In this guide, we provide a comprehensive, practical overview of 100G QSFP28 modules, covering their working principles, module types, key specifications, typical applications, and a step-by-step selection framework to help you make confident, informed decisions for your. In this guide, we provide a comprehensive, practical overview of 100G QSFP28 modules, covering their working principles, module types, key specifications, typical applications, and a step-by-step selection framework to help you make confident, informed decisions for your. Faced with a variety of models such as SR4/LR4/ER4, how should engineers choose? This article uses 5 major classification dimensions + practical selection solutions to help you overcome the selection difficulties! 1. Packaging Determines Performance Boundaries: 100G QSFP28 VS CFP ▶ QSFP28 -. This guide breaks down 100G optical module selection using 5 key dimensions, along with practical solutions to help you optimize performance, cost, and future scalability. QSFP28 (Quad Small Form-factor Pluggable 28) is a hot-pluggable optical transceiver that delivers 100G Ethernet using four 25G NRZ lanes. It has the same physical size as QSFP+ (40G) but requires switch ASICs that support 25G signaling.