What is SFP?

SFP, short for Small Form-Factor Pluggable, is a compact, hot-swappable optical module used in telecom and datacom applications. The SFP optical module can be considered as an upgraded version of the GBIC optical module. Unlike GBIC with SC fiber interface, SFP has LC interface and the body size is only about half of GBIC, so that SFP can save more space. SFP connects the motherboard of a network device (such as a router, switch, media converter, or similar device) to a fiber optic cable or cable. At the same time, SFP is a common industrial specification supported by many network device suppliers. It was designed to support SONET, Gigabit Ethernet, Fibre Channel and other communication standards.

standardization

SFP optical modules are not regulated by any official standard system, but are regulated by the Multilateral Agreement (MSA) between competing manufacturers. SFP is designed according to the GBIC interface and achieves a greater port density (the number of optical modules per centimeter along the edge of the motherboard) than GBIC, which is why SFP is also called mini-GBIC. A related small-package optical module has a similar size to an SFP, but it is soldered to the motherboard as a type of pin, rather than plugged into an edge card slot.

In practice, however, some network equipment vendors use keying mechanisms to break compatibility with "generic" SFPs, adding a verification process to the device firmware so that the device only enables the vendor's own optical modules. For example, in 2003, when Cisco routinely updated the Internet Operating System (IOS) of its Catalyst switch line, it added a feature that caused the switches to not accept non-"Cisco-branded" optical modules.