https://songkou.github.io/tags/400g/Recent content in 400G on Council of ElrondHugoenSun, 19 Jul 2026 18:00:00 +0800https://songkou.github.io/posts/sfp-qsfp-fiber-400g-800g-optics/Sun, 19 Jul 2026 18:00:00 +0800https://songkou.github.io/posts/sfp-qsfp-fiber-400g-800g-optics/<p>Choosing an optical transceiver is harder than matching the number printed on the switch port. A working link has to align the <strong>form factor, host lane rate, Ethernet standard, optical organization, fiber type, connector, wavelength, FEC mode, loss budget, and platform support</strong> at both ends.</p> <p>The first clarification is terminology: <strong>SFP</strong> is a specific one-lane form factor, not the general name for every removable optic. Engineers often say “SFP” informally, but 400G and 800G modules are normally <strong>QSFP112, QSFP-DD, QSFP-DD800, or OSFP</strong>.</p>