Keep 40 GbE aggregation links stable across short- to mid-reach multimode runs with the HPE X142 40G QSFP+ MPO eSR4. Designed for switch-to-switch and switch-to-server uplinks, this transceiver supports 40 Gigabit Ethernet over multimode fiber with an MPO connector and a 300 m reach profile. That makes it a practical fit for campus cores, data center leaf-spine fabrics, and rack-to-row connections where structured cabling and consistent optical performance are non-negotiable. The eSR4 design is aimed at environments that need dense port counts without moving to more expensive long-reach optics. It helps preserve budget for the parts of the network that matter most while still delivering the reach and throughput required for modern aggregation layers. For teams standardizing on HPE/Aruba switching, this module fits naturally into existing 40 GbE architectures and supports clean, parallel-fiber deployment patterns. When uptime, port density, and cabling discipline all matter, this is the kind of optic that earns its place in the bill of materials.