Understanding High-Speed Optical Modules: 100G QSFP28 versus SFP112

Posted on Mar 20, 2024 by

QSFP28 and SFP112 are optical modules used in high-density data centers, computing networks, and telecommunications. QSFP28 has four channels with speeds up to 25 Gbps each, totaling 100 Gbps. SFP112, an extension of SFP+, supports higher speeds but lacks standard recognition, with specifications varying by manufacturer.

What Are 100G QSFP28 and SFP112?

100G QSFP28 is a compact, hot-pluggable optical module used for high-density data center cabling, high-performance computing networks, and telecommunication networks. It supports data transfer rates of up to 100 Gbps through four channels.

SFP112 is not an industry-standard term but refers to modules developed by certain manufacturers as an extension of SFP+. These modules support higher speeds, potentially up to 28 Gbps or more, and are designed to be compatible with SFP+ ports. Their exact specifications and applications may vary by manufacturer and implementation.


Advantages of 100G QSFP28 and SFP112

If we were to discuss a theoretical SFP112 module that operates at 112 Gbps compared to the QSFP28, its advantages might primarily revolve around the following aspects:

  • Higher Data Rate: The supposed data transfer rate of an SFP112 module is 112 Gbps, which is significantly higher than the 100 Gbps of QSFP28. This means that SFP112 could provide faster data transfer speeds for applications requiring higher bandwidth.

  • Single-Channel Configuration: If the SFP112 is a single-channel device, this simplified signal path could potentially reduce the challenges associated with signal integrity. It also might offer a simpler signal multiplexer/demultiplexer (MUX/DEMUX) design in certain scenarios compared to QSFP28's four-channel configuration.

  • Technological Advancement: If SFP112 adopts new signaling processing technologies or modulation techniques, it could show improvements over QSFP28 in aspects such as fiber optic transmission distance, signal integrity, and interference resistance.

  • Capability to Support New Applications: Higher speeds exceeding 100 Gbps may mean that SFP112 could support application scenarios that QSFP28 is unable to handle, such as in edge computing, high-speed data analytics platforms, or high-bandwidth storage networks.

When evaluating QSFP28 versus SFP112 optical modules, key considerations include market adoption, port density, power consumption, and versatility.

  • Familiarity and widespread deployment:The QSFP28 is a widely used and deployed standard for 100Gbps optical modules in data centers and high-performance computing markets. In contrast, if the SFP112 standard is in its infancy or just starting to be applied, it might lack the maturity and recognition of the QSFP28.

  • Port density: The four-channel design of QSFP28 modules aids in achieving high port density on networking equipment. In contrast, SFP112 modules (assuming each is single-channel) may offer less total bandwidth in the same footprint.

  • Power consumption: QSFP28 modules generally strive to maintain low power consumption (typically 3.5W or lower). The power consumption for SFP112 modules may be higher, impacting overall energy costs and cooling requirements.

  • Flexibility: QSFP28 modules support various transmission mediums, including multimode fiber, single-mode fiber, and active and passive direct attach copper cables. If the SFP112 offers a more limited selection of module types or transmission mediums, then QSFP28 would provide more flexible options.

What Is the Difference?

To perform a comparative analysis between the 100G QSFP28 and SFP112 optical modules, we'll need to look at several attributes that define their usability, performance, and suitability for different networking environments:

Data Transfer Rate

The 100G QSFP28 is designed to deliver data transfer rates of 100 Gigabits per second, while the SFP112, as suggested by its name, supports even higher speeds, reaching up to 112 Gbps.

Form Factor

The 100G QSFP28, also known as Quad Small Form-factor Pluggable 28, is a compact and hot-pluggable transceiver that is widely used in the industry due to its balance of high density and high performance. On the other hand, the SFP112 has a form factor that may resemble that of the SFP+ but is engineered for higher bandwidth capabilities. It's important to verify that your equipment has the necessary slots and compatibility to support this format.

Port Density

100G QSFP28 allows for high port density in networking equipment due to its relatively small size. SFP112 may offer a similar or slightly reduced port density compared to QSFP28, depending on its actual dimensions.

Compatibility and Use Cases

100G QSFP28 is supported by a wide range of networking equipment and is a common choice for data centers, enterprise networking, and high-performance computing environments. SFP112 may be needed for applications that are starting to exceed the 100Gbps limit and require higher throughput. It's newer and less common, so ensure compatibility with existing systems.

Connector Types

The 100G QSFP28 transceiver comes with common standards such as the QSFP28-SR4 which is used for short multi-mode fiber connections, QSFP28-LR4 designed for longer single-mode fiber connections, and direct attach cables (DAC) which are ideal for very short distances. The SFP112, while also likely to have a range of standards, is aimed at higher speeds and therefore will have specifications that are designed to meet the requirements for higher throughput demands.

Reach and Applications

100G QSFP28 can support varying distances depending on the type of transceiver (SR, LR, ER) and the fiber used. SFP112 likewise, the reach will vary based on specifications but may be targeted for similar or higher distance applications with enhanced performance.

Power Consumption

100G QSFP28 is generally designed for efficient power consumption given the current technological standards but will vary based on the manufacturer and specific part number. SFP112 potentially has higher power consumption due to the higher data rate. It's important to consider cooling solutions and the overall power budget.

How to Choose 100G QSFP28 and SFP112?

Choosing between the 100G QSFP28 and SFP112 modules for high-speed data transmission mainly depends on several key factors including network bandwidth requirements, port density, device compatibility, link distance, and cost-effectiveness. Here are the factors you may need to consider when choosing:


Bandwidth Requirements

100G QSFP28 modules offer up to 100Gbps data transfer rates and are suitable for scenarios with heavy bandwidth demands. SFP112 typically refers to a 112Gbps rate and is used in applications that require even higher bandwidth.

Device Compatibility

Confirm whether your network equipment, such as switches and routers, supports the form factor and size of the module you are considering. QSFP28 stands for Quad Small Form-factor Pluggable, a compact four-channel interface. SFP112 may refer to a single or multi-channel module with higher rates and might have a different size compared to standard SFP+ or QSFP28 modules.

Port Density

QSFP28 modules often enable higher port density in the same card area due to their smaller size. SFP112 modules might be larger and may not be suitable for scenarios requiring high port density.

Link Distance

Depending on your network design, you need to consider the maximum transmission distance of the link. Both QSFP28 and SFP112 modules come in various media and distance grades, such as SR4, LR4, ER4, etc. Single-mode fiber options might be necessary for long-distance transmission, whereas multi-mode fiber might suffice for shorter distances.

Future Network Planning

Keep in mind any future network expansion and upgrade contingencies. Being forward-thinking is essential when selecting modules.


Choosing between 100G QSFP28 and SFP112 modules for high-speed data transmission mainly depends on factors such as network bandwidth requirements, port density, device compatibility, link distance, and cost-effectiveness. It is important to consider whether your network equipment supports the form factor and size of the module, as well as the maximum transmission distance required. Additionally, comparing prices and considering future network expansion plans can help determine the most suitable option. Ultimately, selecting the appropriate module type based on specific application needs and budget constraints ensures meeting the requirements for high-speed data transmission.

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