Operation Manual

58
LLDP
LinkLayerDiscoveryProtocol(LLDP)istheIEEE802.1AB
standardforSwitchestoadvertisetheiridentity,major
capabilities,andneighborsonthe802LAN.LLDPallows
users to views the discovered information to identify
systemtopologyanddetectfaultycongurationsonthe
LAN. LLDP is essentially a neighbor discovery protocol
that uses Ethernet connectivity to advertise information
to devices on the same LAN and store information
about the network. The information transmitted in
LLDPadvertisementsowinonedirectiononly;from
one device to its neighbors. This information allows the
device to quickly identify a variety of other devices,
resulting in a LAN that interoperates smoothly and
efciently.
LLDP transmits information as packets called LLDP Data
Units (LLDPDUs). A single LLDP Protocol Data Unit (LLDP
PDU)istransmittedwithinasingle802.3Ethernet
frame. A basic LLDPDU consists of a set of Type-
Length-Value elements (TLV), each of which contains
information about the device. A single LLDPDU contains
multiple TLVs. TLVs are short information elements that
communicate complex data. Each TLV advertises a single
type of information.