Luxul XMS-1024P - Manual (Page 240)

240
XMS-1024P
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LUX-UG-XMS-1024P Vers: 081314
Figure 14-1 LLDPDU Format
The maximum length of the LLDPDU is the maximum information fi eld length allowed
by the particular transmission rate and protocol. In IEEE 802.3 MAC for example, the
maximum LLDPDU length is the maximum Data Field length for the basic Untagged
MAC frame (1500 bytes).
LLDP Mechanism
1. LLDP Admin Status
The transmission and the reception of LLDPDUs is enabled for each Port, making it
possible to confi gure an implementation to restrict the Port either to Transmit only,
Receive only or to allow the Port to both Transmit and Receive. Four LLDP admin
statuses are supported.

Tx&Rx: the Port can both Transmit and Receive LLDPDUs.

Rx_Only: the Port can only Receive LLDPDUs.

Tx_Only: the Port can only Transmit LLDPDUs.

Disable: the Port cannot Transmit or Receive LLDPDUs.
2. LLDPDU Transmission

If the Ports are working in TxRx or Tx mode, they will advertise local information by
sending LLDPDUs.

If there is a change made to the local Device, the SNMP change Notifi cation will be
advertised. To prevent a series of successive LLDPDUs during a short period due to
frequent changes to a local Device, a Transmission Delay Timer is set to ensure that
there is a defi ned time between successive LLDP Frame Transmissions.

If the LLDP Admin Status of the Port is changed from Disable/Rx to TxRx/Tx,
the Fast Start Mechanism will become active. The transmit interval changes to 1
second, several LLDPDUs are sent out, then the Transmit Interval returns to the
regular Interval.
3. LLDPDU Processing
When a Port is working in TxRx or Rx mode, the device will check the validity of the
received LLDPDUs and the attached TLVs. Once verifi ed it will save this neighbor
information to the local Device, then set the Aging Time for the information according