HP V1910 Switch Series User Manual page 239

Item
CDP Compatibility
Fast LLDPDU Count
TTL Multiplier
Trap Interval
Reinit Delay
Tx Delay
Description
Select from the drop-down list to enable or disable CDP compatibility of LLDP.
IMPORTANT:

To enable LLDP to be compatible with CDP on a port, you must set the CDP work
mode (or the CDP operating mode) on the port to TxRx in addition to enabling
CDP compatibility on the Global Setup tab.

As the maximum TTL allowed by CDP is 255 seconds, you must ensure that the
product of the TTL multiplier and the LLDPDU transmit interval is less than 255
seconds for CDP-compatible LLDP to work properly with Cisco IP phones.
Set the number of LLDPDUs sent each time fast LLDPDU transmission is triggered.
Set the TTL multiplier.
The TTL TLV carried in an LLDPDU determines how long the device information
carried in the LLDPDU can be saved on a recipient device. You can configure the
TTL of locally sent LLDPDUs to determine how long information about the local
device can be saved on a neighbor device by setting the TTL multiplier. The TTL is
expressed as TTL multiplier × LLDPDU transit interval.
IMPORTANT:

If the product of the TTL multiplier and the LLDPDU transmit interval is greater
than 65535, the TTL carried in transmitted LLDPDUs takes 65535 seconds.

As the maximum TTL allowed by CDP is 255 seconds, you must ensure that the
product of the TTL multiplier and the LLDPDU transmit interval is less than 255
seconds for CDP-compatible LLDP to work properly with Cisco IP phones.
Set the minimum interval for sending traps.
With the LLDP trapping function enabled on a port, traps are sent out the port to
advertise the topology changes detected over the trap interval to neighbors. By
tuning this interval, you can prevent excessive traps from being sent when topology
is instable.
Set initialization delay for LLDP-enabled ports.
Each time the LLDP operating mode of a port changes, its LLDP protocol state
machine re-initializes. To prevent LLDP from being initialized too frequently at times
of frequent operating mode change, initialization delay is introduced. With this
delay mechanism, a port must wait for the specified interval before it can initialize
LLDP after the LLDP operating mode changes.
Set LLDPDU transmit delay.
With LLDP enabled, a port advertises LLDPDUs to its neighbors both periodically
and when the local configuration changes. To avoid excessive number of LLDPDUs
caused by frequent local configuration changes, an LLDPDU transmit delay is
introduced. Thus, after sending an LLDPDU, the port must wait for the specified
interval before it can send another one.
IMPORTANT:
LLDPDU transmit delay must be less than the TTL to ensure that the LLDP neighbors can
receive LLDPDUs to update information about the device you are configuring before it
is aged out.
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