Upon the failure of the active ION device, the standby device transitions to the active state. For LAN high availability, Palo Alto Networks SD-WAN uses VRRP. The new active device takes ownership of the VRRP Virtual IP (VIP) address for any configured Switched Virtual Interfaces (SVIs), ensuring LAN clients have a consistent gateway.

For WAN high availability, physical connectivity is required on both devices. As shown in the topology, the ISP A connection is cabled to both IONs and will remain usable after failover. However, the LTE/5G connection is physically cabled only to the original active device. When this device loses power, the physical connection is severed, making the LTE/5G path unusable by the newly active ION.

A. The LTE/5G connection is physically connected only to the failed device and will become unavailable after the power loss.

C. Sending a gratuitous ARP is a transient action performed during the failover process to update network tables, not a description of the final "end-state".

1. Palo Alto Networks, Prisma SD-WAN Administrator’s Guide 6.2, "High Availability for ION Devices" section, "HA Failover" subsection.

This section states: "When a failover occurs, the backup ION device assumes the role of the active device. It takes over the virtual IP (VIP) addresses for the LAN interfaces and sends gratuitous ARPs (GARPs) to update the ARP caches of the connected devices." This supports that the VIP is moved (Answer B) and that GARP is sent (the action described in C).

2. Palo Alto Networks, Prisma SD-WAN Administrator’s Guide 6.2, "High Availability for ION Devices" section, "High Availability Requirements and Prerequisites" subsection.

This section clarifies WAN connectivity requirements: "For WAN high availability, you must connect the WAN links to both ION devices in the HA pair. If a WAN link is connected to only one of the ION devices, that link is not highly available." This directly supports the reasoning for Answer D, where the LTE/5G link fails because it is not connected to the standby device.