@whereisaaron I have also a port connected to a EAP682 which is also working with 2.5Gbit. It is also working. 

The not working port is also connected to an OPNsense Router. 

Btw.. I have LLDPD running on Proxmox and this information is received. 

The strange thing is, that it was working for some time. 

  @whereisaaron I have several devices transmitting lldp Messages and all of them are received fine. 

Also the structure and content is the Same Like the Message from OPNsense. 

I sniffed it with tcpdump to compare. 

Very Strange... I'll Check again on another Port. 

  @MatthiasL22 

LLDP is not meant to be forwarded; it is only exchanged between directly attached neighbors.
As soon as the frame hits a switch, the switch itself consumes the packet.

A more complete description of Link Layer Discovery Protocol behavior

Basic properties
- LLDP is a Layer-2 protocol (EtherType 0x88CC) that operates at the data-link layer.
- Its purpose is to let adjacent network devices advertise local information (device name, port description, VLAN IDs, system capabilities, etc.).
- Frames are sent to the multicast MAC 01-80-C2-00-00-0E, an address that IEEE 802.1D classifies as one that must not be forwarded by standard bridges.

Forwarding behavior
- Ordinary switches do not forward LLDP frames.
When an LLDP frame arrives:
– The switch recognizes the destination MAC 01-80-C2-00-00-0E.
– Per IEEE 802.1D, the frame is delivered to the switch’s control plane; it is processed locally and then dropped.
– Consequently, LLDP information is visible only on the immediate link and never traverses a third switch or router.

Special cases
- Pure electrical repeaters (hubs) or devices explicitly configured for “LLDP pass-through” may relay the frame.
- Overlay or tunneling technologies (VXLAN, Q-in-Q, etc.) can encapsulate and carry LLDP frames to a remote endpoint, but this is an intentional exception rather than default behavior.

  @Ethan-TP This does not explain, why the packets are ignored by the switch...

  @MatthiasL22 

What equipment is plugged into those 2.5 G ports?
If the port is connected to a gateway and you see LLDP drops, it’s because the gateway does not forward LLDP frames, so they are discarded.

Please also provide the packet-capture files you collected earlier so we can analyze them.

  @Ethan-TP Please find attached the tcpdump.

It is collected at the OPNsense port re1 (FreeBSD router), which is directly connected to the TP-link 2.5 Gbit Port 2.

  @whereisaaron 

Could you also supply a tcdump of the ER7412?

Just because I am interested. 

whereisaaron wrote

@Ethan-TP thanks for the info! I fully understand that LLDP packets are not propagated, that is what I expected. I didn't understand that "Discarded" ment they had been processed, since I thought of the switch as the destination for the LLDP packet. But I get the switch could see it this way, kind of "observe and drop".

 

But, in that case, I don't understand why the same switch is _not_ discarding any of the LLDP packets received from other devices like EAP? You can see below the SG2210XMP-M2 is discarding the LLDP packets received from the ER7412-M2 gateway (port 1), but _not_ discarding the LLDP packets received from the EAP772 devices (ports 2 & 3). based on your info, shouldn't the EAP's LLDP packets also be counted as discarded by the switch?