Hi,

A QSFP28 is a Quad (4-channel) small form factor hot pluggable fibre optical transceiver used for 100 Gigabit Ethernet (100GbE) data communications applications. The QSFP28 integrates 4 transmit and 4 receiver channels. The number 28 means each lane carries up to 28G data rate.

Brocade QSFP28 LR

References:

https://ext-6277115.livejournal.com/2068.html

https://gbic.skyrock.com/3356295928-Unleash-High-Speed-Connectivity-with-QSFP-100G-LR4-Empowering-Optimal.html

Thanks