Question: can sfp work with sfp+?
Answer: SFP Can be Plugged into SFP+ Ports in most cases SFPs will work in SFP+ slot(in some cases firmware needs to be same on both SFP and SFP+ transceivers), but for sure SFP+ optics don't work in SFP slots. As discussed in the above article the speed is 1G not 10G, when SFP module is plugged into the SFP+ port.