Your colleague is installing a new HPE Aruba Networking CX 8100 switch in a data...

The correct answer is B. Request to issue the command no shutdown on the port the DAC cable is connected to. On HPE Aruba Networking CX 8100 and similar data center switch platforms, interfaces are Layer 3 and disabled by default. HPE Aruba Networking AOS-CX IP Services documentation states that, by default, all interfaces on these platforms are Layer 3 and disabled, and its examples explicitly enable the interface with no shutdown. Therefore, even if a supported 10Gb DAC cable is physically attached and the peer switch port is monitored, the link will remain down until the CX 8100 interface is administratively enabled. Option A is not the best answer because the symptom is not that the DAC is in the wrong port; the default shutdown state explains the link-down condition. Option C is incorrect because switching enable is not the AOS-CX command used to bring the port online. Option D is incorrect because DAC cables do not require manual Tx/Rx polarity swapping like separate fiber strands might. ( arubanetworking.hpe.com )