Why multimode fiber cabling for 40 Gbps over eight parallel fibers is still being discussed baffles me. Recent data shows 40 Gbps never has taken off. There has even been a new OM5 multimode fiber standard written to allow wavelength division multiplexing for 100 Gbps, but it’s not cost competitive with single-mode. It’s time to move on—certainly for any links with speeds over 10 Gbps. Single-mode is the logical solution for today (and tomorrow) without replacing the cable for an upgrade. And, single-mode fiber is unlikely to change. What we use today is essentially the same as we used 30 years ago.