Link aggregation can work either in manual load balancing, or in the Link Aggregation Control Protocol (LACP) mode. The main difference between the two modes is whether LACP is used.
Manual load balancing mode
In manual load balancing mode, you must manually create an Eth-Trunk and add member interfaces to the Eth-Trunk. LACP is not used. In this mode, all active links load balance traffic evenly. If an active link fails, the other active links share the traffic evenly.
The manual load balancing mode is suitable in scenarios where the link between two directly connected devices requires a high bandwidth but the devices do not support the LACP protocol.
Static LACP mode
In the static LACP mode, two ends exchange LACPDUs to negotiate link aggregation parameters to determine active and inactive interfaces.
In the static LACP mode, you must manually create an Eth-Trunk and add member interfaces to the Eth-Trunk. Differently from the manual load balancing mode, the static LACP mode selects active member interfaces by sending LACPDUs. That is, when a group of interfaces are added to an Eth-Trunk, devices at the two ends determine active and inactive interfaces by sending LACPDUs to each other.
The static LACP mode is called the M:N mode. In this mode, both load balancing and redundancy can be implemented. In a LAG, M links are active to forward data and perform load balancing, and other N links are inactive. The inactive links function as backup links and do not forward data. When one active link fails, the system selects the link with the highest priority among backup links to replace the faulty link. The link with the highest priority becomes active and starts forwarding data.
