A network performance baseline is a set of metrics that represents the normal or expected behavior of a network under various conditions and scenarios. A network performance baseline can help a network administrator to investigate reports about network performance by comparing the current metrics with the historical metrics and identifying any deviations or anomalies. A network performance baseline can also help to plan and justify network upgrades by showing the trends and patterns of network utilization and performance over time.
A device configuration review is a process that involves checking and verifying the settings and parameters of a network device, such as a switch, router, firewall, or server. A device configuration review can help a network administrator to troubleshoot network issues by finding and fixing any errors, inconsistencies, or vulnerabilities in the device configuration. A device configuration review can also help to ensure compliance with security policies and best practices by applying the latest updates and patches to the device.
An ARP table export is a file that contains the contents of the ARP (Address Resolution Protocol) table of a network device. The ARP table is a data structure that maps IP addresses to MAC addresses on a local network. An ARP table export can help a network administrator to monitor and manage the network devices on a local network by showing their IP addresses and MAC addresses. An ARP table export can also help to detect and prevent ARP spoofing attacks by identifying any duplicate or malicious entries in the ARP table.
A service-level agreement (SLA) is a contract that defines the expectations and responsibilities of both parties in terms of service quality, availability, performance, and response time. An SLA can help a network administrator to provide and maintain a satisfactory level of service to the customers or users of the network by setting and measuring specific goals and metrics. An SLA can also help to resolve any disputes or issues that may arise between the service provider and the service consumer by establishing clear terms and conditions for the service delivery.

Wireless AC is a wireless standard that supports up to 1.3Gbps data rate and operates in the 5GHz frequency band only. Wireless AC is also backward compatible with wireless A and N devices that use the 5GHz band. Wireless AC is suitable for high-performance applications such as HD video streaming and online gaming. Reference: Network+ Study Guide Objective 2.2: Explain the purposes and properties of routing and switching. Subobjective: Wireless standards and their characteristics.

The best metric for a network administrator to check is hop-by-hop network latency. This is because network latency is the time it takes for a packet to travel from the source to the destination, and it affects the loading speed of web pages. Hop-by-hop network latency measures the latency between each pair of routers or switches along the network path, and it can help identify where the delay is occurring. By checking the hop-by-hop network latency, the network administrator can determine if the problem is caused by a slow or congested link, a misconfigured or faulty device, or a routing issue.
Jitter is the variation in latency over time, and it affects the quality of voice and video applications. Jitter does not directly affect the loading speed of web pages, and it is not a useful metric for troubleshooting this issue.
Server interface CRC errors are errors that occur when the cyclic redundancy check (CRC) of a packet does not match the expected value, indicating data corruption. Server interface CRC errors can affect the reliability and integrity of data transmission, and they can be caused by faulty cables, connectors, or interfaces. Server interface CRC errors do not necessarily affect the loading speed of web pages, unless they are severe enough to cause retransmissions or packet loss.
Server NetFlow data is data that is collected and analyzed by the NetFlow protocol, which monitors and reports on network traffic flows. Server NetFlow data can provide information on the volume, type, and direction of traffic that is sent or received by the server, as well as the source and destination IP addresses, ports, and protocols. Server NetFlow data can help identify network usage patterns, trends, and anomalies, but it does not measure the latency or performance of the network.
Reference
What is Network Latency and How to Measure It
How to Troubleshoot Network Latency Issues
What is Jitter and How to Measure It
What is CRC Error and How to Fix It
What is NetFlow and How Does It Work
CompTIA Network+ Certification All-in-One Exam Guide, Eighth Edition (Exam N10-008)

A 110 block is a type of punch-down block that is used to distribute Ethernet to multiple computers in an office. A punch-down block is a device that connects one group of wires to another group of wires by using a special tool that pushes the wires into slots on the block. A 110 block is a non-proprietary standard that supports up to Category 6 cabling and can be used for voice or data applications. Reference: https://www.comptia.org/training/books/network-n10-008-study-guide (page 64)

IPSec is a protocol that provides secure communication between two networks or hosts over an untrusted network, such as the Internet. IPSec uses encryption and authentication to protect the data from eavesdropping, tampering, and replay attacks. IPSec also supports pre-shared key (PSK) as one of the methods for initial authentication between the peers