This article explains LLDP default output under port-info when descriptions are configured on the peer side and how to find the remote port interface-name in such cases. By default, when interface descriptions are configured on the remote side, the port-info shows the interface descriptions and not the name of the connected interface.

DUT:

labroot@b22-33# show | display set

set interfaces xe-0/0/0 description TEST123

set interfaces xe-0/0/0 unit 0 family ethernet-switching

set protocols lldp interface all

PEER Device:

root@b22-35# show | display set

set interfaces xe-0/0/0 description TEST456

set interfaces xe-0/0/0 unit 0 family ethernet-switching

set protocols lldp interface all

DUT output:

labroot@b22-33# run show lldp neighbors

Local Interface   Parent Interface   Chassis Id         Port info         System Name

xe-0/0/0          -                  0c:86:10:80:a2:00  TEST456          b22-35.ultralab.juniper.net

PEER output:

labroot@b22-35# run show lldp neighbors

Local Interface   Parent Interface   Chassis Id         Port info         System Name

xe-0/0/0          -                  0c:86:10:7c:e7:00  TEST123          b22-33.ultralab.juniper.net

This is a default behaviour. If any description is configured on the interface on peer side, the device will show the interface description under port-info column. Only if there are no descriptions configured, it will show the interface-name.

If we want the description and the interface-name to be shown as part of the output, we can use the below knobs on DUT and the peer.

On DUT:

set protocols lldp neighbour-port-info-display port-id

Note: Ensures what kind of information we want to see of the remote neighbour interface.

On Peer device:

set protocols lldp port-id-subtype interface-name

Note: By default, LLDP generates the SNMP index of the interface for the port ID Type, Length, and Value (TLV). Using this knob, you can generate the interface name as the port ID TLV. When the interface-name statement is configured on the remote LLDP neighbor, the show lldp neighbors command output displays the interface name in the Port ID field rather than the SNMP index of the interface, which is displayed by default.

DUT:

labroot@b22-33# show | display set

set interfaces xe-0/0/0 description TEST

set interfaces xe-0/0/0 unit 0 family ethernet-switching

set protocols lldp port-id-subtype interface-name

set protocols lldp neighbour-port-info-display port-id

set protocols lldp interface all

PEER Device:

root@b22-35# show | display set

set interfaces xe-0/0/0 description TEST

set interfaces xe-0/0/0 unit 0 family ethernet-switching

set protocols lldp port-id-subtype interface-name

set protocols lldp neighbour-port-info-display port-id

set protocols lldp interface all

DUT output:

labroot@b22-33# run show lldp neighbors

Local Interface   Parent Interface   Chassis Id         Port info         System Name

xe-0/0/0          -                  0c:86:10:80:a2:00  xe-0/0/0          b22-35.ultralab.juniper.net

PEER output:

root@b22-35# run show lldp neighbors

Local Interface   Parent Interface   Chassis Id         Port info         System Name

xe-0/0/0          -                  0c:86:10:7c:e7:00  xe-0/0/0          b22-33.ultralab.juniper.net