Switches that can perform uplink aggregation

To configure uplink and aggregation switches, use Link Aggregation (LAG) with LACP, starting from the downstream switch and working upstream, ensuring sequential port selection and device compatibility.

Understanding Link Aggregation

Link Aggregation (LAG) combines two or more physical Ethernet ports into a single logical link, increasing bandwidth and providing redundancy. It is commonly used between switches, servers, or NAS devices to improve throughput and maintain network availability if a cable fails. LACP (Link Aggregation Control Protocol) dynamically manages the aggregated links, ensuring both ends agree on the configuration and providing automatic failover .

Step-by-Step Configuration

1. Verify Device Support Ensure both switches and connected devices support LACP or the chosen aggregation protocol. Not all models support aggregation, so check your switch specifications .
2. Plan Your Topology Identify the downstream switch (furthest from the gateway or controller) and the upstream switch. Aggregation should be configured starting from the downstream switch and moving upstream .
3. Select Ports for Aggregation Choose sequential ports on each switch (e.g., ports 3 and 4). Non-sequential ports (e.g., 2 and 4) will not work .
4. Configure the Downstream Switch
   • Access the switch via the UniFi Network Controller or UniFi OS Console.
   • Navigate to Ports → Port Management.
   • Select the first port, choose Aggregate, and then select the additional port(s) to include in the LAG.
   • Name the Link Aggregation Group (LAG) for easy identification.
   • Apply changes and verify the aggregated ports show a green status .
5. Configure the Upstream Switch Repeat the same steps on the upstream switch, ensuring the same number of ports are aggregated and sequentially numbered. Connect the network cables between the aggregated ports of both switches .
6. Verify Operation Use port statistics in the controller to confirm load balancing and redundancy. Traffic from multiple devices should utilize the aggregated link effectively. Remember that a single data stream may not exceed the speed of one physical port, but multiple streams will benefit from the combined bandwidth .

Best Practices

• Use high-quality Ethernet cables (CAT6 or better) to avoid bottlenecks .
• For large networks requiring high resilience, consider MC-LAG (Multi-Chassis Link Aggregation Group) to allow two switches to act as a single logical unit, providing both load balancing and redundancy .
• Always configure downstream switches first to prevent misconfigurations and ensure proper failover .
• Monitor aggregated links regularly to detect any port failures or misconfigurations. By following these steps, you can effectively configure uplink and aggregation switches to maximize network performance, redundancy, and reliability.