What is the first step to t-shoot unidirectional LLDP? I have a scenario (on a backbone circuit) where the A-router (Junos PTX1000) is seeing it's expected LLDP neighbor but the Z-router (Cisco ASR9k) is not. LLDP is configured globally on both A & Z routers and NOT on the individual interfaces. Also, both physical interfaces on the A & Z routers are configured inside LACP bundles. Continuity, fault propagation, light levels on the circuit looks good and LLDP is enabled on the intermediate DWDM nodes. Thanks in advance.

  • You need to give us more information. Please edit your question to give a good description of the network (a diagram would be great), the network device models, and the network device configurations.
    – Ron Maupin
    Mar 4, 2018 at 19:41
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Apr 1, 2018 at 22:19

1 Answer 1


LLDP is only transmitted on a connected link. Any further bridging or tunneling does not/should not (usually) forward LLDP packets. When normal communication is working but there's no LLDP reception there's something in between filtering it (or LLDP isn't sent out at all, check tx statistics).

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