How Lldp Works; Protocols And Standards; Lldp Configuration Task List - 3Com 4210G Series Configuration Manual

How LLDP Works

Transmitting LLDP frames
An LLDP-enabled port operating in TxRx mode or Tx mode sends LLDP frames to its directly
connected devices both periodically and when the local configuration changes. To prevent the network
from being overwhelmed by LLDP frames at times of frequent local device information change, an
interval is introduced between two successive LLDP frames.
This interval is shortened to 1 second in either of the following two cases:
A new neighbor is discovered, that is, a new LLDP frame is received carrying device information
new to the local device.
The LLDP operating mode of the port changes from Disable/Rx to TxRx or Tx.
This is the fast sending mechanism of LLDP. With this mechanism, a specific number of LLDP frames
are sent successively at the 1-second interval to help LLDP neighbors discover the local device as
soon as possible. Then, the normal LLDP frame transmit interval resumes.
Receiving LLDP frames
An LLDP-enabled port operating in TxRx mode or Rx mode checks the TLVs carried in every LLDP
frame it receives for validity violation. If valid, the information is saved and an aging timer is set for it
based on the time to live (TTL) TLV carried in the LLDPDU. If the TTL TLV is zero, the information is
aged out immediately.

Protocols and Standards

The protocols and standards related to LLDP include:
IEEE 802.1AB-2005, Station and Media Access Control Connectivity Discovery
ANSI/TIA-1057, Link Layer Discovery Protocol for Media Endpoint Devices

LLDP Configuration Task List

Complete these tasks to configure LLDP:
Performing
Basic LLDP
Configuration
Configuring CDP Compatibility
Configuring LLDP Trapping
Task
Enabling LLDP
Setting LLDP Operating Mode
Setting the LLDP Re-Initialization Delay
Enabling LLDP Polling
Configuring the TLVs to Be Advertised
Configuring the Management Address and Its Encoding
Format
Setting Other LLDP Parameters
Setting an Encapsulation Format for LLDPDUs
5-6
Remarks
Required
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional