What does Small Form-Factor Pluggable Transceiver (SFP) mean?
A small form-factor pluggable (SFP) transceiver is a compact, hot-swappable, input/output transceiver used in data communication and telecommunications networks. SFP interfaces between communication devices like switches, routers, and fiber optic cables, and performs conversions between optical and electrical signals. SFP transceivers support communications standards including synchronous optical networking (SONET)/synchronous digital hierarchy (SDH), gigabit ethernet, and fiber channel. They also allow the transport of fast Ethernet and gigabit Ethernet LAN packets over time-division-multiplexing-based WANs, as well as the transmission of E1/T1 streams over packet-switched networks.

Picture from: https://commons.wikimedia.org/wiki/File:SFP_board_2.jpg
SFP connects the mainboard and optical fiber or UTP cable of network equipment such as switches and routers. SFP is an industrial specification supported by some fiber optic device providers.
The SFP transceiver supports SONET, Gigabit Ethernet, Fibre Channel (Fibre Channel), and some other communication standards. This standard extends to SFP+ and can support a 10.0 Gbit/s transmission rate, including 8-gigabit Fibre Channel and 10GbE. Introduced the SFP+ module version of the optical fiber and copper core version. Compared with the Xenpak, X2, or XFP version of the module, the SFP+ module leaves the part of the circuit to be implemented on the motherboard, not the module.
SFP Types
SFP transceivers have many different types of transmission and reception, and users can select the appropriate transceiver for each link to provide “optical performance” based on the available fiber types (such as multimode fiber or single-mode fiber). SFP optical modules can be generally divided into the following categories:
- SX: 850 nm wavelength, transmission distance 550 meters, using multimode fiber MMF
- LX: 1310 nm wavelength, 10 km transmission distance, using single-mode fiber SMF
- EX: 1310 nm wavelength, 40 km transmission distance, using single-mode fiber SMF
- ZX: 1550 nm wavelength, 80 km transmission distance, using single-mode fiber SMF
- TX: the electrical port module, using RJ-45 copper cable interface
- CWDM: sparse wavelength division multiplexing SFP optical module
- DWDM: Dense wavelength division multiplexing SFP optical module
Commercial SFP transceivers can provide speeds up to 4.25 G bps. Several packages of 10 Gbps transceivers are XFP, and the new variant “SFP+” is basically the same as the SFP package.
SFP Standardization
SFP transceivers are regulated by a multilateral agreement (MSA) between competing vendors. SFP is designed according to the GBIC interface, allowing a greater port density (number of transceivers per inch on the edge of the motherboard) than GBIC, so SFP is also called “mini-GBIC”. The related small package transceiver (SFF transceiver) is smaller in size than SFP, but SFF is inserted vertically as a pin (as a pin through-hole device) on the motherboard (not hot-swappable), and It is not inserted parallel to the side card slot like SFP (supports hot-swap).
Digital diagnostics monitoring
Modern optical SFP transceivers support standard digital diagnostics monitoring (DDM) functions. This feature is also known as digital optical monitoring (DOM). This capability allows monitoring of the SFP operating parameters in real-time. Parameters include optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage. In network equipment, this information is typically made available via Simple Network Management Protocol (SNMP). A DDM interface allows end-users to display diagnostics data and alarms for optical fiber transceivers and can be used to diagnose why a transceiver is not working.
Some Questions:
A small form-factor pluggable (SFP) transceiver is a compact, hot-swappable, input/output transceiver used in data communication and telecommunications networks. SFP interfaces between communication devices like switches, routers, and fiber optic cables, and performs conversions between optical and electrical signals.
An SFP transceiver, also known as an SFP module, is just a hot-swappable, pinky-sized metal component that, when connected to another device using a cable, allows for the transmission of data.
Form Factor refers to the size, shape and other attributes related to the design of SFP hardware. Optical transceivers are available in a variety of small form-factor pluggable (SFP) modules, including SFP, SFP+, XFP, and more.
Case analysis: This is about connecting 1000Mbps switches on the same rack. SFP port is used instead of RJ45 port which can cause electrical interference. Another reason could be power consumption. When there are more than 100 links, choosing SFP ports is more power-saving than Ethernet ports.
An optical transceiver module is the core part of optical communication devices. It uses fiber optical technology to send and receive data through completing the process of optical signal – electrical signal / electrical signal – optical signal conversion.
SFP and SFP+ transceivers are virtually identical in size and appearance. The primary difference is that SFP+ is an updated version that supports higher speeds up to 10Gbps. The difference in data rate also accounts for a difference in transmission distance—SFP typically has a longer transmission distance.
Removing SFP Modules
1. Remove the cable connected to the SFP or SFP+ module, if any.
2. Open the bale clasp on the module with your index finger in a downward direction.
3. Grasp the module between your thumb and index finger, and carefully pull it towards you out from the port.
Steps
1. Put on antistatic protection.
2. Make sure that your cables are fiber-optic cables by comparing them to the fiber-optic cable shown in the following figure.
3. Insert an SFP transceiver into the port in which the fiber-optic cable will be installed.
4. Install the fiber-optic cable.
When choosing SFP modules, you should consider whether it matches the switch port and the cable you have prepared. If you have a multimode cable, then you can choose GLC-SX-MM 1000BASE SFP. If you use a single-mode fiber cable, you should select GLC-LH-SM 1000BASE SFP.
SFP modules are distinguished by their bandwidth capabilities, wavelength, and distance capability. The SFP you choose must be compatible with the fiber cable you are installing. Single-mode fiber requires a single-mode compatible SFP. Multimode fiber requires a multimode compatible SFP.
SFP, a small form-factor pluggable for short, is a compact, hot-pluggable transceiver module used for both telecommunication and data communications applications. The Quad Small Form-factor Pluggable (QSFP) is a compact, hot-pluggable transceiver used for data communications applications.
SFP and SFP+ transceivers are virtually identical in size and appearance. The primary difference is that SFP+ is an updated version that supports higher speeds up to 10Gbps.
(Small Form-factor Pluggable) A small transceiver that plugs into the SFP port of a network switch and connects to Fibre Channel and Gigabit Ethernet (GbE) optical fiber cables at the other end. Superseding the GBIC transceiver, SFP modules are also called “mini-GBIC” due to their smaller size.
SFPs are mainly classified based on their speed capabilities. Some of the types are 100Base, 1000Base Gigabit, and 10Gig (SFP+). For most Fiber SFP modules, the transmission speed is 1 Gigabit, but the newer versions such as SPF+ have a higher speed of transmission, from 10 to 25 Gigabit.
SFP module is a flexible and necessary device in fiber optical connections. When you choose SFP modules in the market, you’d better consider the corresponding switches and cables for the applications. FS.COM provides high-quality network switches, fiber cables, and compatible SFP modules.
References
- Small form-factor pluggable transceiver – Wikipedia
- Small Form-Factor Pluggable Transceiver (SFP) – techopedia