AppDynamics

Catalyst Center

ThousandEyes

Meraki

In theDesigning and Implementing Enterprise Network Assurance (300-445 ENNA)architecture, each platform is positioned to address a distinct domain of visibility and management within the modern IT visibility framework.

AppDynamics(matched to Case 1) is specifically engineered for Full-Stack Observability and Application Performance Monitoring (APM). Its unique focus is linking technical application performance—such as code-level execution and database queries—directly to business outcomes and real-time business metrics. By doing so, it allows organizations to pinpoint how application latency impacts revenue or user satisfaction, making it the primary choice for business impact analysis.

Catalyst Center, formerly DNA Center (matched to Case 2), serves as the foundational controller for campus and enterprise network infrastructure. It leverages AI-driven insights to automate network operations, enforce security policies, and provide at-a-glance health monitoring for local devices and clients. It is the definitive management system for connecting and securing "inside" the corporate network perimeter.

ThousandEyes(matched to Case 3) provides "Internet Intelligence" and is the key solution for monitoring the service delivery chain across environments the enterprise does not own. By utilizing a global network of Cloud, Enterprise, and Endpoint agents, it provides end-to-end visibility from any user location to any application (SaaS or Cloud) over any network (Internet, ISP, or WAN).

Meraki(matched to Case 4) is a cloud-first platform designed for managing highly distributed network environments and IoT deployments. It provides end-to-end visibility through a simplified dashboard that integrates wireless health, switching, and security across thousands of sites, making it ideal for lean IT teams managing distributed retail or branch locations.

Each platform utilizes different data collection methods—active synthetic testing for ThousandEyes and passive monitoring/AI telemetry for Catalyst Center—to ensure comprehensive network assurance across the entire enterprise ecosystem.

In theDesigning and Implementing Enterprise Network Assurance (300-445 ENNA)framework, baselining is the process of establishing a "normal" performance profile for network infrastructure to enable the detection of anomalies. When the metric of interest is the internal health of a physical device, such asCPU utilizationon a core router,SNMP (Simple Network Management Protocol)is the industry-standard data source.

SNMP provides direct visibility into the device's control plane and hardware performance. By polling specific Object Identifiers (OIDs) from the router's Management Information Base (MIB), a monitoring system likeCisco Catalyst Centeror a third-party NMS can collect granular data on CPU cycles, memory allocation, and temperature. This "inside-out" telemetry is essential for baselining because it reflects the actual resource consumption of the router during various traffic loads.

Conversely, ThousandEyes tests (Options A, B, and D) provide "outside-in" synthetic data. WhileDNS resolution time(Option A),HTTP response times(Option B), andPath Visualization(Option D) are excellent for measuring end-to-end service delivery and network transit health, they do not report on the router's internal hardware state. For instance, a router could have 99% CPU utilization (indicating a potential crash), yet a ThousandEyes path test might still show a "green" path if the data plane (ASICs) is still forwarding packets efficiently. Therefore, to establish a reliable baseline for hardware-specific metrics like CPU,SNMP data(Option C) is the only appropriate source among the choices.

In the context ofDesigning and Implementing Enterprise Network Assurance (300-445 ENNA), analyzing page-load metrics within Cisco ThousandEyes requires identifying the primary bottlenecks that contribute to theTotal Page Load Time. The provided screenshot displays a "Page Breakdown" of 7 resources totaling 953 kB. A critical observation of the pie chart reveals thatImages(the teal-colored segment) constitute the vast majority of the page's payload and resource count.

When the goal is to reduce the page-load time from1023 msto below500 ms, the engineer must target the heaviest components.Lazy loadingis a design pattern that defers the initialization of non-critical resources at page load time. Instead of loading all images simultaneously when the userfirst navigates to the URL, lazy loading ensures that images are only downloaded as they are about to enter the viewport. This significantly reduces the initial DOM load time and the total Page Load Time because the browser does not have to wait for large image files to be fully retrieved before declaring the page "loaded."

Alternative options are less effective in this specific scenario based on the data:

AJAX (XHR/Fetch):The chart shows that XHR and Fetch resources represent a negligible sliver of the total weight; optimizing them would yield minimal gains.

Moving IMG elements:While moving scripts to the bottom can help with rendering, moving image elements to the bottom of the body does not stop the browser from initiating the download requests immediately, thus failing to significantly reduce the total load time.

