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)

See the answer and solution below
Explanation:
Network Health:
WAN 2 appears to have a lower average latency and loss percentage, which would make it the preferred WAN station for VoIP traffic. VoIP traffic requires low latency and packet loss to ensure good voice quality and reliability. WAN 1 seems to have higher RAM and processor usage, which could also affect the performance of VoIP traffic.
Here's the summary of the key metrics for WAN 1 and WAN 2 from the image provided:
WAN 1:
Uplink Speed: 10G
Total Usage: 26.969GB Up / 1.748GB Down
Average Throughput: 353MBps Up / 23.42MBps Down
Loss: 2.51%
Average Latency: 24ms
Jitter: 9.5ms
WAN 2:
Uplink Speed: 1G
Total Usage: 930GB Up / 138GB Down
Average Throughput: 12.21MBps Up / 1.82MBps Down
Loss: 0.01%
Average Latency: 11ms
Jitter: 3.9ms
For VoIP traffic, low latency and jitter are particularly important to ensure voice quality. While WAN 1 has higher bandwidth and throughput, it also has higher latency and jitter compared to WAN 2. However, WAN 2 has much lower loss, lower latency, and lower jitter, which are more favorable for VoIP traffic that is sensitive to delays and variation in packet arrival times.
Given this information, WAN 2 would generally be preferred for VoIP traffic due to its lower latency, lower jitter, and significantly lower loss percentage, despite its lower bandwidth compared to WAN 1. The high bandwidth of WAN 1 may be more suitable for other types of traffic that are less sensitive to latency and jitter, such as bulk data transfers.

Device Monitoring:
the device that is experiencing connectivity issues is the APP Server or Router 1, which has a status of Down. This means that the server is not responding to network requests or sending any dat a. You may want to check the physical connection, power supply, and configuration of the APP Server to troubleshoot the problem.

10GBASE-LR SFP transceivers are designed for long-range transmissions over single-mode fiber optics and can support connections over distances of up to 10 kilometers, making them the appropriate choice for this scenario where the data centers are 6.2 miles apart. These transceivers are specifically engineered for longer distances and are suitable for interconnecting data centers across greater distances.