During a data-center expansion, a systems administrator must connect the SFP cage of several new rack servers to an existing aggregation switch 180 m away. The building already has a duplex OM3 multimode fiber run terminated with LC patch panels between the two locations. The project scope limits the link to 1 Gb/s and must minimize cost; upgrading to single-mode fiber or 10 Gb/s optics is not allowed. Which SFP transceiver should the administrator deploy to meet these requirements?
1000BASE-SX is the short-wavelength (850 nm) Gigabit Ethernet optic designed for multimode fiber and is typically the lowest-cost gigabit SFP. Per the IEEE 802.3z standard, it supports distances up to 550 m over quality 50 µm multimode fiber (such as OM3), which is well beyond the 180 m requirement. 1000BASE-LX uses a 1310 nm long-wavelength laser primarily intended for single-mode fiber; it can operate on multimode fiber for up to 550 m, but may require special mode-conditioning patch cords over longer distances, adding expense and complexity the project seeks to avoid. 1000BASE-ZX is engineered for long-haul single-mode links of roughly 70 km and is unnecessary and costly in this situation. 10GBASE-SR SFP+ provides 10 Gb/s, exceeds the speed requirement, and will not link to a 1 Gb/s SFP port. Therefore, the 1000BASE-SX SFP is the most appropriate and cost-effective choice.