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Cisco 3750X does not send LLDP packets

I am struggling with an issue here for quite some time now. I have a 3750X switch with LLDP configured to send a network policy to advertise a voice vlan to IP phones. However on some ports I cant get it to send out any LLDP packets, so the connected Phone does not end up in the voice VLAN.


This is my config:


Vlan 1130



lldp run


network-policy profile 1

 voice vlan 1130


interface range gi1/0/1-10,gi1/0/12,gi1/0/14-18,gi1/0/20-21, gi1/0/23-27

 auto qos voip trust

 mls qos trust dscp

 network-policy 1


I have tried shutting and no shutting the port (also waiting for the holdtimer of 120 seconds to time out). Also adjusting the lldp timer to 5 seconds. Clearing the LLDP table. Changing the access vlan on the port. Nothing seems to help.

In my wireshark traces I see that when the switchport comes up, the switch immediately starts sending lldp messages and advertising the network policy attribute with the correct VLAN for all working phones. For the none working phones I see only the Phone sending packets and not the switch.


Any suggestions? Thanks


Everyone's tags (4)

Add lldp transmit and receive

Add lldp transmit and receive on the interface:


Switch(config-if)#lldp transmit

!--- Enable the interface to receive LLDP.

Switch(config-if)#lldp receive

!--- Return to privileged EXEC mode.




Community Member

Hi Daniele,Thanks for your

Hi Daniele,

Thanks for your reply.

That is enabled by default. I added it anyway, but it does not seem to help.



Hi. Are the non working

Hi. Are the non working phones connected to one of these ports: interface range gi1/0/1-10,gi1/0/12,gi1/0/14-18,gi1/0/20-21, gi1/0/23-27?

What IOS is running?



Community Member

Hi Daniele,The problem

Hi Daniele,

The problem occured om port gi1/0/21 and later on 1/0/19 (which I enabled for lldp en auto qos voip at the time).

The software I'm running is 15.0(2)SE2.


regards Sebastian

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