QSFP+ has a size of 18mm x 72mm, while QSFP28 has a size of 18mm x 84mm.

QSFP+ (Quad Small Form-Factor Pluggable) and QSFP28 (Quad Small Form-Factor Pluggable 28) are both form factors for transceiver modules used in high-speed data communication. The primary difference between them lies in their maximum data rates. QSFP+ supports data rates up to 40 Gbps, while QSFP28 supports data rates up to 100 Gbps.

In terms of physical size, the QSFP+ and QSFP28 modules have the same form factor. They both have the same dimensions, which are approximately 18.4 mm in width and 72 mm in length. The height may vary slightly based on the specific design of the module.

The common physical characteristics and form factor between QSFP+ and QSFP28 allow for backward compatibility in many cases, meaning that QSFP28 ports can often support QSFP+ modules. However, it's essential to check the specifications and compatibility of the specific networking equipment you are working with, as variations may exist between different manufacturers and models.

25Gb/s SFP28 850nm 100m Transceiver