92
LLDP CONFIGURATION
When configuring LLDP, go to these sections for information you are interested in:
■ “Introduction to LLDP” on page 1181
■ “LLDP Configuration Tasks List” on page 1184
■ “Performing Basic LLDP Configuration” on page 1184
■ “Configuring LLDP Trap” on page 1188
■ “Displaying and Maintaining LLDP” on page 1188
■ “LLDP Configuration Example” on page 1189
Introduction to LLDP
Overview Link Layer Discovery Protocol (LLDP) operates on data link layer. It stores and
maintains the information about the local device and the devices directly
connected to it for network administrators to manage networks through NMS
(network management systems). In LLDP, device information is encapsulated in
LLDPDUs in the form of TLV (meaning type, length, and value) triplets and is
exchanged between directly connected devices. Information in LLDPDUs received
is restored in standard MIB (management information base).
LLDP Fundamental LLDP operating mode
LLDP can operate in one of the following modes.
■ TxRx mode. A port in this mode sends and receives LLDPDUs.
■ Tx mode. A port in this mode only sends LLDPDUs.
■ Rx mode. A port in this mode only receives LLDPDUs.
■ Disable mode. A port in this mode does not send or receive LLDPDUs.
LLDP is initialized when an LLDP-enabled port changes to operate in another LLDP
operating mode. To prevent LLDP from being initialized too frequently, LLDP
undergoes a period before being initialized on an LLDP-enabled port when the
port changes to operate in another LLDP operating mode. The period is known as
initialization delay, which is determined by the re-initialization delay timer.
Sending LLDPDUs
An LLDP-enabled device operating in the TxRx mode or Tx mode sends LLDPDUs to
its directly connected devices periodically. It also sends LLDPDUs when the local
configuration changes to inform the neighboring devices of the change timely. In
any of the two cases, an interval exists between two successive operations of
sending LLDPDUs. This prevents the network from being overwhelmed by
LLDPDUs even if the LLDP operating mode changes frequently.
To Next Page
Loading...
