LLDP is a network layer 2 protocol, called “Link Layer Discovery Protocol”.
It transmits many information about the device and ports to all
network neighbors. It is vendor independent and specified in IEEE 802.1AB
There are many similar vendor specific protocols, f.e. CDP (Cisco) and FDP (Foundry/Brocade).
The information is sent as a LLDPDU in a TLV (Type, Length, Value) format at a fixed
interval. Included in the transmitted data is the hostname, description, port name and many
How is LLDP used on a Brocade FastIron device?
Enabling LLDP is easy: device(config)# lldp run
At this time, LLDP is enabled globally and transmits and receives LLDPDUs.
To see neighbour information, use show lldp neighbors or show lldp neighbors detail
See something? Exactly, there are not only information about the other router, but
also about linux servers. More on that later.
Here is an example of the detail output:
Using LLDP on Linux
As seen on the above examples, not only network devices are able to use LLDP, but also
Linux. The software is called lldpd and can
simply be installed with apt-get install lldpd
After starting lldpd, LLDPDUS are received and transmitted on all local network
interfaces. To query the received information, the included tool lldpcli tool
can be used:
The lldpd software not only speaks LLDP, but also a bunch of other similar protocols:
Many network management tools are able to draw a network map using this information.