LLDP

LLDP is a vendor-neutral link layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities, and neighbors on an IEEE 802 local area network, principally wired Ethernet. The protocol is formally referred to by the IEEE as Station and Media Access Control Connectivity Discovery specified in IEEE 802.1AB and IEEE 802.3-2012 section 6 clause 79.

LLDP performs functions similar to several proprietary protocols, such as CDP, FDP, NDP and LLTD.

Information gathered with LLDP is stored in the device as a MIB and can be queried with SNMP as specified in RFC 2922. The topology of an LLDP-enabled network can be discovered by crawling the hosts and querying this database. Information that may be retrieved include:

  • System Name and Description
  • Port name and description
  • VLAN name
  • IP management address
  • System capabilities (switching, routing, etc.)
  • MAC/PHY information
  • MDI power
  • Link aggregation

Configuration

set service lldp
Enable LLDP service
set service lldp management-address <address>
Define IPv4/IPv6 management address transmitted via LLDP. Multiple addresses can be defined. Only addresses connected to the system will be transmitted.
set service lldp interface <interface>
Enable transmission of LLDP information on given <interface>. You can also say all here so LLDP is turned on on every interface.
set service lldp interface <interface> disable
Disable transmit of LLDP frames on given <interface>. Useful to exclude certain interfaces from LLDP when all have been enabled.
set service lldp snmp enable
Enable SNMP queries of the LLDP database
set service lldp legacy-protocols <cdp|edp|fdp|sonmp>

Enable given legacy protocol on this LLDP instance. Legacy protocols include:

  • cdp - Listen for CDP for Cisco routers/switches
  • edp - Listen for EDP for Extreme routers/switches
  • fdp - Listen for FDP for Foundry routers/switches
  • sonmp - Listen for SONMP for Nortel routers/switches

Operation

show lldp neighbors

Displays information about all neighbors discovered via LLDP.

[email protected]:~$ show lldp neighbors
Capability Codes: R - Router, B - Bridge, W - Wlan r - Repeater, S - Station
                  D - Docsis, T - Telephone, O - Other

Device ID                 Local     Proto  Cap   Platform             Port ID
---------                 -----     -----  ---   --------             -------
BR2.vyos.net              eth0      LLDP   R     VyOS 1.2.4           eth1
BR3.vyos.net              eth0      LLDP   RB    VyOS 1.2.4           eth2
SW1.vyos.net              eth0      LLDP   B     Cisco IOS Software   GigabitEthernet0/6
show lldp neighbors detail

Get detailed information about LLDP neighbors.

[email protected]:~$ show lldp neighbors detail
-------------------------------------------------------------------------------
LLDP neighbors:
-------------------------------------------------------------------------------
Interface:    eth0, via: LLDP, RID: 28, Time: 0 day, 00:24:33
  Chassis:
    ChassisID:    mac 00:53:00:01:02:c9
    SysName:      BR2.vyos.net
    SysDescr:     VyOS 1.3-rolling-201912230217
    MgmtIP:       192.0.2.1
    MgmtIP:       2001:db8::ffff
    Capability:   Bridge, on
    Capability:   Router, on
    Capability:   Wlan, off
    Capability:   Station, off
  Port:
    PortID:       mac 00:53:00:01:02:c9
    PortDescr:    eth0
    TTL:          120
    PMD autoneg:  supported: no, enabled: no
      MAU oper type: 10GigBaseCX4 - X copper over 8 pair 100-Ohm balanced cable
  VLAN:         201 eth0.201
  VLAN:         205 eth0.205
  LLDP-MED:
    Device Type:  Network Connectivity Device
    Capability:   Capabilities, yes
    Capability:   Policy, yes
    Capability:   Location, yes
    Capability:   MDI/PSE, yes
    Capability:   MDI/PD, yes
    Capability:   Inventory, yes
    Inventory:
      Hardware Revision: None
      Software Revision: 4.19.89-amd64-vyos
      Firmware Revision: 6.00
      Serial Number: VMware-42 1d 83 b9 fe c1 bd b2-7
      Manufacturer: VMware, Inc.
      Model:        VMware Virtual Platform
      Asset ID:     No Asset Tag
-------------------------------------------------------------------------------
show lldp neighbors interface <interface>
Show LLDP neighbors connected via interface <interface>.
show log lldp
Used for troubleshooting.