With the introduction of new technologies and economic drivers, many companies’ data center landscapes are moving toward higher speeds, scalability, and performance levels. As we all know, a broader technology shift requires more networks and bandwidth. Therefore, more and more organizations are upgrading from 10GbE to 25GbE technology.

This article briefly overviews 10G and 25G Ethernet (25GbE) technologies, focusing on the SFP+ transceiver and SFP28 transceiver. We want to provide practical information for Cio, IT, and network directors, to understand their differences.

Keep reading to learn more about SFP+ vs. SFP28.

SFP28 vs SFP+, What is the difference?

 

SFP+ and SFP28 have the same appearance and are mating compatible. However, SFP+ is suitable for operating at 8G or 10G speed, whereas SFP28 is for working at 25G speed. SFP28 has increased bandwidth, superior impedance control, and less crosstalk than the SFP+ solution. Also, the SFP28 transceiver and SFP28 DAC cable have significantly greater bandwidth and lower loss when compared to the SFP+ version.
Below is the comparison chart for SFP28 and SFP+.

Form	Standard	Datarate	Wavelength	Media	Distance	Connector	DOM	Size	Power Consumption	Application	Price
SFP+	SFP+ MSA	8G 10G 16G	850nm 1310nm 1550nm CWDM DWDM BiDi Copper	OM3 OM4 SMF Twinax	120km	LC RJ-45	Yes	Similar to SFP	Lower	Ethernet Fiber Channel CPRI Datacenter	$$
SFP28	IEEE 802.3by SFP28 MSA	25G 32G	850nm 1310nm CWDM DWDM BiDi Copper	OM3 OM4 SMF Twinax	40km	LC	Yes	Similar to SFP	Higher	Datacenter Cloud computing	$$$

 
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.
 
 
 
 
 

What do SFP28 and SFP+ represent respectively?

What is SFP28?

SFP28 stands for Small Form-factor Pluggable 28. It is a compact, hot-pluggable transceiver module used for high-speed data communication. SFP28 modules support data rates of up to 28 gigabits per second (Gbps) and are commonly used in Ethernet applications, such as data centers and enterprise networks.
 

What is SFP+?

SFP+ stands for Small Form-factor Pluggable Plus. It is a compact, hot-pluggable transceiver module used for high-speed data communication. SFP+ modules support data rates of up to 10 gigabits per second (Gbps) and are commonly used in Ethernet applications, including data centers and enterprise networks. SFP+ is an upgrade over the original SFP module, providing higher data rates and improved performance.
 
 

10GbE Basics

10 Gigabit Ethernet (10 GbE, 10 GE, or 10 GigE) is a disruptive telecommunications technology that transmits packets over Ethernet at a rate of 10 billion bits per second. This innovation extends the reach of traditional and familiar Ethernet in local area networks (LANs) to a broader range of network applications, including high-speed storage area networks (SANs), wide area networks (WANs), and metropolitan area networks (MANs).
10G Ethernet provides a more efficient and cheaper way to move data over network backbone connections. The IEEE 802.3ae standard allows up to 100 kilometers between physical locations on a single mode fiber. Both single-mode and multimode fiber systems can use for 10 GbE applications.
The 10 GbE standard is fully interoperable with existing Ethernet protocols. It differs from traditional Ethernet in that it is a full-duplex protocol, which does not require the Carrier Sense Multiple Access/Collision Detection (CSMA/CD) protocols.
In other respects, 10 GbE is identical to the original Ethernet protocol. That is important for network administrators, since 10G Ethernet can be easily deployed in existing networks when speed requirements increase. It is yet providing cost-effective technology that supports high-speed, low-latency needs.
 
 

Some questions:

 

Can I use SFP+ transceivers on SFP28 ports?

Concept

SFP28 ports are backward compatible with SFP+ transceivers; however, the port can only support up to 10 Gbps network speed when connected to a SFP+ transceiver.
Small form-factor pluggable (SFP) network interface modules have distinct form factors, when an SFP+ transceiver is connected to an SFP28 port, the device automatically detects the inserted module's form factor and adjusts the network speed accordingly.
SFP28 ports are designed to support up to 25 Gbps, whereas SFP+ transceivers are designed to support data rates up to 10 Gbps.
QNAP recommends contacting the transceiver manufacturer prior to using SFP+ transceivers on SFP28 ports.
 

Is SFP28 the same as SFP+?

The answer is definitely yes: SFP28 adopts the same form factor as SFP+, just running at 25 Gb/s instead of 10Gb/s, which offers better performance and higher speed. So SFP28 will work sufficiently on SFP+ ports, and SFP+ cables can be plugged into SFP28 ports although they are not designed for 25Gb/s data rates.

Is SFP+ compatible with QSFP28?

In brief, the new-gen optical transceiver is backward compatible with the previous version in most situations. In other words, SFP+ ports can take SFPs, it is possible to plug SFP+ into SFP28 ports to run 10G, and QSFP+ optics work fine in QSFP28 ports, but not vice versa.

What is the difference between QSFP28 and SFP28?

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.

Can I use an SFP transceiver in SFP28 ports?

Can I use SFP28 Transceivers in SFP+ ports? The answer is yes because SFP28 is backward compatible with SFP+ ports and can be fully functional. SFP+ optical modules and SFP+ cables can be plugged into the SFP28 port, but do not support 25Gb / s data rate.

Does QSFP28 support 10G?

QSFP28 transceivers have the same form factor as the QSFP optical transceiver. The former has just 4 electrical lanes that can be used as a 4x 25GBE and also a 4x 10GbE, while the latter supports 40G ( 4x 10G).

Is QSFP56 compatible with QSFP28?

As seen from their industry names, QSFP56, QSFP28, and QSFP+ are very similar in that they share the same QSFP form factor as their postfix shows, and they have the same size as each other.