Free Paloalto Networks SD-WAN-Engineer Practice Exam with Questions & Answers | Set: 2

Comprehensive and Detailed Explanation

In Prisma SD-WAN, Custom Applications are global policy objects managed centrally on the controller.

Immediate Propagation: When an administrator creates or modifies a Custom Application definition (e.g., updating the IP subnet or port for an internal app), the Prisma SD-WAN controller automatically pushes this update to all connected ION devices in the tenant.

No Manual Push: Unlike some legacy firewall management paradigms (like Panorama "Commit and Push"), the Prisma SD-WAN architecture is "intent-based" and continuously synchronized. A change to a global object like an App Definition is considered a live configuration change and is distributed immediately via the secure control channel.

No Reboot: The ION data plane updates its classification engine dynamically without interrupting traffic or requiring a reboot. This ensures that policy enforcement (steering "Inventory_App" to the correct path) remains accurate in real-time.

Comprehensive and Detailed Explanation

When deploying Prisma Access for Remote Networks (connecting branch offices), the licensing and throughput model is based on aggregate bandwidth allocated to specific compute locations (regions).

Bandwidth Allocation (Option D): Administrators must purchase and allocate a specific amount of bandwidth (e.g., 500 Mbps, 1 Gbps) to a Prisma Access "Compute Location" (e.g., US West, Europe Central). This allocated bandwidth is then shared as a pool among all the branch sites (Remote Networks) that onboard and terminate their IPSec tunnels at that specific location. The system does not allocate bandwidth on a strict per-site basis but rather enforces the limit on the aggregate throughput of the compute node itself.

Policy Enforcement (Option A): Security policies for Prisma Access are enforced in the cloud (at the Prisma Access Service Processing Node), not pushed down to the branch ION devices for local enforcement. The ION device handles local segmentation (ZBFW) and traffic steering, but the "Remote Network" security stack resides in the cloud.

Path Usage (Option C): Prisma SD-WAN is designed to utilize Active/Active paths. When a branch has multiple internet circuits connected to Prisma Access, the CloudBlade and ION automatically build tunnels on all compatible paths and can load-balance traffic across them based on application performance (SLA), rather than defaulting to a strict Active/Standby model for internet traffic.

Prisma SD-WAN Copilot is an AI-powered operational tool designed to simplify network management through Natural Language Processing (NLP). Traditionally, identifying a bandwidth "hog" required manual navigation through multiple dashboards, such as WAN Clarity and the Flow Browser, to correlate source IP addresses with specific application flows and timestamps. Copilot transforms this workflow by allowing administrators to interact with the system using conversational queries.

When an administrator inputs a query like “Show top bandwidth source IPs at SD-WAN Branch X over last 3 hours,” Copilot leverages its underlying machine learning models and integrated data lake to aggregate telemetry across the entire fabric. It instantly identifies the specific source IPs responsible for the highest throughput and correlates that data with application visibility. Instead of providing a static report or redirecting the user to other tools, Copilot presents an interactive, summarized view directly within the interface. This view highlights the top-consuming users and breaks down their consumption by application, such as YouTube, Netflix, or business-critical SaaS tools.

This capability significantly reduces the Mean Time to Resolution (MTTR) for performance issues. By bypassing the need for manual data correlation, Copilot provides immediate "Day 2" operational insights. It effectively acts as a virtual assistant that understands the context of the network topology, site names, and time ranges, allowing the administrator to quickly determine if a branch's slow performance is due to an individual user's behavior or a broader infrastructure issue.

In the Prisma SD-WAN (formerly CloudGenix) architecture, the security and authenticity of device-to-controller communication are paramount. When a new ION (Instant-On Network) device is powered on and connected to the internet, it initiates a secure "phone home" process to the Prisma SD-WAN Cloud Controller. To ensure that the controller is communicating with a genuine Palo Alto Networks hardware or software instance, the system utilizes a Manufacturer Installed Certificate (MIC).

