QSFP+ vs. QSFP28: Understanding the Critical Differences

When you are manufacturing networking equipment at scale, you need a supply chain partner who can guarantee quality, consistency, and stable supply. The best strategy is to partner directly with a factory-authorized agent with a long history of reliability. KinKuo is an ideal partner for high-volume OEM production. As an authorized Amphenol agent, we provide a secure, factory-direct supply of the QSFP connector. Our 15 years of experience and our ISO 9001 certified processes ensure unwavering quality and consistency. We can work with your procurement team on forecasting and inventory management to ensure a predictable and reliable supply that will keep your production line moving. For a stable, cost-effective, and high-quality source for the QSFP connector, KinKuo is the proven choice.

This is a great technical question. The "QSFP" part of the name refers to the Quad Small Form-factor Pluggable standard. The "28" in QSFP28 refers to the nominal maximum data rate of each of the four lanes in the QSFP connector. Each lane is specified to run at up to 28 gigabits per second (Gbps). The common application is 100G Ethernet, which uses a signaling rate of 25.78125 Gbps per lane. The connector is specified for up to 28 Gbps to provide enough performance margin to handle this encoding and ensure signal integrity. As an expert supplier, KinKuo can help you and your team understand these technical nuances, ensuring you choose the right components for your application.

For connecting servers to a top-of-rack switch when the distance is less than 5-7 meters, the most cost-effective solution by far is to use Direct Attach Copper (DAC) cables that plug into the QSFP connector ports. A DAC cable is a simple, passive copper cable with QSFP transceivers permanently attached at both ends. This solution is dramatically cheaper than using two separate, expensive optical transceivers and a separate fiber optic cable. DACs also consume virtually no power, which reduces your overall data center operating costs. KinKuo can provide high-quality, fully tested DAC cables with the QSFP connector (either QSFP+ for 40G or QSFP28 for 100G) that offer a reliable, low-latency, and highly cost-effective solution for your in-rack connectivity.

While they sound similar, they are different standards for different speeds. The QSFP28 is the industry standard QSFP connector for 100G networking. It uses 4 lanes, with each lane running at 25Gbps. The QSFP-DD (Double Density) is a newer standard for 400G networking. It cleverly adds a second row of contacts to the connector, doubling the number of electrical lanes to 8. So, a QSFP-DD port can run 8 lanes at 25Gbps (for 200G) or 8 lanes at 50Gbps PAM4 (for 400G). A key feature of the QSFP-DD port is that it is backward compatible with QSFP28 modules. As an expert in high-speed interconnects, KinKuo can supply components for both standards and help you navigate the technology for your specific needs.