Network Security Administrator SD-WAN-Engineer Updated Exam

Comprehensive and Detailed Explanation

The Prisma SD-WAN (ION) QoS engine utilizes a hierarchical queuing structure designed to provide granular control over application performance. Each WAN interface on an ION device supports a total of 16 QoS queues.

This 16-queue structure is derived from a matrix of 4 Classes (often referred to as Priority Classes) multiplied by 4 Application Criteria (Traffic Types).2

4 Priority Classes: The system defines four high-level business priority categories:3

Platinum (Highest priority)4

Gold

Silver

Bronze (Lowest priority/Best Effort)5

4 Application Criteria (Sub-queues): Within each of the four priority classes, the system further categorizes traffic into four specific application types to ensure proper handling (e.g., ensuring voice doesn't get stuck behind bulk data even within the same priority level):6

Real-Time Video

Real-Time Audio

Transactional

Bulk7

Calculation: 4 Priority Classes × 4 Application Types = 16 Total Queues per interface. This structure allows the scheduler to ensure that a "Platinum" voice call is prioritized over "Platinum" bulk data, and both are prioritized over "Gold" traffic.

Prisma SD-WAN is built on an application-defined fabric that prioritizes deep visibility into network traffic and application performance.1 To deliver the high-fidelity flow data and application visibility required for modern operations, Prisma SD-WAN utilizes IPFIX (Internet Protocol Flow Information Export).2 IPFIX is a standardized protocol based on NetFlow v9 that allows for the export of IP flow information from network devices to a collector or management system.3

In the Prisma SD-WAN architecture, ION devices act as the exporters.4 Because the system is application-aware, it doesn't just export basic 5-tuple information (source/destination IP, ports, and protocol); it exports rich metadata including application IDs, performance metrics (latency, jitter, packet loss), and path information. This allows the Prisma SD-WAN Controller and the associated Analytics engine to reconstruct a complete picture of every flow in the network.

While other protocols like SNMPv3 are supported for basic device health monitoring (such as CPU or interface status) and ADEM (Autonomous Digital Experience Management) provides end-to-end visibility for mobile users or SASE-connected branches, IPFIX is the primary "engine" for flow-level data across the SD-WAN fabric. Unlike traditional IP SLA, which relies on synthetic probes, the IPFIX-based monitoring in Prisma SD-WAN uses real-time application traffic to assess performance. This ensures that the visibility provided in the Flow Browser and Analytics dashboards accurately reflects the actual user experience, enabling granular troubleshooting and proactive capacity planning.

Comprehensive and Detailed Explanation

Prisma SD-WAN separates real-time visibility from historical summarization.

Reports (C): The Reports section is the dedicated engine for generating historical summaries. Administrators can create custom report templates (e.g., "Monthly Executive Summary") that include specific widgets like "Top Applications by Volume," "Site Availability," or "Circuit Utilization." Crucially, this feature allows for Scheduling, where the system automatically generates the PDF report at a set interval (e.g., first day of the month) and emails it to a distribution list.

Activity Charts (A) / Media Analytics (B): These provide interactive, visual graphs for ad-hoc analysis but are not designed for generating downloadable, scheduled PDF summaries for management.

Flow Browser (D): This is for deep-dive troubleshooting of individual sessions, not for high-level aggregate reporting.

Comprehensive and Detailed Explanation

Prisma SD-WAN calculates the Mean Opinion Score (MOS) to provide a standardized metric (1-5) for voice quality. To ensure the system always knows the "voice readiness" of a path—even before a call starts—it uses Active Probes (synthetic UDP packets).

While latency is measured, the MOS calculation algorithm is most heavily penalized by Packet Loss (D) and Jitter (B).

Packet Loss: Even a small amount of loss (e.g., >1%) dramatically reduces voice clarity, causing dropouts.

Jitter: High variance in packet arrival time (jitter) causes the "robotic" voice effect and buffer underruns.

The system continuously measures these specific metrics on all WAN links using synthetic probes. If the packet loss or jitter exceeds the threshold defined in the "Path Quality Profile" (e.g., Voice Profile), the path is marked as non-compliant, and the MOS score drops, triggering a policy action to move the flow. Throughput (C) is less critical for voice as calls consume very little bandwidth (e.g., 64-100 Kbps), making congestion (loss/jitter) the primary enemy, not raw speed.