It stated "multiple devices with network iSOLATION(separated) on a single switch port".
Therefore, its referring to Subinterfaces. Subinterfaces is a virtual interface that divides one physical interface into multiple logical interface.

Confidentiality is the principle of preserving authorized restrictions on information access and disclosure, including means for protecting personal privacy and proprietary information1.
By creating a VLAN that will only allow executives to connect to a data source, the network administrator is implementing a form of network segmentation that enhances the confidentiality of the data.
This prevents unauthorized users or processes from accessing or modifying the data, which could compromise its integrity or availability. Confidentiality is one of the components of the CIA triad, a widely used information security model that guides the efforts and policies aimed at keeping data secure234.
References: Defending Your Network: A Comprehensive Guide to VLAN Hopping AttacksThe CIA triad:
Definition, components and examples | CSO OnlineExecutive Summary - NIST SP 1800-25 documentationThe CIA Triad - Confidentiality, Integrity, and Availability ExplainedConfidentiality, Integrity and Availability - DevQA.io

The show config command (or some variation of it) is used to examine the configuration of a network device. For example, on a Cisco router, the show running-configuration command permits you to see the current configuration of the device, which is stored in the RAM of the device. To view the saved configuration that is loaded when the system is rebooted, you can use the show startup-configuration command.
The show route command (or some variation of it) is used to view the routing table configuration of the network device. On a Cisco router, you can use show ip route to view the IPv4 routing table.
Remember this is on a ROUTER, so netstat (Win/UNIX) does not work.

Explanation
"Bad cables, incorrect pinouts, or bent pins: Faulty cables (with electrical characteristics preventing successful transmission) or faulty connectors (which do not properly make connections) can prevent successful data transmission at Layer 1. A bad cable could simply be an incorrect category of cable being used for a specific purpose. For example, using a Cat 5 cable (instead of a Cat 6 or higher cable) to connect two 1000BASE-TX devices would result in data corruption. Bent pins in a connector or incorrect pinouts could also cause data to become corrupted."

The MAC address table is a way to map each port to a MAC address. The technician can use the MAC table to find which MAC address is connected to which port.