I have a LAG that runs between two SG350 switches. Each switch has a single Ubiquiti Unifi AC PRO Access Point (f/w 4.0.54.10625) attached to it. The AP's are trunked and have four VLANs associated with them. They, for the most part, work just fine.
The issue I'm having is that when I roam between the two access points, the DCHP negotiation will fail. I've watched the negotiation happen, by doing a tcpdump on the router, and it only fails to perform the last step in the DHCP negotiation, and the device isn't issued an IP address. Eventually, in about 5 to 15 minutes or so, the device is allowed to join the network again.
Configuration:
- Main Switch: SG350-28
- Secondary Switch: SG350X-24
- Current firmware on both switches: 2.5.0.83
- Router: Ubiquiti Edgerouter 4 with f/w 2.0.6
- 2 * Ubiquiti Unifi AC PRO Access Point f/w 4.0.54.10625
- Unifi, under docker, older version 5.10.26 (been waiting for a container update for ages)
- LAG is dual Gigabit Ethernet
- 7 VLANs, registered in the switches, these work fine
- Each VLAN has a DHCP relay back to the DHCP server, DHCP relay is set up in both switches
- DHCP is on Router for each VLAN
- VLANs are Isolated
Tests performed:
- When I directly connect the two switches via a single trunk, DHCP works fine
- Connecting the AP's to the same (Main) switch works fine
- STP enabled or disabled makes no difference (Set in default Rapid STP) while LAG'd
- No issues when reconnecting to the same AP repeatedly on either switch/AP
Not sure what to try next other than dump LAG, which I'd rather not.
edit: Added AP f/w an updated Unifi info
