A WLAN controller is a device that manages and controls multiple wireless access points (WAPs) in a wireless LAN (WLAN). A WLAN controller has the capability to centrally manage configuration, logging, and firmware versioning for distributed WAPs. A WLAN controller can also provide load balancing, security, and quality of service (QoS) for the WLAN.
References: Network+ Study Guide Objective 3.1: Explain the purposes and use cases for advanced networking devices.

The subnet mask is a binary value that defines how many bits of an IP address are used to identify the network and how many bits are used to identify the host. The subnet mask also determines the size and number of subnets in a network. The ipconfig command shows the current IP configuration of a device, including the subnet mask. In this case, the subnet mask is misconfigured because it does not match the network address of the device. The device has an IP address of 192.168.1.55, which belongs to the network 192.168.1.0/24 (with a subnet mask of 255.255.255.0). However, the subnet mask is set to 225.225.225.224, which is an invalid value that does not correspond to any network prefix length. This causes the device to be unable to communicate with other devices on the same network or access the default gateway. Reference: CompTIA Network+ N10-008 Certification Study Guide, page 109; The Official CompTIA Network+ Student Guide (Exam N10-008), page 5-4.

A tone generator is a device that emits an audible signal on a wire. A tone probe is a device that detects the signal on the wire. By attaching the tone generator to one end of the cable and using the tone probe to scan the other end, the technician can identify which switchport the cable is connected to. This method does not require any knowledge of the computer's IP or MAC address, or access to the switch configuration. It is also faster and more reliable than physically tracing the cable or disconnecting the cable and looking for the link light to go out on the switch.
References: How to find what port im connected to on a switch from my PC?
Switch Port Monitoring Guide - ComparitechFinding Out

The ifconfig eth0 promisc command should be run on the Linux computer to enable promiscuous mode, which allows the computer to capture all network traffic passing through the switch mirror port. Reference: CompTIA Network+ Certification Study Guide, Chapter 7: Network Devices.