Small Form-factor Pluggable

Small Form-factor Pluggable (SFP) is a compact, hot-pluggable network interface module format used for both telecommunication and data communications applications.

[1] The advantage of using SFPs compared to fixed interfaces (e.g. modular connectors in Ethernet switches) is that individual ports can be equipped with different types of transceivers as required, with the majority including optical line terminals, network cards, switches and routers.

[2] The SFP replaced the larger gigabit interface converter (GBIC) in most applications, and has been referred to as a Mini-GBIC by some vendors.

[3] SFP transceivers exist supporting synchronous optical networking (SONET), Gigabit Ethernet, Fibre Channel, PON, and other communications standards.

[13] An even larger sibling, the Octal Small Format Pluggable (OSFP), had products released in 2022[14] capable of 800 Gbit/s links between network equipment.

[17] SFP transceivers are available with a variety of transmitter and receiver specifications, allowing users to select the appropriate transceiver for each link to provide the required optical or electrical reach over the available media type (e.g. twisted pair or twinaxial copper cables, multi-mode or single-mode fiber cables).

Using a simple adapter or a special direct attached cable it is possible to connect those interfaces together using just one lane instead of four provided by the QSFP/QSFP+/QSFP28/QSFP56 form factor.

10 Gbit/s SFP+ modules are exactly the same dimensions as regular SFPs, allowing the equipment manufacturer to re-use existing physical designs for 24 and 48-port switches and modular line cards.

Identical in mechanical dimensions to SFP and SFP+, SFP28 implements one 28 Gbit/s lane[39] accommodating 25 Gbit/s of data with encoding overhead.

[40] SFP28 modules exist supporting single-[41] or multi-mode[42] fiber connections, active optical cable[43] and direct attach copper.

[44][45] The compact small form-factor pluggable (cSFP) is a version of SFP with the same mechanical form factor allowing two independent bidirectional channels per port.

According to the SFD-DD MSA website: "Network equipment based on the SFP-DD will support legacy SFP modules and cables, and new double density products.

Currently, the following speeds are defined: Quad Small Form-factor Pluggable (QSFP) transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required optical reach over multi-mode or single-mode fiber.

[62] SFP sockets are found in Ethernet switches, routers, firewalls and network interface cards.

[71] Modern optical SFP transceivers support standard digital diagnostics monitoring (DDM) functions.