How to Configure LAG (LACP) on Omada Switches in Controller Mode

LAG, including static link aggregation and LACP (Link Aggregation Control Protocol), is a technology that can aggregate multiple physical ports into a logical interface, increasing link bandwidth and providing backup ports to enhance connection reliability.

Network Requirements:

In this example, we will use the TL-SG3428X and TL-SG3210 to configure LACP in controller mode.

Note: Before you start configuring LAG, please connect two switches with one Ethernet cable. After finishing the LAG configuration, we can connect switches with the other Ethernet cable.

Configuration Steps:

1. Go to the Devices page to adopt the switches in the Controller.

2. Configure LACP on both switches.

Configure the first switch (TL-SG3210): click on it, go to Port, and edit the port (Port6) to be configured. Check the Profile Overrides box, select Aggregating and select the port (Port7) you want to use, set LAG ID to 1, and select the desired LACP mode. Click Apply.

Configure the settings on the second switch (TL-SG3428X) in a similar way.

Note:

（1）Ensure that both ends of the aggregation link work in the same LAG mode. For example, if the local end works in LACP mode, the peer end should also be set in LACP mode.

（2）There are two modes of LACP: 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 to set one side as Active mode and the other side as Passive mode.

3. Verification

Go to Ports > LAG to check LAG status of both switches.

TL-SG3428X:

TL-SG3210:

After configuring LACP, you may need to change Hash Algorithm. Please go to Devices > Config to change it.

Note:

If you fail to configure LAG, please ensure that the two switches use the same number of physical ports with the same speed and duplex. You may go to Devices > Port > LAG, click Edit, check the Profile Overrides box, then you can change the link speed.

Q&A on Link Aggregation (LAG)

1. Advantages of LAG

LAG can increase link bandwidth by bundling multiple physical interfaces into a logical interface. LAG can also provide link redundancy, so that if one link in the aggregated link fails, the other links can take over the traffic of the failed link, ensuring network continuity.

2. When to use LAG

LAG is commonly used in the backbone links of medium to large-sized networks to improve network reliability and performance, such as in data centers, enterprise networks, and service provider networks. Home users usually do not need to use LAG.

Before configuring LAG, first understand your network requirements, including bandwidth, redundancy, and failover, to avoid incorrectly configuring LAG and wasting network resources.

3. Which devices support LAG

Except for Unmanaged Switches, most Omada Switches support LAG, but Easy Smart Switches usually only support Static LAG.

Some EAPs (such as AP9778) also support LAG.

4. Static LAG vs. LACP

Static LAG does not require protocol support, but needs to be manually configured, and all configured links are active links. A Static LAG group can have up to 8 member links normally.

LACP can automatically manage link aggregation, and in addition to active links, you can also configure backup links. When an active link fails, the backup link with a higher priority will become the active link, ensuring higher link reliability. A LACP group can have up to 16 member links.

5. Active LACP vs. Passive LACP

In Active mode, the port can actively send LACP packets, while in Passive mode, the port can only send LACP packets after receiving a LACP packet. It is recommended to set one device to Active mode and the other device to Passive mode.