Authentic Paloalto Networks Certification Exam SD-WAN-Engineer Questions Answers

Comprehensive and Detailed Explanation

According to the Prisma SD-WAN Performance Policy Default Behavior documentation, the default action configured for applications (including real-time media) when a path experiences poor performance (violates the SLA thresholds for latency, jitter, or packet loss) is to Move Flows.

The Prisma SD-WAN ION device continuously monitors the health of all available paths. If the active path for a media application degrades and fails to meet the specified SLA, the default policy dictates that the traffic should be steered (moved) to an alternate, compliant path that meets the performance criteria.

While Forward Error Correction (FEC) is a powerful feature available in Prisma SD-WAN to mitigate packet loss for real-time applications, it is an optional action that must be explicitly enabled or configured within the performance policy rules. It is not the default action in the base system configuration; the primary default mechanism for handling performance issues is to leverage the multi-path fabric to switch to a better link.

Comprehensive and Detailed Explanation

The Prisma SD-WAN (CloudGenix) solution is designed with a separation of the control plane (Controller) and the data plane (ION devices).1 In the event that an ION device loses connectivity to the Cloud Controller (often referred to as running in "headless mode"), the device continues to forward traffic and maintain existing VPN tunnels using the keys it currently holds.2

However, for security purposes, the VPN session keys (shared secrets) used for the Secure Fabric have a finite validity period. The system is designed such that these keys are rotated regularly.3 If the controller is unreachable, the ION device can continue to rotate keys locally and maintain the VPNs for a maximum default period of 72 hours (exactly 3 days).4

If the connection to the controller is not restored within this 72-hour window, the keys will eventually expire, and the ION will be unable to retrieve new authorized key material from the controller.5 Consequently, the VPN tunnels will go down, and the "out of shared secret key" error will be observed in the VPN status logs. This mechanism ensures that a permanently compromised or stolen device cannot maintain network access indefinitely without central authorization.

For a massive rollout involving 1,000 branch sites, Prisma SD-WAN (formerly CloudGenix) provides a specialized workflow known as Bulk Site Configuration. This method is designed to minimize manual intervention and maximize deployment velocity by leveraging Site Templates and Device Shells.

In this scenario, the primary architectural advantage of Option C is the use of Pre-Staging. By exporting an empty SD-WAN device CSV from the Prisma SD-WAN Controller and populating it with data from the corporate CMDB, administrators can perform a bulk upload to create hundreds or thousands of sites and device shells simultaneously in the management portal. A "Device Shell" acts as a placeholder for a physical ION device that has not yet connected to the cloud. It contains all the site-specific configuration—such as interface roles, circuit labels, and IP addressing—waiting for a serial number to be associated with it.

When the field technician performs the physical "rack and stack," they simply connect the ION device to the internet (via ISP modem or cellular). Through Zero Touch Provisioning (ZTP), the device automatically "phones home" to the Prisma SD-WAN Cloud Controller using its Manufacturer Installed Certificate (MIC). Because the configuration was pre-created via the CSV bulk upload, the controller recognizes the device (once assigned to its shell) and immediately pushes the complete configuration. This eliminates the need for the field tech to access a console port or perform local configuration, reducing their on-site time to the bare minimum. While APIs (Option D) can be used for automation, the built-in CSV template workflow is the standard, documented "best practice" for rapidly translating CMDB data into a functioning SD-WAN fabric at this scale.