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LLDPD(8) System Manager's Manual LLDPD(8)

NAME

lldpd — LLDP daemon

SYNOPSIS

lldpd [-dxcseiklr] [-S description] [-X socket] [-m management] [-I interfaces] [-M class] [-H hide]

DESCRIPTION

lldpd is a daemon able to receive and send LLDP frames. The Link Layer Discovery Protocol is a vendor-neutral Layer 2 protocol that allows a network device to advertise its identity and capabilities on the local network.
lldpd also implements an SNMP subagent using AgentX protocol to interface to a regular SNMP agent like Net-SNMP. To enable this subagent, you need something like that in your snmpd.conf(5): 
master agentx
This daemon implements both reception and sending. It will collect various information to send LLDP frames to all Ethernet interfaces, including management address, speed and VLAN names.
The options are as follows:
-d
Do not daemonize. If this option is specified, lldpd will run in the foreground and log to stderr. This option can be specified many times to increase verbosity.
-k
Disable advertising of kernel release, version and machine. Kernel name (ie: Linux) will still be shared, and Inventory software version will be set to 'Unknown'.
-S description
Override system description with the provided description. The default description is the kernel name, the node name, the kernel version, the build date and the architecture (except if you use the -k flag described above).
-x
Enable SNMP subagent. With this option, lldpd will enable an SNMP subagent using AgentX protocol. This allows you to get information about local system and remote systems through SNMP.
-X socket
Enable SNMP subagent using the specified socket. lldpd will enable an SNMP subagent using AgentX protocol for the given socket. This option implies the previous one. The default socket is usally /var/agentx/master. You can specify a socket like tcp:127.0.0.1:705 for example. Since the process that will open this socket is enclosed in a chroot, you need to specify an IP address (not a hostname) when using a TCP or UDP socket.
-c
Enable the support of CDP protocol to deal with Cisco routers that do not speak LLDP. If repeated, CDPv1 packets will be sent even when there is no CDP peer detected.
-f
Enable the support of FDP protocol to deal with Foundry routers that do not speak LLDP. If repeated, FDP packets will be sent even when there is no FDP peer detected.
-s
Enable the support of SONMP protocol to deal with Nortel routers and switches that do not speak LLDP. If repeated, SONMP packets will be sent even when there is no SONMP peer detected.
-e
Enable the support of EDP protocol to deal with Extreme routers and switches that do not speak LLDP. If repeated, EDP packets will be sent even when there is no EDP peer detected.
-l
Force to send LLDP packets even when there is no LLDP peer detected but there is a peer speaking another protocol detected. By default, LLDP packets are sent when there is a peer speaking LLDP detected or when there is no peer at all.
-r
Receive-only mode. With this switch, lldpd will not send any frame. It will only listen to neighbors.
-m management
Specify the management address of this system. lldpd only sends one management address. It will use the first one that it finds or the one that you specify with this option. This option can use wildcards.
-I interfaces
Specify which interface to listen to. Without this option, lldpd will listen on all available interfaces. This option can use wildcards. Several interfaces can be specified separated by commas. It is also possible to blacklist an interface by suffixing it with an exclamation mark. When an interface is both specified with and without an exclamation mark, it is blacklisted. For example, with eth*,!eth1,!eth2 lldpd will only listen to interfaces starting by eth with the exception of eth1 and eth2.
-M class
Enable emission of LLDP-MED frame. The class should be one of the following value:
1
Generic Endpoint (Class I)
2
Media Endpoint (Class II)
3
Communication Device Endpoints (Class III)
4
Network Connectivity Device
-i
Disable LLDP-MED inventory TLV transmission. lldpd will still receive (and publish using SNMP if enabled) those LLDP-MED TLV but will not send them. Use this option if you don't want to transmit sensible information like serial numbers.
-H hide
Filter neighbors. See section FILTERING NEIGHBORS for details.

FILTERING NEIGHBORS

In a heterogeneous network, you may see several different hosts on the same port, even if there is only one physically plugged to this port. For example, if you have a Nortel switch running LLDP which is plugged to a Cisco switch running CDP and your host is plugged to the Cisco switch, you will see the Nortel switch as well because LLDP frames are forwarded by the Cisco switch. This may not be what you want. The -H hide parameter will allow you to tell lldpd to discard some frames that it receives and to avoid to send some other frames.
Incoming filtering and outgoing filtering are unrelated. Incoming filtering will hide some remote ports to get you a chance to know exactly what equipment is on the other side of the network cable. Outgoing filtering will avoid to use some protocols to avoid flooding your network with a protocol that is not handled by the nearest equipment. Keep in mind that even without filtering, lldpd will speak protocols for which at least one frame has been received and LLDP otherwise (there are other options to change this behaviour, for example -cc, -ss, -ee, -ll and -ff ).
When enabling incoming filtering, lldpd will try to select one protocol and filter out neighbors using other protocols. To select this protocol, the rule is to take the less used protocol. If on one port, you get 12 CDP neighbors and 1 LLDP neighbor, this mean that the remote switch speaks LLDP and does not filter CDP. Therefore, we select LLDP. When enabling outgoing filtering, lldpd will also try to select one protocol and only speaks this protocol. The filtering is done per port. Each port may select a different protocol.
There are two additional criteria when enabling filtering: allowing one or several protocols to be selected (in case of a tie) and allowing one or several neighbors to be selected. Even when allowing several protocols, the rule of selecting the protocols with the less neighbors still apply. If lldpd selects LLDP and CDP, this means they have the same number of neighbors. The selection of the neighbor is random. Incoming filtering will select a set of neighbors to be displayed while outgoing filtering will use the selected set of neighbors to decide which protocols to use: if a selected neighbor speaks LLDP and another one CDP, lldpd will speak both CDP and LLDP on this port.
There are some corner cases. A typical example is a switch speaking two protocols (CDP and LLDP for example). You want to get the information from the best protocol but you want to speak both protocols because some tools use the CDP table and some other the LLDP table.
The table below summarize all accepted values for the -H hide parameter. The default value is 15 which corresponds to the corner case described above. The filter column means that filtering is enabled. The 1proto column tells that only one protocol will be kept. The 1neigh column tells that only one neighbor will be kept.
incoming outgoing
filter 1proto 1neigh filter 1proto 1neigh
0
1 x x x x
2 x x
3 x x
4 x x
5 x
6 x
7 x x x x x
8 x x x
9 x x x x
10 x x
11 x x
12 x x x x
13 x x x
14 x x x x
15 x x x
16 x x x x x
17 x x x x
18 x x x
19 x x x

FILES

/var/run/lldpd.socket
Unix-domain socket used for communication with lldpctl(8).

SEE ALSO

lldpctl(8), snmpd(8)

HISTORY

The lldpd program is inspired from a preliminary work of Reyk Floeter.

AUTHORS

The lldpd program was written by Pierre-Yves Ritschard ⟨pyr@openbsd.org⟩, and Vincent Bernat ⟨bernat@luffy.cx⟩.
August 21, 2008 Debian