Build faster uplinks without changing your multimode fiber strategy. The AddOn Networks 321-2133-AO is a compatible 100GBASE-SR4 QSFP28 transceiver intended for short-reach enterprise and data center environments where 100 GbE capacity must fit into a compact port footprint. This module is a strong fit for spine-and-leaf fabrics, high-throughput aggregation, and server-adjacent switching where dense optics are the difference between a clean upgrade and a disruptive redesign. QSFP28 keeps the hardware footprint small while supporting 100 GbE transport over MMF, helping teams preserve existing cabling investments as bandwidth demands rise. For organizations that require TAA-compliant sourcing, this transceiver aligns technical performance with procurement requirements. It is the kind of component that earns its place in a production network by delivering the reach, density, and speed needed for modern east-west traffic patterns without overcomplicating the deployment.