The Device Status chart on the "Network Health" tab indicates one device has a status of "Down," representing a complete connectivity failure. The user-reported symptoms—performance issues accessing application servers and intermittent internet for wireless users—are consistent with the failure of a core network device like a router. While the chart does not explicitly label the red segment, Router A's failure as a critical infrastructure component would cause such widespread issues, making it the device experiencing the most severe connectivity problem.

The Top Hosts table on the "Network Health" tab provides metrics on data transfer for various IP addresses. The "Bits" column represents the total volume of traffic. The IP address 206.208.133.9 is listed with 104.69 Gb, which is the highest value in the table. This indicates it is the workstation responsible for generating the most network traffic among the top hosts.

Voice over IP (VoIP) performance is highly dependent on low latency, low jitter, and minimal packet loss. The table on the "Device Monitoring" tab shows that WAN 2 is superior to WAN 1 in all of these critical metrics. WAN 2 has significantly lower loss (0.01% vs. 2.51%), lower average latency (11ms vs. 24ms), and lower jitter (3.9ms vs. 9.5ms). Due to its superior and more stable

Kurose, J. F., & Ross, K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson.

In Chapter 5, Section 5.1 ("Multimedia Networking Applications"), the text details the network requirements for real-time conversational voice/video, emphasizing sensitivity to delays greater than 400ms and the impact of packet loss and jitter on user-perceived quality. This supports the reasoning for selecting WAN 2 based on its lower latency, jitter, and loss metrics for VoIP.

Cisco. (2008). Enterprise QoS Solution Reference Network Design Guide Version 4.0.

In Chapter 2, "QoS Functional and Design Requirements," the document outlines the generally accepted performance targets for voice traffic: one-way latency of 150 ms or less, average jitter of 30 ms or less, and packet loss of 1% or less (pp. 2-5 to 2-6). This official vendor documentation validates the criteria used to evaluate WAN 1 and WAN 2, confirming that WAN 2's metrics (11ms latency, 3.9ms jitter, 0.01% loss) are well within the high-quality thresholds for VoIP.

Stallings, W. (2014). SNMP, SNMPv2, SNMPv3, and RMON 1 and 2 (3rd ed.). Addison-Wesley Professional.

Chapter 6 discusses the IF-MIB (Interface Management Information Base) for SNMP. Specifically, the ifOperStatus object (OID 1.3.6.1.2.1.2.2.1.8) defines the operational states of a network interface, including "up" (1), "down" (2), and "testing" (3). The "down" state in the simulation's "Device Status" widget directly corresponds to this standardized management object, indicating a non-functional interface or device.