During a rack expansion, you must connect a new rack-mount server's 10-Gbps network interface card to the top-of-rack switch. Both devices provide empty SFP+ cages, the distance between ports is about 2 m inside the same cabinet, and management wants the lowest-cost, lowest-power solution that avoids purchasing separate optical modules. Which cabling option will best meet these requirements while providing 10 GbE performance?
A passive SFP+ direct-attach copper (twinax) cable contains fixed SFP+ connectors at each end, so no separate optical or 10GBASE-T transceivers are needed. Because it runs short-reach electrical signaling over inexpensive twinax and draws almost no additional power, it is the least-cost, least-power 10 GbE option for in-rack links of just a few meters.
A Cat6a patch cord would also carry 10 GbE, but only when paired with two 10GBASE-T SFP+ modules-adding much higher cost and 2-3 W of extra power per port. Multimode or single-mode fiber jumpers likewise require a pair of 10GBASE-SR or 10GBASE-LR optical transceivers, which are still more expensive and unnecessary for a 2-m run. Therefore, the direct-attach twinax cable is the only choice that satisfies all stated constraints.