Hi as Chris says, SFP stands for Small Form-Factor Pluggable adapters .. these adapters are used for Ethernet and allow either twisted pair or fibre Ethernet connections.
As far as you wiring, then Ethernet runs usually in multiples of 10 so will most likely at 100 Mbps or 1000Mbps.
It sounds like you have a network switch...so you can check your streamer cable goes back to it. Having longer runs of Ethernet cable I say is beneficial sonically over short runs, so a 50foot run would be ideal.
I am not familiar with the manufacturer of your switch and router, but a quick google shows it has 5 LAN switch ports (basically a switch built into it), so you could connect your streamer to one of these instead of your switch if you want... which ever is most convenient.