QSFP+ vs. QSFP28: Understanding the Critical Differences

This is a very common application called a "breakout" or "fan-out," and it is one of the great strengths of the QSFP connector architecture. To achieve this, you need a specific type of cable called a breakout cable. KinKuo can supply a high-quality breakout cable that has a single QSFP28 connector on one end (to plug into your 100G switch port) and four separate SFP28 connectors on the other end. The switch port is configured to operate in breakout mode, and it will treat the single QSFP28 port as four independent 25G interfaces. This is a highly efficient and cost-effective way to connect a high-speed switch to multiple servers. KinKuo can provide the high-quality, fully tested breakout cables you need to reliably implement this architecture.

While the QSFP connector itself doesn't generate heat, the cage that surrounds it plays a vital role in removing heat from the optical transceivers, which can get extremely hot. If you are using a low-quality or poorly designed cage, it may not be making proper thermal contact with the transceiver module, trapping the heat and causing the port area to overheat. This can lead to transceiver failures and network instability. The solution is to use a high-quality, precision-engineered QSFP connector and cage system from a top-tier manufacturer like Amphenol, supplied by KinKuo. These cages are designed and tested for optimal thermal performance, ensuring they effectively draw heat away from the optics and protect your valuable equipment.

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.

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.