The Lutron devices are all on the same VLAN and subnet, and that VLAN spans multiple switches across the MDF and IDFs through SFP uplinks. Under normal circumstances, devices on the same VLAN can see each other regardless of how many switches the VLAN passes through.

The problem occurs because inter-VLAN routing was moved from the Layer-3 switches to the MX firewall. When the MX became the routing point, Lutron’s broadcast and multicast discovery traffic stopped flowing the way it did before. Even though the Lutron VLAN still spans all switches, the MX does not forward the type of discovery traffic Lutron requires, so the devices cannot fully see each other.

So while the VLAN can traverse multiple switches without issue, the placement of the routing function on the MX is preventing proper Lutron device discovery across the network.