To switch two ports for aggregation, ensure consistent configuration, use LACP if dynamic, and configure the downstream switch first before the upstream switch.

Key Considerations

When aggregating ports, all ports in the group must share consistent settings, including STP configuration, VLAN membership, port speed, duplex mode, and link type. Only full duplex is supported, and ports can be configured as trunk, hybrid, or access links . If a port's attributes are modified, the other ports in the aggregation group will automatically synchronize .

Static vs Dynamic Aggregation

• Static (ON mode): Ports are manually added to a group without negotiation. LACP is not required, but misconfiguration can cause link issues .
• Dynamic (Active/Passive LACP): Ports negotiate automatically using LACP (802.3ad). Active mode initiates negotiation, while passive mode responds to negotiation requests . LACP ensures both ends agree on aggregation settings and provides automatic failover .

Steps to Switch Ports

1. Disconnect the ports from any active connections to avoid traffic disruption .
2. Verify port compatibility: Ensure the new ports have the same speed, duplex, and media type as the existing aggregation group .
3. Configure the downstream switch first: Apply the aggregation settings on the switch closer to the client or endpoint before configuring the upstream switch .
4. Add the new ports to the aggregation group: Use the switch interface to select the target ports and assign them to the LAG or EtherChannel. For LACP, set the mode to active or passive as needed .
5. Test connectivity and redundancy: Verify that traffic is properly balanced across the aggregated links and that failover works if one port goes down .

Best Practices

• Use sequential port numbers when possible, especially on UniFi switches .
• Avoid connecting aggregated ports to unsupported devices or gateways .
• For high-performance links, consider SFP+ or fiber connections to maximize throughput .
• When aggregating switches in different locations, run cables over separate physical paths to reduce the risk of simultaneous link failure . By following these steps and ensuring consistent configuration, you can safely switch two ports for aggregation while maintaining network performance and redundancy.