The MIC is a unique digital certificate burned into the hardware's Trusted Platform Module (TPM) or secure storage during the manufacturing process. This certificate acts as the device's foundational identity. When a customer "claims" a device in the Prisma SD-WAN portal using its serial number, the controller maps that serial number to the specific MIC associated with that unit.

Once the device is claimed and attempts to connect, a mutual TLS (mTLS) handshake occurs. The ION device presents its MIC to the controller to prove its identity, and the controller validates this against its records. This method eliminates the need for manual staging, pre-configuration, or the complexity of managing a Customer Installed Certificate (CIC) or a private Public Key Infrastructure (PKI) during the initial deployment phase. By leveraging the MIC, Prisma SD-WAN achieves true Zero Touch Provisioning (ZTP), ensuring that only authorized, authentic devices can join the fabric and receive configuration policies, thereby maintaining a secure and automated onboarding workflow.

Prisma SD-WAN addresses inconsistent application performance through Application Acceleration, which encompasses a suite of features designed to mitigate the effects of latency and packet loss.1 While basic SD-WAN functionality handles path selection, Application Acceleration goes further by employing Layer 4 (TCP) and Layer 7 (Application) optimizations. These optimizations are particularly effective for organizations with diverse branch environments where network conditions are unpredictable.

At Layer 4, Prisma SD-WAN implements TCP optimization techniques such as window scaling, selective acknowledgments, and congestion control algorithms.2 These mechanisms allow the ION devices to "trick" the end hosts into sending data faster by acknowledging packets locally, effectively shielding the application from the round-trip time (RTT) delays inherent in long-distance WAN circuits. This significantly boosts throughput for bulk data transfers and legacy protocols that were not originally designed for high-latency environments.

At Layer 7, the system can perform application-specific optimizations, such as metadata caching or protocol-specific acceleration for services like SMB or HTTP.3 By reducing the number of "chatty" exchanges required to complete a transaction, Prisma SD-WAN ensures a snappy, consistent user experience regardless of whether the user is on a high-speed fiber link or a degraded cellular connection. This is distinct from Forward Error Correction (FEC) (Option C) or Packet Duplication (Option A), which focus on reconstructing lost packets rather than optimizing the protocol throughput itself. By combining these L4 and L7 techniques, Application Acceleration ensures that business-critical SaaS and data center applications perform optimally across the entire distributed enterprise.

In the Prisma SD-WAN solution, multi-tenancy and network isolation are achieved through the use of Virtual Routing and Forwarding (VRF) instances. However, there are many operational scenarios—such as providing shared access to a common service (e.g., DNS, NTP) or a central Internet gateway—where traffic must transition between these isolated routing domains. This process is known as route leaking.

In the Prisma SD-WAN management interface, route leaking is specifically configured within the VRF Profile. Unlike traditional CLI-based routers where route leaking might be configured under a global routing table or individual VRF definitions via import/export targets, Prisma SD-WAN utilizes a profile-based approach to ensure scalability and consistency across multiple sites. A VRF Profile acts as a template that defines the routing behavior for specific VRFs across the fabric.

When an administrator navigates to the VRF Profile settings, they can define "Leaking Rules." These rules specify the "From VRF" (source) and "To VRF" (destination) parameters, along with the specific prefixes or default routes that should be shared. By placing this configuration within the VRF Profile rather than a site-specific configuration, Palo Alto Networks allows for a "configure once, apply many" workflow. Once the VRF Profile is updated with the leaking rules, any ION device associated with that profile will automatically update its local routing table to allow the specified inter-VRF communication. This centralized orchestration simplifies the management of complex segmentation requirements in large-scale SD-WAN deployments.

In the Prisma SD-WAN (Instant-On Network) architecture, the "Secure Fabric" is a key feature that simplifies VPN orchestration through automation. When an ION device is deployed at a site and associated with a specific role, the Prisma SD-WAN Controller automatically manages the establishment of encrypted VPN tunnels without requiring manual IPsec configuration.

