To meet these growing bandwidth requirements, access switches must have optical downlink ports. These ports can then use optical fibers that offer a higher transmission rate for access, achieving fiber to the room. An all-optical Ethernet switch is a network switch whose service ports are entirely optical, meaning every interface uses fiber rather than copper. They can function as core, aggregation, and access devices on campus networks and connect to upstream and downstream devices. At its core, 1000BASESX SFP refers to a Gigabit Ethernet optical transceiver designed for short-range transmission over multimode fiber.