(Small Form-factor Pluggable) A small transceiver that plugs into the SFP port of a network switch and connects to fiber optic and Gigabit Ethernet (GbE) fibers at the other end. The SFP modules replaced by the GBIC receiver are also called “mini-GBIC” due to their smaller size. By choosing the right SFP module, the same electrical port on the switch can be connected to fibers of different wavelengths and types (multimode or single mode). In case of fiber upgrade, the SFP module is replaced.
SFP converts serial electrical signals to serial optical signals and vice versa. SFP modules are hot-swappable and contain ID and system information for the switch.
Composite SFP ports
Composite ports are associated with Ethernet ports. For example, if an SFP transceiver is connected to SFP port 24, Ethernet port 24 will be disabled even if the cable is powered.
10Gb support (SFP+ and XFP)
XFP transceivers were developed to handle 10 Gigabit optical lines, as SFP only supported 4.25 Gbps. The same module size as SFP, SFP+ was later introduced to handle 10 Gbps but required more circuitry in the host device. As a result, SFP+ ports are mostly found on add-in cards for enterprise servers and switches. See Transceiver and GBIC.
SFP+ and XFP (10 GB)
Both support 10 Gigabit Ethernet, the SFP+ module (left) is narrower and shorter than the XFP module (right). A cable can be connected to SFP+ on one end and XFP on the other end.