Exam SD-WAN-Engineer Topic 3 Question 85 Discussion
Actual exam question for Palo Alto Networks's SD-WAN-Engineer exam
Question #: 85
Topic #: 3
Question #: 85
Topic #: 3
A network engineer is troubleshooting a user complaint regarding "slow application performance" for an internal web application. While viewing the Flow Browser in the Prisma SD-WAN portal, the engineer notices that the Server Response Time (SRT) is consistently high (over 500ms), while the Network Transfer Time (NTT) and Round Trip Time (RTT) are low (under 50ms).
What does this data indicate about the root cause of the issue?
What does this data indicate about the root cause of the issue?
Suggested Answer: B Vote an answer
Comprehensive and Detailed Explanation
The Flow Browser and App Response Time metrics in Prisma SD-WAN are critical tools for isolating the fault domain-determining whether a problem lies in the "Network" or the "Application."
* Network Transfer Time (NTT) / Round Trip Time (RTT): These metrics measure the time it takes for packets to traverse the network (WAN/LAN) and for acknowledgments to return. A low NTT (e.g.,
<50ms) confirms that the network pipes (SD-WAN overlay, Underlay circuits) are healthy and transporting packets quickly.
* Server Response Time (SRT): This metric specifically measures the time between the server receiving a request and the server sending the first byte of the response. It essentially measures the "processing time" of the backend server.
In the scenario described, the network metrics (NTT/RTT) are excellent, effectively ruling out WAN congestion, packet loss, or latency (Option A and C). However, the Server Response Time (SRT) is very high (500ms). This signature is a definitive indicator that the network delivered the request instantly, but the application server took a long time to process it. This points the troubleshooting effort toward the server infrastructure (e.g., a slow SQL query, an overloaded web server, or lack of compute resources) rather than the SD-WAN environment.
The Flow Browser and App Response Time metrics in Prisma SD-WAN are critical tools for isolating the fault domain-determining whether a problem lies in the "Network" or the "Application."
* Network Transfer Time (NTT) / Round Trip Time (RTT): These metrics measure the time it takes for packets to traverse the network (WAN/LAN) and for acknowledgments to return. A low NTT (e.g.,
<50ms) confirms that the network pipes (SD-WAN overlay, Underlay circuits) are healthy and transporting packets quickly.
* Server Response Time (SRT): This metric specifically measures the time between the server receiving a request and the server sending the first byte of the response. It essentially measures the "processing time" of the backend server.
In the scenario described, the network metrics (NTT/RTT) are excellent, effectively ruling out WAN congestion, packet loss, or latency (Option A and C). However, the Server Response Time (SRT) is very high (500ms). This signature is a definitive indicator that the network delivered the request instantly, but the application server took a long time to process it. This points the troubleshooting effort toward the server infrastructure (e.g., a slow SQL query, an overloaded web server, or lack of compute resources) rather than the SD-WAN environment.
by May at Feb 14, 2026, 08:00 AM
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