Quanta Cloud Technology QuantaMesh QNOS5, Configuration Manual

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not in sync, the MLAG behavior is undefined. Once the above configuration is in place and consistent, the two
switches will form a MLAG that operates in the desired manner. The MLAG may form even if the
configuration is not consistent, however, it may not operate consistently in all situations.
3.5.3. MLAG Fast Failover
Prior to QNOS version, when the primary switch fails, secondary switch restarts the LACP protocol on its
MLAG member ports. STP is also restarted on secondary device’s MLAG member ports. Until the LACP and
STP reconverges, the partner device is disconnected from the MLAG domain.
With fast failover support, neither LACP reconvergence nor STP reconvergence occurs, and minimal traffic
loss is observed when primary device fails. During the failover, traffic that is being forwarded using the links
connected to primary device will failover to links connected to the secondary device. The traffic disruption
is limited to the time required for the partner devices dual-attached to the MLAG domain to detect the link
down(links connected to primary device) and redistribute the traffic using the links connected to the
secondary device.
3.5.4. MLAG Configuration
Refer to Figure 8 for a visual overview of the MLAG configuration steps.
Figure 3-8: MLAG Configuration Diagram
To configure MLAG:
1. Enter VLAN data base mode and create the MLAG VLANs.
(QCT) (Config)#vlan database
(QCT) (Vlan)#vlan 1-100
2. Enable the MLAG feature.