The standard Quad Small Form-Factor Pluggable (QSFP) transceiver was initially designed to support data rates of 40 Gigabits per second (Gbps) and 100 Gbps. However, with advancements in technology and the increasing demand for higher data rates, variants of the QSFP standard have been developed to support 25 Gigabit Ethernet (25GbE).

The specific variant designed for 25GbE is known as QSFP25 or QSFP28. QSFP28 supports four channels of 25 Gbps, providing a total data rate of 100 Gbps. While the original QSFP standard did not include 25 Gbps support, the subsequent development of QSFP28 has addressed the need for 25GbE in modern networking applications.

It's important to distinguish between the original QSFP, which primarily supports 40 Gbps and 100 Gbps, and the newer variants like QSFP28, which can support 25 Gbps per channel. As technology continues to advance, it's possible that further iterations or new standards may emerge to meet evolving networking requirements.