The lldpd  daemon implements the IEEE802.1AB (Link Layer Discovery Protocol, or LLDP) standard. LLDP allows you to know which ports are neighbors of a given port. By default, lldpd runs as a daemon and is started at system boot. lldpd command line arguments are placed in /etc/default/lldpdlldpd configuration options are placed in /etc/lldpd.conf or under /etc/lldpd.d/.

For more details on the command line arguments and config options, please see man lldpd(8).

lldpd supports CDP (Cisco Discovery Protocol, v1 and v2). lldpd logs by default into /var/log/daemon.log with an lldpd prefix.

lldpcli is the CLI tool to query the lldpd daemon for neighbors, statistics and other running configuration information. See man lldpcli(8) for details.

Contents

 (Click to expand)

Commands

  • lldpd (daemon)
  • lldpcli (interactive CLI)

Man Pages

  • man lldpd
  • man lldpcli

Configuring LLDP

You configure lldpd settings in /etc/lldpd.conf or /etc/lldpd.d/. Such a configuration persists when you reboot the switch.

Here is an example configuration:

cumulus@switch:~$ sudo cat /etc/lldpd.conf
configure lldp tx-interval 40
configure lldp tx-hold 3
configure system interface pattern-blacklist "eth0"

lldpd logs to /var/log/daemon.log with the lldpd prefix:

cumulus@switch:~$ sudo tail -f /var/log/daemon.log  | grep lldp
Aug  7 17:26:17 switch lldpd[1712]: unable to get system name
Aug  7 17:26:17 switch lldpd[1712]: unable to get system name
Aug  7 17:26:17 switch lldpcli[1711]: lldpd should resume operations
Aug  7 17:26:32 switch lldpd[1805]: NET-SNMP version 5.4.3 AgentX subagent connected

Example lldpcli Commands

To see all neighbors on all ports/interfaces:

cumulus@switch:~$ sudo lldpcli show neighbors
---------------------------------------------------------------------
LLDP neighbors:
---------------------------------------------------------------------
Interface:    eth0, via: CDPv1, RID: 72, Time: 0 day, 00:33:40
Chassis:
   ChassisID:    local test-server-1
   SysName:      test-server-1
   SysDescr:     Linux running on
Linux 3.2.2+ #1 SMP Mon Jun 10 16:21:22 PDT 2013 ppc
   MgmtIP:       192.0.2.72
   Capability:   Router, on
Port:
   PortID:       ifname eth1
---------------------------------------------------------------------
Interface:    swp1, via: CDPv1, RID: 87, Time: 0 day, 00:36:27
nChassis:
   ChassisID:    local T1
   SysName:      T1
   SysDescr:     Linux running on
Cumulus RMP
   MgmtIP:       192.0.2.15
   Capability:   Router, on
Port:
   PortID:       ifname swp1
   PortDescr:    swp1
---------------------------------------------------------------------
... and more (output truncated to fit this doc)

To see neighbors on specific ports:

cumulus@switch:~$ sudo lldpcli show neighbors ports swp1,swp2
 ---------------------------------------------------------------------
 Interface:    swp1, via: CDPv1, RID: 87, Time: 0 day, 00:36:27
 Chassis:
    ChassisID:    local T1
    SysName:      T1
    SysDescr:     Linux running on
 Cumulus RMP
    MgmtIP:       192.0.2.15
    Capability:   Router, on
 Port:
    PortID:       ifname swp1
    PortDescr:    swp1
 ---------------------------------------------------------------------
 Interface:    swp2, via: CDPv1, RID: 123, Time: 0 day, 00:36:27
 Chassis:
    ChassisID:    local T2
    SysName:      T2
    SysDescr:     Linux running on
 Cumulus RMP
    MgmtIP:       192.0.2.15
    Capability:   Router, on
 Port:
    PortID:       ifname swp1
    PortDescr:    swp1

To see lldpd statistics for all ports:

cumulus@switch:~$ sudo lldpcli show statistics
----------------------------------------------------------------------
LLDP statistics:
----------------------------------------------------------------------
Interface:    eth0
  Transmitted:  9423
  Received:     17634
  Discarded:    0
  Unrecognized: 0
  Ageout:       10
  Inserted:     20
  Deleted:      10
--------------------------------------------------------------------
Interface:    swp1
  Transmitted:  9423
  Received:     6264
  Discarded:    0
  Unrecognized: 0
  Ageout:       0
  Inserted:     2
  Deleted:      0
---------------------------------------------------------------------
Interface:    swp2
  Transmitted:  9423
  Received:     6264
  Discarded:    0
  Unrecognized: 0
  Ageout:       0
  Inserted:     2
  Deleted:      0
---------------------------------------------------------------------
Interface:    swp3
  Transmitted:  9423
  Received:     6265
  Discarded:    0
  Unrecognized: 0
  Ageout:       0
  Inserted:     2
  Deleted:      0
----------------------------------------------------------------------
... and more (output truncated to fit this document)

To see lldpd statistics summary for all ports:

cumulus@switch:~$ sudo lldpcli show statistics  summary
---------------------------------------------------------------------
LLDP Global statistics:
---------------------------------------------------------------------
Summary of stats:
  Transmitted:  648186
  Received:     437557
  Discarded:    0
  Unrecognized: 0
  Ageout:       10
  Inserted:     38
  Deleted:      10

To see the lldpd running configuration:

cumulus@switch:~$ sudo lldpcli show running-configuration
--------------------------------------------------------------------
Global configuration:
--------------------------------------------------------------------
Configuration:
  Transmit delay: 1
  Transmit hold: 4
  Receive mode: no
  Pattern for management addresses: (none)
  Interface pattern: (none)
  Interface pattern for chassis ID: (none)
  Override description with: (none)
  Override platform with: (none)
  Advertise version: yes
  Disable LLDP-MED inventory: yes
  LLDP-MED fast start mechanism: yes
  LLDP-MED fast start interval: 1
--------------------------------------------------------------------
 Runtime Configuration (Advanced)

A runtime configuration does not persist when you reboot the switch — all changes are lost.

To configure active interfaces:

lldpcli configure system interface pattern "swp*"

To configure inactive interfaces:

lldpcli configure system interface pattern-blacklist "eth0"

 

The active interface list always overrides the inactive interface list.

To reset any interface list to none:

lldpcli configure system interface pattern-blacklist ""

Enabling the SNMP Subagent in LLDP

LLDP does not enable the SNMP subagent by default. You need to edit /etc/default/lldpd and enable the -x option. 

cumulus@switch:~$ sudo nano /etc/default/lldpd 
# Uncomment to start SNMP subagent and enable CD
P, SONMP and EDP protocol 
#DAEMON_ARGS="-x -c -s -e" # Enable CDP by default DAEMON_ARGS="-c" DAEMON_ARGS="-x"

Configuration Files

  • /etc/lldpd.conf
  • /etc/lldpd.d
  • /etc/default/lldpd

Caveats and Errata

  • Annex E (and hence Annex D) of IEEE802.1AB (lldp) is not supported.