LLDP frame transmission
After LLDP is enabled on a device, the device periodically sends LLDP frames to neighbors. When the local configuration changes, the device sends LLDP frames to notify neighbors of the changes. To reduce the number of LLDP frames sent when the local information changes frequently, the device waits for a period before sending the next LLDP frame.
LLDP frame reception
An LLDP-capable device checks the validity of received LLDP frames and the TLVs in those frames. When determining that an LLDP frame and its TLVs are valid, the local device saves neighbor information and sets the aging time of neighbor information on the local device to the TTL value carried in the received LLDPDU. If the TTL value carried in the received LLDPDU is 0, the neighbor information ages out immediately.