I have a Cisco SG220 and a ZyXel USG20 firewall appliance. I'm new to the SG220 and SFP ports in general. Where is the optimal place to plug in the Firewall to the Switch. Normally I would just plug it into any port on the switch, but with the SFP I'm not sure. 
Where to Plug the Firewall: SFP or Normal Port?
ethernetroutingsfpswitch
Best Answer
USG20 supports 1Gbps so I would connect to SG220 over one of two GigabitEthernet Ports which are usually used for uplinks next to port 0/23 and 0/24. Unfortunately USG20 doesn't support LCAP/PaGP so you won't be able to create bundle for redundancy purposes. But to be honest as @Ron Maupin said doesn't matter where exactly you will connect more likely your limited factor will be WAN.