The ION device's Analytics mode is specifically designed for passive monitoring and auditing of network traffic. In this mode, the device is deployed out-of-band, typically connected to a SPAN or mirror port on a switch. It analyzes a copy of the site's traffic to provide visibility into network and application performance without being in the active data path. This allows an organization to audit a new site's traffic patterns and gather baseline data before implementing active traffic steering and policy enforcement, perfectly matching the scenario's requirements.

A. Access: This is not a primary deployment mode for an ION device. The term typically refers to an interface role in an active deployment for connecting end-user segments.

B. Control: In Control mode, the ION device is deployed in-path and actively manages, forwards, and steers traffic as the branch controller for the SD-WAN fabric.

C. Disabled: A disabled device is non-operational and cannot perform any function, including auditing or analyzing network traffic.

1. Palo Alto Networks Prisma SD-WAN Administrator’s Guide: In the "Deployment Modes" section, it states, "In Analytics mode, the ION device is deployed out-of-band and does not participate in routing or forwarding of traffic. The ION device is connected to a SPAN/mirror port on a switch to monitor traffic and provide visibility into the network and application performance." This directly supports the use of Analytics mode for auditing without steering.

2. Palo Alto Networks Prisma SD-WAN Design and Sizing Guide: The guide discusses deployment scenarios, including proof-of-concept (PoC) deployments. It describes using Analytics mode to "gather baseline analytics on the existing network performance before cutting over to an in-path deployment." This aligns with the use case of auditing a newly acquired site.