Comprehensive and Detailed Explanation
The stability of VPN tunnels in the Prisma SD-WAN + Prisma Access integration relies on standard IPSec mechanisms.
Dead Peer Detection (DPD): The CloudBlade configuration automatically enables DPD on the IPSec tunnels it provisions.
* Mechanism: DPD is a standard keepalive mechanism where the ION device sends periodic "R-U- THERE" messages to the Prisma Access gateway (and vice versa). If no acknowledgment is received after a specific count/timer, the ION marks the tunnel as down and attempts to re-key or switch to a backup path.
* Synthetic Probes (B): While Synthetic Probes (part of ADEM or Path Quality monitoring) can be configured to measure latency/loss, the fundamental mechanism that keeps the IPSec security association (SA) active and detects link failure is DPD, not an application-layer probe.