Layer 1 - What Are SFP, SFP+, XFP, QSFP/QSFP+ and CFP?

 What Are  SFP, SFP+, XFP, QSFP/QSFP+ and CFP?

We can see some products information about fiber optic transceivers, such SFP, SFP+, XFP, QSFP and QSFP+ . 

SFP 

SFP, small form­factor pluggable for short, is a compact, hot­pluggable transceiver module used for both telecommunication and data communications applications. SFPtransceiver can be regarded as the upgrade version of GBIC module. Unlike GBIC with SC fiber optic interface, SFP is with LC interface and the main body size of SFP is only about half of GBIC, which makes the SFP space saving. SFP interfaces a network device mother board (for a router, switch, media converter or similar devices) to a fiber optic or copper networking cable. Meanwhile, SFP is a popular industry format supported by many network component vendors. SFP transceiver modules are designed to support SONET, Gigabit Ethernet, Fibre Channel, and other communications standards.

SFP+

SFP+ is an enhanced version of the SFP that supports data rates up to 10 Gbit/s. SFP+ supports 8 Gbit/s Fibre Channel, 10­gigabit Ethernet and Optical Transport Network standard OTU2. It is a popular industry format supported by many network component vendors. Initial standard applications focused on 8G Fibre Channel, 10G Ethernet and 10G Fibre Channel, where the electrical interface to the host board is a standardized serial interface called SFI. The applications have expanded to include SONET OC­192, SDH STM­64, OTN G.709, CPRI wireless, 16G Fibre Channel, and the emerging 32G Fibre Channel application.

XFP

XFP has appeared before the SFP+. It is also a standardized form factor for serial 10 Gb/s fiber optic transceivers. It is protocol­independent and fully compliant to the following standards: 10G Ethernet, 10G Fibre Channel, SONET OC­192, SDH STM­64 and OTN G.709, supporting bit rate from 9.95G through 11.3G. XFP transceivers are used in datacom and telecom optical links and offer a smaller footprint and lower power consumption than other 10 Gb/s transponders. The electrical interface to the host board is a standardized serial 10 Gb/s interface called XFI.

QSFP

QSFP is short for quad (4­channel) small form­factor pluggable. It is a compact, hot­pluggable transceiver also used for data communications applications. QSFP+ evolved as the standard to support 10Gb/s data rates per SFF8436. Compared with QSFP+, QSFP products support Quarter Small Form­factor Pluggable with the different data rate so that there is no change in the product solution. Nowadays, QSFP+ gradually replace QSFP and is widely used by people as it can provide higher bandwidth

CFP 

CFP, namely C form­factor pluggable, is a multi­source agreement to produce a common form­factor for the transmission of high­speed digital signals. The c stands for the Latin letter C used to express the number 100 (centum), since the standard was primarily developed for 100 Gigabit Ethernet systems. It can support a wide range of 40 and 100 Gb/s applications such as 40G and 100G Ethernet, OC­768/STM­256, OTU3, and OTU4.