QSFP28 stands for Quad Small Form-Factor Pluggable 28. It is a compact, hot-pluggable transceiver module used for high-speed data communication applications. The "Quad" in QSFP refers to the four channels, and "28" indicates that each channel can support data rates up to 28 gigabits per second (Gbps). Therefore, a QSFP28 module can provide aggregate data rates of up to 100 Gbps, as it typically incorporates four lanes.

QSFP28 modules are commonly used in data center interconnects, high-performance computing (HPC) environments, and telecommunications networks to facilitate fast and efficient data transmission.