CDN for Fonts:The "Font" category is also a small fraction of the total 953 kB. While a CDN is a best practice for latency, it does not address the primary "weight" issue caused by the images.

Therefore, implementinglazy loading(Option C) is the most impactful recommendation. It directly addresses the largest resource consumer (Images) identified in the ThousandEyes Page Breakdown, allowing the engineer to reach the sub-500 ms performance target.

56

In theDesigning and Implement7ing Enterpr8ise Network Assurance (300-445 ENNA)framework, configuring effective alert rules is critical for distinguishing between standard network noise and actionable application-layer failures. ForWeb - HTTP Servertests, ThousandEyes allows engineers to monitor both network-level metrics (like Connect time) and application-level indicators (like HTTP response codes).

The requirement is to trigger an alert specifically when the HTTP server responds with aserver error. In the HTTP protocol, server errors are categorized as the5XXseries of status codes (e.g., 500 Internal Server Error, 503 Service Unavailable, 504 Gateway Timeout). To meet this requirement, the engineer must configure a location alert condition where theMetricis set toResponse Codeand the condition value isserver error(5XX)(Option D).

Reviewing the other options:

Error type is any (Option A):While this would capture server errors, it would also trigger for 4XX client errors (like 404 Not Found) and network-layer timeouts, making it too broad for a specific "server error" requirement.

Wait Time is Dynamic (Option B):This monitors the time-to-first-byte using statistical baselining. While high wait times oftenprecede5XX errors, this condition only alerts on latency, not on the actual error code itself.

Response Time (Option C):Similar to wait time, this monitors performance speed rather than the logical success or failure of the server's response.

By specifically selectingResponse Code: server error(5XX), the engineer ensures that the operations team is only notified when the application backend is experiencing a functional failure, rather than just a slow response or a client-side misconfiguration.

In wireless network assurance, high channel utilization and increased retransmissions are clear indicators of RF interference or over-subscription. Retransmissions are particularly damaging to voice call quality because they introduce significant jitter and late-arrival packet loss that the jitter buffer cannot overcome.

The recommended optimization is tochange the access point to a different, less congested channel(Option B). This directly reduces the competition for airtime (Channel Utilization) and the likelihood of collisions from neighboring access points (Co-Channel Interference), which in turn lowers the retransmission rate. Modern wireless controllers usingRadio Resource Management (RRM)often automate this, but a manual adjustment based on SNMP telemetry is a valid operational fix.

Other options are technically flawed:

Option A:Increasing transmit power oftenincreasesinterference and channel utilization for surrounding cells, making the problem worse for everyone.

Option C:Disabling all non-voice traffic is an extreme measure that is rarely feasible in a real business environment.

Option D:Admission control limits thenumberof users but doesn't solve the underlying issue of poor channel health for those already connected.

In theDesigning and Implementing Enterprise Network Assurance (300-445 ENNA)curriculum, identifying routing anomalies such as BGP Hijacking is a critical aspect of external network assurance. A BGP Hijack occurs when an Autonomous System (AS) illegitimately announces a prefix it does not own, causing traffic intended for the rightful owner to be misdirected.

By contrastingExhibit 3.4-1(Before the Outage) andExhibit 3.4-2(During the Outage), a definitive change in the routing path is observed. In the baseline view (Exhibit 3.4-1), traffic from the Los Angeles agent reaches the destination network 54.239.104.0/23, which is correctly associated withAmazon.com, Inc. (AS 16509). However, during the outage (Exhibit 3.4-2), the path visualization shows the traffic being redirected into a different network:eNET Inc. (AS 10297). At this new location, the traffic encounters100% Forwarding Lossat the node ten7-8.core-2.xlhost.com.

Thechange in the Autonomous System (AS) numberfrom 16509 to 10297 (Option B) is the most concrete indicator of a BGP Hijack. While symptoms such asAvailability Drop(Option A),Response Delay(Option C), andPacket Loss(Option D) are clearly visible in the ThousandEyes telemetry, these symptoms are generic and could be caused by various other issues like physical link failures or congestion. The shift in the AS path—specifically to an AS that does not legitimately host the target's IP prefix—provides the forensic evidence needed to identify the root cause as a routing takeover. This visualization allows network administrators to bypass internal troubleshooting and immediately focus on external remediation with upstream providers.