Small form-factor pluggable
Small Form-factor Pluggable ( short: SFP , colloquially also Mini- GBIC ) are small, standardized modules for network connections .
SFP is a specification of a generation of modular optical or electrical transceivers . These devices are designed as connectors for high-speed Ethernet , Fiber Channel and SONET . The original specification is defined for up to 5 Gbit / s ( gigabits / second).
SFP modules fit into an SFP cage and can be exchanged quickly and easily (“hot swap”). Network devices can therefore easily be switched to other media and can be quickly repaired in the event of a defect. SFPs are smaller and more space-saving than GBICs and thus enable the production of devices with significantly higher port densities.
Depending on the cable type ( multimode or single mode fiber ), wavelength (850 nm, 1310 nm, 1550 nm or CWDM - typically between 1311 and 1611 nm) and data rate, the SFPs are available in different versions. The LC connector is used as standard. Modules for multimode fibers have a black, sometimes beige release lever, modules for single-mode fibers have a blue one. SFPs for twisted pair cables (1000BASE-T) are also available, but not all devices support them.
There are also SFP modules that only require a single fiber instead of a fiber pair ("BX optics"). The sending and receiving directions are implemented using two different wavelengths.
Use with Gigabit Ethernet
| Type | wavelength | Range | medium | IEEE 802.3 Standard / Notes |
|---|---|---|---|---|
| 1000BASE-SX | 850 nm | 0.5 km | 50 µm / 125 µm fiber pair | Clause 38 |
| 0.22 km | 62.5 µm / 125 µm fiber pair | |||
| 1000BASE-LX | 1310 nm | 5 km | 9 µm / 125 µm fiber pair | Clause 38 |
|
1000BASE-LX10 1000BASE-LH |
10 km | Clause 59, often only "1000BASE-LX" | ||
| 1000BASE-EX | 1310 nm | 40 km | 9 µm / 125 µm fiber pair | no IEEE 802.3 standard, identical to -LX with more powerful optics |
| 1000BASE-ZX | 1550 nm | 80 km | 9 µm / 125 µm fiber pair | no IEEE 802.3 standard, similar to -LX, longer wavelength, more powerful optics |
| 1000BASE-EZX | 1550 nm | 120 km | 9 µm / 125 µm fiber pair | no IEEE 802.3 standard |
|
1000BASE-BX10 1000BASE-BX |
1490 nm (-D) 1310 nm (-U) |
10 km | 9 µm / 125 µm single fiber | Clause 59, CWDM with 1490 nm "downstream" and 1310 nm "upstream" in the direction of the data center |
| 1000BASE-T | - | 0.1 km | Twisted pair Cat-5e | Clause 40, complex coding in the SFP module necessary |
Other variants
In addition to the normal SFP modules, there are also further developed versions, some of which also differ in design and enable significantly higher transmission rates.
QSFP
Quad Small Form-factor Pluggable (4 Gbit / s)
is four times the data rate of SFP. They are available for use in singlemode or multimode applications and can support 4 independent channels that can transmit individually at up to 1.25 Gbit / s per channel for a combined total speed of 4.3 Gbit / s. However, due to technological advances, these optics are rarely used.
SFP +
Enhanced Small Form-factor Pluggable (10 Gbit / s)
It is the successor to SFP. SFP + supports data rates of up to 16 Gbit / s and is used in particular for 10 Gigabit Ethernet. The module size is identical to SFP, so that some SFP + ports also support SFP transceivers.
SFP28
Small form-factor pluggable 28 (25 Gbit / s)
SFP28 for up to 25 Gbit / s was derived from 100 Gbit Ethernet, which was previously transmitted as 4 × 25 Gbit / s lanes. With the same size as SFP and SFP +, SFP28 supports a lane with a maximum of 28 Gbit / s (25 Gbit / s + coding + forward error correction ). SFP28 can also be used to split a 100 Gb port into four 25 Gb ports.
QSFP +
Enhanced Quad Small Form-factor Pluggable (40 Gbit / s)
The QSFP + transceiver (Quad = quadruple) is an optical transceiver for a maximum data transmission of up to 40 Gbit / s and is intended to replace 4 × 10 Gbit / s SFP +. The transceiver has a built-in Mux / Demux and supports four multiplex channels. These are 1271 nm, 1291 nm, 1311 nm and 1331 nm. The transceiver connects via a standard port with a 148-pin CFP connector and is hot-pluggable. This enables the system technician to make changes to the configuration during operation. The transceiver works with a 3.3 V supply voltage.
Key figures:
- 4 CWDM channel MUX / DEMUX design
- up to 11.2 Gbit / s per wavelength
- QSFP + MSA Compatible
- up to 100 km range via SMF
- Duplex LC connector
- integrated digital diagnostic function
- RoHS compliance
QSFP28
Quad Small Form-factor Pluggable 28 (100 Gbit / s)
QSFP28 supports four lanes of 28 Gbit / s each and is used for 100 Gigabit Ethernet. Some ports also support a division into four ports with 25 Gbit / s (fanout).
See also
- Small Form Factor Special Interest Group (SFF-SIG)
- Stackable Unified Module Interconnect Technology (SUMIT)
- Gigabit Interface Converter (GBIC)
- en: XFP transceiver
- en: XENPAK
- en: C Form-factor Pluggable (CFP)
- Media converter
Web links
- SNIA Technology Affiliate SFF Technical Working Group - Public Documents
- INF-8074I SFP 1 Gb / s Transceiver specification
- SFP + 1X 10 Gb / s Pluggable Transceiver Solution (SFP10) specification
- QSFP, QSFP + and QSFP28. What's the difference?
Individual evidence
- ↑ FAQs for SFP + . The Siemon Company. August 20, 2010. Retrieved February 22, 2016.
- ↑ Ethernet Summit SFP28 examples .
- ↑ QSFP data , netram.de, accessed on August 13, 2013