LLDP Configuration on Cisco

In this configuration lesson, we will focus on Cisco LLDP Configuration. To understand LLDP better, let’s check the configuration of LLDP on the Cisco IOS. The most important commands related with LLDP configuration is showed below.

 

LLDP Configuration TopologyLLDP is disabled by default. To enable LLDP on the device, use “lldp run” on the global configuration mode. Again, “no lldp run” is used to disable lldp on that device.

 

RouterA(config)# lldp run

RouterA(config)# no lldp run

To specify the TLVs on the device, use “lldp med-tlv-select tlv” command. Here, tlv can be inventory-management, power-management, network-policy, location etc.

 

RouterA(config)# lldp med-tlv-select tlv

Like other protocols, LLDP (Link Layer Discovery Protocol) has also timers. The default values of reinit is 2, timer is 30 and holdtime is 120. Reinit is the initialization delay. Timer is the update time. And holdtime is the time that it waits without an update and then discards the entry.

 

LLDP timers can be configured like below:

 

RouterA(config)# lldp reinit 2
RouterA(config)# lldp timer 30
RouterA(config)# lldp holdtime 120

You can disable or enable receiving and transmitting the LLDP packets on a specific interface. To do this, use “lldp transmit” and “lldp receive” commands under that interface. To disable, you can also use the no versions of this commands.

 

RouterA(config)# interface fastethernet 0/1
RouterA(config-if)# lldp transmit
RouterA(config-if)# lldp receive

 

RouterA(config)# interface fastethernet 0/2
RouterA(config-if)# no lldp transmit
RouterA(config-if)# no lldp receive

To see the lldp related information on the device, use the below show commands:

 

RouterA# show lldp
RouterA# show lldp traffic
RouterA# show lldp entry entry
RouterA# show lldp interface interface-id
RouterA# show lldp neighbors interface-id
RouterA# show lldp errors

To reset the lldp counters to zero, use “clear lldp counters” command.

RouterA# clear lldp counters