Web Management Guide

Chapter 12 | Basic Administration Protocols
Link Layer Discovery Protocol
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Setting LLDP Timing
Attributes
Use the Administration > LLDP (Configure Global) page to set attributes for general
functions such as globally enabling LLDP on the switch, setting the message
ageout time, and setting the frequency for broadcasting general advertisements or
reports about changes in the LLDP MIB.
Parameters
These parameters are displayed:
◆ LLDP – Enables LLDP globally on the switch. (Default: Enabled)
◆ Transmission Interval – Configures the periodic transmit interval for LLDP
advertisements. (Range: 5-32768 seconds; Default: 30 seconds)
◆ Hold Time Multiplier – Configures the time-to-live (TTL) value sent in LLDP
advertisements as shown in the formula below. (Range: 2-10; Default: 4)
The time-to-live tells the receiving LLDP agent how long to retain all
information pertaining to the sending LLDP agent if it does not transmit
updates in a timely manner. Note that if the local interface attached to a remote
device is shut down or otherwise disabled, information about the remote
device is purged immediately.
TTL in seconds is based on the following rule:
minimum value ((Transmission Interval * Holdtime Multiplier), or 65535)
Therefore, the default TTL is 4*30 = 120 seconds.
◆ Delay Interval – Configures a delay between the successive transmission of
advertisements initiated by a change in local LLDP MIB variables.
(Range: 1-8192 seconds; Default: 2 seconds)
The transmit delay is used to prevent a series of successive LLDP transmissions
during a short period of rapid changes in local LLDP MIB objects, and to
increase the probability that multiple, rather than single changes, are reported
in each transmission.
This attribute must comply with the rule:
(4 * Delay Interval) ≤
Transmission Interval
◆ Reinitialization Delay – Configures the delay before attempting to re-initialize
after LLDP ports are disabled or the link goes down. (Range: 1-10 seconds;
Default: 2 seconds)
When LLDP is re-initialized on a port, all information in the remote systems
LLDP MIB associated with this port is deleted.
◆ Notification Interval – Configures the allowed interval for sending SNMP
notifications about LLDP MIB changes. (Range: 5-3600 seconds; Default: 5
seconds)
This parameter only applies to SNMP applications which use data stored in the
LLDP MIB for network monitoring or management.
Information about changes in LLDP neighbors that occur between SNMP
notifications is not transmitted. Only state changes that exist at the time of a