229
Type Description
Extended Power-via-MDI
Allows a network device or terminal device to advertise power supply
capability. This TLV is an extension of the Power Via MDI TLV.
Hardware Revision
Allows a terminal device to advertise its hardware version.
Firmware Revision
Allows a terminal device to advertise its firmware version.
Software Revision
Allows a terminal device to advertise its software version.
Serial Number
Allows a terminal device to advertise its serial number.
Manufacturer Name
Allows a terminal device to advertise its vendor name.
Model Name
Allows a terminal device to advertise its model name.
Asset ID
Allows a terminal device to advertise its asset ID. The typical case is
that the user specifies the asset ID for the endpoint to facilitate
directory management and asset tracking.
Location Identification
Allows a network device to advertise the appropriate location
identifier information for a terminal device to use in the context of
location-based applications.
Management address
The network management system uses the management address of a device to identify and manage the
device for topology maintenance and network management. The management address TLV
encapsulates the management address.
How LLDP works
Operating modes of LLDP
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.
Each time the LLDP operating mode of a port changes, its LLDP protocol state machine re-initializes. A
re-initialization delay, which is user configurable, prevents LLDP from being initialized too frequently at
times of frequent changes to the operating mode. With this delay configured, before a port can initialize
LLDP, it must wait for the specified interval after the LLDP operating mode changes.
Transmitting LLDPDUs
An LLDP-enabled port operating in TxRx mode or Tx mode sends LLDPDUs to its directly connected
devices both periodically and when the local configuration changes. To prevent LLDPDUs from
overwhelming the network during times of frequent changes to local device information, an interval is
introduced between two successive LLDPDUs.
This interval is shortened to 1 second in either of the following cases:
•
A new neighbor is discovered. A new LLDPDU is received and carries device information new to the
local device.
•
The LLDP operating mode of the port changes from Disable or Rx to TxRx or Tx.
