Receiving Lldp Frames; Lldp Reinitialization Delay; Lldp Trapping; Lldp Tlvs - HPE OfficeConnect 1950 Series User Manual

overwhelming the network during times of frequent changes to local device information, LLDP uses
the token bucket mechanism to rate limit LLDP frames.
LLDP automatically enables the fast LLDP frame transmission mechanism in either of the following
cases:
•
A new LLDP frame is received and carries device information new to the local device.
•
The LLDP operating mode of the LLDP agent changes from Disable or Rx to TxRx or Tx.
The fast LLDP frame transmission mechanism successively sends the specified number of LLDP
frames at a configurable fast LLDP frame transmission interval. The mechanism helps LLDP
neighbors discover the local device as soon as possible. Then, the normal LLDP frame transmission
interval resumes.

Receiving LLDP frames

An LLDP agent operating in TxRx mode or Rx mode confirms the validity of TLVs carried in every
received LLDP frame. If the TLVs are valid, the LLDP agent saves the information and starts an
aging timer. The initial value of the aging timer is equal to the TTL value in the Time To Live TLV
carried in the LLDP frame. When the LLDP agent receives a new LLDP frame, the aging timer
restarts. When the aging timer decreases to zero, the saved information ages out.
By setting the TTL multiplier, you can configure the TTL of locally sent LLDPDUs. The TTL is
expressed by using the following formula:
TTL = Min (65535, (TTL multiplier × LLDP frame transmission interval + 1))
As the expression shows, the TTL can be up to 65535 seconds. TTLs greater than 65535 will be
rounded down to 65535 seconds.

LLDP reinitialization delay

When the LLDP operating mode changes on a port, the port initializes the protocol state machines
after an LLDP reinitialization delay. By adjusting the delay, you can avoid frequent initializations
caused by frequent changes to the LLDP operating mode on a port.

LLDP trapping

LLDP trapping notifies the network management system of events such as newly detected
neighboring devices and link failures.

LLDP TLVs

A TLV is an information element that contains the type, length, and value fields. LLDPDU TLVs
include the following categories:
•
Basic management TLVs
•
Organizationally (IEEE 802.1 and IEEE 802.3) specific TLVs
•
LLDP-MED (media endpoint discovery) TLVs
Basic management TLVs are essential to device management.
Organizationally specific TLVs and LLDP-MED TLVs are used for enhanced device management.
They are defined by standardization or other organizations and are optional for LLDPDUs.
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