Extend a 400 GbE port over multimode fiber with a QSFP-DD SR8 transceiver built around an MPO-16 optical interface. SR8 uses eight optical lanes for short-reach 400 Gigabit Ethernet connectivity, while the QSFP-DD module format fits compatible high-density network equipment. The specified multimode-fiber reach is up to 100 m. This module fits data-center links where high-bandwidth switching or routing ports need an optical path between nearby racks, rows, or distribution points. An MPO-16 fiber path is required at both ends of the connection. Its short-reach multimode design suits structured fiber environments that need 400 GbE capacity without deploying a longer-reach optical platform. Aruba R9B41A specifically combines 400G operation, QSFP-DD host connectivity, SR8 optics, and an MPO-16 interface in one module. Those interface details matter when matching transceivers to installed fiber: an MPO-16 connection and multimode cable plant are not interchangeable with duplex optical interfaces or single-mode fiber. Confirm the host port accepts a QSFP-DD 400G SR8 module and that the end-to-end channel remains within the 100 m reach.