Choosing between single-mode (SMF/OS2) and multimode (MMF/OM3–OM5) fiber is more than a cabling preference, it determines your reachable distance, optics cost, upgrade path, and even day-to-day operability (polarity, cleaning, testing). The differences are well known in theory, but real-world projects still stumble ...

If you’re upgrading leaf–spine fabrics, stitching campus buildings, or extending metro/edge links, a reliable Optical Transceiver Module at 100 Gbps is table stakes. This guide breaks down NS-branded QSFP28 modules—SR4, LR4, and DR—with practical advice on reach, fiber types, connectors, power, DOM, interoperability...