The QSFP-40G-CSR-S is a pluggable optical transceiver with a duplex LC connector interface used for connectivity with multimode fiber (MMF). The Cisco 40GBASE-CSR modules support link lengths of 300 meters and 400 meters, respectively, on laser-optimized OM3 and OM4 multimode fibers. Customers benefit from reusing their existing 10 gigabit duplex MMF infrastructure as they migrate to 40 Gigabit Ethernet while maintaining the same supported link distances as 10G Ethernet. Each QSFP-40G-CSR-S operates at four different wavelengths, with each wavelength operating at 10G over existing duplex multimode fiber using standard LC connectors. The Cisco QSFP-40G-CSR-S transceiver does not support FCoE.