Keep short-reach 100 GbE links compact and predictable. The AddOn 845966-B21-AO is an HPE-compatible QSFP28 MPO 100G-SR4 transceiver intended for multimode fiber deployments. Its SR4 design fits the common data center pattern of high-density switch-to-switch and switch-to-server uplinks where short optical reach is enough and port efficiency matters. QSFP28 packaging preserves front-panel density while supporting 100 Gb throughput, which is exactly what modern leaf-spine fabrics demand. The MPO connector aligns with parallel optics architectures used in short-reach environments, helping teams standardize around a familiar cabling model. For infrastructure groups managing mixed vendor estates, compatibility-focused optics like this reduce friction during qualification and rollout. Choose this module when you need a cost-conscious 100 Gb optic for short distances and want to avoid paying for reach you will not use. It is a straightforward fit for enterprise data centers that value density, interoperability, and disciplined network design.