DAC vs AOC vs Optic: How to Choose a Short Server-to-Switch Link

Most data center server-to-switch connections span only a metre or two and can be built with a direct attach copper cable, an active optical cable, or a transceiver paired with a fiber patch cord. All three carry identical data at the same speed but differ in cost, reach, power draw, and how they fail. Passive copper DACs are the cheapest and lowest-power option for runs within a rack, though their reach shrinks at higher speeds and they expose no diagnostic data. AOCs extend reach to tens of metres and are lighter, but they usually offer no light-level monitoring and cannot be repaired in the field. Pluggable optics with fiber cords cost the most for short runs but reach hundreds of metres, report diagnostics at both ends, and allow each component to be replaced independently.