What is SFP port?
SFP means small form-factor pluggable it is used in network and storage devices and is a hot swappable interface that connects fibre or RJ45 cables between switches and the network.
In the picture above you can see two SFP ports one sfp in switch.
In 2006, SFP+ specification brought speeds up to 10 Gbit/s and the SFP28 iteration is designed for speeds of 25 Gbit/s. The SFP replaced the larger GBIC in most applications, and has been referred to as a Mini-GBIC by some vendors.