Link Layer Discovery Protocol
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/lldpd. lldpd 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.
Configuring LLDP
You configure lldpd settings in /etc/lldpd.conf or /etc/lldpd.d/.
Here is an example persistent configuration:
cumulus@switch:~$ sudo cat /etc/lldpd.conf
configure lldp tx-interval 40
configure lldp tx-hold 3
configure system interface pattern *,!eth0,swp*
The last line in the example above shows that LLDP is disabled on eth0.
You can disable LLDP on a single port by editing the
/etc/default/lldpd file. This file specifies the default options to
present to the lldpd service when it starts. The following example
uses the -I option to disable LLDP on swp43:
cumulus@switch:~$ sudo nano /etc/default/lldpd
# Add "-x" to DAEMON_ARGS to start SNMP subagent
# Enable CDP by default
DAEMON_ARGS="-c -I !swp43"
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: LLDP, RID: 1, Time: 0 day, 17:38:08
Chassis:
ChassisID: mac 08:9e:01:e9:66:5a
SysName: PIONEERMS22
SysDescr: Cumulus Linux version 2.5.4 running on quanta lb9
MgmtIP: 192.168.0.22
Capability: Bridge, on
Capability: Router, on
Port:
PortID: ifname swp47
PortDescr: swp47
-------------------------------------------------------------------------------
Interface: swp1, via: LLDP, RID: 10, Time: 0 day, 17:08:27
Chassis:
ChassisID: mac 00:01:00:00:09:00
SysName: MSP-1
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.9
MgmtIP: fe80::201:ff:fe00:900
Capability: Bridge, off
Capability: Router, on
Port:
PortID: ifname swp1
PortDescr: swp1
-------------------------------------------------------------------------------
Interface: swp2, via: LLDP, RID: 10, Time: 0 day, 17:08:27
Chassis:
ChassisID: mac 00:01:00:00:09:00
SysName: MSP-1
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.9
MgmtIP: fe80::201:ff:fe00:900
Capability: Bridge, off
Capability: Router, on
Port:
PortID: ifname swp2
PortDescr: swp2
-------------------------------------------------------------------------------
Interface: swp3, via: LLDP, RID: 11, Time: 0 day, 17:08:27
Chassis:
ChassisID: mac 00:01:00:00:0a:00
SysName: MSP-2
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.10
MgmtIP: fe80::201:ff:fe00:a00
Capability: Bridge, off
Capability: Router, on
Port:
PortID: ifname swp1
PortDescr: swp1
-------------------------------------------------------------------------------
Interface: swp4, via: LLDP, RID: 11, Time: 0 day, 17:08:27
Chassis:
ChassisID: mac 00:01:00:00:0a:00
SysName: MSP-2
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.10
MgmtIP: fe80::201:ff:fe00:a00
Capability: Bridge, off
Capability: Router, on
Port:
PortID: ifname swp2
PortDescr: swp2
-------------------------------------------------------------------------------
Interface: swp49s1, via: LLDP, RID: 9, Time: 0 day, 16:55:00
Chassis:
ChassisID: mac 00:01:00:00:0c:00
SysName: TORC-1-2
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.12
MgmtIP: fe80::201:ff:fe00:c00
Capability: Bridge, on
Capability: Router, on
Port:
PortID: ifname swp6
PortDescr: swp6
-------------------------------------------------------------------------------
Interface: swp49s0, via: LLDP, RID: 9, Time: 0 day, 16:55:00
Chassis:
ChassisID: mac 00:01:00:00:0c:00
SysName: TORC-1-2
SysDescr: Cumulus Linux version 3.0.0 running on QEMU Standard PC (i440FX + PIIX, 1996)
MgmtIP: 192.0.2.12
MgmtIP: fe80::201:ff:fe00:c00
Capability: Bridge, on
Capability: Router, on
Port:
PortID: ifname swp5
PortDescr: swp5
-------------------------------------------------------------------------------
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: 30
Transmit hold: 4
Receive mode: no
Pattern for management addresses: (none)
Interface pattern: (none)
Interface pattern blacklist: (none)
Interface pattern for chassis ID: (none)
Override description with: (none)
Override platform with: Linux
Override system name with: (none)
Advertise version: yes
Update interface descriptions: no
Promiscuous mode on managed interfaces: no
Disable LLDP-MED inventory: yes
LLDP-MED fast start mechanism: yes
LLDP-MED fast start interval: 1
Source MAC for LLDP frames on bond slaves: local
Portid TLV Subtype for lldp frames: ifname
--------------------------------------------------------------------
Runtime Configuration (Advanced)
A runtime configuration does not persist when you reboot the switch - all changes are lost.
To configure active interfaces:
cumulus@switch:~$ sudo lldpcli configure system interface pattern "swp*"
To configure inactive interfaces:
cumulus@switch:~$ sudo lldpcli configure system interface pattern *,!eth0,swp*
The active interface list always overrides the inactive interface list.
To reset any interface list to none:
cumulus@switch:~$ sudo lldpcli configure system interface pattern ""
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
# Add "-x" to DAEMON_ARGS to start SNMP subagent
# Enable CDP by default
DAEMON_ARGS="-c"
Caveats and Errata
- Annex E (and hence Annex D) of IEEE802.1AB (lldp) is not supported.