A Link Aggregation Group (LAG) optimizes port usage by linking a group of ports together to form a single, logical, higher-bandwidth link. Aggregating ports multiplies the bandwidth and increases port flexibility for the switch. Link Aggregation is most used to link bandwidth intensive network devices, such as a server, to the backbone of a network.
The participating ports are called members of a port trunk group. Since all ports of the trunk group must be configured to operate in the same manner, the configuration of one port of the trunk group is applied to all ports of the trunk group. Thus, you will only need to configure one of the ports in a trunk group. A specific data communication packet will always be transmitted over the same port in a trunk group. This ensures the delivery of individual frames of a data communication packet will be received in the correct order. The traffic load of the LAG will be balanced among the ports according to aggregate arithmetic. If the connections of one or several ports are broken, the traffic of these ports will be transmitted on the normal ports to guarantee reliable connection.