Differences between SFP vs SFP+ vs SFP28 vs QSFP+ vs QSFP28

Selecting the right connector is essential to build a network that functions correctly at an efficient price point. There are five form factors: SFP, SFP+, SFP28, QSFP+ and QSFP28. They are substantially more popular than the rest in the world of fiber connectivity. But, How to choose between these five form factors? What are their differences?

Comparison: SFP vs SFP+ vs SFP28 vs QSFP+ vs QSFP28

Optics Type	Standard	Data Rate	Wavelength	Fiber Type	Max Distance	Typical Connector	DOM	Operating Temperature
SFP(Product)	SFP MSA	155Mbps 622Mbps 1.25Gbps 2.125Gbps 2.5Gbps 3Gbps 4.25Gbps	850nm 1310nm 1550nm CWDM DWDM BIDI	OM1 OM2 OS1 OS2	160km	LC SC RJ-45	NO or YES	Commercial/Industrial
SFP+(Product)	IEE802.3ae SFF-8431 SFF-8432	6Gbps 8.5Gbps 10Gbps	850nm 1310nm 1550nm CWDM DWDM BIDI Tunable Copper	OM3 OM4 OS1 OS2	120km	LC RJ-45	YES	Commercial/Industrial
QSFP+ (Product)	IEEE 802.3ba QSFP+ MSA SFF-8436 SFF-8636 Infiniband 40G QDR	41.2Gbps	850nm 1310nm 832-918nm	OM3 OM4 OS1 OS2	40km	LC MTP/MPO	YES	Commercial/Industrial
SFP28(Product)	IEEE 802.3by SFP28 MSA SFF-8472 SFF-8432	25.78Gbps	850nm 1310nm	OM3 OM4 OS1 OS2	10km	LC	YES	Commercial/Industrial
QSFP28(Product)	IEEE 802.3bm QSFP28 MSA SFF-8665 SFF-8636	103Gbps 112Gbps	850nm 1310nm CWDM4	OM3 OM4 OS1 OS2	80km	LC MTP/MPO-12	YES	Commercial/Industrial

SFP vs SFP+

Same size with different speed and compatibility. SFP+ is used in 10-Gigabit Ethernet applications while SFP is for 100BASE or 1000BASE applications. SFP complies with standards of IEEE802.3 and SFF-8472 while SFP+ is based on SFF-8431. SFP+ ports can accept SFP optics but at a reduced speed of 1 Gbit/s. And an SFP+ transceiver can not be plugged into an SFP port, otherwise, the product or port may be damaged. Normally, SFP+ is more expensive than SFP.

SFP+ vs SFP28

SFP+ is mainly linked to 10G, while SFP28 is commonly associated with 25G connections. They use the same form factor, and the pinouts of SFP28 and SFP+ connectors are mating compatible. So SFP28 will work with SFP+ optics but at a reduced speed of 10 Gbit/s. And SFP+ modules will work well with the SFP28 port on a network switch if the port can be set up for 10G transmission, otherwise, the SFP+ modules can not work.

25G SFP28 Transceiver Module Overview

SFP+ vs QSFP+

The primary difference between QSFP and SFP is the quad form. QSFP+ is an evolution of QSFP to support four 10 Gbit/s channels carrying 10-Gigabit Ethernet, 10G Fiber Channel, or InfiniBand, which allows for 4X10G cables and stackable networking designs that achieve better throughput. QSFP+ can replace 4 standard SFP+ transceivers, resulting in greater port density and overall system cost savings over SFP+.

What Is QSFP+ Module: QSFP+ Transceiver Wiki and Types

SFP28 vs QSFP28

SFP28 and QSFP28 transceivers actually adopt different sizes and working principles. SFP28 supports only one channel with 25 Gbit/s, while QSFP28 supports 4 separate lanes, and each is 25 Gbit/s. Both of them can be used in 100G networks, but the SFP28 is applied in the form of QSFP28 to the SFP28 breakout solution.

100G QSFP28 Optical Transceiver Comparison

It's clear that the main driving force behind the evolution of optical transceivers is the need to achieve higher bandwidth rates with smaller form-factor. In modern, dense networks, small form factors are a constant necessity. After a clear understanding of them, you also have to consider your network traffic, transmission distance, and future-proof networking requirements for ensuring the right selection.