(Optional) Optimizing LLDP Performance
This section describes how to adjust LLDP parameters based on the load of a network to reduce the consumption of system resources and optimize the LLDP performance.
Context
Both the LLDP packet sending interval and delay should be shorter than the time that device information is held in neighbors (TTL). Otherwise, the neighbor device cannot receive the LLDP packets sent by the FW after the information about the FW ages on the neighbor device. And TTL = Min (65535, (interval x hold)), so when adjusting the value of Interval between sending LLDP packets, delay in sending LLDP packets, or hold time multiplier of device information on neighbors, you should consider the other values because they are restricted.
Interval between sending LLDP packets
When the LLDP status of the device keeps unchanged, the device sends LLDP packets to the neighbors at a certain interval.
Delay in sending LLDP packets
There is a delay before the device sends an LLDP packet to the neighbor when the device status changes frequently.
Hold time multiplier of device information on neighbors
The hold time multiplier is used to calculate the Time to Live (TTL), which determines how long information about a device can be saved on the neighbors. The storage time calculation formula is: TTL = Min (65535, (interval x hold)).
- TTL is the smaller value between 65535 and (interval x hold).
- interval indicates the interval at which the device sends LLDP packets to neighbors.
- hold indicates the hold time multiplier of device information on neighbors.
Number of packets rapidly sent to the neighbor node
The number of packets rapidly sent is the value of count, that is, the number of packets consecutively sent from an interface to the neighbor node when the working mode of the interface changes from disable or rx to tx or txrx. This can help neighbors quickly obtain information about the local device, and help the NMS quickly detect network topology.
A device sends LLDP packets to neighbors every 1 second if LLDP packets are being sent in quick succession and are not restricted by the delay time. After sending a set number of LLDP packets in quick succession, the device periodically sends LLDP packets to neighbors based on the interval set by the lldp message-transmission interval command.
Interface initialization latency
When the LLDP working mode of an interface changes, the system initializes the interface status. By setting the interface initialization latency, you can avoid the repeated initialization of the interface due to frequent working mode changes.
Interval in polling check mode
After the polling function is enabled, LLDP packets are rapidly sent to notify other devices of the changes if certain configurations change.
Procedure
- Access the system view.
- Specify the interval for sending LLDP packets.
lldp message-transmission interval interval
By default, the interval is 30 seconds.
- Specify the delay for sending LLDP packets.
lldp message-transmission transmit-delay interval
By default, the delay is 2 seconds.
- Configure the TTL multiplier.
lldp message-transmission hold-multiplier hold-multiplier
By default, the TTL multiplier is 4.
- Configure the number of LLDP packets rapidly sent by the FW to a neighbor node.
lldp message-transmission fast count
By default, the number of LLDP packets rapidly sent is 3.
- Set the interface initialization latency.
lldp restart-delay interval
By default, the interface initialization latency is 2 seconds.
- Enable the checks in polling mode and specify the check interval.
lldp check-change-interval interval
By default, the polling function is not enabled.