2:46 pm

Re: Failed connection to EnvisaLink 4 - resolved

Postby Anarchy2007 » Sat Aug 15, 2020 4:53 am

thanks jamesfpb, made my life much easier.

I just bought an EdgeRouter X and had the same micro packet drop issues. Disabling LLDP for switch0 seemed to resolve the issue for me.

Just as a side note I seemingly had the same issue years ago with a TP-Link MR200 (I think, I know it wasn't the MR400).

Here's a link to the issue mentioned above:

"Anyhow, I personally looked at your problem and looking some archival entries in our KB I found your issue. TP-LINK has a long-standing problem relating to an old version of Linux they use in their routers. This affects about 5 different models. The exact issue is that small UDP datagrams, like the encrytped Envisalink Event Packets, get their checksums corrupted by the router and dropped by subsequent network equipment. The Envisalerts firewall and load balancing servers drop all improperly formatted packets just like any other public service would."

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