Your L2 switch only supports one subnet/vlan. Your R710 has 2 Ethernet ports.
If you run Solo AP firmware, you can define Local Networks with 192.168.33.0/24 and 192.168.55.0/24
and assign them to Eth1 and Eth2 respectively.
You could then have 2 SSID, one for 33 subnet and one for 55 subnet.
But you could only attach "many" devices thru your current switch, on one R710 Eth port.
You would need another switch, or would be limited to one other device on the other subnet/Eth port.
It could do that, with just an R710 and a switch. (No Internet of course without a Router/WAN link)
