How to configure LACP on our Smart/ Managed Switch?

Introduction

LACP (Link Aggregation Control Protocol) is defined in IEEE802.3ad and enables the dynamic link aggregation and disaggregation by exchanging the LACP packets with its partner. The switch can dynamically group similar ports into a single logical link, which will highly extend the bandwidth and flexibly balance the load.

Application scenario

As is shown in the picture above, we take TL-SG5428 and T3700 as example and we will configure ports 26,27,28 on TL-SG5428 and ports 21,22,2 on T3700 correspondingly as LACP.

Note: For the member ports in an aggregation group, their basic configurations must be the same. The basic configuration includes STP, QOS, GVRP, VLAN, port attributes, MAC Address Learning mode and other associated settings. If you are not sure about these basic configurations, you can export the config file and reset the device and then try it again. We highly suggest you configure the LAG function before configuring any other function for member ports.

Configuration

Step1: login to the management interface of the TL-SG5428, and go to Switch--LAG--LACP, you can designate a System Priority for the TL-SG5428 or leave as default value, The default value is 32768. And then choose the ports 26/27/28, designate an Admin Key 2 for these ports. The ports with the same Admin Key will be aggregated to the same group. Choose the Mode as Active and Status as Enable. And then click Apply to take the setting into effect. The result will show as below:

Note:

1.A lower system priority value indicates a higher system priority. When exchanging information between systems, the system with higher priority determines which link aggregation a port belongs to, and the system with lower priority adds the proper ports to the link aggregation according to the selection of its partner. If the System Priority value is the same, the device with smaller MAC address owns higher priority.

2.There are two mode of the port, Active and Passive. In Active mode, the port can send LACP packets actively while in Passive mode, the port can only send LACP packets after it has received a LACP packet. It is suggested that set one side as Active mode and the other side as Passive mode.

Step2: almost the same settings as the T3700. Login to the management interface of the T3700, and go to Switch--LAG--LACP, you can designate a System Priority for the T3700 or leave as default value, The default value is 32768. And then choose the ports 21/22/23, designate an Admin Key 3 for these ports. Choose the Mode as Passive and Statusas Enable. And then click Apply to take the setting into effect. The configuration will show as below:

Now, the configuration is done, and we can check the result in the LAG Table. Since the lines are aggregated or disaggregated dynamically into the group, we can only see the ports that are added to the group at this moment in the Member.