The most fundamental tunnel type is Branch gateway to data center (Option B). By default, the system follows a hub-and-spoke model where every branch ION device automatically attempts to build secure tunnels to all available Data Center clusters within its domain. This ensures that branch locations have immediate, redundant connectivity to centralized corporate resources and applications as soon as they are brought online.

Additionally, Prisma SD-WAN supports automated Branch gateway to branch gateway connectivity (Option C). Unlike traditional architectures that backhaul all traffic through a central hub, the Prisma SD-WAN fabric can dynamically establish "spoke-to-spoke" tunnels between branch gateways to facilitate direct communication. This is particularly useful for latency-sensitive applications like Voice over IP (VoIP) or video conferencing. While this can be configured as a "full mesh" where all sites build tunnels to all other sites, the controller intelligently manages these connections based on the defined site roles and domain configurations to optimize resource usage and performance. Options A and D are incorrect because the fabric orchestration logic is primarily focused on the functional roles of the gateways (Branch vs. Data Center) rather than "domains" in the context of tunnel initiation.

Comprehensive and Detailed Explanation

According to Palo Alto Networks Prisma SD-WAN administrator documentation regarding Path Policy configuration, specific rules apply when utilizing Standard VPNs (IPSec tunnels to non-ION devices, such as Prisma Access or third-party firewalls) as an L3 Failure Path.

When a Path Policy rule is configured, the administrator defines Active Paths, Backup Paths, and L3 Failure Paths. The L3 Failure Path is a "last resort" mechanism used when all Active and Backup paths are unavailable (Layer 3 down).

If Standard VPN is selected as the L3 Failure Path type, the system explicitly requires that the administrator also associates it with a specific Standard Services and DC Group within that same policy rule.

The ION device uses the Standard Services and DC Group to identify the specific remote endpoint (tunnel destination) where the traffic should be routed. Unlike a "Direct" (Internet) path which can simply route out to the WAN, a Standard VPN represents a logical tunnel. If the policy rule designates "Standard VPN" as the failure path but leaves the "Standard Services and DC Group" field empty or unselected, the ION effectively has a directive to "use a VPN" but lacks the instruction on which VPN group to use for this specific application context. Consequently, even if the IPSec tunnel to Prisma Access is physically up and stable, the policy engine cannot resolve the next hop for the "SuperSaaSApp" traffic, resulting in the packets being dropped. To resolve this, the administrator must edit the Path Policy rule to ensure the specific Standard Service/DC Group representing Prisma Access is checked/selected for the L3 Failure Path.

Comprehensive and Detailed Explanation

Prisma SD-WAN utilizes a sophisticated decision engine for Application-Based Path Selection that goes beyond simple failover. When configuring a Path Policy, the administrator defines "Active" paths and a "Path Quality Profile" (SLA).

SLA Compliance (The Filter): First, the system filters the available paths based on the Path Quality Profile. In this scenario, both ISP-A and ISP-B have 40ms latency against a 150ms threshold. Both are "green" or compliant paths.

Selection Criteria (The Tie-Breaker): When multiple paths are configured as "Active" and all meet the performance SLA, the ION device aims to optimize the overall user experience and network utilization. The default behavior for load balancing across healthy, compliant active paths is to select the path with the highest available bandwidth capacity.

By steering new flows to the link with the most "headroom" (available Mbps), the system prevents the saturation of a smaller link (e.g., a 20Mbps DSL line) while a larger link (e.g., 1Gbps Fiber) sits underutilized. This maximizes the aggregate throughput for the site. While latency is the qualifier, bandwidth availability is often the selector for compliant paths. Note that if the application was defined as "Real-Time" and configured for packet duplication, behavior would differ, but for standard traffic, capacity-based distribution is the standard active/active logic.

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.