How to Easily Connect QSFP28 to SFP28: A Quick Overview

As the number of 100G QSFP28 devices in data centers continues to rise, along with the growing demand for high-speed data processing, the need for enhanced transmission capabilities has become critical. Data centers must ensure faster and more efficient data transfer rates to meet these demands. Recently, 25G SFP28 and 100G QSFP28 technologies have gained significant attention for their ability to provide a streamlined pathway to high-speed connectivity. But how can one effectively connect 100GBASE Ethernet to 25GBASE Ethernet? This article explores four key QSFP28 to SFP28 connection solutions to help you choose.

Introduction to QSFP28 Transceiver Technology

The QSFP28 (Quad Small Form-factor Pluggable 28) module, introduced in 2013, is a compact, high-density transceiver that supports data rates up to 100 Gbps. Its design enables four channels, each transmitting at 25 Gbps, making it ideal for high-speed networks in data centers, cloud computing, and enterprise environments. Compared to other modules like SFP+ (10 Gbps) and SFP28 (25 Gbps), QSFP28 provides superior speed and space efficiency, integrating four channels in a single package. Its ability to support multi-mode and single-mode fibers further enhances its flexibility in various networking scenarios. With this foundation, let’s explore how QSFP28 seamlessly connects to SFP28 for versatile network expansion.

Exploring Four QSFP28 to SFP28 Connection Solutions

Connecting QSFP28 to SFP28 with MTP Breakout Cable

To connect a single 100G QSFP28 transceiver to four 25G SFP28 transceivers, an 8-fiber MTP to 4 x LC harness cable is an ideal solution. This approach is particularly effective for short-distance connections, such as those within the same rack or cabinet.

MTP breakout cables facilitate the transition from multi-fiber cables to individual or duplex connectors, making them versatile for various applications across different network and equipment requirements, including 100G SFP modules. These cables offer a reliable, cost-effective, and efficient wiring system, enabling a seamless migration from traditional 25G connections to higher-speed 100G Ethernet.

For instance, the FS 4 LC Duplex MTP Breakout Cable is specifically designed to connect four 25G SFP28 transceivers to a single 100G QSFP28, providing an optimal solution for modern data center connectivity needs.

Connecting QSFP28 to SFP28 with 100G DAC Breakout Cables

The 100G QSFP28 DAC breakout cable is ideal for equipment links within 5 meters of the rack. This cable features a connection at one end to a 100G port and splits into four 25G SFP28 ports on the other, providing an excellent solution for replacing 100G optical modules in short-distance (1-5 meters) Ethernet connections.

If your 100GbE network is set up within a 5-meter rack, the 100G QSFP28 to SFP28 DAC passive high-speed cable is perfect for your needs. Additionally, in terms of power consumption, DAC cables are more efficient than AOC cables. Passive DAC cables do not require power, resulting in nearly zero power consumption, whereas Active Optical Cables typically consume around 2W. This gives high-speed DAC cables a clear advantage in power efficiency, making them a smart choice for modern networking solutions.

Connecting QSFP28 to SFP28 with 100G AOC Breakout Cables

The 100G QSFP28 Active Optical Cable (AOC) provides an efficient solution for connecting a 100G QSFP28 port to four 25G SFP28 ports. This cable features one end that connects to a 100G port and the other end that branches out to four 25G SFP28 ports, with lengths ranging from 1 to 70 meters. When using OM3 fiber, the maximum transmission distance is 70 meters, while OM4 fiber can support distances up to 100 meters.

This type of cable is primarily used for interconnecting servers, storage devices, switches, and other equipment. While AOC cables typically come at a higher cost than Direct Attach Copper (DAC) cables, they offer several advantages. AOC cables are lighter and thinner than their DAC counterparts and have a smaller minimum bend radius, making them easier to manage within cabling systems. The 100G QSFP28 to 4x 25G SFP28 AOC breakout cable is an excellent choice for high-performance networking.

QSFP28 to SFP28 Converter Module

The QSFP28 Adapter (QSA) Module offers a seamless and cost-effective solution for upgrading to 100 Gigabit Ethernet on platforms with QSFP28 interfaces. Converting a QSFP28 port into an SFP28 port allows lower-speed SFP28 modules or cables, ensuring compatibility with existing infrastructure and devices operating at lower speeds.

This module brings several key advantages to network infrastructure. It seamlessly integrates high-speed QSFP28 modules with SFP28 ports, allowing organizations to maintain their current setup while expanding bandwidth. Its backward compatibility avoids the need for a complete system overhaul.

Additionally, the QSA Module enables network administrators to mix and match transceiver types based on bandwidth needs, offering flexibility to manage varying data traffic. By reducing rack space and power consumption, it lowers costs while supporting more than 100G Ethernet connections. High-density configurations also help optimize resources like cooling, allowing networks to scale efficiently as demand for faster connectivity grows across large distances.

Conclusion

This article presents four different QSFP28 to SFP28 interconnect solutions. The MTP breakout cable connects one 100G QSFP28 transceiver to four 25G SFP28 transceivers directly. The 100G QSFP28 to 4x25G SFP28 DAC breakout cable supports connections within racks for distances up to 5 meters, while the 100G QSFP28 to 4x25G SFP28 AOC breakout cable can cover distances of 1 to 70 meters between switches, enabling the transmission of 100G Ethernet data. Finally, the 100G QSFP28 to SFP28 converter module allows the use of an adapter with SFP28 modules or cables to connect to lower-speed ports on the other end of the network. The key differences between these four solutions are summarized in the following table：

When selecting the right interconnect solution, key factors such as cost, transmission distance, device port density, and power consumption should be considered. FS provides a comprehensive range of 100G optical transceivers, offering high-density, cost-effective, and low-power Ethernet connectivity solutions. Whether upgrading a data center, optimizing a distribution layer, or enhancing service provider infrastructure, FS’s data center solutions are designed to meet your networking demands with precision and reliability. Explore FS’s lineup today for top-tier performance and support in modern network environments.