When the LLDP status of the device keeps unchanged and the device does not discover new
neighbors, the interface module sends LLDP packets to the neighbors at a certain interval. After
the LLDP transmission interval is set on the device, the LLDP enabled interfaces send LLDP
packets to neighbors at this interval. The interfaces may send LLDP packets at different time
points. The LLDP transmission interval should be set properly and adjusted according to network
loads.
l
A long interval reduces the LLDP packet interaction frequency, and thus saves system
resource. However, if the interval is too long, the device cannot notify neighbors of its
status in time, and the NMS cannot discover the network topology changes in real time.
l
A short interval increases the LLDP packet transmission frequency and enables the NMS
to discover network topology changes in real time. However, if the interval is too short, the
LLDP packets are exchanged frequently, and thus the system load is increased.
There is a delay before the interface module sends an LLDP packet to the neighbor when the
device status changes frequently. After the LLDP transmission delay is set on the device, the
LLDP enabled interfaces send LLDP packets to neighbors after a delay (the delay is the same
as or longer than the delay you specified). The interfaces may send LLDP packets at different
time points. If the device status changes frequently, extend the delay to prevent the device from
frequently sending traps to the NMS. A delay suppresses the network topology flapping. The
LLDP transmission delay should be set properly and adjusted according to network loads.
l
A long delay reduces the LLDP packet interaction frequency, and thus saves system
resource. However, if the delay is too long, the device cannot notify neighbors of its status
in time, and the NMS cannot discover the network topology changes in real time.
l
A short delay increases the LLDP packet transmission frequency and enables the NMS to
discover network topology changes in real time. However, if the delay is too short, the
LLDP packets are exchanged frequently, and thus the system load is increased.
You should consider the value of delay when adjusting the value of interval because it is restricted
by the value of delay.
l
The value of
interval
ranges from 5 to 32768.
l
The value of
interval
must be equal to or greater than four times the value of
delay
.
Therefore, if you want to set
interval
to be smaller than four times the value of
delay
, first
reduce the
delay
value to be equal to or smaller than a quarter of the new
interval
value,
and then reduce the
interval
value.
NOTE
If the
interval
value is smaller than four times the
delay
value, the system displays an error message when
you run the
undo lldp message-transmission delay
command. To run the
undo lldp message-
transmission delay
command in this case, increase the
interval
value to at least four times the
delay
value
first.
Hold time multiplier of device information on neighbors
The hold time multiplier is the Time to Live (TTL) of the packets sent by the local device. You
can specify the storage time of device information on the neighbors. After receiving the LLDP
packets, the neighbors update the aging time of the device information from the sender according
to the TTL.
The storage time calculation formula is: TTL = Min (65535, (
interval
x
hold
)).
l
TTL is the device information storage time. It is the smaller value between 65535 and
(
interval
x
hold
).
Huawei AR150&200 Series Enterprise Routers
Configuration Guide - Network Management
3 LLDP Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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