Huawei AR530 Series, Руководство по настройке

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As shown in Figure 2-8 , Port 1, Port 2, and Port 3 are member interfaces of an Eth-Trunk;
DeviceA acts as the Actor; the upper threshold for the number of active interfaces is 2;
LACP priorities of Port 1, Port 2, and Port 3 are 10, 20, and 30 respectively. When LACP
negotiation is complete, Port 1 and Port 2 are selected as active interfaces because their
LACP priorities are higher, and Port 3 is used as the backup interface.
Figure 2-8 LACP preemption
DeviceA DeviceB
Eth-Trunk
Active link
Backup link
LACP port priority
Port 1 10
Port 2 20
Port 3 30
Port 1
Port 2
Port 3
Actor
LACP preemption is used in the following situations:
– Port 1 becomes faulty, and then recovers. When Port 1 fails, Port 3 replaces Port 1 to
transmit services. After Port 1 recovers, if LACP preemption is not enabled on the Eth-
Trunk, Port 1 still retains in backup state. If LACP preemption is enabled on the Eth-
Trunk, Port 1 and Port 3 become the active interface and backup interface respectively.
– If LACP preemption is enabled and Port 3 needs to replace Port 1 or Port 2 to become
the active interface, set the highest LACP priority value for Port 3. When LACP
preemption is not enabled, the system does not re-select the active interface even if the
priority of a backup interface is higher than that of the active interface.
l LACP preemption delay
After LACP preemption occurs, a backup link waits for a given period of time and then
switches to the active status. This period is called LACP preemption delay. The LACP
preemption delay is used to prevent unstable data transmission over an Eth-Trunk link
caused by frequent status changes of member links.
As shown in Figure 2-8 , Port 1 becomes inactive due to a link fault. Then the link of Port
1 recovers. If LACP preemption is enabled and the LACP preemption delay is set, Port 1
switches to be active after the LACP preemption delay.
l Switchover between active and inactive links
In LACP mode, a link switchover in an LAG is triggered if a device at one end detects one
of the following events:
–
An active link goes Down.
– Ethernet OAM detects a link fault.
– LACP detects a link fault.
–
An active interface becomes unavailable.
– When LACP preemption is enabled, a backup interface's priority is changed to be higher
than that of the current active interface.
When any of the preceding events occurs, perform the following operations:
1. Shut down the faulty link.
Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
2 Link Aggregation Configuration
Issue 01 (2014-11-30) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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