An SFP or a small form-factor pluggable is a small metal hardware that you plug into a device to allow it to communicate with another device. It acts as a transceiver (a transmitter and receiver), which enables data transmission between two devices that are as far as 6–7 feet away from each other.

As a transceiver, an SFP is like a telephone that transmits and receives data at the same time—you don’t need other equipment to do those processes separately. However, SFPs are mostly used in computer networks to allow the flow of high-speed Internet connection. And since it works with copper and fiber optics, an SFP is compatible with a variety of connection options.

Other interesting terms…

Read More about an “SFP”

To visualize what an SFP is, take a look at an example below.


An SFP transceiver goes into the SFP port of a device, a slot specially designed for it. An ethernet cable is then plugged into the SFP transceiver. The setup looks like this when the SFP and cable are plugged in and ready to take action:


The Evolution of SFPs

Like everything else in the hardware department, pluggables (the category that SFPs belong to) weren’t small at first. They were not even called “small” form-factor pluggables when they were developed in 1995. Instead, they were called gigabit interface converters (GBICs). A GBIC works the same way as an SFP but is considerably larger in size. Hence, an SFP is also called a “mini-GBIC.”

The figure below shows the evolution of pluggables from a GBIC to the latest SPF model.


Xenpak, XFP, and modern SFPs are different pluggable models that vary in the amount of bandwidth they can transmit.

Advantages of Using SFPs

SFPs are widely used today primarily because of three characteristics that define them. 

First and foremost, SFPs are small, making them suitable for tight spaces. They are also hot-swappable, an electronic term for components that can be plugged into and removed easily while a computer or device is running. Because of this characteristic, networks can be expanded without redesigning its cable infrastructure.

Lastly, you can choose from several SFP connection options, making the hardware compatible with almost any network. SFPs are also compatible with different communication standards, such as synchronous optical networking (SONET), ethernet, and fiber.

How Does an SFP Work?

An SFP transceiver needs to be plugged into an SFP port to work. Usually, the right port of an SFP is the receiver, while the left port is the transmitter. You should hear a click when you plug the SFP into a port. Watch the video below to see an actual SFP transceiver plugged into a CISCO switch:

Types of SFPs

Several types of SFPs exist, depending on network type, wavelength, module, and distance between devices. The tables below provide a simplified differentiation of the various SFP types. There are two types of SFPs for short-distance transmission.

what is an spf

For long distance-transmission, these are the SFP types:

Small Form-factor Pluggable (SPF)

You may also watch this video to learn more about the different types of SFPs:

From floppy disks to USB flash drives and family computers to laptops, we see the same trend in the evolution of pluggables—from GBICs to SFPs. Aside from the change in size, however, the functionality has also improved, allowing for more bandwidth and less power consumption.